Brake-Based Backup Steering for Autonomous Vehicle Yaw Control
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Solution Overview
Problem
Existing autonomous and semi-autonomous vehicles lack effective redundancy in steering systems, as primary and secondary steering systems may fail to perform desired functions, posing safety risks during vehicle operation.
Innovation Solution
The method employs brake pressure and propulsion energy to steer the vehicle by converting steering requests into desired yaw rates, curvatures, or accelerations, using a lateral control module to deliver signals to brake calipers or propulsion systems, thereby providing an alternative steering mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary and secondary steering systems are used in autonomous vehicles, then steering functionality is provided, but reliability is reduced because these systems may fail and lack effective redundancy
Solution Approach 1:
The brake system is designed to perform its primary function of deceleration while also serving as a backup steering mechanism. The lateral control module enables the brake system to generate yaw moments by selectively applying brake pressure to individual wheels, allowing one system to fulfill multiple functions and improve overall reliability without adding dedicated backup steering hardware.
Solution Approach 2:
The lateral control module acts as an intermediary between the brake system and steering function. It receives steering commands and translates them into appropriate brake pressure distributions across individual wheels, enabling the brake system to produce yaw moments that achieve the desired steering effect while maintaining system reliability.
2Reliability
If brakes are used to steer the vehicle as a backup system, then reliability is improved by providing alternative steering capability, but device complexity increases due to the need for lateral control module and individual wheel brake control
Solution Approach 1:
The lateral control module is designed to manage multiple functions including normal braking, stability control, and backup steering. By consolidating these functions into a single control system that can operate in different modes, the patent avoids the need for separate dedicated systems for each function, thereby improving reliability without proportionally increasing overall system complexity.
Solution Approach 2:
The brake system serves itself by using its existing components (brake calipers, hydraulic pressure systems, sensors) to perform the backup steering function. Rather than requiring entirely separate actuators and mechanisms, the system leverages its own infrastructure to provide redundant steering capability, reducing the complexity increment associated with adding backup functionality.
3Measurement precision
If individual caliper brake control is implemented for backup steering, then steering precision is improved by enabling differential brake pressure application, but ease of operation is reduced due to complex brake pressure calculation and delivery
Solution Approach 1:
The lateral control module serves as an intelligent intermediary that automatically performs the complex calculations and decision-making required for differential brake application. It receives high-level steering commands, computes the appropriate brake pressure distribution across individual wheels based on vehicle dynamics models, and executes the control without requiring manual intervention from the driver or operator, thereby maintaining precision while simplifying operation.
Solution Approach 2:
The system replaces manual mechanical steering operations with automated electronic brake control. Instead of requiring the driver to physically manipulate steering mechanisms, the lateral control module uses electronic signals to control brake pressure distribution, substituting complex mechanical steering actions with automated electro-hydraulic brake control that achieves the desired steering effect with simpler operator input.
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 safety by enabling continued control and path adjustment even if primary or secondary steering systems fail, allowing the vehicle to be steered to a safer position or maintaining speed and control during system failures.
Implementation Method 1
using brakes to steer the vehicle... calculating at least one of a brake pressure... delivering at least one of a brake pressure... signals... to the individual calipers of at least one brake on a wheel of the vehicle... so that the... brake pressure... yaw the vehicle
Data Source
AI summary
A number of variations may include a method including using at least one of brakes or propulsion energy to steer an autonomous or semi-autonomous vehicle if a primary, secondary or other redundant steering system for an autonomous or semi-autonomous vehicle has failed or is insufficiently unhealthy to perform a desired function, the method including determining if a primary, secondary or other redundant steering system of an autonomous or semi-autonomous vehicle has failed or is not sufficiently healthy to perform a desired function, and if so, converting a steer request into a desired yaw rate, curvature, curvature over time, radius, radius or time or yaw rate acceleration, calculating a brake pressure sufficient to produce the desired yaw rate, curvature, curvature over time, radius, radius or time or yaw rate acceleration, delivering brake pressures signals via a lateral control module to an actuator for at least one brake connected to a wheel of the vehicle so that the brake pressure causes the vehicle yaw at the desired yaw rate, curvature, curvature over time, radius, radius or time or yaw rate acceleration.