MDPS Steering Control With Disturbance Estimation for Stable Response
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Solution Overview
Problem
Existing motor driven power steering systems face challenges in enhancing instantaneous responsiveness during autonomous driving, particularly in emergency situations, while maintaining stability against noise from external factors, which can lead to reduced control responsiveness and unintentional vibration.
Innovation Solution
An apparatus and method that include a steering angle position controller, current controller, and disturbance estimator to adjust gain values and filter frequencies, and apply noise removal techniques using variable high-pass filters and Q-filters to enhance responsiveness and stability, specifically by compensating for steering angle and current errors, and estimating and removing noise from command currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor of the MDPS is controlled to enhance responsiveness during autonomous driving, then instantaneous responsiveness is improved, but control stability is reduced due to noise from external factors, frictional force, and sensor noise
Solution Approach 1:
The disturbance estimator proactively estimates noise and disturbance forces before they significantly impact the steering control, and the controller preemptively compensates for these disturbances by adjusting motor output. This preliminary action prevents instability from developing while maintaining high responsiveness to actual steering commands.
Solution Approach 2:
The system continuously monitors steering angle, motor current, and vibration signals, feeding this information back to the disturbance estimator and controller. This closed-loop feedback enables real-time detection of instability caused by noise and friction, allowing the controller to adjust motor output dynamically to maintain stability while preserving responsiveness.
2Speed
If the responsiveness is unintentionally enhanced too much, then instantaneous responsiveness is improved, but control stability is reduced causing unintentional vibration
Solution Approach 1:
The system converts the harmful effect of vibration and noise into useful information by using vibration sensors to detect unwanted oscillations. The disturbance estimator then uses this vibration data to calculate compensatory forces that counteract the harmful vibrations, transforming the problem of vibration detection into a solution that eliminates the vibration while maintaining responsiveness.
Solution Approach 2:
The controller dynamically adjusts motor control parameters including gain values and filtering characteristics based on real-time feedback about vibration levels and disturbance forces. By changing these parameters adaptively, the system can suppress unintentional vibrations when they occur while maintaining high responsiveness during normal operation.
3Stability of the object's composition
If noise removal techniques are applied to stabilize performance against external factors, then control stability is improved, but responsiveness to sudden steering requirements may be reduced
Solution Approach 1:
The system uses dynamic filtering where the characteristics of noise removal filters are adjusted in real-time based on operating conditions. During sudden steering events, the filter characteristics are modified to preserve high-frequency response components, ensuring responsiveness is maintained while still removing stable background noise and disturbance forces during normal operation.
Data Source
AI summary
Disclosed are an apparatus and a method for controlling a motor driven power steering system. The apparatus for controlling a motor driven power steering system includes a steering angle position controller configured to control a steering angle by adjusting a gain value based on a steering angle error between a command steering angle inputted by an autonomous driving system and a current steering angle; a current controller configured to compensate for a current error between a second command current outputted from the steering angle position controller and a sensor current; and a disturbance estimator configured to estimate noise due to an external factor, to remove the estimated noise in advance from a third command current outputted from the current controller, and to apply the third command current with no noise to an MDPS.