Steering Motor Restoration Torque for High-Speed Turn Stability
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Solution Overview
Problem
High-performance vehicles experience reduced steering restoration performance during high-speed turns due to low lateral input load, leading to unintended vehicle direction and potential oversteer or spinning, especially when accelerating rapidly.
Innovation Solution
A vehicle steering control method that determines if the vehicle is in a high-speed turning state and provides restoration compensation torque using a steering motor based on steering torque, wheel speed, engine revolutions, and steering angular speed, calculated by a controller to improve steering restoration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rapid acceleration is applied during high-speed turning to escape from a turn path, then vehicle speed increases, but steering restoration performance deteriorates due to reduced lateral input load
Solution Approach 1:
The control system applies preliminary anti-action by detecting the high-speed turning state and rapid acceleration condition, then proactively generates a restoration compensation torque through the steering motor before the vehicle can deviate from the intended path. This preemptive counter-torque opposes the reduced lateral input load effect, maintaining steering restoration performance even during rapid acceleration.
Solution Approach 2:
The steering motor acts as an intermediary element that mediates between the driver's steering input and the vehicle's steering response. During rapid acceleration in high-speed turning, the steering motor provides additional restoration compensation torque to supplement the insufficient lateral input load, ensuring the steering system maintains adequate restoration capability.
2Speed
If lateral input load is reduced during rapid acceleration, then vehicle responsiveness improves, but steering restoration becomes inoperable when load falls below friction threshold
Solution Approach 1:
The restoration compensation torque generated by the steering motor functions as a counterweight to compensate for the reduced lateral input load. When the lateral load drops below the friction threshold during rapid acceleration, this counter-torque ensures that the total restoration torque remains sufficient to overcome steering friction and maintain operable steering restoration.
3Reliability
If restoration compensation torque is provided using steering motor, then steering restoration performance improves, but device complexity increases
Solution Approach 1:
The steering motor is designed with multi-functionality, serving both as the primary power assist device for normal steering operations and as the restoration compensation device during high-speed turning with rapid acceleration. This universal design avoids adding a separate dedicated restoration mechanism, thereby limiting the increase in device complexity while still improving steering restoration performance.
Solution Approach 2:
The steering control system dynamically adjusts the restoration compensation torque based on real-time detection of vehicle speed, steering angle, lateral acceleration, and acceleration rate. The torque magnitude and direction are continuously optimized according to the current driving state, allowing the system to provide precise restoration assistance only when needed, rather than operating at fixed complexity levels.
Data Source
AI summary
A method for a steering control of a vehicle to improve steering restoration when the vehicle escapes from a turn path via acceleration during high-speed turning. The vehicle steering control method includes determining whether or not a vehicle is rapidly accelerating in a high-speed turning state, and providing a restoration compensation torque in a vehicle steering restoration direction using a steering motor when it is determined that the vehicle is rapidly accelerating in the high-speed turning state. In particular, the restoration compensation torque is determined based on a relationship of a steering torque, a wheel speed, a number of revolutions of an engine, and a steering angular speed of the vehicle.