Motor-Driven Power Steering Compensation Gain for Rapid Turn Acceleration
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Solution Overview
Problem
Conventional motor-driven power steering systems using yaw rate and lateral acceleration sensors face issues with responsiveness and accuracy due to signal delays and noise, leading to inadequate compensation for instantaneous steering pulls during rapid vehicle acceleration, causing unstable vehicle behavior and a sense of heterogeneity for the driver.
Innovation Solution
A motor-driven power steering apparatus and control method that generates a compensation gain using vehicle speed, steering angle, and column torque to counteract steering pulls, by calculating lateral acceleration and steering angular velocity gains, and applying these gains to adjust the auxiliary output in the opposite direction of the steering pull, thereby improving steering stability and feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If yaw rate sensor or lateral acceleration sensor is used for oversteer compensation, then vehicle stability can be improved, but signal delay and noise cause poor responsiveness and insufficient compensation accuracy
Solution Approach 1:
The system calculates expected yaw rate and lateral acceleration in advance based on steering angle and vehicle speed before actual oversteer occurs. By predicting the desired vehicle behavior proactively, the system can prepare compensation signals without waiting for sensor feedback, thereby eliminating signal delay while maintaining vehicle stability.
Solution Approach 2:
The patent introduces an intermediary calculation model that translates steering inputs into expected vehicle responses. This intermediary system acts as a bridge between driver input and vehicle behavior, generating reference yaw rate and lateral acceleration values that serve as intermediaries for comparing actual sensor data and determining compensation needs.
2Reliability
If conventional sensor-based compensation is used, then some oversteer can be addressed, but noise and errors in sensor signals reduce measurement precision and compensation accuracy
Solution Approach 1:
The system creates a virtual copy of the expected vehicle behavior through calculation models rather than relying solely on physical sensor measurements. By generating reference yaw rate and lateral acceleration through mathematical models based on steering angle and vehicle speed, the system obtains noise-free reference values for comparison and compensation determination.
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with a computational model-based system. Instead of directly using noisy sensor signals for compensation, the system substitutes them with calculated expected values from mathematical models, thereby eliminating the impact of sensor noise and measurement errors on compensation accuracy.
3Power
If rapid acceleration during turn is allowed for high-performance driving, then vehicle power and acceleration capability are improved, but instantaneous steering pull occurs causing heterogeneous steering feel and driver discomfort
Solution Approach 1:
The system continuously compares actual vehicle behavior (from sensors) with expected behavior (from calculations) during rapid acceleration. When deviations indicating steering pull are detected, the feedback loop automatically adjusts power steering assistance to compensate, maintaining smooth steering feel even during high-performance rapid acceleration maneuvers.
Data Source
AI summary
A motor-driven power steering apparatus includes an auxiliary output generation unit configured to generate an auxiliary output of a motor by using at least one of a vehicle speed, a steering angle and a column torque; a compensation gain generation unit configured to generate a compensation gain for compensating for a steering pull of a vehicle by a rapid acceleration during a turn, by using at least one of the vehicle speed, the steering angle and the column torque; and an auxiliary output compensation unit configured to compensate for an auxiliary output by applying the compensation gain outputted by the compensation gain generation unit to the auxiliary output.