Turning Controller for Multi-Wheel Vehicles
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Solution Overview
Problem
Existing steer-by-wire systems for vehicles with multiple independently turning wheels face challenges in maintaining vehicle controllability when a malfunction occurs, particularly in vehicles with three or more wheels, as they do not effectively manage drive limitations across all wheels, leading to potential loss of control and inability to follow a target trajectory.
Innovation Solution
A turning controller system that includes independent turning actuator controllers for each wheel, which communicate and coordinate drive limit information to ensure that each actuator operates within safe limits, allowing for balanced control of wheel angles and currents, even when one actuator is limited, thereby maintaining vehicle controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each turning actuator operates independently without coordination, then the system structure is simple and ease of operation is improved, but vehicle controllability deteriorates when one actuator is limited
Solution Approach 1:
The patent combines independent actuator control with coordinated limit management by having each actuator controller communicate drive limit information to others. When one actuator is limited, the controllers coordinate to adjust other actuators accordingly, merging individual independence with system-wide coordination to maintain controllability.
Solution Approach 2:
The system implements feedback by having actuator controllers continuously monitor and communicate drive limit status among themselves. When a limit is detected in one actuator, the feedback mechanism allows other actuators to adjust their operation accordingly, maintaining overall system controllability while preserving independent operation capability.
2Device complexity
If drive limits are not coordinated across multiple wheels, then device complexity is reduced, but the system cannot maintain target trajectory under malfunction conditions
Solution Approach 1:
The actuator controllers are designed with multi-functionality, serving both independent control and coordinated limit management functions. Each controller not only manages its own actuator but also communicates and responds to limit conditions in other actuators, providing universal control capability that maintains trajectory following without excessive complexity.
3Productivity
If the system allows unlimited drive to each actuator, then productivity and responsiveness are improved, but safety and reliability deteriorate due to potential uncontrollable states
Solution Approach 1:
The system dynamically adjusts drive limits based on real-time conditions. When an actuator approaches its limit or experiences a malfunction, the controllers dynamically coordinate to redistribute drive authority among remaining actuators. This dynamic adaptation maintains safe operation while preserving high productivity and responsiveness under normal conditions.
Data Source
AI summary
A turning controller controls turning of each wheel in a vehicle having three or more wheels. The wheels are not mechanically constrained to each other and are turned independently. The turning controller includes turning actuator controllers provided in correspondence with turning actuators for turning each wheel. The turning actuator controllers control a driving current applied to the turning actuators so that a turning angle output by the turning actuator becomes a desired value. A set of a turning actuator and a turning actuator controller corresponding to each of the wheels is a unit. The turning actuator controllers communicates drive limit information, which is information regarding a drive limit of the turning actuator, with each other. The turning actuator controllers also limit a drive of the turning actuator of their own unit based on the drive limit information of their own unit and the other units.