Steering Control Device Torsion Angle Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing steer-by-wire steering systems face challenges in maintaining a good feeling of steering and improving turning responsiveness due to excessive changes in steering reaction force, which can lead to driver discomfort and reduced handling performance.
Innovation Solution
A steering control device that calculates a command value for the reaction motor based on the steering state, incorporating a torsion angle compensation mechanism to adjust the steering angle, thereby curbing sudden changes in the command value and enhancing responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the target turning angle is adjusted to increase turning responsiveness, then the turning responsiveness is improved, but the responsiveness of the steering reaction force becomes excessively high causing sudden changes in command value and steering reaction force
Solution Approach 1:
The torsion angle is calculated in advance based on the steering torque and added to the steering angle before computing the target turning angle. This preliminary compensation action anticipates the elastic deformation of the steering shaft, allowing the control system to pre-adjust the command value and prevent sudden changes in steering reaction force while maintaining improved turning responsiveness.
Solution Approach 2:
The torsion angle acts as an intermediary parameter that mediates between the steering torque and the target turning angle. By introducing this intermediate calculation step, the system smoothly transitions the steering torque information into the target turning angle computation, preventing direct abrupt changes in the steering reaction force command while still achieving responsive turning behavior.
2Speed
If the torsion angle is added to the steering angle to improve turning responsiveness, then the turning responsiveness is enhanced, but the command value changes suddenly deteriorating the steering feel
Solution Approach 1:
The torsion angle compensation is performed in advance by calculating the torsion angle from the steering torque and adding it to the steering angle before target turning angle computation. This preliminary action prevents sudden changes in the command value by anticipating the elastic deformation effects, thereby maintaining smooth steering feel while achieving improved turning responsiveness.
Solution Approach 2:
The system changes the parameter composition of the steering angle by adding the torsion angle component. This parameter modification transforms the raw steering angle into a compensated steering angle that accounts for elastic deformation, enabling the system to achieve better turning responsiveness without causing abrupt changes that would deteriorate the steering feel.
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
The solution ensures a better steering feel and improved turning responsiveness by dynamically adjusting the torsion angle based on the steering state, reducing excessive responsiveness and maintaining a comfortable driving experience.
Implementation Method 1
a steering torque acquired from a torsion angle of a torsion bar twisting with an operation of the steering wheel
Data Source
AI summary
A steering control device includes an electronic control unit. The electronic control unit is configured to calculate a target rotation angle of a shaft rotating with a turning operation of turning wheels based on a steering angle of a steering wheel acquired from a rotation angle of a reaction motor, to calculate a command value based on the target rotation angle and a steering torque acquired from a torsion angle of a torsion bar twisting with an operation of the steering wheel, and to compensate for the torsion angle by adding the torsion angle as a compensation value to the steering angle. The electronic control unit is configured to change a value of the torsion angle that is added to the steering angle according to a degree of change of a state variable used to calculate the command value.