MDPS Stick-Slip Compensation Using Torque and Speed Feedback
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Solution Overview
Problem
The Motor Driven Power Steering (MDPS) system experiences stick-slip issues when the steering wheel is rotated from either end to the center, particularly due to mechanical problems that arise with increased vehicle mileage, which degrades steering performance and increases part replacement costs.
Innovation Solution
An apparatus and method that include a column torque detection unit, a vehicle speed sensor, a steering angular velocity detection unit, a condition determination unit, a stick-slip compensation controller, and a compensation unit. This system detects column torque, vehicle speed, and steering angular velocity, determines if compensation conditions are met, and outputs a compensation current to the MDPS controller to mitigate stick-slip effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the MDPS system is used to assist steering operations, then steering ease is improved, but stick-slip occurs due to mechanical problems increasing with mileage
Solution Approach 1:
The patent changes the control parameters of the MDPS system by introducing compensation current based on detected stick-slip conditions. The controller adjusts motor current parameters dynamically to compensate for mechanical degradation, thereby maintaining steering reliability without affecting the ease of operation provided by power assistance.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors steering operations and detects stick-slip conditions. Based on this feedback, the system automatically adjusts motor output to compensate for mechanical problems, resolving the contradiction between maintaining power assistance and preventing stick-slip degradation.
2Ease of operation
If the steering wheel is rotated from either end to the center, then steering maneuverability is improved, but stick-slip occurs degrading steering performance
Solution Approach 1:
The patent modifies operational parameters by introducing compensation current that adjusts motor torque based on detected stick-slip conditions during steering wheel rotation. This maintains precise steering performance while preserving the maneuverability benefit of rotating the steering wheel from ends to center.
Solution Approach 2:
The system detects stick-slip conditions during steering operations and applies compensatory motor torque in advance or concurrently to counteract the harmful effects. This preliminary anti-action prevents degradation of steering performance precision while maintaining steering maneuverability.
3Ease of operation
If mechanical components are used in the MDPS system, then steering assistance function is achieved, but part replacement cost increases due to wear and stick-slip
Solution Approach 1:
The patent partially replaces mechanical solutions with electronic control by using motor current compensation to address mechanical wear issues. Instead of relying solely on mechanical component durability, the system uses electronic parameter adjustment to compensate for mechanical degradation, reducing part replacement costs while maintaining steering assistance function.
Solution Approach 2:
The system changes operational parameters through compensation current adjustment to extend the service life of mechanical components. By modifying control parameters dynamically, the patent reduces wear and stick-slip occurrence, thereby lowering maintenance and part replacement costs while preserving the steering assistance function.
Data Source
AI summary
An apparatus for compensating for a stick-slip of a Motor Driven Power Steering (MDPS) system may include: a column torque detection unit to detect column torque applied to a steering shaft as a driver operates a steering wheel; a vehicle speed sensor to detect vehicle speed; a steering angular velocity detection unit to detect a steering angular velocity of a steering wheel; a condition determination unit to determine whether at least one of the column torque, the vehicle speed and the steering angular velocity satisfies a preset compensation condition; a stick-slip compensation controller to output a compensation current for compensating the stick-slip using at least one of the steering angular velocity, the column torque and the vehicle speed; and a compensation unit to compensate for an output of an MDPS controller by applying the compensation current to the output of the MDPS controller.