Active Suspension SystemJosh Rose, Xander Serrurier, Rhydon Vassay, Chase Ramseyer

Advisor: Steven Gutschlag4/27/2017

Outline

1. Project Summary

2. Previous Work

3. Functional Description

4. System Block Diagram

5. Work Completed/Results

6. Future Work

7. Questions

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Project SummarySuspension Systems

● Purpose○ Used to support the chassis of a vehicle on

its axles○ Used to prevent chassis movements

caused by road imperfections to the car’s passengers

● Primary types○ Passive○ Active○ Hybrid (semi-active)

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Suspension system type Passive suspension system Semi-active suspension system

Active suspension system

Regulatory element General shock absorber Adjustable damping Hydraulic system or Servo motor system

Action principle Damping constant Damping continuously adjustable

Adjust the force between wheel and vehicle body

Control method No Hydraulic Electronics or fluid control

Bandwidth Unknown Up to 20Hz > 15Hz

Energy consumption Zero Minimal Significant

Lateral dynamics control Poor Moderate Good

Vertical dynamics control Poor Moderate Good

Cost Lowest Middle Highest

Project SummarySuspension Systems

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Project SummaryObjectives

● Redesign existing active suspension system● Design/implement safety measures● Design power electronics to operate existing

hardware● Develop rudimentary control software

● Real-time disturbance minimization● Applications

○ Cars, tractors, off-road vehicles○ Chassis suspension○ Cab/seat suspension

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Project SummaryACTSS Overview

● Developed power electronics○ H-bridge○ Snubber circuits○ Isolation circuits

● Developed proportional control system● Disturbance cancelled:

○ 75% with load○ 87.5% without load

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Project SummaryPrevious Work

Previous WorkHardware Specifications

● EMAC Micropac 535○ 11MHz on-board crystal○ Separate LCD/keypad interfaces○ 8 10-bit ADC channels○ 24 digital IO○ 3 EIA-232 serial ports○ Programmed in Assembly

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● MSK4227 H-Bridge○ 200V, 20A rating (Tc = 25° C)○ 20µA logic input current○ 1µs minimum switching dead time

required○ Direct-mounted heatsink with forced

convection

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Previous WorkHardware Specifications

● 4N25 Optical Isolator○ 5V supply voltage○ 10mA enable current○ Max 70V output○ 50mA output current○ 2µs switching speed○ 5000V isolation voltage

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Previous WorkHardware Specifications

● IDC EC2-H Electric Cylinder○ 160V DC, 12A○ 3600N max thrust○ 930mm/sec max no load speed

■ 1 in/ 27.2ms○ 5.0N-m max torque

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Previous WorkHardware Specifications

● Position Sensors (P1613)○ Light duty potentiometer○ 2 in bidirectional travel○ 2K Ohms

● 3-Phase Motor (4Z394)● Camshaft (VPLE-212)

○ 1in displacement

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Previous WorkHardware Specifications

● Atmel ATmega 128 Microcontroller○ Personal extensive experience○ Code development in embedded C○ 6MHz on-board crystal○ 8 10-bit ADC channels○ 53 digital IO channels○ 2 serial ports

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Current Hardware List

● 6N137 Optical Isolator○ 5V supply voltage○ 15mA enable current○ Logic-level output○ 50mA output current○ 10Mega-Baud switching speed○ 5300V isolation voltage

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Current Hardware List

Functional DescriptionSystem Overview

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System Block DiagramsSubsystem Overview

PWMAD

C

Upper Position Sensor

Pow

er

Ele

ctro

nics

Act

uato

r

Upper Platform

Keypad Microcontroller

Em_Stop

Linear Actuator

PWM

Mot

or

Lower Position Sensor

LCD

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System Block DiagramsConceptual Flow Chart

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System Block DiagramsH-Bridge Overview

NC

NC

+VCC

+VB

HINA

LINA

HINB

LINB

COM

COM

V+

V+

B0

B0

A0

A0

BV-

BV-

AV-

AV-

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Work Completed/ResultsH-Bridge Isolation

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Gate Drive Circuit

HINA

LINA

LINB

HINB

Work Completed/ResultsH-Bridge With Isolation

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H-bridge output(e.g. A0)

Optical Isolator output

Switching Signal(From Function Generator)

Work Completed/ResultsH-Bridge Testing

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Work Completed/ResultsTesting the Potentiometer

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Work Completed/ResultsVoltage Regulator Circuits

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Work Completed/ResultsSnubber Circuit

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Work Completed/ResultsPSpice Simulations

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Work Completed/ResultsPSpice Simulations

Load Current

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Work Completed/ResultsPSpice Simulations

Load Voltage

● PWM creation○ Timer/count match interrupt

● Feedback○ ADC interrupt

● User interface○ Keypad○ LCD○ External interrupts

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Work Completed/ResultsSoftware

SoftwarePWM Creation

● Timer/counter 1 ○ Fast PWM mode

● Output compare○ OCCR1A○ OCCR1B

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● ADC interrupt○ Indicates conversion

complete● Calculation

○ Input from potentiometer○ Determines position based

on voltage

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SoftwareFeedback (ADC)

● Run with control system

● Run without control system

● Manually extend/retract actuator

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SoftwareUser Interface

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ResultsSimulations

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ResultsSimulations

● Physical isolation● Reduced reaction time● Heat dissipation● Emergency control

○ Limit switches○ Emergency stop

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ResultsSafety Design

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ResultsSafety Design

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Part Description Quantity Cost ($) Supplier Purchased

Atmega128A Dev Kit Microcontroller and Development Board

1 39.99 Waveshare Y

Keypad Keypad 1 7.49 Vetco Y

LCD (HD44780) LCD Display 1 5.28 Ebay Y

AVR Dragon Atmega128 Programmer 1 53.75 Mouser Y

MSK4227 H-Bridge 1 Unavailable MSK N

PS21A79 Replacement H-Bridge 2 73.47 Digikey Y

6N137 Optical Isolator 4 0.49 Mouser N

IDC Electric Cylinder EC2H Linear Actuator 1 540.00 Amazon N

Maurey Linear Motion Sensor P1613

Position Sensor 2 300.00 Process Industrial Surplus Corp N

Maxi-Torq 4z394 3-Phase Motor 1 535.00 Amazon N

VPLE-212 Camshaft 1 83.10 Motion Industries N

Parts List

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Part Description Quantity Cost ($) Supplier Purchased

ADXL335 Accelerometer 1 9.90 Digikey Y

51-256.025 Emergency Stop 23.91 Newark Y

HEV2AN-P-DC24V Power Relay 1 66.47 Newark Y

MY4N-D2-DC24 4 Pole Relay 2 30.73 Digikey N

NBF-32016 Enclosure 1 22.20 Amazon Y

LM317 Voltage Regulator 2 0.71 Digikey N

7805 Voltage Regulator 1 0.62 Digikey N

7815 Voltage Regulator 1 0.64 Digikey N

EE80251S2-000U-999 Cooling Fan 1 3.42 Digikey N

Parts List

Total Cost $445.45

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Task Worked on by Completed

Research All Yes

Software Development Xander, Chase Yes

Test Actuator Rhydon, Josh Yes

Test H-Bridge All Yes

Test Position Sensors Josh, Rhydon Yes

Snubber Circuit Design Rhydon, Josh Yes

PSpice Simulations Josh Yes

Develop Rudimentary Control System Xander, Chase Testing

Safety Design Chase, Josh Yes

Assemble System All Yes

Run Test Cases on System All Testing

Documentation All Yes

Division of Labor

● Design/mount additional physical safety measures○ Front shield○ Top shield

● Develop a more complex position-based control scheme

● Design and implement an acceleration-based control system using an accelerometer

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Future Work

● Previous Senior Projects:○ Patrice Jackson and Shawn Downey (2003)

http://ee.bradley.edu/projects/proj2003/vanchoco/

○ Blake Boe and Tyson Richards (2006)

http://ee.bradley.edu/projects/proj2006/actss/

● Research Papers○ [1] W.K.N. Anakwa. “Development and Control of a

Prototype Pneumatic Active Suspension System.” Bradley University, IL, Oct. 2001.

○ [2] Q. Zhou. “Research and Simulation on New Active Suspension Control System.” Lehigh University, PA, 2013.

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References

Questions?

Regulator Power Calculations

P12V = 2.328WP15V = 0.030WP5V = 0.114W

TJ = PRJA + TA

T12V = 106.48 ℃

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Actuator Motion

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