Backup Steering Control Using Wheel Braking During ABS Disable
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Solution Overview
Problem
Autonomous vehicles lack a reliable manual intervention mechanism to counteract malfunctioning steering systems, potentially leading to hazardous situations.
Innovation Solution
A backup motion control system that determines the difference between current and desired vehicle motion, disables the anti-lock braking system, and engages the wheel brakes of steerable wheels to stabilize the vehicle and maintain a straight path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anti-lock braking system is enabled to prevent wheel lock during braking, then braking safety is improved, but the ability to apply maximum brake force for emergency steering correction is reduced
Solution Approach 1:
The system dynamically switches the anti-lock braking system between enabled and disabled states based on the vehicle's operational context. During normal braking, ABS is enabled to prevent wheel lock. During emergency steering malfunction scenarios, the system disables ABS to allow maximum brake force application, achieving optimal performance for each operational state
Solution Approach 2:
The system changes the operational parameter of the anti-lock braking system from a fixed enabled state to a dynamically adjustable state. By modifying the ABS intervention threshold or disabling it entirely during emergency steering correction, the system allows wheel lock and maximizes brake force, resolving the contradiction between braking safety and emergency correction capability
2Stability of the object's composition
If a backup motion control system disables ABS and engages wheel brakes to correct steering malfunctions, then vehicle stability is improved, but the risk of wheel lock and loss of steering control increases
Solution Approach 1:
The system applies preliminary anti-action by disabling the anti-lock braking system before engaging the wheel brakes for emergency correction. This preemptive measure prevents ABS from interfering with the maximum brake force application needed for steering correction, while the system accepts temporary loss of steering control as a necessary trade-off for vehicle stability
Solution Approach 2:
The system converts the harmful effect of wheel lock (which normally indicates braking failure) into a beneficial emergency correction mechanism. By intentionally allowing wheel lock through ABS disablement, the system creates a controlled skid that can stabilize the vehicle during steering malfunction, transforming a failure mode into a safety feature
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 solution effectively handles steering malfunctions by maximizing brake force and saturating friction in the longitudinal direction, preventing the vehicle from leaving its lane and ensuring safe operation.
Implementation Method 1
maximizing brake force and saturating friction in the longitudinal direction
Data Source
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AI summary
The present invention relates to a method of controlling a backup motion control system for an autonomous vehicle, the autonomous vehicle comprising a primary steering system for controlling steering operations of a pair of steerable wheels, wherein each of the steerable wheels comprises a wheel brake, the wheel brakes being connected to an anti-lock braking system for preventing the wheel brakes from being locked when the anti-lock braking system is arranged in an enabled state, the method comprising determining a current motion for the autonomous vehicle, the current motion being generated by a steering operation of the pair of steerable wheels caused by the primary steering system; comparing the current motion with a desired motion for the autonomous vehicle; and when a difference between the current motion and the desired motion exceeds a predetermined threshold limit: controlling the anti-lock braking system for the wheel brakes of the steerable wheels to be arranged in a disabled state; and engaging the wheel brakes of each of the steerable wheels.