Steer-by-Wire Power Threshold Control for Backup Source Failure
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Solution Overview
Problem
Existing steer-by-wire steering systems do not effectively manage situations where the main power source becomes abnormal when the backup power source is also faulty, as they fail to initiate abnormal-situation control at an appropriate time to ensure continued system functionality.
Innovation Solution
A steer-by-wire steering system with a dual power source configuration, where the controller detects voltage thresholds to initiate abnormal-situation control earlier when the backup power source is abnormal, ensuring sufficient time for control execution by switching to the main power source before the voltage drops too low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller uses a fixed voltage threshold to initiate abnormal-situation control, then the control logic is simple, but the system cannot execute abnormal-situation control in time when the backup power source is abnormal
Solution Approach 1:
The patent applies dynamics by making the voltage threshold dynamic rather than fixed. The controller switches between a first voltage threshold (when backup power source is normal) and a second voltage threshold (when backup power source is abnormal). This dynamic adjustment ensures timely initiation of abnormal-situation control while maintaining manageable control logic through clear switching conditions.
Solution Approach 2:
The patent changes the parameter of voltage threshold based on the operational state of the backup power source. When the backup power source is abnormal, the controller switches to a higher second voltage threshold, causing earlier initiation of abnormal-situation control. This parameter change resolves the contradiction by adapting the control timing to system conditions without requiring complex predictive logic.
2Loss of time
If the controller waits for voltage to drop below a low threshold before initiating abnormal-situation control, then energy management is efficient, but the system loses sufficient time to execute control when backup power source fails
Solution Approach 1:
The patent applies preliminary action by initiating abnormal-situation control earlier when the backup power source is abnormal, before the main power source voltage drops to critical levels. The controller monitors the operational state of the backup power source and proactively switches to a higher voltage threshold, ensuring control execution begins while sufficient voltage remains available, thus preventing time loss without wasteful early activation.
3Reliability
If the system switches to backup power source immediately when main power source voltage decreases, then power supply reliability is improved, but the system cannot adapt when backup power source is already abnormal
Solution Approach 1:
The patent applies dynamics by implementing a dynamic power source management strategy. The controller continuously monitors the operational state of the backup power source and adjusts the voltage threshold accordingly. When the backup power source is abnormal, the system adapts by using a higher second voltage threshold instead of the normal first threshold, ensuring timely control initiation while maintaining reliable power supply management through adaptive switching criteria.
Solution Approach 2:
The patent changes the voltage threshold parameter based on the backup power source's operational state. This parameter adaptation allows the system to maintain high reliability by switching to appropriate control modes while adapting to the actual system condition, resolving the contradiction between reliable power supply and adaptable switching behavior.
Data Source
AI summary
A steer-by-wire steering system includes: a steering device including a steering motor powered by a main power source and/or a backup power source; and a controller configured to control the steering device based on a steering request. When the backup power source is normal, the controller executes an abnormal-situation control based on electric power supplied to the steering motor by the main power source and/or the backup power source when the controller determines that the voltage of the main power source is less than a first threshold. When the backup power source is abnormal, the controller executes the abnormal-situation control based on electric power supplied to the steering motor by the main power source when the controller determines that the voltage of the main power source is less than a second threshold that is greater than the first threshold.