1. What is frame grabber?
It is a hardware device used to capture and store the digital image.
2. What is the common imaging device used for robot vision system?
Black and white vidicon camera, charge coupled devices, solid state camera, charge injection devices.
3. What is pixel?
Picture elements are also known as pixels
4. What is a frame of a vision data?
The digital image of the camera is called frame of vision data
5. What is segmentation?
Segmentation is the method to group areas of an image having similar characteristics or features into distinct entities representing part of the image.
6. What is thresholding?
Thresholding is a binary conversion technique in which each pixel is converted into a binary value either black or white.
7. What is region growing?
Region growing is a collection of segmentation techniques in which pixels are grouped in regions called grid elements based on attribute similarities.
8. What are the functions of machine vision system?
Sensing and digitizing image data Image Processing and analysis Application
9. What are the applications of machine vision system?
Inspection Identification Visual Servoing and navigation
10. What is a sensor?
Sensor is a transducer that is used to make a measurement of a physical variable of interest.
11. Transducer is a device which convert the one form of information into another form without changing the information content
12. What are the basic classifications of sensors?
Tactile Sensors, Proximity Sensors, Range sensors, Voice sensors etc
13. What are the desirable features of a sensor?
Good Accuracy, High Precision, Wide operating range, Instant speed of response, Good Repealibility, Low cost and ease in operation
14. What is a tactile sensor?
Tactile sensor is device which indicate the contact between themselves and some other solid objects.
15. List the different types of tactile sensor?
Digital (Touch ) Sensor and Analogue (Force) Sensor
16. .What is a touch sensor?
Sensor which senses the presence or absence of the object by having physical contact between the object
17. List the components of the force wrist
Metallic frame, Bracket for tool mounting and strain gauges.
18. What is a tactile array sensor?
Tactile array sensor is a special type of force senor composed of a matrix of force sensing elements.
19. What is a Proximity sensor?
Sensor which senses the presence or absence of the object without having physical contact between the object
20. What are the classifications of a proximity sensor?
Inductive Sensor Capacitive Sensor Ultrasonic Sensor Magnetic Sensor
21. What is a range sensor?
Sensor which senses the range of the object
22. What is a voice Sensor?
It is a advanced sensor system used to communicate commands or information orally to robot.
23. What is a vision Sensor?
It is a advanced sensor system used in conjunction with pattern recognition and other technique to view and interpret event occurring in the robot work space.
24. What is a potentiometer?
Potentiometer is an electrical meter to measure the voltage.
Sunday, September 5, 2010
Sunday, August 15, 2010
Industrial Robotics and Expert systems
Test your understanding in the subject
1. Explain the importance of Robotics in Automation.
b) Discuss briefly about various sensors.
2 .a) Explain about the controllers in detail.
b) Explain about the Robot Anatomy and configuration.
3.a) Explain about homogeneous Transformations in Robotics kinematics.
b) Discuss briefly about path control and path generation.
4. Describe about D-H Transformation for a forward Kinematics problems of planar 3 dof manipulator.
5.a) Discuss in detail about the Grippers and its types.
b) Explain about the Image processing and Image data Reduction.
6.a) Describe about the selection and design of grippers. B. Give the classification of Robots.
7.a) How do you specify a robot? Is robotics automation? Discuss the different classification systems of robots.
b) Define the terms ‘Robot’ and ‘Robotics’. Discuss the role of robots in engineering.
8.a) What are the different actuators used in the robots? Describe them briefly.
b) Discuss the different feedback components used in robots.
9. Explain briefly the two stage control of manipulator using interpolation of end effectors position method.
10 .a) Explain the working of magnet grippers used for robots.
b) Discuss the applications and working principle of the following
sensors. i) Range sensors ii) Acoustic sensors iii) Tactile sensors.
(i) Compare common robot configurations.
(ii) Describe the five types of joints used in industrial robot construction.
11. (a) Name four different types of end effectors.Compare and contrast the end effectors from the view point of their functions
12. a) Discuss the basic operational charcteristics of the following proxinsity sensors:
(i) Inductive sensor
(ii) Hall effect sensor
(iii)Capacitive sensors
(iv) Ultrasonic sensors
13. Why are SCARA robots preferred for assembly operations? Compare and contrast revolute robots and SCARA robots from the view point of assembly operations
(ii) Describe briefly the operations involved in robotic spot welding .What are the advantages of robotic welding over manual welding?
14. (b) Describe the use of robots in the following:(i) Material handling. (ii) Loading and unloading.
15. Differentiate between force control and position control of robotic manipulators. Give suitable examples. ' - Derive expressions for, homogeneous transformation matrices both for rotated as well as translated frame.
16. Differentiate between servo and non servo manipulators
17. Discuss the direct and inverse kinematic models.
18. Write short note on the following:
(a) Force Control of robotic manipulator. (b) Optical encoder
19. Sketch and explain the following configurations of the robot TRR, TRL:R, RR:R
20. Explain trajectory planning and show how trajectory planning is done in case of point to point robot having constant maximum velocity, finite acceleration and deceleration.
21. A vacuum gripper is used to lift a steel plate 900 x 600 x 7 mm . two suction cups of 125 mm are located 450mm apart for lifting it. Take FOS as 1.7 , density of steel is 8.54.3 kg/cub.m find the negative pressure needed to lift the plate.
22.Explain the principle of force sensing.Describe force sensing with strain gauges and force sensing wrist.
23. Explain the terms related to robots :compliance, payload, precision and accuracy.
24.What are the different electrical actuators? Explain the working principle of a stepper motor. Explain the micro stepping using stepper motors.
25.Explian the specifications of an Industrial robot. Explain each of them individually.
1. Explain the importance of Robotics in Automation.
b) Discuss briefly about various sensors.
2 .a) Explain about the controllers in detail.
b) Explain about the Robot Anatomy and configuration.
3.a) Explain about homogeneous Transformations in Robotics kinematics.
b) Discuss briefly about path control and path generation.
4. Describe about D-H Transformation for a forward Kinematics problems of planar 3 dof manipulator.
5.a) Discuss in detail about the Grippers and its types.
b) Explain about the Image processing and Image data Reduction.
6.a) Describe about the selection and design of grippers. B. Give the classification of Robots.
7.a) How do you specify a robot? Is robotics automation? Discuss the different classification systems of robots.
b) Define the terms ‘Robot’ and ‘Robotics’. Discuss the role of robots in engineering.
8.a) What are the different actuators used in the robots? Describe them briefly.
b) Discuss the different feedback components used in robots.
9. Explain briefly the two stage control of manipulator using interpolation of end effectors position method.
10 .a) Explain the working of magnet grippers used for robots.
b) Discuss the applications and working principle of the following
sensors. i) Range sensors ii) Acoustic sensors iii) Tactile sensors.
(i) Compare common robot configurations.
(ii) Describe the five types of joints used in industrial robot construction.
11. (a) Name four different types of end effectors.Compare and contrast the end effectors from the view point of their functions
12. a) Discuss the basic operational charcteristics of the following proxinsity sensors:
(i) Inductive sensor
(ii) Hall effect sensor
(iii)Capacitive sensors
(iv) Ultrasonic sensors
13. Why are SCARA robots preferred for assembly operations? Compare and contrast revolute robots and SCARA robots from the view point of assembly operations
(ii) Describe briefly the operations involved in robotic spot welding .What are the advantages of robotic welding over manual welding?
14. (b) Describe the use of robots in the following:(i) Material handling. (ii) Loading and unloading.
15. Differentiate between force control and position control of robotic manipulators. Give suitable examples. ' - Derive expressions for, homogeneous transformation matrices both for rotated as well as translated frame.
16. Differentiate between servo and non servo manipulators
17. Discuss the direct and inverse kinematic models.
18. Write short note on the following:
(a) Force Control of robotic manipulator. (b) Optical encoder
19. Sketch and explain the following configurations of the robot TRR, TRL:R, RR:R
20. Explain trajectory planning and show how trajectory planning is done in case of point to point robot having constant maximum velocity, finite acceleration and deceleration.
21. A vacuum gripper is used to lift a steel plate 900 x 600 x 7 mm . two suction cups of 125 mm are located 450mm apart for lifting it. Take FOS as 1.7 , density of steel is 8.54.3 kg/cub.m find the negative pressure needed to lift the plate.
22.Explain the principle of force sensing.Describe force sensing with strain gauges and force sensing wrist.
23. Explain the terms related to robots :compliance, payload, precision and accuracy.
24.What are the different electrical actuators? Explain the working principle of a stepper motor. Explain the micro stepping using stepper motors.
25.Explian the specifications of an Industrial robot. Explain each of them individually.
Tuesday, July 27, 2010
Position sensors
POSITION SENSOR
Position sensors are used to electronically monitor the position or movement of a mechanical component. The position sensor produces data that may be expressed as an electrical signal that varies as the position of the mechanical component changes. Position sensors are typically used in machines to monitor the physical state of a moving mechanical component of an automated system.
Position sensing devices detect the movement and position of the control device and translate that movement and position into a control signal that may be further processed and used to control the movement of a vehicle or equipment. Position sensors are frequently employed in automotive vehicles to sense and monitor the position of an object that may travel through various positions.
For example, position sensors are commonly employed to monitor the position of an electrically powered door so as to determine whether the door is in the open position or closed position.
Automotive vehicles increasingly are equipped with electrically powered devices such as side entry doors and rear entry doors, each of which are powered by an electric motor that receives electric current from the vehicle battery. Each of these power doors also typically employs an absolute position sensor in order to determine the absolute position of the door.
In a power door application , the use of an absolute position sensor allows for the determination of the absolute position of the power door relative to the open and closed positions. It is also known to use a position sensor device to detect the movement and location of a control device, such as a controller, joystick control, vehicle throttle control, and an accelerator device.
A position sensor may be used in a computer interface device to detect a user's manipulation of the device. The detected manipulation may then be used to provide input to a computer system to control computer-generated objects and environments, to control physical objects, and/or to instruct the computer to perform tasks.
In one application, a user interacts with a computer-generated environment, such as a game, a surgical simulation, a graphical user interface, or other environment generated in response to an application program, by manipulating an object such as a mouse, joystick, trackball, gamepad, rotary knob, or three dimensionally translatable object to control a graphical image within a graphical environment or to otherwise control the operation of the computer.
Techniques for position sensing
There are a variety of known techniques for position sensing. Optical, resistive, electrical, electrostatic and magnetic fields are all used with apparatus to measure position.
Position sensing apparatus for using these energies for sensing include resistive contacting sensors, inductively coupled ratio detectors, variable reluctance devices, capacitively coupled ratio detectors, optical detectors using the Faraday effect, photo-activated ratio detectors, radio wave directional comparators, and electrostatic ratio detectors. Optical systems often use position sensing detectors to determine the position of an optical spot that is incident upon the active surface of a device. The optical spot may be a reflected laser beam from the surface of an optical recording medium.
The optical detector is constructed using photodetectors, such as photo-diodes or PIN-diodes. Signals required for the X and Y displacement of the spot is found by suitably subtracting currents from adjacent cells, followed by normalization to the total intensity of the optical spot. Optical sensors, however, are also susceptible to failures caused by problems inherent in the nature of their components.
For example, optical sensors tend to become unreliable as a result of large changes in ambient light, misalignments between the light source and the detector, reduced light levels caused by dirt or debris accumulation, reduced light levels caused by the aging of the internal light sources, and manufacturing differences in sensitivity between devices.
Capacitance-based position sensors are widely known. Many such sensors employ a variable capacitor having a value that varies with relative position of a pair of objects. In these systems, the relative position of the objects can be determined by measuring the capacitance. Single-electrode capacitive sensors for sensing the proximate presence of an object are commonly configured to provide a binary output and operate by measuring a value of electrical capacitance to an electric ground. If the sensor is configured as a "proximity sensor" it provides an output determinative of proximate presence when the value of the measured capacitance exceeds a predetermined threshold valve. If the sensor is configured as a "motion sensor" it provides the determinative output when the rate of change of capacitance exceeds a predetermined threshold value.
Among position sensing technologies, magnetic sensing is known to have a unique combination of long life components and excellent resistance to contaminants. Magnetic sensors typically rely upon permanent magnets to detect the presence or absence of a magnetically permeable object within a certain predefined detection zone relative to the sensor. In combination with the permanent magnet, some sensors of this type utilize Hall Effect and/or magnetoresistive components located at particular positions relative to the permanent magnet and other.
Generally, a magnet is used to create a magnetic field which is measured by an IC (integrated circuit) containing a magnetically sensitive feature. The magnet is connected to the element to be measured and moves relative to the IC. The changing magnetic field at the IC is converted into an output signal proportional to the movement.
A hall sensor is a type of magnetic sensor that uses the Hall effect to detect a magnetic field. The Hall effect occurs when a current-carrying conductor is placed into a magnetic field. A voltage is generated perpendicular to both the current and the field. The voltage is proportional to the strength of the magnetic field to which it is exposed. Hall position sensors are usually deployed as an integral part of closed loop feedback control systems which are used in a variety of fields such as automotive vehicle component testing and manufacturing, semiconductor manufacturing, industrial automation and robotics and the like. While Hall sensors are very reliable and have many useful applications, they are not as sensitive as magnetoresistive (MR) sensors. Hall sensors may also be more limited to the type of magnet used than an MR sensor.
Magnetoresistive sensors are a type of magnetic sensor that uses the magnetoresistive effect to detect a magnetic field. Ferromagnetic metals, such as the nickel-iron alloy commonly known as Permalloy, alter their resistivity in the presence of a magnetic field. When a current is passed through a thin ferromagnetic film in the presence of a magnetic field, the voltage will change. This change in voltage represents the strength or direction of the magnetic field. Some magnetic position sensors provide an indication of the displacement of the mechanical component by using a magnetic field sensing device which reports the intensity of a magnetic field from a magnet which is positioned on the mechanical component. The magnet is positioned and the magnetic field sensing device is located relative to the magnet in such a fashion as to cause the magnetic field to vary in the magnetic field sensing device as the magnet moves.
Magnetic position sensors are generally a non-contact type of sensors which are devices that generate change to an electronically interrogated physical parameter that is proportional to the movement of a structure, such as, for example, an actuator shaft operatively coupled to the sensor. This change is achieved without physical contact between the parameter and the interrogation device. Magnetic position sensors consist of a magnetic field sensing device which is usually stationary and a magnet that is attached to a moving component. As the magnet approaches the sensing device the magnetic field of the magnet is detected and the sensing device generates an electrical signal that is then used for counting, display, recording and/or control purposes. In magnetic position sensing, the magnitude of magnetic field strength is generally measured by an appropriate measuring device, such as a Hall-effect element or magneto-resistive element. The value of the measured field intensity is translated through the measuring device to a voltage or current value that is uniquely representative of the specific rotational position of the actuator shaft. Magnetic sensing devices have many applications, including navigation, position sensing, current sensing, vehicle detection, and rotational displacement. There are many types of magnetic sensors, but essentially they all provide at least one output signal that represents the magnetic field sensed by the device. One of the benefits of using magnetic sensors is that the output of the sensor is generated without the use of contacts. This is a benefit because over time contacts can degrade and cause system failures. Because such a position sensor bases positional detection on magnetic properties, this type of sensor inherently excels in resistance to exposure to common environmental contaminants such as water, oil, etc. A problem with such sensors is that they depend on movement of the magnet and they are not able to provide information as to the static position of a mechanical component.
Angular and linear position sensors are widely used in automatic control systems as feedback-sensing devices in one or more control loops of the system. Various types of angular position sensors are currently used in conjunction with vehicle steering wheels, or hand wheels, including relative, absolute, analog and digital angular position sensors. Known technologies that can be used to determine angular position include contact measurement, such as a resistance stripe, or non-contact measurement effects, based on inductance, capacitance, optical, or magnetic field.
A relative angular position sensor measures the angular position of a rotating object by either incrementing or decrementing a counter, depending upon the rotational direction of the object, and relating that information to an angular reference point.
Rotary position sensing is used in a number of applications, such as motor position feedback control and/or commutation, cam and crank shaft position sensing for controlling ignition timing, misfire detection, engine speed monitoring etc, robotics, and machine tool position control. Rotary position sensors utilize a magnetic field and a magnetosensitive device, such as a Hall effect device or a magnetoresistor located within the magnetic field. Absolute position sensors provide a sensed position signal which contains information about the absolute position relative to a predetermined position.
An absolute position sensor indicates very precisely the position of the moving components, so that they can be controlled and, above all, so that these components can be relocated when the system in which they are integrated is activated. An absolute position sensor delivers a number of output signals in the case of a parallel digital output signal, but in the case of a series digital output signal, the sensor delivers a single signal resulting from a shaping according to a data transmission protocol and executed from the signals in parallel described in therein.
Position sensors are used to electronically monitor the position or movement of a mechanical component. The position sensor produces data that may be expressed as an electrical signal that varies as the position of the mechanical component changes. Position sensors are typically used in machines to monitor the physical state of a moving mechanical component of an automated system.
Position sensing devices detect the movement and position of the control device and translate that movement and position into a control signal that may be further processed and used to control the movement of a vehicle or equipment. Position sensors are frequently employed in automotive vehicles to sense and monitor the position of an object that may travel through various positions.
For example, position sensors are commonly employed to monitor the position of an electrically powered door so as to determine whether the door is in the open position or closed position.
Automotive vehicles increasingly are equipped with electrically powered devices such as side entry doors and rear entry doors, each of which are powered by an electric motor that receives electric current from the vehicle battery. Each of these power doors also typically employs an absolute position sensor in order to determine the absolute position of the door.
In a power door application , the use of an absolute position sensor allows for the determination of the absolute position of the power door relative to the open and closed positions. It is also known to use a position sensor device to detect the movement and location of a control device, such as a controller, joystick control, vehicle throttle control, and an accelerator device.
A position sensor may be used in a computer interface device to detect a user's manipulation of the device. The detected manipulation may then be used to provide input to a computer system to control computer-generated objects and environments, to control physical objects, and/or to instruct the computer to perform tasks.
In one application, a user interacts with a computer-generated environment, such as a game, a surgical simulation, a graphical user interface, or other environment generated in response to an application program, by manipulating an object such as a mouse, joystick, trackball, gamepad, rotary knob, or three dimensionally translatable object to control a graphical image within a graphical environment or to otherwise control the operation of the computer.
Techniques for position sensing
There are a variety of known techniques for position sensing. Optical, resistive, electrical, electrostatic and magnetic fields are all used with apparatus to measure position.
Position sensing apparatus for using these energies for sensing include resistive contacting sensors, inductively coupled ratio detectors, variable reluctance devices, capacitively coupled ratio detectors, optical detectors using the Faraday effect, photo-activated ratio detectors, radio wave directional comparators, and electrostatic ratio detectors. Optical systems often use position sensing detectors to determine the position of an optical spot that is incident upon the active surface of a device. The optical spot may be a reflected laser beam from the surface of an optical recording medium.
The optical detector is constructed using photodetectors, such as photo-diodes or PIN-diodes. Signals required for the X and Y displacement of the spot is found by suitably subtracting currents from adjacent cells, followed by normalization to the total intensity of the optical spot. Optical sensors, however, are also susceptible to failures caused by problems inherent in the nature of their components.
For example, optical sensors tend to become unreliable as a result of large changes in ambient light, misalignments between the light source and the detector, reduced light levels caused by dirt or debris accumulation, reduced light levels caused by the aging of the internal light sources, and manufacturing differences in sensitivity between devices.
Capacitance-based position sensors are widely known. Many such sensors employ a variable capacitor having a value that varies with relative position of a pair of objects. In these systems, the relative position of the objects can be determined by measuring the capacitance. Single-electrode capacitive sensors for sensing the proximate presence of an object are commonly configured to provide a binary output and operate by measuring a value of electrical capacitance to an electric ground. If the sensor is configured as a "proximity sensor" it provides an output determinative of proximate presence when the value of the measured capacitance exceeds a predetermined threshold valve. If the sensor is configured as a "motion sensor" it provides the determinative output when the rate of change of capacitance exceeds a predetermined threshold value.
Among position sensing technologies, magnetic sensing is known to have a unique combination of long life components and excellent resistance to contaminants. Magnetic sensors typically rely upon permanent magnets to detect the presence or absence of a magnetically permeable object within a certain predefined detection zone relative to the sensor. In combination with the permanent magnet, some sensors of this type utilize Hall Effect and/or magnetoresistive components located at particular positions relative to the permanent magnet and other.
Generally, a magnet is used to create a magnetic field which is measured by an IC (integrated circuit) containing a magnetically sensitive feature. The magnet is connected to the element to be measured and moves relative to the IC. The changing magnetic field at the IC is converted into an output signal proportional to the movement.
A hall sensor is a type of magnetic sensor that uses the Hall effect to detect a magnetic field. The Hall effect occurs when a current-carrying conductor is placed into a magnetic field. A voltage is generated perpendicular to both the current and the field. The voltage is proportional to the strength of the magnetic field to which it is exposed. Hall position sensors are usually deployed as an integral part of closed loop feedback control systems which are used in a variety of fields such as automotive vehicle component testing and manufacturing, semiconductor manufacturing, industrial automation and robotics and the like. While Hall sensors are very reliable and have many useful applications, they are not as sensitive as magnetoresistive (MR) sensors. Hall sensors may also be more limited to the type of magnet used than an MR sensor.
Magnetoresistive sensors are a type of magnetic sensor that uses the magnetoresistive effect to detect a magnetic field. Ferromagnetic metals, such as the nickel-iron alloy commonly known as Permalloy, alter their resistivity in the presence of a magnetic field. When a current is passed through a thin ferromagnetic film in the presence of a magnetic field, the voltage will change. This change in voltage represents the strength or direction of the magnetic field. Some magnetic position sensors provide an indication of the displacement of the mechanical component by using a magnetic field sensing device which reports the intensity of a magnetic field from a magnet which is positioned on the mechanical component. The magnet is positioned and the magnetic field sensing device is located relative to the magnet in such a fashion as to cause the magnetic field to vary in the magnetic field sensing device as the magnet moves.
Magnetic position sensors are generally a non-contact type of sensors which are devices that generate change to an electronically interrogated physical parameter that is proportional to the movement of a structure, such as, for example, an actuator shaft operatively coupled to the sensor. This change is achieved without physical contact between the parameter and the interrogation device. Magnetic position sensors consist of a magnetic field sensing device which is usually stationary and a magnet that is attached to a moving component. As the magnet approaches the sensing device the magnetic field of the magnet is detected and the sensing device generates an electrical signal that is then used for counting, display, recording and/or control purposes. In magnetic position sensing, the magnitude of magnetic field strength is generally measured by an appropriate measuring device, such as a Hall-effect element or magneto-resistive element. The value of the measured field intensity is translated through the measuring device to a voltage or current value that is uniquely representative of the specific rotational position of the actuator shaft. Magnetic sensing devices have many applications, including navigation, position sensing, current sensing, vehicle detection, and rotational displacement. There are many types of magnetic sensors, but essentially they all provide at least one output signal that represents the magnetic field sensed by the device. One of the benefits of using magnetic sensors is that the output of the sensor is generated without the use of contacts. This is a benefit because over time contacts can degrade and cause system failures. Because such a position sensor bases positional detection on magnetic properties, this type of sensor inherently excels in resistance to exposure to common environmental contaminants such as water, oil, etc. A problem with such sensors is that they depend on movement of the magnet and they are not able to provide information as to the static position of a mechanical component.
Angular and linear position sensors are widely used in automatic control systems as feedback-sensing devices in one or more control loops of the system. Various types of angular position sensors are currently used in conjunction with vehicle steering wheels, or hand wheels, including relative, absolute, analog and digital angular position sensors. Known technologies that can be used to determine angular position include contact measurement, such as a resistance stripe, or non-contact measurement effects, based on inductance, capacitance, optical, or magnetic field.
A relative angular position sensor measures the angular position of a rotating object by either incrementing or decrementing a counter, depending upon the rotational direction of the object, and relating that information to an angular reference point.
Rotary position sensing is used in a number of applications, such as motor position feedback control and/or commutation, cam and crank shaft position sensing for controlling ignition timing, misfire detection, engine speed monitoring etc, robotics, and machine tool position control. Rotary position sensors utilize a magnetic field and a magnetosensitive device, such as a Hall effect device or a magnetoresistor located within the magnetic field. Absolute position sensors provide a sensed position signal which contains information about the absolute position relative to a predetermined position.
An absolute position sensor indicates very precisely the position of the moving components, so that they can be controlled and, above all, so that these components can be relocated when the system in which they are integrated is activated. An absolute position sensor delivers a number of output signals in the case of a parallel digital output signal, but in the case of a series digital output signal, the sensor delivers a single signal resulting from a shaping according to a data transmission protocol and executed from the signals in parallel described in therein.
Thursday, April 1, 2010
Design for machining
Download the material of today's class lecture in the topic design for machining.[ holes and machining ]
Design for machining
Design for machining
Monday, March 22, 2010
Class lectures - Next activity
Today's and the previous day's class lectures are uploaded . Go through this and give your feed back
Activity submission date: 25 March 2010
Use of Group technology in Industrial departments
Lecture1: Casting design considerations
Lecture 2: Group Technology
Activity submission date: 25 March 2010
Use of Group technology in Industrial departments
Lecture1: Casting design considerations
Lecture 2: Group Technology
Sunday, March 14, 2010
Design for environment
In this presentation , you can learn design for recyclability, concepts in energy efficiency, AT&T's Environmentally responsible product assesment matrix, design to regulations and standards
Pl go through the presentation and give your views
" Concepts"
Pl go through the presentation and give your views
" Concepts"
Activities for students
1. The first activity given was to identify the design guidelines followed in forging, and assembly. Students were instructed to choose the components of their choice and present their work for five minutes
2. The next activity given was to do a life cycle assesment of a component of their choice.
3. The third activity given was to go through a technical paper about the topic "design for environment" , present the hard copy of the paper and present the case study discussed in the paper , the deadline given was 12.march.2010
2. The next activity given was to do a life cycle assesment of a component of their choice.
3. The third activity given was to go through a technical paper about the topic "design for environment" , present the hard copy of the paper and present the case study discussed in the paper , the deadline given was 12.march.2010
Thursday, March 11, 2010
Remanufacturing
Remanufacturing is the process of disassembly and recovery at the module level and, eventually, at the component level. It requires the repair or replacement of worn out or obsolete components and modules.
Remanufacturing differs from other recovery processes in its completeness: a remanufactured machine should match the same customer expectation as new machines. There are three types of remanufacturing activities, each with different operational challenges.
Download our class lecture file here
Remanufacturing differs from other recovery processes in its completeness: a remanufactured machine should match the same customer expectation as new machines. There are three types of remanufacturing activities, each with different operational challenges.
Download our class lecture file here
Saturday, February 20, 2010
GD & T Test
Find the useful link for writing test in GD &T.
You will find it interesting and useful. Write your comments and suggestions through the box provided below
GD&T Test
You will find it interesting and useful. Write your comments and suggestions through the box provided below
GD&T Test
Wednesday, February 17, 2010
Learn This GD&T
Here is a link provided for you to download a free trial for learning GD&T .
Download this exe file and have an experience. Do let me know your comments after this.
If it is possible to have a full version , pl give me the link to make it visible to others
"The GD&T software"
Download this exe file and have an experience. Do let me know your comments after this.
If it is possible to have a full version , pl give me the link to make it visible to others
"The GD&T software"
Saturday, February 13, 2010
GD & T Definitions
Definitions:
Actual Size - Actual size is the measured size of the produced feature.
Angularity - Angularity is the condition of a surface, axis, or center plane, which is at a specified angle (other than 0, 90, 180 or 270 deg.) from a datum plane or axis. Symbol:
Basic Dimension - A basic dimension is a theoretically exact value used to describe the exact size, profile, orientation or location of a feature. A basic dimension should always associated with a feature control frame or datum target. Block tolerance does not apply and the applicable tolerance will be given within the feature control frame. Basic dimensions are enclosed within a box. Symbol:
Bilateral Tolerance - A bilateral tolerance is a tolerance in which variation is permitted in both directions from a specified nominal size or dimension (example +- .005).
Circularity - See Roundness.
Clearance Fit - A clearance fit is one having limits of size defined such that a clearance exists between mating parts when assembled.
Concentricity - Concentricity describes a condition in which two or more features (cylinders, cones, spheres, etc.) in any combination have a common axis. Measurement requirements for concentricity involves the complex task of mapping the referenced feature by way of opposed point measurements. A through understanding of the measurement process should be investigated before defining feature relationships using concentricity. Symbol:
Coaxial - Coaxial describes a condition where two or more features have the same axis or centerline.
Coordinate Dimension - (1) Either of two coordinates that locate a point on a plane and measured its distance from either of two intersecting straight-line axes along a line parallel to the other axis. (2) Any of three coordinates that locate a point in space and measure its distance from any of three intersecting coordinate planes measured to that one of three straight-line axes that is the intersection of the other two planes.
Coplanar - Coplanar describes a condition of two or more surfaces having all elements in the same plane.
Cylindricity - Cylindricity describes a condition of a surface of revolution in which all points of a surface are equidistant from a common axis.
Datum - Datum's are points, lines, planes, cylinders, axes, etc., from which the location or geometric relationship of other features may be established or related.
Datum Axis - the datum axis is the theoretically exact centerline of the datum cylinder as established by the extremities or contacting points of the actual datum feature cylindrical surface or the axis formed at the intersection of two datum planes.
Datum Feature - A datum feature is the actual surface component used to establish a datum.
Datum Line - A datum line is that which has length but no breadth or depth, such as, an intersection line of two planes, centerline or axis of holes or cylinders and/or reference line for functional tooling or gauging purposes.
Datum Point - A datum point is that which has position, but no extent; such as, the apex of a pyramid or cone, center point of a sphere or reference point on a surface for functional tooling or gauging purposes.
Datum Reference - A datum reference is a datum feature.
Datum Reference Plane - is a set of three mutually perpendicular datum planes or axis established from the simulated datum in contact with datum surfaces or features and used as a basis for dimensions for designs, manufacture, and inspection measurement.
Datum Simulator - A datum simulator a surface of adequate precision oriented to the high points of a designated datum from which the simulated datum is established. Examples: gage pin, block, surface of granite block.
Diameter Symbol - the diameter symbol indicates a circular feature when used on the field of a drawing or indicates that a defined tolerance is diametrical when used in a feature control frame.
Datum Target - is a specified point, line, or area on a part that is used to establish the Datum Reference Plane for manufacturing and inspection operations.
Dimension - A dimension is a numerical value expressed in appropriate units of measure and indicated on a drawing.
Feature - Features are specific component portions of a part and may include one or more surfaces, such, as holes, screw threads, profiles, faces or slots. Features may be individual or interrelated.
Feature of Size - One cylindrical or spherical surface, or a set of two plane parallel surfaces, each of which is associated with a size dimension.
Feature Control Frame - The feature control frame is a rectangular box containing the geometric characteristics symbol, spcified tolerance and datums references as required.
Fit - Fit is a general term used to signify the range of tightness or looseness which may result from the application of a specific combination of allowances and tolerance in the design of mating part features. Fits are of four general types: interference, transition, line and clearance.
Flatness - Flatness is the condition of a surface having all elements in one plane. Symbol:
Form Tolerance - A form tolerance states how far an actual surface is permitted to vary from desired geometric form. Expressions of these tolerances refer to limits of size, flatness, straightness, parallelism, perpendicularly, angularity, roundness, cylindricity, profile of a surface and profile of a line.
Free State Variations - Free state variation is a term used to describe the distortion of a part after removal of forces applied during manufacture or assembly.
Geometric Characteristics - Geometric characteristics refer to the basic elements or building blocks which form the language of geometric dimensioning and tolerancing. Generally, the term refers to all the symbols used in form, runout, profile and locational tolerancing.
Geometric Tolerance - The general term applied to the category of tolerances used to control form, profile, orientation, location, and runout.
Interference Fit - An interference fit is one having limits of size so prescribed that an interference will occurs when mating parts are assembled.
Least Material Condition - (LMC) - This term implies that the condition of a feature of size wherein it contains the least (minimum) amount of material for the stated limits of size; examples, largest hole size and smallest shaft size. It is the opposite materiasl condition to maximum material condition (MMC). Symbol:
Limit Dimensions - In limit dimensioning only the maximum and minimum dimensions are specified. When used with dimension lines, the high limit is placed over the low limit. When used with a leader line or note, the low limit precedes the high limit.
Limits of Size - The specified maximum and minimum size of a given feature.
Limits of Size Concept - The limits of size concept calls for perfect form at maximum material condition. Also called Rule #1.
Line to Line Fit - A line fit is one having limits of size so prescribed that surface contact or clearance may result when mating parts as assembled.
Location Tolerance - A location tolerance states how far or near a feature may vary from the perfect location implied by the drawing as related to datum's or other features. Expressions of these tolerances refer to the category of geometric characteristics containing position, concentricity, and symmetry.
Maximum Material Condition - (MMC) Maximum material condition is that condition of a part feature wherein it contains the maximum amount of material within the stated limits of size. That is: minimum hole size and maximum shaft size. Symbol:
Modifier - A modifier is the term used to describe the application of MMC and LMC.
Nominal Size - The nominal size is the stated designation which is used for the purpose of general identification, examples: 1.400, .050 .
Parallelism - Parallelism is the condition of a surface, line, or axis which is equidistant at all points from a datum plane or axis. Symbol:
Perpendicularity - Perpendicularity is the condition of a surface, axis, or line, which is 90 deg. From a datum plane or a datum axis. Symbol:
Position Tolerance - Position tolerance defines a zone within which the axis or center plane of a feature is permitted to vary from true (theoretically exact) position. Symbol:
Principle of Independency - This principle sets no limits to the number of errors of form possessed by individual features of a work piece.
Profile of a Line - Profile of a line is the condition permitting an amount of surface element variation ether unilaterally or bilaterally along a line element of a feature. Symbol:
Profile of a Surface - Profile of a surface is the condition permitting an amount of surface 3D variation ether unilaterally or bilaterally of a surface. Symbol:
Projected Tolerance Zone - A projected tolerance zone applies to a feature, such as pin, stud, screw, or similar. The projected tolerance zone is a tolerance boundary that extends above or beyond the surface of the part within which the controlling element of the feature must fall within - axis of a hole for example. Symbol:
Reference Dimension - A dimension, usually without tolerance that is used for information purposes only. It does not govern production or inspection operations. A reference dimension is a repeat of a dimension or is derived from other values on the drawing or related drawings. Symbology: (.250)
Regardless of Feature Size - (RFS) - This is the condition where the stated tolerance limits must be met irrespective of as built feature size or location.
Roundness - Roundness describes the condition on a surface of revolution (cylinder, cone, or sphere) where all points of the surface intersected by any plane are; (1) perpendicular to a common axis (cylinder, cone), (2) passing through a common center (sphere) are equidistant from the center. Symbol:
Runout, Circular - Runout, Circular is the composite deviation from the desired form of a part surface of revolution through one full rotation (360 deg) of the part on a datum axis. Symbol:
Runout Tolerance - Runout tolerance states how far an actual surface of a feature is permitted to deviate from the desired form implied by the drawing during one full rotation of the part on a datum axis.
Size Tolerance - A size tolerance states how far individual features may vary from the desired size. Size tolerances are specified with ether unilateral, bilateral or limit tolerance methods.
Specified Datum - A specified datum is a surface or feature identified with a datum identification symbol of note.
Squareness - See Perpendicularity.
Straightness - Straightness describes a condition where a line element of a surface, axis, or center plane is a straight line. Symbol:
Symmetry - Symmetry is a condition in which a feature (or features) are symmetrically disposed about the center plane of a datum feature.
Transition Fit - A transition fit is one having limits of size so prescribed that either a clearance or an interference may result when mating parts as assembled.
Total Runout - Total runout is the simultaneous composite control of all elements of a surface at all circular and profile measuring positions as the part is rotated through 360. Symbol:
Unilateral Tolerance - A unilateral tolerance is a tolerance in which variation is permitted only in one direction from the specified dimension, example, 1.400 +.000/ -.006.
Virtual Condition (Size) - The boundary generated by the collective effects of MMC, size limit of a feature and any associated geometric tolerance, virtual condition must be considered in determining the fit between mating parts. The term "virtual condition" is preferred over "virtual size."
Actual Size - Actual size is the measured size of the produced feature.
Angularity - Angularity is the condition of a surface, axis, or center plane, which is at a specified angle (other than 0, 90, 180 or 270 deg.) from a datum plane or axis. Symbol:
Basic Dimension - A basic dimension is a theoretically exact value used to describe the exact size, profile, orientation or location of a feature. A basic dimension should always associated with a feature control frame or datum target. Block tolerance does not apply and the applicable tolerance will be given within the feature control frame. Basic dimensions are enclosed within a box. Symbol:
Bilateral Tolerance - A bilateral tolerance is a tolerance in which variation is permitted in both directions from a specified nominal size or dimension (example +- .005).
Circularity - See Roundness.
Clearance Fit - A clearance fit is one having limits of size defined such that a clearance exists between mating parts when assembled.
Concentricity - Concentricity describes a condition in which two or more features (cylinders, cones, spheres, etc.) in any combination have a common axis. Measurement requirements for concentricity involves the complex task of mapping the referenced feature by way of opposed point measurements. A through understanding of the measurement process should be investigated before defining feature relationships using concentricity. Symbol:
Coaxial - Coaxial describes a condition where two or more features have the same axis or centerline.
Coordinate Dimension - (1) Either of two coordinates that locate a point on a plane and measured its distance from either of two intersecting straight-line axes along a line parallel to the other axis. (2) Any of three coordinates that locate a point in space and measure its distance from any of three intersecting coordinate planes measured to that one of three straight-line axes that is the intersection of the other two planes.
Coplanar - Coplanar describes a condition of two or more surfaces having all elements in the same plane.
Cylindricity - Cylindricity describes a condition of a surface of revolution in which all points of a surface are equidistant from a common axis.
Datum - Datum's are points, lines, planes, cylinders, axes, etc., from which the location or geometric relationship of other features may be established or related.
Datum Axis - the datum axis is the theoretically exact centerline of the datum cylinder as established by the extremities or contacting points of the actual datum feature cylindrical surface or the axis formed at the intersection of two datum planes.
Datum Feature - A datum feature is the actual surface component used to establish a datum.
Datum Line - A datum line is that which has length but no breadth or depth, such as, an intersection line of two planes, centerline or axis of holes or cylinders and/or reference line for functional tooling or gauging purposes.
Datum Point - A datum point is that which has position, but no extent; such as, the apex of a pyramid or cone, center point of a sphere or reference point on a surface for functional tooling or gauging purposes.
Datum Reference - A datum reference is a datum feature.
Datum Reference Plane - is a set of three mutually perpendicular datum planes or axis established from the simulated datum in contact with datum surfaces or features and used as a basis for dimensions for designs, manufacture, and inspection measurement.
Datum Simulator - A datum simulator a surface of adequate precision oriented to the high points of a designated datum from which the simulated datum is established. Examples: gage pin, block, surface of granite block.
Diameter Symbol - the diameter symbol indicates a circular feature when used on the field of a drawing or indicates that a defined tolerance is diametrical when used in a feature control frame.
Datum Target - is a specified point, line, or area on a part that is used to establish the Datum Reference Plane for manufacturing and inspection operations.
Dimension - A dimension is a numerical value expressed in appropriate units of measure and indicated on a drawing.
Feature - Features are specific component portions of a part and may include one or more surfaces, such, as holes, screw threads, profiles, faces or slots. Features may be individual or interrelated.
Feature of Size - One cylindrical or spherical surface, or a set of two plane parallel surfaces, each of which is associated with a size dimension.
Feature Control Frame - The feature control frame is a rectangular box containing the geometric characteristics symbol, spcified tolerance and datums references as required.
Fit - Fit is a general term used to signify the range of tightness or looseness which may result from the application of a specific combination of allowances and tolerance in the design of mating part features. Fits are of four general types: interference, transition, line and clearance.
Flatness - Flatness is the condition of a surface having all elements in one plane. Symbol:
Form Tolerance - A form tolerance states how far an actual surface is permitted to vary from desired geometric form. Expressions of these tolerances refer to limits of size, flatness, straightness, parallelism, perpendicularly, angularity, roundness, cylindricity, profile of a surface and profile of a line.
Free State Variations - Free state variation is a term used to describe the distortion of a part after removal of forces applied during manufacture or assembly.
Geometric Characteristics - Geometric characteristics refer to the basic elements or building blocks which form the language of geometric dimensioning and tolerancing. Generally, the term refers to all the symbols used in form, runout, profile and locational tolerancing.
Geometric Tolerance - The general term applied to the category of tolerances used to control form, profile, orientation, location, and runout.
Interference Fit - An interference fit is one having limits of size so prescribed that an interference will occurs when mating parts are assembled.
Least Material Condition - (LMC) - This term implies that the condition of a feature of size wherein it contains the least (minimum) amount of material for the stated limits of size; examples, largest hole size and smallest shaft size. It is the opposite materiasl condition to maximum material condition (MMC). Symbol:
Limit Dimensions - In limit dimensioning only the maximum and minimum dimensions are specified. When used with dimension lines, the high limit is placed over the low limit. When used with a leader line or note, the low limit precedes the high limit.
Limits of Size - The specified maximum and minimum size of a given feature.
Limits of Size Concept - The limits of size concept calls for perfect form at maximum material condition. Also called Rule #1.
Line to Line Fit - A line fit is one having limits of size so prescribed that surface contact or clearance may result when mating parts as assembled.
Location Tolerance - A location tolerance states how far or near a feature may vary from the perfect location implied by the drawing as related to datum's or other features. Expressions of these tolerances refer to the category of geometric characteristics containing position, concentricity, and symmetry.
Maximum Material Condition - (MMC) Maximum material condition is that condition of a part feature wherein it contains the maximum amount of material within the stated limits of size. That is: minimum hole size and maximum shaft size. Symbol:
Modifier - A modifier is the term used to describe the application of MMC and LMC.
Nominal Size - The nominal size is the stated designation which is used for the purpose of general identification, examples: 1.400, .050 .
Parallelism - Parallelism is the condition of a surface, line, or axis which is equidistant at all points from a datum plane or axis. Symbol:
Perpendicularity - Perpendicularity is the condition of a surface, axis, or line, which is 90 deg. From a datum plane or a datum axis. Symbol:
Position Tolerance - Position tolerance defines a zone within which the axis or center plane of a feature is permitted to vary from true (theoretically exact) position. Symbol:
Principle of Independency - This principle sets no limits to the number of errors of form possessed by individual features of a work piece.
Profile of a Line - Profile of a line is the condition permitting an amount of surface element variation ether unilaterally or bilaterally along a line element of a feature. Symbol:
Profile of a Surface - Profile of a surface is the condition permitting an amount of surface 3D variation ether unilaterally or bilaterally of a surface. Symbol:
Projected Tolerance Zone - A projected tolerance zone applies to a feature, such as pin, stud, screw, or similar. The projected tolerance zone is a tolerance boundary that extends above or beyond the surface of the part within which the controlling element of the feature must fall within - axis of a hole for example. Symbol:
Reference Dimension - A dimension, usually without tolerance that is used for information purposes only. It does not govern production or inspection operations. A reference dimension is a repeat of a dimension or is derived from other values on the drawing or related drawings. Symbology: (.250)
Regardless of Feature Size - (RFS) - This is the condition where the stated tolerance limits must be met irrespective of as built feature size or location.
Roundness - Roundness describes the condition on a surface of revolution (cylinder, cone, or sphere) where all points of the surface intersected by any plane are; (1) perpendicular to a common axis (cylinder, cone), (2) passing through a common center (sphere) are equidistant from the center. Symbol:
Runout, Circular - Runout, Circular is the composite deviation from the desired form of a part surface of revolution through one full rotation (360 deg) of the part on a datum axis. Symbol:
Runout Tolerance - Runout tolerance states how far an actual surface of a feature is permitted to deviate from the desired form implied by the drawing during one full rotation of the part on a datum axis.
Size Tolerance - A size tolerance states how far individual features may vary from the desired size. Size tolerances are specified with ether unilateral, bilateral or limit tolerance methods.
Specified Datum - A specified datum is a surface or feature identified with a datum identification symbol of note.
Squareness - See Perpendicularity.
Straightness - Straightness describes a condition where a line element of a surface, axis, or center plane is a straight line. Symbol:
Symmetry - Symmetry is a condition in which a feature (or features) are symmetrically disposed about the center plane of a datum feature.
Transition Fit - A transition fit is one having limits of size so prescribed that either a clearance or an interference may result when mating parts as assembled.
Total Runout - Total runout is the simultaneous composite control of all elements of a surface at all circular and profile measuring positions as the part is rotated through 360. Symbol:
Unilateral Tolerance - A unilateral tolerance is a tolerance in which variation is permitted only in one direction from the specified dimension, example, 1.400 +.000/ -.006.
Virtual Condition (Size) - The boundary generated by the collective effects of MMC, size limit of a feature and any associated geometric tolerance, virtual condition must be considered in determining the fit between mating parts. The term "virtual condition" is preferred over "virtual size."
Sunday, February 7, 2010
Mechanisms explained with sketches
Students of Post Graduate -Engg Design are directed to download the full content of the various mechanisms through the following link.
follow the link to download Mechanisms
follow the link to download Mechanisms
DFM syllabus
DESIGN FOR MANUFACTURE, ASSEMBLY AND ENVIRONMENTS
3 0 0 100
1. INTRODUCTION 5
General design principles for manufacturability - strength and mechanical factors, mechanisms selection, evaluation method, Process capability - Feature tolerances Geometric tolerances - Assembly limits -Datum features - Tolerance stacks.
2. FACTORS INFLUENCING FORM DESIGN 13
Working principle, Material, Manufacture, Design- Possible solutions - Materials choice - Influence of materials on form design - form design of welded members, forgings and castings.
3. COMPONENT DESIGN - MACHINING CONSIDERATION 8
Design features to facilitate machining - drills - milling cutters - keyways - Doweling procedures, counter sunk screws - Reduction of machined area- simplification by separation - simplification by amalgamation - Design for machinability - Design for economy - Design for clampability - Design for accessibility - Design for assembly.
4. COMPONENT DESIGN - CASTING CONSIDERATION 10
Redesign of castings based on Parting line considerations - Minimizing core requirements, machined holes, redesign of cast members to obviate cores.
Identification of uneconomical design - Modifying the design - group technology - Computer Applications for DFMA
5. DESIGN FOR THE ENVIRONMENT 9
Introduction – Environmental objectives – Global issues – Regional and local issues – Basic DFE methods – Design guide lines – Example application – Lifecycle assessment – Basic method – AT&T’s environmentally responsible product assessment - Weighted sum assessment method – Lifecycle assessment method – Techniques to reduce environmental impact – Design to minimize material usage – Design for disassembly – Design for recyclability – Design for remanufacture – Design for energy efficiency – Design to regulations and standards.
Total 45
3 0 0 100
1. INTRODUCTION 5
General design principles for manufacturability - strength and mechanical factors, mechanisms selection, evaluation method, Process capability - Feature tolerances Geometric tolerances - Assembly limits -Datum features - Tolerance stacks.
2. FACTORS INFLUENCING FORM DESIGN 13
Working principle, Material, Manufacture, Design- Possible solutions - Materials choice - Influence of materials on form design - form design of welded members, forgings and castings.
3. COMPONENT DESIGN - MACHINING CONSIDERATION 8
Design features to facilitate machining - drills - milling cutters - keyways - Doweling procedures, counter sunk screws - Reduction of machined area- simplification by separation - simplification by amalgamation - Design for machinability - Design for economy - Design for clampability - Design for accessibility - Design for assembly.
4. COMPONENT DESIGN - CASTING CONSIDERATION 10
Redesign of castings based on Parting line considerations - Minimizing core requirements, machined holes, redesign of cast members to obviate cores.
Identification of uneconomical design - Modifying the design - group technology - Computer Applications for DFMA
5. DESIGN FOR THE ENVIRONMENT 9
Introduction – Environmental objectives – Global issues – Regional and local issues – Basic DFE methods – Design guide lines – Example application – Lifecycle assessment – Basic method – AT&T’s environmentally responsible product assessment - Weighted sum assessment method – Lifecycle assessment method – Techniques to reduce environmental impact – Design to minimize material usage – Design for disassembly – Design for recyclability – Design for remanufacture – Design for energy efficiency – Design to regulations and standards.
Total 45
Mechanisms an introduction
Mechanisms an introduction
Introduction
A mechanism considered to be an assembly of mechanical items designed to achieve a specific purpose within a machine. There are clearly an infinite number of mechanisms available but the notes and links are concentrating on the specific ones as listed below.
Motion Control Using Computers
The notes below relate generally to mechanical methods for providing relative motion and forces. There is an increasing tendency to produce motions using servo hydraulic systems and stepping motors under the control of digital computers. Although the mechanism design often requires creativity and a high level of analysis the final product is often low priced and provides reliable, efficient, predictable performance. However a mechanism is generally made to perform a fixed operation, reliably and predictably. Computer controlled motions can be continuously monitored and if necessary modified. If the output motion is changed from a harmonic motion to a periodic square wave motion or a sawtooth motion then changing the control parameters for a computer controlled system is often very convenient. If a large number of systems have been developed then the cost of modifying the software or firmware is much less than modifying a large number of mechanisms..
Although the motions of many of high technology machines and computer systems are being controlled by computers. The need for mechanisms is also increasing in consumer goods e.g. mechanisms in consumer goods, toys, lifting equipment, vehicles, aircraft, industrial machines, gardening implements,etc etc etc... ......
Classification Of Mechanisms
There are many methods of classifying mechanisms. The following list is a functional list based on the type of motion required. This list is based on that provided in Theory of Machines and Mechanisms ..Uicker, Pennock, and Shigley. The notes below are low level descriptions. Additional notes will be included soon..
1. Snap-Action Mechanisms
2. Linear Actuators
3. Fine Adjustment Mechanisms
4. Clamping Mechanisms
5. Location Devices
6. Ratchets
7. Escapements
8. Indexing Mechanisms
9. Swinging or Rocking Mechanisms
10. Reciprocating Mechanisms
11. Reversing Mechanisms
12. Couplings and Connectors
13. Sliding Connectors
14. Stop Pause and Hesitation Mechanisms
15. Curve Generators
16. Straight Line generators
17. Tracing Mechanisms
Introduction
A mechanism considered to be an assembly of mechanical items designed to achieve a specific purpose within a machine. There are clearly an infinite number of mechanisms available but the notes and links are concentrating on the specific ones as listed below.
Motion Control Using Computers
The notes below relate generally to mechanical methods for providing relative motion and forces. There is an increasing tendency to produce motions using servo hydraulic systems and stepping motors under the control of digital computers. Although the mechanism design often requires creativity and a high level of analysis the final product is often low priced and provides reliable, efficient, predictable performance. However a mechanism is generally made to perform a fixed operation, reliably and predictably. Computer controlled motions can be continuously monitored and if necessary modified. If the output motion is changed from a harmonic motion to a periodic square wave motion or a sawtooth motion then changing the control parameters for a computer controlled system is often very convenient. If a large number of systems have been developed then the cost of modifying the software or firmware is much less than modifying a large number of mechanisms..
Although the motions of many of high technology machines and computer systems are being controlled by computers. The need for mechanisms is also increasing in consumer goods e.g. mechanisms in consumer goods, toys, lifting equipment, vehicles, aircraft, industrial machines, gardening implements,etc etc etc... ......
Classification Of Mechanisms
There are many methods of classifying mechanisms. The following list is a functional list based on the type of motion required. This list is based on that provided in Theory of Machines and Mechanisms ..Uicker, Pennock, and Shigley. The notes below are low level descriptions. Additional notes will be included soon..
1. Snap-Action Mechanisms
2. Linear Actuators
3. Fine Adjustment Mechanisms
4. Clamping Mechanisms
5. Location Devices
6. Ratchets
7. Escapements
8. Indexing Mechanisms
9. Swinging or Rocking Mechanisms
10. Reciprocating Mechanisms
11. Reversing Mechanisms
12. Couplings and Connectors
13. Sliding Connectors
14. Stop Pause and Hesitation Mechanisms
15. Curve Generators
16. Straight Line generators
17. Tracing Mechanisms
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