By: Craig Chan & Olusegun Michael Abidoye Advisor: Steven Gutschlag 27 April 2005

1. Active Suspension System Test PlatformBradley UniversityDepartment of Electrical & Computer Engineering By: Craig Chan & Olusegun Michael Abidoye Advisor: Steven Gutschlag 27 April 2005

2. Outline • Project Summary • Division of Labor • Functional Description • Block Diagrams • Subsystems • Test Results • Parts List • Questions?

3. Project Summary • Providing a test platform for active/passive suspension system • Testing vehicle suspension system • Actuator driven and micro-controller based • Common feedback control applications • CNC fabrication machines • Aviation control

4. Division of Labor • Craig • Design and build power electronics to drive a 115 Volt DC motor • Microcontroller isolation circuitry • H-Bridge design • Control algorithm • Testing and debugging • Mike • Microcontroller based feedback control system • Control Algorithm • A/D converter • PWM (Timer 2) • Testing and debugging

5. Functional Description • Microcontroller feedback system ensures proper output independent of load. • The mode of operation will be determined by the user via a keypad on the micro-controller. • Sinusoidal • Step • Triangular • Flexibility in selecting desired speed and travel distance of the platform

6. Overall Control Block Diagram Pe Pi Pa Perror = Pinput – Pactuator Output (Platform Position)

7. System Block Diagram Analog Position Input Keypad Input (Desired Platform Motion) A/D Converter Display ( user input) EMAC Micropac 535 Micro-Controller Interface Power Electronics Output (Platform Motion) Test Platform POSITION FEEDBACK

8. Hardware Subsystem

9. Hardware Configuration Power MOSFETS

10. 4N25 Phototransistor Optocouplers • Infrared emitting diode driving a phototransistor • Provides voltage isolation between the microcontroller and the IR2213

11. IR640NPower MOSFET’s • Drain to Source Voltage Max = 200 Volts • Continuous Drain Current Max = 18A

12. IR2213 High & Low Side DriverConfiguration • Load supply voltage up to +1200 volts • N-Channel MOSFETs (Faster & Cheaper)

13. IR2213 High & Low Side Driver Charge Pump Bootstrap Circuit Decoupling Capacitors Decoupling Capacitor

14. H-Bridge IR 2213 (Signal to MOSFETs) IR 2213 (Signal to MOSFETs) Vcc A B ON ON ON ON C D Gnd

15. Software Subsystem

16. Initializes the microcontroller Setups interrupt vector tables Setups necessary peripherals Configures interrupt priority Jumps to main module Setup Module

17. Main Module • Welcomes the user • Prompts the user platform parameters • Amplitude and frequency • Waveform (single or continuous)

18. Keypad Module • EX1 interrupt handler • Fetches keys pressed via kpad subroutine • Translates keys to ASCII equivalent • Performs necessary task for each key • Key A = Single Step input • Key B = Backspace • Key C = Continuous waveform input • Key D = Stop suspension • Key E = Start suspension

19. Lcd Module • Displays prompts • Displays user’s entries

20. Timer 2 Module • Configuration • Auto reload , mode 0 • Compare mode 1 (16 bits) • Subroutines • PWM Subroutine • Timer 2 interrupt handler • EX4 interrupt handler (when T2 register = CC1) • EX5 interrupt handler (when T2 register = CC2)

21. PWM Subroutine • Generates two PWM signals at P4.1 and P4.2 • Decides which one to turn on, via direction flag • Generates three interrupts • T2 interrupt (overflow) • CC1 = T2  EX4 interrupt • CC2 = T2  EX5 interrupt

22. PWM Subroutine • Checking direction flag • Forward Pwm • Reverse Pwm

23. Timer 2 interrupt handler

24. EX4 interrupt handler Forward PWM

25. EX5 interrupt handler Reverse PWM

26. A/D Module • Determines status of direction flag • A/D_pi • Fetches input signal from AN0 • A/D_pa • Fetches position feedback from AN2

27. Control Block Diagram Gain Input Voltage Signal Representing the Desired Platform Motion (Provided by the Waveform Generator) Output (Platform Motion) Old Duty Cycle

28. Suspension Module • DC_new = DC_old + K * Pe • Pe = Pi – Pa (Pi > Pa, clr dir flag, forward PWM) • DC_new = DC_old – K *Pe • Pe = Pa – Pi (Pa > Pi, setb dir flag, reverse PWM)

29. Test Platform Subsystem

30. Rated DC Motor Specifications • RPM Max 1725 • Horse Power 1/3 • Volts 115 • Amps 3.4

31. Screw Jack Specifications(Nook Industries) • 18 Inches of Stroke Length • Gear Ratio 5:1 • Turns of worm per inch travel = 10 • Max Horse Power 1/3 • Max load = 1000 Lbs • Max worm speed at rated load = 868 RPM • Max load at 1750 RPM = 496 lbs • Assembled with a top plate

32. Without Top Plate With Top Plate Inch Ball Screw Jack

33. Preliminary Experimental ResultsElectrak mini actuator Pi = Input signal Pa = Actuator Position

34. Sinusoidal Input Pi = Input signal Pa = Actuator Position

35. Triangular Input Pi = Input signal Pa = Actuator Position

36. Parts List • Micro Pac 535 (EMAC Kit # 5) • High and Low Side Driver (IR2213) • Phototransistor (4N25) • N-channel Power MOSFETS (IR640) • Electrak mini actuator • Screw Jack (0.5HL-BSJU) • DC Motor (437698-AW)

37. QUESTIONS ?