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

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

P07307: Project Description Develop 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 will consist of 2 accelerometers mounted: center of gravity & front right wheel 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: Matches the valving requirements for regular shocks (1-6) Max. damping co-efficient ≈ 240 lbs@ 8in/sec Min. damping co-efficient ≈ 50 lbs@ 8in/sec - Easy to modify: System parameters can be easily modified before the race begins

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 Proposed Mitigations: Add yaw rate sensor to detect turns Determine response time through shock dyno or in the final implementation on the car Add software logic to return shock to “safe” state and LED indicator

P07307: Product Development Process Phase Phase 0/1: SD I -planning, concept development, system-level design Phase1: Detail design- finalizing full system design/ PCB layouts/ cabling Phase 2: Testing & refinement- Assembly of PCB, system interfacing, bench testing Phase 3: Integration into car and testing Current Phase of Project Development 1 2 3 MSD I MSD II

P07307: Current State of Design Design is feasible and meets most customer requirements except: Bump sense: may not sense during power sliding Design meets all engineering specifications for the full system and subsystems except: Response time: could be over 25ms Available project budget is $1000 Project BOM budget: $740 Extra evaluation board for demo/bench test: $150-$200 Mitigations for non-compliances Can still respond to turns and bumps in straightaway

P07307: Budget Distribution

P07307: MSDII Project Schedule Milestones Mar 2: Order Materials and Components Mar 23: Finalize full Detailed Design (PCB Layout) Mar 30: Machine Shock Fixtures & Order PCBs April 13: Assemble and Bench Test PCBs (system with rough software) April 20: Software Interfacing & Data Collection on Tensile Tester April 21: System Case Mounting, Field Testing April 28 (end of 7th week): Overall software integration for Control System May18: Documentation, Final Project Review