Steering Reaction Force Control After Reset Recovery
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Solution Overview
Problem
In steer-by-wire steering devices, the control calculation unit may instantaneously stop due to power source failure or microcomputer reset, leading to unintended steering wheel or turning wheel behavior during the correction process of the steering and turning positions.
Innovation Solution
A steering control device with first and second reaction force control circuits, each executing a preparation process including automatic steering wheel rotation, and storing completion information. Upon reset, if the preparation process was normally completed, the reaction force control circuit skips re-execution, transitioning directly to the control state of the unreset circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the correction process for position relation is executed whenever the control calculation unit returns to normal operating state, then the position relation between steering position and turning position is corrected, but unintended behavior of steering wheel or turning wheels occurs causing driver strangeness feeling
Solution Approach 1:
The patent applies preliminary action by storing completion information of the preparation process before any reset occurs. When a reset happens, the control calculation unit checks this pre-stored information to determine whether the preparation process had been completed before the reset. This allows the system to avoid re-executing the preparation process unnecessarily, thereby preventing unintended behavior while ensuring proper correction when needed.
2Reliability
If the preparation process is re-executed after reset, then the position relation correction is ensured, but the steering wheel or turning wheels exhibit unintended behavior
Solution Approach 1:
The patent implements feedback by having the control calculation unit check the stored completion information after a reset to determine whether the preparation process was already completed before the reset occurred. This feedback mechanism allows the system to intelligently decide whether to re-execute the preparation process, avoiding unnecessary re-execution that would cause unintended behavior while ensuring correction is performed when actually needed.
3Reliability
If the control calculation unit instantaneously stops due to power source failure or reset, then the system recovers to normal operating state, but the correction process may be executed inappropriately
Solution Approach 1:
The patent applies preliminary action by storing the completion information of the preparation process before any reset or power failure occurs. This pre-stored information persists through the reset event, allowing the control calculation unit to recover properly and accurately determine whether the preparation process had been completed before the interruption, thus preventing inappropriate re-execution after system recovery.
Data Source
AI summary
A steering control device includes a first reaction force control circuit and a second reaction force control circuit. Each of the first reaction force control circuit and the second reaction force control circuit are configured to control a reaction force motor, to execute, at a starting time, a preparation process including a process that requires the steering wheel to automatically rotate through the reaction force motor, and to store, at a time of execution completion of the preparation process, information indicating whether the preparation process has been normally completed. In a case where the first reaction force control circuit has been reset, when the information indicates that the preparation process has been normally completed, the first reaction force control circuit that has been rest is configured to not execute the preparation process at a time of restarting after completion of the reset.