MDPS Column Torque Vibration Compensation
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Solution Overview
Problem
The MDPS system in vehicles experiences vibrations such as shimmy and brake judder, which degrade steering feel and stability, and existing solutions require mechanical devices to reduce these vibrations.
Innovation Solution
An apparatus and method that use a column torque sensor, vehicle velocity sensor, and controller to filter out steering vibrations by determining a filtering gain based on vehicle velocity and using a lead-lag compensator to attenuate the column torque signal, thereby improving steering stability without mechanical modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mechanical devices are added to reduce steering vibrations, then vibration reduction effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical vibration reduction devices with an electronic control system that uses sensors (torque sensor, steering angle sensor, vehicle velocity sensor) and a controller to detect steering vibrations and generate compensatory assist torque. This substitution eliminates the need for additional mechanical components while achieving vibration reduction through software-based signal processing and torque compensation algorithms.
Solution Approach 2:
The patent introduces an electronic control unit as an intermediary between the driver's steering input and the power steering system. This controller receives signals from various sensors, processes them to detect vibration frequencies and magnitudes, and generates compensatory torque signals that counteract the detected vibrations, thereby mediating the interaction between driver input and steering system response without requiring mechanical vibration dampers.
2Stability of the object's composition
If mechanical vibration reduction devices are installed, then steering stability is improved, but manufacturing cost and ease of manufacture deteriorate
Solution Approach 1:
The patent replaces mechanical vibration reduction devices with an electronic control system that uses sensors (torque sensor, steering angle sensor, vehicle velocity sensor) and a controller to detect steering vibrations and generate compensatory assist torque. This substitution eliminates the need for additional mechanical components while achieving vibration reduction through software-based signal processing and torque compensation algorithms.
Solution Approach 2:
The patent utilizes existing MDPS system components (motor, torque sensor, steering angle sensor, vehicle velocity sensor) for multiple purposes: normal power steering assistance and vibration reduction. The controller processes sensor signals to detect vibrations and generates compensatory torque, allowing the existing system to serve dual functions without requiring separate dedicated vibration reduction hardware, thereby simplifying manufacturing.
3Object-affected harmful factors
If filtering gain is increased to attenuate vibrations more strongly, then vibration reduction effectiveness is improved, but steering feel and responsiveness deteriorate
Solution Approach 1:
The patent dynamically adjusts the filtering gain based on real-time vehicle conditions, including vehicle velocity, steering angle, and detected vibration characteristics. The controller modifies the attenuation level adaptively, reducing gain when strong vibration attenuation is needed and increasing gain when responsive steering feel is prioritized, thereby optimizing the balance between vibration reduction and steering responsiveness under different operating conditions.
Solution Approach 2:
The patent changes the filtering gain parameter dynamically based on vehicle velocity and steering conditions. The controller adjusts this parameter in real-time to optimize vibration attenuation while maintaining acceptable steering feel, using velocity-dependent gain schedules and vibration magnitude-based adjustments to modulate the filtering strength according to the current operating state.
Data Source
AI summary
An apparatus for compensating for a column torque in an MDPS (Motor Driven Power Steering) system including: a column torque sensor configured to sense a column torque applied to a steering shaft and output a column torque signal; a vehicle velocity sensor configured to sense a vehicle velocity; and a controller configured to receive the column torque signal to extract a vibration frequency of steering vibration caused in a steering apparatus, determine a filtering gain based on the vehicle velocity sensed by the vehicle velocity sensor, and filter the column torque signal such that a column torque signal corresponding to the extracted vibration frequency is attenuated to an attenuation length which is determined according to the filtering gain.