Active Suspension System Test Platform Bradley University Department of Electrical & Computer Engineering By: Craig Chan & Olusegun Michael Abidoye Advisor: Steven Gutschlag 27 April 2005

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

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

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

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

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

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

Hardware Subsystem

Hardware Configuration Power MOSFETS

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

IR640N Power MOSFET’s Drain to Source Voltage Max = 200 Volts Drain to Source Voltage Max = 200 Volts Continuous Drain Current Max = 18A Continuous Drain Current Max = 18A

IR2213 High & Low Side Driver Configuration Load supply voltage up to volts Load supply voltage up to volts N-Channel MOSFETs (Faster & Cheaper) N-Channel MOSFETs (Faster & Cheaper)

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

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

Software Subsystem

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

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

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

Lcd Module Displays prompts Displays prompts Displays user’s entries Displays user’s entries

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

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

PWM Subroutine Checking direction flag Forward Pwm Reverse Pwm

Timer 2 interrupt handler Timer 2 interrupt handler

EX4 interrupt handler EX4 interrupt handler Forward PWM Forward PWM

EX5 interrupt handler EX5 interrupt handler Reverse PWM Reverse PWM

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

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

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

Test Platform Subsystem

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

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

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

Preliminary Experimental Results Electrak mini actuator Pi = Input signal Pa = Actuator Position

Sinusoidal Input Pi = Input signal Pa = Actuator Position

Triangular Input Pi = Input signal Pa = Actuator Position

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

QUESTIONS?