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Dynamic Traction Control. By: Thiago Avila, Mike Sinclair & Jeffrey McLarty. Drastically improve vehicle performance and safety by maintaining optimal wheel traction in all road conditions. Motivation. Motivation.
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Dynamic Traction Control By: Thiago Avila, Mike Sinclair & Jeffrey McLarty
Drastically improve vehicle performance and safety by maintaining optimal wheel traction in all road conditions Motivation
FSAE car is currently traction limited and would benefit from the use of a traction control system • System must follow FSAE guidelines • Minimal cost solution should be pursued Needs Assessment
Meet FSAE Guidelines • Predict slip with enough time to adjust engine output • Reduced FSAE 75m acceleration times • Improve FSAE skid pad testing results Design Criteria and Constraints
The traction control system is required to prevent driver error from overloading any of the four wheels and causing slip, through either throttle or brake application Problem Formulation
Physics model sensors • 3-axis Accelerometer • Linear Potentiometer Cost & Complexity • Engine Power Control • Cutting Spark Difficult to Predict Power • Limiting Fuel Improper Fuel Ratio • Drive by wire throttle Infringes FSAE rules • Electronic Air Restrictor Abstraction
Slip Model • Vehicle Dynamics and Sensing • Vehicle Control • Electronic Restrictor Proposed Solution Breakdown
Slip Model • Dynamic Physics Model • Dynamic Coefficient of Friction • Understeer Detection Proposed Solution
Slip Angle Radius External Sensors X/Y/Z Acceleration - CBR 600 F4i Engine Physics Model (Saturator) Driver Pedal Wheels + RPM Throttle Pos. μs/μk Wheel Slip Detector ECU Design Layout
Engine Speed • Interpolate Between Four Points on Torque Map • Interpolate between Engine Speeds at Throttle 1 Throttle Interpolation
Engine Speed • Interpolate Between Four Points on Torque Map • Interpolate between Engine Speeds at Throttle 1 • Interpolate between Engine Speeds at Throttle 2 Throttle Interpolation
Engine Speed • Interpolate Between Four Points on the Torque Map • Interpolate between Engine Speeds at Throttle 1 • Interpolate between Engine Speeds at Throttle 2 • Interpolate between results at different Throttles Throttle Interpolation
Engine Speed • Interpolate Between Four Points on the Torque Map • Interpolate between Engine Speeds at Throttle 1 • Interpolate between Engine Speeds at Throttle 2 • Interpolate between results at different Throttles Throttle Interpolation
Engine Speed • Interpolate Between Four Points on the Torque Map • Interpolate between Engine Speeds at Throttle 1 • Interpolate between Engine Speeds at Throttle 2 • Interpolate between results at different Throttles • Engine Power from 4 point Interpolation = Done Throttle Interpolation
Installed Sensors • Steering Wheel Angle • 2-D Acceleration • Suspension Deflection • Wheel Velocity • Brake Pressure • Engine RPM • Throttle Position • Air Mass Flow Rate Data Acquisition
Calculate Engine Torque @ T(0) Slip Detected Calculate Vertical Force @ T(0) Calculate Coefficient of Friction and Update Model μs Dynamic Coefficient of Friction Calculator
Maintain current μs No Slip Detected Is μs at the limit? Increase μs Yes No Initial Value New Limit Calculated Values Optimize Performance
Turning Radius: • Desired vs. Actual • Major Factor: • Wheel Slip Angle Understeer Detection
Vehicle Control • Electronic Restrictor • Brake Pressure Controller Proposed Solution
Rotary Potentiometer Servo Gears Butter -Fly- Valve Electronic Restrictor
Slip Angle Radius External Sensors X/Y/Z Acceleration - CBR 600 F4i Engine Physics Model (Saturator) Driver Pedal Wheels + RPM Throttle Pos. μs/μk Wheel Slip Detector ECU Patents
Slip Angle Radius External Sensors X/Y/Z Acceleration - CBR 600 F4i Engine Physics Model (Saturator) Driver Pedal Wheels + RPM Throttle Pos. μs/μk Wheel Slip Detector ECU Possibly patentable: Continuously Improving Predictive Traction Control Patents
Start Order Parts & Materials Program PSoC with Physics Model & Interpolation 1 day 3.5 weeks Finish Build Restrictor Install Restrictor 2 weeks 1 week Test & Optimize Create Controller based on Design Criterion 4 weeks 2.5 weeks Commissioning Critical Path ~10 weeks The Plan
Questions? Comments?
The End Thank you!