Vehicle Steering Device Dynamic Torque Weighting
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Solution Overview
Problem
Existing vehicle steering devices with automatic and manual control using the same electric motor face limitations in rapidly switching between control modes, particularly during emergency situations, due to a fixed transition time that cannot be adjusted by driver steering operations.
Innovation Solution
A vehicle steering device with an electric motor, a first setting portion for target assist torque, a second setting portion for angle controlling target torque, an estimator for compensation object load, and a calculating portion for weighted addition of target steering torques based on driver input, allowing seamless and rapid switching between automatic and manual steering controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the transition control uses a fixed time-based weighting factor adjustment, then the target actuator torque fluctuation is suppressed, but the transition control time cannot be adjusted rapidly in emergency situations
Solution Approach 1:
The patent applies dynamics by making the transition control adaptable to different situations. The control system dynamically adjusts the weighting factor adjustment amount based on whether the system is in normal mode or emergency mode, allowing the transition characteristics to change according to operational requirements rather than being fixed
Solution Approach 2:
The patent changes the parameter of weighting factor adjustment amount based on the operational mode. In normal mode, a first adjustment amount is used to ensure smooth transition, while in emergency mode, a second (larger) adjustment amount is used to enable rapid transition, thus resolving the contradiction between stability and speed
2Ease of operation
If the weighting factor Kauto gradually decreases with time, then the transition from automatic to manual steering is smooth, but the transition time is always constant and cannot be reduced for rapid response
Solution Approach 1:
The transition control is made dynamic by allowing the weighting factor adjustment rate to change based on the operational mode. The system can switch between a gradual adjustment mode for smooth transitions and a rapid adjustment mode for time-critical situations
Solution Approach 2:
The patent changes the parameter of weighting factor adjustment amount based on mode. In normal mode, the adjustment amount is smaller to ensure smooth transition and driver comfort. In emergency mode, the adjustment amount is larger to reduce transition time and enable rapid response
Data Source
AI summary
A vehicle steering device includes a first setting portion 41 that sets a target assist torque in accordance with a steering torque, a second setting portion 42 that sets an angle controlling target torque for bringing an angular deviation between a target steering angle and an actual steering angle close to zero, an estimator that estimates a compensation object 43 load with respect to the angle controlling target torque, a first calculating portion 44 that calculates a target automatic steering torque based on the angle controlling target torque set by the second setting portion and the compensation object load estimated by the estimator, and a second calculating portion 44 that performs weighted addition of the target automatic steering torque and the target assist torque in accordance with a value that changes in accordance with a driver input to calculate a target motor torque that is a target value of a motor torque of the electric motor.