Introduction to Mechatronics and Measurement Systems

1. SMJP 3333 (Mechatronics) Introduction to Mechatronics and Measurement Systems by Dr.Aung Lwin Moe REF:Prof. I. Charles Ume

2. Mechatronics The synergistic combination of mechanical, electrical, and computer engineering • Emphasis on integrated design for products • Optimal combination of appropriate technologies

3. Mechatronics Systems Computers Cars Tools Stealth Bomber Consumer Electronics High Speed Trains MEMS Micro to Macro Applications

4. Mechatronics Systems -Manufacturing Applications- Micro Factory Micro Factory Drilling Unit • Desktop sized Factory • Build small parts with a small factory • Greatly reduces space, energy, and materials

5. Mechatronics Systems CNC Bending • Fully automated bending: load sheet metal and the finished bent parts come out • Can bend complex shapes

6. Mechatronics Systems CNC Machining Advantages • Deliver the highest accuracies • Can create very complex shapes

7. Mechatronics Systems -Transportation Applications- Automobiles Typical Applications • Brake-By-Wire system • Steer-By-Wire • Integrated vehicle dynamics • Cam-less engines • Integrated starter alternator OEM Driven • Reliability • Reduced weight • Fuel economy • Manufacturing flexibility • Design freedom • Advanced safety features • Cost

8. Mechatronics Systems - Door System/Module- “Smart” Mirror motor-unit pin-header “Smart” Doorlock CAM Bus Switchboard with CAN Bus Gateway “Smart” Window Lift-unit

9. Mechatronics Systems -Seat System/Module- Seat Harness Architecture showing various smart connector interconnections solutions

10. Mechatronics Systems High Speed Trains • Train Position and Velocity constantly monitored from main command center. • Error margin in scheduling no more than 30 seconds • Fastest trains use magnetic levitation JR-MaglevTop Speed: 574 km/h (357 mph)Country: Japan Magnetic Levitation TransrapidTop Speed: 550 km/h (340 mph) Country: German

11. Mechatronics Systems Segway Systems Uses • Tilt and pressure sensors • Microcontroller • Motors • Onboard power source Advantages • Simple and intuitive personal transportation device

12. Mechatronics Systems -Smart Robotics Application- BigDog System Can • Carry 340 lb • Run 4 mph • Climb, run, and walk • Move over rough terrain Advantages • Robot with rough-terrain mobility that could carry equipment to remote location.

13. Mechatronics Systems Vacuum Floors • Robots can vacuum floors and clean gutters so you don't have to. Cleans Gutter

14. Mechatronics Systems -Space Exploration Application- Phoenix Mars Lander's System Can • Collect specimens • Has automated onboard lab for testing specimens Advantages • Robot that can travel to other planets and take measurements automatically.

15. Mechatronics Systems -Medical Applications- Prosthetics • Arms, Legs, and other body parts can be replaced with electromechanical ones.

16. Mechatronics Systems Pace Maker -Medical Applications- Used by patients with slow or erratic heart rates. The pacemaker will set a normal heart rate when it sees an irregular heart rhythm. Implantable Defibrillation Monitors the heart. If heart fibrillates or stops completely it will shock the heart at high voltage to restore a normal heart rhythm.

17. Mechatronics Systems -Defense Applications- • Advanced technology is making our soldiers safer. • Some planes can now be flown remotely. Stealth Bomber Unmanned Aerial Vehicle

18. Mechatronics Systems -Sanitation Applications- System Uses • Proximity sensors • Control circuitry • Electromechanical valves • Independent power source Advantages • Reduces spread of germs by making device hands free • Reduces wasted water by automatically turning off when not in use

19. Mechatronics Systems Systems Uses • Motion sensors • Control circuitry • Electromechanical actuators • Independent power source Paper Towel Dispenser Soap Dispenser Advantages • Reduces spread of germs by making device hands free • Reduces wasted materials by controlling how much is dispensed

20. Mechatronics Systems -Sports Applications- Running Shoes Advantages Automatically changes cushioning in shoe for different running styles and conditions for improved comfort

21. Mechatronics Systems -Smart Home Applications- Washing Machine Solution Power Supply Rectifiers/Regulator Pressure Sensor MPX5006/MPX2010

22. Mechatronics Systems -Smart Home Applications- Smoke Detector System

24. Copy Machine • It includes analog and digital circuits, sensors, actuators, and microprocessors. • A high intensity light source scans the original and transfers the corresponding image as a charge distribution to a drum. • The image is transferred onto the paper with an electrostatic deposition of ink toner powder that is heated to bond to the paper. • Analog circuits control the lamp, heater, and other power circuits in the machine. • Digital circuits control the digital displays, indicator lights, buttons, and switches forming the user interface. Other digital circuits include logic circuits and microprocessors that coordinate all of the functions in the machine.

25. Inkjet printer components

26. Elements of a measurement system It is important for designers and users of measurement systems to develop confidence in their use, to know their important characteristics and limitations, and to be able to select the best elements for the measurement task at hand. The following figure shows an example of a measurement system. The thermocouple is a transducer that converts temperature to a small voltage; the amplifier increases the magnitude of the voltage; the A/D (analog-to-digital) converter is a device that changes the analog signal to a coded digital signal; and the LEDs (light emitting diodes) display the value of the temperature.

27. DC motor power-op-amp speed controller • The light-emitting diode (LED) provides a visual cue to the user that the microcontroller is running properly. • The speed input device is a potentiometer (or pot), which is a variable resistor. • The resistance changes as the user turns the knob on top of the pot. The pot can be wired to produce a voltage input. • The voltage signal is applied to a microcontroller to control a DC motor to rotate at a speed proportional to the voltage. • Voltage signals are “analog” but microcontrollers are “digital,” so we need analog-to digital (A/D) and digital-to-analog (D/A) converters Finally, we need a power amplifier to boost the voltage and source the necessary current

28. The power-amp speed controller

29. Functional diagram of the stepper motor position and speed controller • The input devices include a pot to control the speed manually, four buttons to select predefined positions, and a mode button to toggle between speed and position control. • In position control mode, each of the four position buttons indexes the motor to specific angular positions relative to the starting point (0 , 45 , 90 , 180 ). In speed control mode, turning the pot clockwise (counterclockwise) increases (decreases) the speed. • The LED provides a visual cue to the user to indicate that the PIC is cycling properly. • A/D converter is used to convert the pot’s voltage to a digital value. • A microcontroller uses that value to generate signals for a stepper motor driver circuit to make the motor rotate

30. Photograph of the stepper motor position and speed controller

31. Functional diagram for the DC motor position and speed controller

32. A numerical keypad enables user input, and a liquid crystal display (LCD) is used to display messages and a menu-driven user interface. • The motor is driven by an H-bridge, which allows the voltage applied to the motor (and therefore the direction of rotation) to be reversed. The H-bridge also allows the speed of the motor to be easily controlled by pulse-width modulation (PWM), where the power to the motor is quickly switched on and off at different duty cycles to change the average effective voltage applied. • A digital encoder attached to the motor shaft provides a position feedback signal. This signal is used to adjust the voltage signal to the motor to control its position or speed. • This is called a servomotor system because we use feedback from a sensor to control the motor. Servomotors are different from stepper motors in that they move smoothly instead of in small incremental steps. • Two PIC microcontrollers are used in this design because there are a limited number of input/output pins available on a single chip. The main (master) PIC gets input from the user, drives the LCD, and sends the PWM signal to the motor. • The secondary (slave) PIC monitors the digital encoder and transmits the position signal back to the master PIC upon command via a serial interface.

33. Photograph of the DC motor position and speed controller

34. ■CLASS DISCUSSION ITEM • Household Mechatronic Systems • What typical household items can be characterized as mechatronic systems? • What components do they contain that help you identify them as mechatronic systems? • If an item contains a microprocessor, describe the functions performed by the microprocessor. • ??????????????

35. Measurement Fundamentals 1. Be able to define SI units and use them in calculations 2. Know how to use statistics fundamentals to characterize measured data 3. Be able to compute the error associated with a measurement

37. SYSTEMS OF UNITS • Fundamental to the design, analysis, and use of any measurement system is a complete understanding of a consistent system of units used to quantify the physical parameters being measured. • To define a system of units, we must select units of measure for fundamental quantities to serve as a basis for the definition of other physical parameters. • Units for mass, length, time, temperature, electric current, amount of • substance, and luminous intensity form one possible combination that • serves this purpose. • Other units used to measure physical quantities in mechatronic systems can be defined in terms of these seven base units. • The seven base units we use to define mass, length, time, temperature, electric current, amount of substance, and luminous intensity are the kilogram, meter, second, Kelvin, ampere, mole, and candela.

38. The kilogram is the only unit defined in terms of a material standard. It is • established by a platinum-iridium prototype in the laboratory of the Bureau des • Poids et Mesures in Paris. • The meter is defined as 1,650,763.73 wavelengths of the emission resulting from the transition between the 2p10 and 5d5 electron energy levels of the krypton 86 atom. This atomic standard for the meter was proposed long ago by Maxwell (1873) but not implemented until 1960. • The second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom. • The unit of absolute thermodynamic temperature is the Kelvin. The Kelvin scale has an absolute zero of 0 K, and no temperatures exist below this level. • The ampere is defined as the constant current that, if maintained in two straight parallel conductors of infinite length and negligible circular cross section and placed 1 meter apart in a vacuum • The mole is defined as the amount of substance that contains as many elementary entities as there are atoms in 0.012 kg of carbon 12 ( 12C). • The candela is defined as the luminous intensity, in the perpendicular direction, of a surface area of 1/600,000 m 2 of a black body at the freezing point of platinum under a pressure of 101,325 N/m 2 • .

39. Three Classes of SI Units SI units are divided into three classes: base units, derived units, and supplementary units. The complete set of SI base units and their symbols are listed in Table A.1 .

40. Derived units are expressed as algebraic combinations of the base units. Any known physical parameter can be quantified using a derived unit. Some examples of derived units are listed in Table A.2 .

41. Several derived units have been given special names and symbols, which may be used themselves to express other derived units in a simpler way than in terms of base units. Some examples of these supplemental units are listed in Table A.3 Often the base, derived, and supplemental units are modified with prefixes to enable convenient representation of large numerical ranges.

42. Often the base, derived, and supplemental units are modified with prefixes to enable convenient representation of large numerical ranges. The prefixes express orders of magnitude (powers of 10) of the unit, providing an alternative to scientific notation. The prefix names, symbols, and values are listed in Table A.4 .

43. Conversion Factors English units are still common in engineering practice in the United States. Table A.5 lists several factors that help when converting between English and SI units.

44. SIGNIFICANT FIGURES Whenever we deal with numerical data, we need to be aware of precision, accuracy, and different ways to present the data. Also, in establishing a rational approach to making numerical calculations with measured values, we must present decimal numbers with the appropriate number of digits. The significant digits or significant figures in a number are those known with certainty. A measured value represented by N digits consists of N -1 significant digits that are certain and 1 digit that is estimated.

45. STATISTICS When we process sets of data obtained from experimental measurements, we must handle the data in a rational, systematic, and organized fashion. The field of statistics provides models and rules for doing this properly

47. ERROR ANALYSIS • The process of making measurements is imperfect, and uncertainty will always be associated with measured values. It is important to recognize sources of error and estimate the magnitude of error when one makes a measurement. Usually a manufacturer defines the accuracy of an instrument in published specifications, but other factors come into play. • A systematic error is one that reoccurs in the same way each time a measurement is made. The method used to minimize the magnitude of systematic error is calibration, where the measurement instrument is used to record values from a standard input and is adjusted to compensate for any discrepancy. • Random errors occur due to the stochastic variations in a measurement process. Some of the statistical tools presented in the previous section enable us to reduce the effects of these errors. • Blunders occur when the engineer or scientist makes a mistake. Blunders can be avoided by careful design and review and through the use of methodical procedures.

48. Figure A.3 illustrates systematic and random errors. The center of the target represents the desired value, and the shot pattern represents measured data. The systematic error, called inaccuracy, is associated with the shift of the shot pattern from the center of the target and could be corrected by improved sighting, known as calibration .The random error, called imprecision, is the size of the shot pattern and cannot be improved by adjusting the sighting. Accuracy is the closeness to the true value, and precision is the repeatability or consistency of the measurements.

49. Rules for Estimating Errors