UNIT -5- ACTUATORS AND MECHATRONICS SYSTEM DESIGN.pdf
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The document provides an overview of mechatronics focusing on actuators, specifically types of motors including stepper and servo motors, their working principles, and design processes. It contrasts traditional mechanical designs with mechatronic systems, highlighting the advantages of flexibility and accuracy in modern mechatronic design. Various application case studies such as robot mechanisms and engine management systems are also discussed, emphasizing their reliance on advanced control systems.
UNIT -5- ACTUATORS AND MECHATRONICS SYSTEM DESIGN.pdf
- 1. 20ME702 - MECHATRONICS UNIT-5 ACTUATORS AND MECHATRONICS SYSTEMS DESIGN Prepared by S.Chandra Kumar AP/MECHANICAL Kongunadu College of Engineering and Technology
- 2. CONTENT Types of stepper and servo motors – construction, working principle Design process - Stages in designing mechatronics system Traditional and mechatronic design concept Possible design solution Case studies of mechatronics systems Pick and place robot Engine management system Automatic car park barrier
- 3. DC MOTORS • DC motor used in large number of Mechatronics design. • Torqe speed characteristica achieveble • PRINCIPLE: – When a current carrying conductor is placed in a magnetic field, it experiences a force. – When conductor moves in a magnetic field E.M.F is induced.
- 5. VARIABLE TYPES OF DC MOTOR
- 6. Types of DC motor • PERMANENT MAGNET MOTOR – Permanent magnet is high – Reverse switching takes place – Position and speed control application • SERIES MOTOR – Windings in series so starting torques – High variable speed • SHUNT MOTOR – Constant speed over a large range of loading – Lowest torque, good speed of regulation
- 7. Types of DC motor • COMPOUND MOTOR – Combined characteristics of both series and shunt motor. – High starting torque and speed regulation(stability). • SEPARATE WOUND MOTOR – It is the special case of shunt motor. – Separate control of armature and field windings.
- 8. AC INDUCTION MOTOR • Main parts of AC induction motor are ROTOR (Rotating element) and STATOR (Stationary element) • Rotor construction look like squirrel cage, so it is called as SQUIRREL CAGE INDUCTIIN MOTOR.
- 9. AC motor • Electric motor driven by altering current. • AC motor consists of two basic parts: – OUTSIDE STATIONARY STATOR – INSIDE ROTOR
- 10. WORKING • Winding generating the pluses instead of rotating , • When rotor is stationary, stator field induces current in motor • Current generates rotor field opposite polarity to the stator • Opposition of the field creates TURNING FORCE upper and lower parts of rotor to 180 degree from its position.
- 12. WORKING • Motor is not self starting, number of methods to make self start • Rotor differs from this frequency of rotation about 1% to 3% and difference is termed as slip.
- 13. THREE PHASE INDUCTION MOTOR • It is similar to single phase induction motor • Three windings located in 120 degree connected in lines of supply. • Three phase current produces a magnetic field • Attraction and repulsion of magetic field causes rotor to turn. • Single phase motors used for low power requirement areas, domestic applications such as AC compressor, hydraulic pumps, Etc,.
- 14. STEPPER MOTOR • Stepper motor is a special type of DC motor • The spindle of stepper motor rotates in step increments • Stepper motor gives accurate angular increments • Stepper motor requires 48 pulses rotate through one complete revolution • Input signal 96 pulses cause motor to rotate 120 rev/min
- 15. • Stepper motor is manufacturing with step revolution 12,24,72,144,180,and 200 • Resulting the shaft increments are 30,15,5,2.5,2,1.8 degrees • Angular increments from 180 degree to 0.75 degree PEFORMANCE CHARACTERISTICS: – Rotate both the directions – Precise angular increments – Holding torque at zero speed
- 16. PROPERTIES OF STEPPER MOTOR: – Certain number of steps moving the mechanical element – High torque at small angular velocities – When high holding torque the property of being self locking – Stepper motor is directly compatible with digital control techniques interface with microprocessor or computer – Motor construction is simple.
- 17. TYPES OF STEPPER MOTOR 1. Variable reluctance stepper motor 2. Permanent magnet stepper motor 3. Hybrid stepper motor
- 18. Variable reluctance stepper motor • Number of poles at the rotor is less then poles at the stator • Motor usually 8 stator and 6 rotor teeth • Excitation determines the step angle • Stator coils windings are energized with DC current poles becomes magnetized • Rotor moves t a minimum gap between stator and its teeth is called minimum reluctance • Full stepping sequence for clockwise step angle is 60 degree.
- 19. • Two phase have to be energized simultaneously during some steps.
- 20. PERMANENT MAGNET STEPPER MOTOR • It is often referred as CANSTACK motor • The stator and rotor poles are not teethed • We used permanent magnet. • Rotor is magnitized altering north poles , south poles situated in a straight line parallel to a rotor shaft • Each pole 90 degree • Each pole wound in field winding • Low speed low torque device angles from 15 to 120 degree.
- 22. HYBRID STEPPER MOTOR • Combination of both permanent magnet and variable relectance • Best features • Eight salient features with two phase windings • Magnetic rotor has two cups • One is north pole , second is south pole. • No. of teeth decides the step angle of the motor
- 24. Step modes for stepper motor • FULL STEP MODE – 200 Full steps – Dividing 200 steps in to 360 degree – Equals 1.8 full step angle • HALF STEP MODE – Motor rotates 400 steps per revolution – Half step means 0.9 degree • MICRO STEP MODE – New stepper motor technology – Micro steps 1/256, fine over a wide range of speed
- 25. SERVO MOTOR • Special type of application of electrical motor where the rotation of motor is required • Not continuously for a long period of time • For certain angle rotation for a given input • Precise degree of rotation • Quick response • High accuracy • Fast and accurate speed • Direction control • Remote operation
- 26. • Servo motor is a electrical motor combined with a positionong sensor, control a specific angular rotation with servo mechanism • Closed loop feed back • Servo motors used when a object to rotate for a required degree FUNDMENTAL CHARACTERISTICS – TORQUE output proportional to voltage applied – Torque developed by servo motor depends up on polarity
- 27. CONSTRUCTION AND WORKING OF SERVO MOTOR • CLOSED LOOP SYSTEM
- 28. EXAMPLE OF SERVO MOTOR CONTROL SYSTEM • INPUT-OUTPUT = RESULT
- 29. TYPES OF SERVO MOTOR 1. AC servomotors AC powered servomotor is called AC servomotor 2. DC servomotors DC powered servomotor is called DC servomotor
- 30. • AC SERVOMOTOR: – Two phase induction motor capable in reverse operation. – To achieve dynamic requirements of servo motor have small diameter. – The low inertia allows fast starts, stops and reverse direction. – Rotor provides for almost accurate control. • DC SERVOMOTOR: – Not used for continuously energy conversion – Large size than conventional motors
- 31. TYPES OF DC SERVO MOTOR • SERIES MOTOR – High starting torque, reversing mechanism. • SPLIT SERIES MOTOR – Seperately excited field control motor. – Rapid reduction in torque increase in speed • SHUNT CONTROL MOTOR – Two separate windings – Both windings connected to DC supply • PERMANENT MAGNET SHUNT MOTOR – Field is actually supplied by a permanent magnet
- 32. APPLICATIONS OF SERVO MOTOR • High voltage power systems • Application in INKJET printers and RC helicopter • Used in robots , computers, tools tracking system. PERFORMANCE SPECIFICATIONS: • Shaft speed • Terminal voltage • Torque – Starting torque and continuous torque
- 33. ADVANTAGES AND DISADVANTAGES • High output power • Determines accuracy and resolution • High torque to inertia ratio • Current proportional to load • High speed torque • Peak power at higher speeds • Poor motor cooling • Design is complex • Safety circuits are required • Brush wear out limits 2000 hrs.
- 34. Stages in designing mechatronics system Need for design Analysis of problem Preparation of specification Generation of possible solution Evaluation Production of detailed design Production of working drawing Implementation of design
- 35. Traditional design A mechanical system Mechanical linkages , drives etc., Hydraulic and pneumatic actuators Electrical motors, switches etc.,
- 36. Mechatronic design A mechanical system Mechanical linkages , drives etc., Hydraulic and pneumatic actuators Electronic components, computers & IT systems Electrical motors, switches etc.,
- 37. Comparison of traditional and mechatronics design Traditional design • It is based on a traditional systems such as mechanical, hydraulic and pneumatic systems • Less flexible • Less accurate • More complicate mechanism in design • It involve more components and moving parts Mechatronics design • It is based on mechanical, electronics, computer technology and control engineering. • More flexible • More accurate • Less complicate mechanism in design • It involve fewer components and moving parts
- 38. Possible design solution • Timer switch • Windscreen wiper motion • Weighing scales
- 39. Timer switch
- 40. Possible solution for timer switch
- 41. ADVANTAGES OF PLC OVER TRADITIONAL METHOD • PLC is compact • It is not affected by the vibration and electrical effect • Plc can handled with unskilled labours • Plc is rigid and compact
- 43. Possible solution for Windscreen wiper motion
- 44. • Full step configuration • Half step configuration – By the excitation table we refer the steps of the stepper motor
- 45. Weighing scales Weighing Scales Weighing Scales mechanism
- 46. Wheatstone bridge arrangement with ADC
- 47. Wheatstone bridge with microcontroller
- 48. Case studies • Pick and place robot • Autonomous mobile robot • Wireless surveillance balloon • Engine management system • Automatic car park barrier
- 49. Pick and place robot
- 50. Gripper mechanism of a robot
- 51. Microcontroller circuit for pick and place robot
- 53. Elements of autonomous mobile robot
- 55. Applications of wireless surveillance Ballon • Border security (TARS) in military • Enhancing battle field situational awareness • Coastal surveillance • Platform for mounting telecommunication, television, radio transmitters etc., • Aerial platform for scientific instrument testing
- 56. ENGINE MNAGEMANT SYSTEMS Basic components • Electronic control unit • Fuel delivery system • Ignition system • Various sensors – Throttle position sensors – Exhaust gas oxygen sensors – Manifold absolute pressure sensors – Temperature sensors – Engine speed/Timing sensors – Exhaust gas regulation sensors
- 59. Automatic car park barrier
- 60. Interfacing of sensors with controller in Automatic car park barrier