Steering Torque Control for Vehicle Stabilization
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Solution Overview
Problem
Existing vehicle stabilization systems face challenges in providing reliable and comfortable steering assistance during braking on inhomogeneous roadways with varying coefficients of friction, leading to excessive or insufficient additional steering torque, which can result in uncomfortable or inappropriate driver interventions.
Innovation Solution
A method and device that apply an additional steering torque to the vehicle's steering line, determined by the difference between the nominal and instantaneous steering angles, with consideration of the load moment acting on the steering line, including a disturbance variable observer unit to estimate the load moment and adapt the torque accordingly, allowing for independent calculation of control components from steering angle deviation and load moment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the additional steering torque is determined only from steering angle deviation without considering load moment, then the control is simple, but the steering torque becomes excessively high or insufficient under varying road conditions
Solution Approach 1:
The system implements feedback by continuously estimating the load moment acting on the steering line and using this information to adjust the additional steering torque. The disturbance variable observer unit monitors steering line conditions and feeds this information back to the torque determination process, enabling the system to adapt to varying road conditions and maintain reliable steering assistance.
Solution Approach 2:
The system uses self-service by estimating the load moment from the steering line's own operational data without requiring external sensors. The disturbance variable observer unit derives load moment information from existing steering system parameters, allowing the system to self-adjust and optimize performance under different driving conditions.
2Reliability
If the additional steering torque is increased to provide stronger stabilization assistance, then vehicle stabilization improves, but driver comfort deteriorates due to excessive or inappropriate torque
Solution Approach 1:
The system applies dynamics by making the additional steering torque variable rather than fixed. The torque is dynamically adjusted based on the estimated load moment and steering angle deviation, allowing the system to provide strong stabilization when needed while reducing torque when the situation allows, thereby maintaining both vehicle stability and driver comfort.
Solution Approach 2:
The system changes parameters by adjusting the additional steering torque based on varying operating conditions. The disturbance variable observer unit continuously estimates the load moment, and this parameter is used to modify the torque magnitude, enabling the system to adapt to different road conditions, vehicle states, and driver inputs.
3Productivity
If aggressive brake intervention is applied to maximize deceleration, then stopping distance is reduced, but vehicle stability deteriorates due to yaw torque from asymmetric brake forces
Solution Approach 1:
The system applies preliminary anti-action by providing steering assistance before the driver completes the steering correction. The additional steering torque counteracts the yaw torque generated by asymmetric brake forces, preventing vehicle instability and allowing aggressive brake intervention to be applied safely without compromising stability.
Data Source
AI summary
Disclosed is a method for assisting an operator of a vehicle in adjusting a nominal steering angle at steerable wheels of the vehicle for the vehicle stabilization. An additional steering torque is applied to the steering line of the vehicle, which is determined dependent on a difference between a nominal steering angle and an instantaneous steering angle. The method is characterized in that a value of a load moment acting on the steering line of the vehicle is estimated, and that the additional steering torque is established dependent on the estimated value for the load moment.