Redundant Steering Assist Current Control Under Controller Failure
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Solution Overview
Problem
Existing steering control systems with redundant controllers face issues of reduced steering assistance power when a specific controller fails, leading to overheating and potential damage to normal controllers, and delayed steering response times.
Innovation Solution
A steering assist system with multiple steering control devices that include a fail recognition mechanism to adjust command currents based on the status of other devices, applying reduced currents when a failure occurs to prevent overheating and ensure stable steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundant system with two or more controllers is implemented to improve driving stability, then steering control reliability is improved, but the risk of overheating and damage to normal controllers increases when a specific controller fails
Solution Approach 1:
The system dynamically adjusts the command current applied to the steering motor based on the operational status of controllers. When one controller fails, the remaining normal controller increases its command current to compensate for the failure, while implementing a preset application pattern to prevent overheating. This dynamic current adjustment resolves the contradiction by maintaining steering reliability through adaptive current control while preventing thermal damage.
Solution Approach 2:
The system applies command current to the steering motor according to a preset application pattern when a controller failure is detected. This periodic or pulsed current application rather than continuous full current prevents excessive heat generation in the normal controller while still providing sufficient steering assistance. The periodic action resolves the contradiction between maintaining control reliability and preventing thermal damage.
2Power
If full command current is applied to the steering motor when a controller fails to maintain steering performance, then steering assistance power is maintained, but the normal controller may overheat and be damaged
Solution Approach 1:
When a controller failure is detected, the system applies a command current that exceeds the normal operating current (partial excessive action) to maintain steering assistance power, but implements a preset application pattern that limits the duty cycle or duration of current application. This prevents the normal controller from overheating while still providing sufficient steering power during critical situations.
Solution Approach 2:
The system changes the command current parameters (magnitude, duration, or duty cycle) based on the operational status of controllers. When one controller fails, the remaining normal controller adjusts current parameters to provide adequate steering assistance while preventing thermal damage through reduced duty cycle or pulsed application. This parameter adjustment resolves the contradiction between maintaining power and controlling temperature.
3Object-affected harmful factors
If command current is reduced to prevent overheating when a controller fails, then controller damage is prevented, but steering response time may be delayed
Solution Approach 1:
The system uses periodic or pulsed command current application with optimized timing to minimize steering response delay while preventing controller overheating. The preset application pattern is designed to provide sufficient current during critical steering moments while allowing thermal management during less critical periods, thus resolving the contradiction between response time and temperature control.
Data Source
AI summary
The present disclosure relates to a steering assistance system, a steering control device, and a steering control method. Specifically, the steering control device according to the present invention calculates a target rack stroke on the basis of steering information input by a driver and calculates a target instruction current according to the target rack stroke, wherein different instruction currents are calculated depending on whether other steering control devices fail, and are applied to a steering motor according to predetermined application patterns.