Vehicle Traction Control via Brake Torque Modulation
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Solution Overview
Problem
Conventional vehicle traction control systems fail to effectively manage wheel slip in low-friction conditions, particularly for novice drivers, leading to excessive wheel spin and potential damage to surfaces like grass, and struggle to maintain traction in varying friction environments.
Innovation Solution
A control system that applies both brake torque and drive torque to wheels to maintain a controlled slip within a predetermined range, adjusting based on surface characteristics and vehicle speed, using a combination of electric machines, friction-based braking, and powertrain modulation to prevent excessive wheel spin and ensure traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If drive torque is applied to wheels in low-friction conditions, then vehicle motion is initiated, but excessive wheel spin occurs leading to loss of traction
Solution Approach 1:
The system applies brake torque in advance to counteract the tendency of wheels to spin excessively when drive torque is applied. The brake torque is modulated to maintain wheel slip within an optimal range, preventing loss of traction before it occurs.
Solution Approach 2:
The control system dynamically adjusts the ratio of brake torque to drive torque based on wheel slip conditions, surface friction characteristics, and vehicle speed. This parameter modulation optimizes traction by maintaining wheel slip within a predetermined range that maximizes friction utilization.
2Reliability
If brake torque is applied to prevent wheel spin, then traction is maintained, but vehicle acceleration is reduced
Solution Approach 1:
The system dynamically modulates brake torque in real-time based on wheel slip feedback, allowing aggressive braking when slip exceeds the optimal range and reducing brake torque when slip is within the optimal range. This dynamic adjustment maximizes acceleration while maintaining traction control.
Solution Approach 2:
The control system continuously monitors wheel slip and uses this feedback to adjust the brake torque application. When wheel slip is within the optimal range, brake torque is reduced or eliminated, allowing maximum acceleration. When slip exceeds the range, brake torque is increased to restore optimal slip conditions.
3Ease of operation
If conventional traction control is used by novice drivers, then vehicle operation is simple, but excessive wheel spin occurs due to lack of driver awareness
Solution Approach 1:
The system automatically monitors wheel slip conditions and adjusts brake and drive torque without driver intervention. The control system self-regulates to maintain optimal traction, eliminating the need for novice drivers to manually manage wheel spin while preventing the harmful effects of excessive slip.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reduces the risk of wheel flare, maintains effective traction, and allows smooth vehicle progression over low-friction surfaces by finely controlling wheel slip, ensuring stable vehicle motion and minimizing surface damage.
Implementation Method 1
friction-based braking
Implementation Method 2
electric machines
Data Source
AI summary
A method of setting a vehicle in motion over a driving surface and/or maintaining motion of said vehicle over the driving surface implemented by a control system, said method comprising initiating motion control, initiating motion control comprising: commanding by the control system application of brake torque and drive torque to one or more wheels such that the vehicle is held stationary; subsequently initiating motion from rest while brake torque continues to be applied to the one or more wheels. The strategy may also be implemented to maintain vehicle progress on low friction surfaces. The vehicle driver may be commanded to vary a control input, such as accelerator pedal position, in order to facilitate the maintaining of progress.