Single-Wheel Brake Lockup for Severe Yaw Correction
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Solution Overview
Problem
Conventional vehicle stability control systems, such as ESC, often fail to provide sufficient yaw correction in severe understeer or oversteer situations, limiting their ability to maintain vehicle control and stability, especially when conventional wheel lockup is avoided.
Innovation Solution
The system employs intentional wheel lockup on selected wheels to create a greater yaw moment by applying sufficient brake torque to correct understeer or oversteer conditions, determining the required yaw moment and duration of lockup to achieve the desired vehicle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESC systems avoid wheel lockup to maintain vehicle stability, then vehicle directional control is preserved, but yaw correction capability becomes insufficient in severe understeer or oversteer situations
Solution Approach 1:
The patent inverts the conventional ESC approach by intentionally allowing wheel lockup to occur. Instead of preventing lockup to maintain stability, the system deliberately induces lockup on selected wheels to generate maximum yaw moment for correcting severe understeer or oversteer conditions, thereby resolving the contradiction between maintaining directional control and achieving sufficient yaw correction
Solution Approach 2:
The system dynamically changes the braking parameter from controlled slip ratio (conventional ABS/ESC) to complete wheel lockup. By transitioning the wheel braking state from rolling with controlled slip to full lockup, the system achieves maximum friction force and yaw moment generation capability, enabling effective correction of severe stability deviations
2Object-generated harmful factors
If wheel lockup is intentionally induced to create greater yaw moment, then yaw correction capability is enhanced, but risk of loss of control increases
Solution Approach 1:
The patent applies local quality by inducing wheel lockup only on specifically selected wheels rather than all wheels. The control system identifies which wheel(s) will generate the most effective yaw moment for correcting the current stability deviation and applies lockup only to those wheels, thereby achieving maximum correction capability while maintaining overall vehicle control stability
Solution Approach 2:
The system continuously monitors vehicle state parameters including yaw rate, steering angle, and wheel speeds to detect understeer or oversteer conditions. This feedback mechanism enables the control system to determine when wheel lockup is necessary, select which wheels to lockup, and monitor the correction effect, thereby enhancing yaw correction capability while preventing loss of control through real-time adjustment
3Reliability
If brake torque is applied to lockup a single wheel to correct understeer or oversteer, then vehicle stability is improved, but complexity of control system increases
Solution Approach 1:
The patent segments the vehicle's four wheels and treats them individually for stability control purposes. Rather than applying uniform braking to all wheels or using complex multi-wheel independent control, the system identifies a single critical wheel whose lockup will generate the necessary yaw moment, thereby improving vehicle stability while avoiding excessive control system complexity
Solution Approach 2:
The system applies partial action by using wheel lockup on only one wheel rather than all wheels. This selective approach provides sufficient yaw moment for correction in most severe stability situations while keeping the control logic relatively simple. The system may escalate to locking additional wheels if the single-wheel lockup proves insufficient
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
This approach enhances vehicle control and stability by providing more aggressive correction than conventional ESC systems, allowing for improved handling and mitigation of accidents, especially in autonomous driving scenarios where additional control inputs like steering can be integrated.
Implementation Method 1
applying a brake torque to a single wheel of the vehicle, wherein an amount of brake torque applied is sufficient to lock up the single wheel to create a yaw moment on the vehicle
Data Source
AI summary
Systems and methods for controlling a vehicle may include receiving sensor data from a plurality of sensors, the sensor data including vehicle parameter information for the vehicle; using the sensor data to determine a vehicle state for a vehicle negotiating a corner, wherein the vehicle state comprises information regarding a magnitude of an effective understeer gradient for the vehicle; computing a yaw moment required to correct the effective understeer gradient based on the magnitude of the effective understeer gradient; and applying a brake torque to a single wheel of the vehicle, wherein an amount of brake torque applied is sufficient to lock up the single wheel to create a yaw moment on the vehicle to achieve the computed yaw moment required to correct the effective understeer gradient.