1. P07307: Controls for Dynamic Suspension
Mark Lifson Project Manager
Todd Simon Technical Lead
Kapil Chandersen Engineer
Khue Ho Engineer
Sponsor: After Hour Racing LLC

2. P07307: Design Concept Shock position Coil-over spring
MR shock replacing the mechanically adjustable shock
Rear right tire

3. P07307: Overall Design Power Filtering Circuit
Current Amplifying circuitry
MCU
Accelerometers
Yaw rate sensor

4. P07307: Project Description
Developed a Dynamic Suspension System
- controls the damping co-efficient on a sprint race car
- responds to significant track conditions e.g. banking degree, corner radii, roughness etc.
- suspension system controlled through adjustment of rear right shock
- uses magneto rheological fluid to dynamically adjust the damping co efficient
- sensors consist of 2 accelerometers- mounted: center of gravity & front right wheel, 1 yaw rate sensor
Gives a better control over the sprint car and hence win races
Key high level customer needs / engineering specs:
- Basic Requirements: Max value for current of approx. 1A
Response time ≈ 25ms
Power consumption < 50 watts
System weight < 20lbs
- General Dynamics: System valving requirements for regular shocks (1-6)
System uses valving rating of 3-5 for
regular shocks
Max. damping co-efficient ≈ 240 8in/sec
Min. damping co-efficient ≈ 50 8in/sec

5. P07307: Technical Risk Assessment
Risks:
Ability to accurately sense turns
Ability to sense bumps with front, right wheel
Determination of shock response time
Possible system lockup
Mitigations:
Added yaw rate sensor to detect turns
Determined response time through shock dyno or in the final implementation on the car
Added software logic to return shock to “safe” state and LED indicator

6. P07307: Current State of Design
Robust Design
Design is feasible and meets customer requirements
Would require technical expertise for system modification (software)
Design meets all engineering specifications for the full system except:
Unable to validate response time
Current Limiting Circuit may have Linearity/Stability Issues
Available project budget is $1000
Project BOM budget: $538
Miscellaneous: $170
PCB costs: $155
Remaining Balance: $136

7. P07307: Budget Distribution

8. P07307: Future Enhancements
Improve operator interface (add functionality)
Look into tensile testing of the shock to determine better sampling rate and shock response time
Look into Mechanical Bench testing
Improvement of PCB layout
Addition of further functionality:
More complex control algorithms
Multiple, independent shocks