Steering Wheel Position Hold via Reaction Force Actuator
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Solution Overview
Problem
Existing steer-by-wire steering systems face challenges in preventing unintended rotation of the steering wheel during disembarkation or embarkation, which can lead to instability or injury, and current solutions like mechanical rotation prevention mechanisms increase manufacturing costs and weight.
Innovation Solution
A steering operation control apparatus that includes a steering control portion to manage the steering actuator and a reaction force control portion to control a reaction force actuator on the steering wheel, which outputs a stop position maintaining signal to keep the steering wheel in place when the driver is detected getting out or in.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical rotation prevention mechanism (gear tooth and engagement pin) is used to prevent unintended rotation of the steering wheel, then the reliability of preventing steering wheel rotation is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the mechanical rotation prevention mechanism (gear tooth and engagement pin) with an electrical control system. The reaction force actuator, controlled by the control unit, generates a holding force to prevent steering wheel rotation during disembarkation/embarkation, eliminating the need for additional mechanical components while achieving the same safety function.
Solution Approach 2:
The patent extracts the rotation prevention function from the mechanical steering system and relocates it to the electrical reaction force control system. By separating this function and implementing it through electrical control, the mechanical complexity is reduced while maintaining the essential safety function.
2Reliability
If a mechanical rotation prevention mechanism is added to prevent steering wheel rotation, then the safety during disembarkation/embarkation is improved, but the weight of the steering system increases
Solution Approach 1:
The patent substitutes heavy mechanical components (gear teeth, engagement pins, and associated mechanical linkages) with a lightweight electrical control system. The reaction force actuator, already present in the steer-by-wire system, is repurposed to provide holding force during disembarkation/embarkation, adding minimal weight while ensuring driver safety.
Solution Approach 2:
The patent makes the reaction force actuator multi-functional by using it both for normal steering operations and for preventing unintended rotation during disembarkation/embarkation. This eliminates the need for dedicated mechanical prevention components, reducing overall system weight while maintaining safety functionality.
3Adaptability or versatility
If the steering wheel is mechanically decoupled from the steering mechanism to enable steer-by-wire control, then the adaptability for autonomous driving and variable gear ratio control is improved, but the steering feeling comfort deteriorates
Solution Approach 1:
The patent introduces the reaction force actuator as an intermediary between the driver and the steering mechanism. This actuator generates and applies reaction force torque to the steering wheel, mediating the interaction between the driver's steering input and the mechanically decoupled steering mechanism, thereby restoring natural steering feedback and improving comfort in steer-by-wire systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively suppresses unintended rotation of the steering wheel during disembarkation or embarkation, enhancing driver safety and stability without increasing manufacturing costs or weight.
Implementation Method 1
a reaction force electric motor on the steering wheel and generate a reaction force torque based on the steering mechanism using this reaction force electric motor
Implementation Method 2
outputting a stop position maintaining signal required for the reaction force actuator to maintain a present position of the steering wheel
Data Source
AI summary
A steering operation control apparatus and steering operation control method capable of suppressing an unintended rotation of a steering wheel with a simple configuration. The steering operation control apparatus includes a steering control portion configured to control a steering actuator configured to operate a steering mechanism configured to drive a steering target wheel, and a reaction force control portion coupled with a steering wheel and configured to control a reaction force actuator configured to provide a reaction force. The reaction force control portion has a function of outputting a stop position maintaining signal required for the reaction force actuator to maintain a present position of the steering wheel to the reaction force actuator when a driver is detected to get out of or get into a vehicle. This aspect just feeds the stop position maintaining signal for maintaining the present position of the steering wheel to the reaction force actuator.