Electric Steering Control Device Noise Robustness
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Solution Overview
Problem
Existing electric steering control devices are adversely affected by noise in steering torque detection, leading to vibration and low responsiveness due to follow-up control based on driver-operated torque values.
Innovation Solution
An electric steering control device that generates a target steering torque value from estimated state amounts, using a motor to output assist torque, with a command value generation unit reducing deviations between target and detected steering torque values below a threshold, thereby improving noise robustness and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target value of steering torque is set based on the detection value of steering torque, then the control follows the driver's operation, but noise is superimposed on the detection value causing vibration and reducing control responsiveness
Solution Approach 1:
The patent introduces a target value generation unit that acts as an intermediary between the steering torque detection and motor control. This unit generates a target steering torque value based on the detected steering torque and vehicle speed, filtering out noise while preserving the essential steering intent. The intermediary processing enables both noise robustness and responsive control by separating the raw detection signal from the control command generation.
Solution Approach 2:
The target value generation unit performs preliminary processing of the steering torque detection value before it is used for motor control. By pre-calculating the target steering torque value considering vehicle speed and other factors, the system prepares a refined control target that is less susceptible to noise, thereby improving both reliability and responsiveness in the subsequent control stage.
2Ease of operation
If the target value of steering torque is set based on the detection value of steering torque, then the control responds to driver operation, but the follow-up control nature reduces responsiveness
Solution Approach 1:
The system performs preliminary calculation of the target steering torque value by combining the detected steering torque with vehicle speed information and control gain. This pre-processing creates a predictive control target that anticipates the desired steering assistance before the full control loop executes, thereby reducing the lag inherent in pure follow-up control and improving responsiveness.
3Force
If assist torque is generated by driving the motor to reduce the difference between target value and detection value of steering torque, then steering assistance is provided, but noise in detection value adversely affects motor control
Solution Approach 1:
The target value generation unit serves as a mediator that processes the noisy detection value of steering torque before it reaches the motor control system. By generating a refined target steering torque value that incorporates vehicle speed and control gain, the intermediary unit protects the motor control from noise interference while still enabling the motor to generate the necessary assist torque for steering assistance.
Data Source
AI summary
An electric steering control device controls a steering characteristic by outputting an assist torque using a motor, and the assist torque corresponds to a detection value of a steering torque which is applied to a steering shaft. The electric steering control device includes a steering target value generation unit generating a target value of the steering torque based on a state amount estimated from the target value of the steering torque and the assist torque, a command value generation unit generating a command value for controlling the motor to reduce a deviation between the target value of the steering torque and the detection value of the steering torque to a level lower than a predetermined threshold, and a motor drive unit driving the motor based on the command value.