Vehicle Yaw Rate Arbitration for Steering Actuator Limits
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Solution Overview
Problem
Existing vehicle control systems fail to appropriately control lateral movement when the steering actuator cannot realize the intended steering command, leading to unexpected vehicle behavior and reduced responsiveness.
Innovation Solution
A vehicle control device that acquires steering angle and yaw rate as control commands from driving support applications, allowing parallel control of brake or drive actuators to manage lateral movement, even if the steering actuator cannot achieve the desired steering angle, by distributing braking or driving force between wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the steering actuator is controlled based on the steering angle from the arbitration unit, then the steering command is executed, but the vehicle lateral movement cannot be appropriately controlled when the steering actuator fails or cannot realize the intended steering angle
Solution Approach 1:
The system changes the control parameter from steering angle (geometric parameter) to yaw rate (dynamic parameter). When the steering actuator cannot achieve the desired steering angle, the arbitration unit switches to controlling the vehicle's yaw rate through differential braking or drive forces, thereby maintaining lateral movement control capability despite steering actuator limitations
Solution Approach 2:
The control system segments the lateral movement control function into two independent pathways: steering angle-based control through the steering actuator, and yaw rate-based control through brake/drive actuators. This segmentation allows the system to select the appropriate control pathway based on steering actuator availability and performance
2Device complexity
If only the steering actuator is used for lateral movement control, then the control system is simple, but the vehicle behavior becomes unexpected when the steering actuator cannot realize the intended steering angle
Solution Approach 1:
The brake actuators and drive actuators, originally designed for longitudinal vehicle control, are given the additional function of lateral movement control through yaw rate control. This multi-functionality allows the system to maintain lateral control capability even when the steering actuator is unavailable or insufficient
3Ease of operation
If the steering angle exceeds the maximum steering angle of the steering actuator, then the arbitration unit can still issue the command, but the actual steering angle deviates from the commanded angle
Solution Approach 1:
The system implements feedback control by continuously monitoring the actual steering angle and comparing it with the commanded steering angle. When the deviation exceeds a threshold or the commanded angle exceeds the maximum steering angle, the arbitration unit detects this discrepancy and switches to yaw rate control mode, using feedback from yaw rate sensors to maintain accurate lateral movement control
Data Source
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AI summary
The vehicle control device includes an arbitration unit (21) configured to arbitrate between a plurality of control commands acquired from a plurality of driving support applications that respectively implements driving support functions, configured to output instructions based on a control command after arbitration to a first control unit (33) that is able to control a steering actuator (43) and a second control unit (31, 32) that is able to control at least one of a brake actuator (42) or a drive actuator (41), and configured to acquire a steering angle and a yaw rate as the control commands from the driving support applications.