Steer-by-Wire Reaction Actuator Torque Control
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Solution Overview
Problem
In steer-by-wire vehicles, the existing reaction actuator overheats when continuously applying high torque to lock the steering wheel during external forces, leading to degradation and impaired steering control.
Innovation Solution
A control apparatus that executes rotation suppression control by determining a rotation suppression torque based on steering parameters, allowing the steering wheel to rotate slightly while preventing excessive rotation, thus reducing the need for high torque and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the reaction actuator completely locks the steering wheel by outputting large torque to prevent rotation during external force application, then the steering wheel stability is improved, but the reaction actuator overheats and degrades
Solution Approach 1:
The system dynamically adjusts the reaction actuator's torque output based on real-time detection of steering wheel rotation and external force conditions. Instead of maintaining constant high torque for complete locking, the actuator applies variable torque levels - high torque when rotation is detected during external force application, and reduced torque when conditions are normal, thereby preventing overheating while maintaining stability when needed
Solution Approach 2:
The control system changes the torque parameter of the reaction actuator based on detected steering wheel rotation and external force conditions. When rotation is detected during external force application, the system increases torque to prevent rotation; when no rotation occurs or external force is absent, the system reduces torque to prevent overheating, thus resolving the contradiction between stability and temperature
2Stability of the object's composition
If the reaction actuator continuously outputs large torque to lock the steering wheel during prolonged external force application, then the steering wheel does not rotate, but the reaction actuator overheats and requires overheat protection control
Solution Approach 1:
The system continuously monitors steering wheel rotation and external force conditions, using this feedback to adjust the reaction actuator's torque output in real-time. When rotation is detected during external force application, the system increases torque to maintain stability; when conditions are normal, it reduces torque to prevent overheating and degradation, thereby maintaining reliability while ensuring stability when needed
Solution Approach 2:
The reaction actuator operates dynamically rather than statically, adjusting its torque output based on real-time conditions. This dynamic operation allows the system to maintain steering wheel stability during external force application while avoiding continuous high torque output that would cause overheating and reliability issues
3Stability of the object's composition
If the steering wheel is completely locked to prevent rotation during external force, then the steering wheel stability is improved, but the usability of the steering wheel for non-steering purposes deteriorates
Solution Approach 1:
The system changes the torque parameter of the reaction actuator based on detected conditions. When steering wheel rotation is detected during external force application, the system increases torque to prevent rotation and maintain stability; when no rotation occurs or external force is absent, the system reduces or eliminates torque, allowing the steering wheel to rotate freely for non-steering purposes such as driver support during boarding, thus improving usability
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
Improves the usability of the steering wheel for non-steering tasks without overheating the reaction actuator, maintaining normal steering control and reducing degradation.
Implementation Method 1
the reaction actuator applies a reaction torque corresponding to a steering reaction force to the steering wheel
Implementation Method 2
the reaction actuator applies a rotation suppression torque for suppressing the rotation of the steering wheel
Data Source
AI summary
A steer-by-wire vehicle includes a steering actuator configured to turn a wheel and a reaction actuator configure to apply a torque to a steering wheel. An electronic control unit of a control apparatus for the vehicle is configured to execute normal steering control for turning the wheel and applying a reaction torque to the steering wheel according to a rotation of the steering wheel, and, when an activation condition including that the normal steering control is not needed is satisfied, execute rotation suppression control for suppressing the rotation of the steeling wheel without prohibiting the rotation of the steering wheel. Specifically, the electronic control unit is configured to, based on a steering speed or a steering torque, determine a rotation suppression torque for suppressing the rotation of the steering wheel, and control the reaction actuator such that the rotation suppression torque is applied to the steering wheel.