Dither Noise Attenuation in Electric Power Steering Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dither noise in electric motor systems, such as Electric Power Steering (EPS) systems, caused by handwheel torque sensors, leads to discomfort for operators due to inherent noise in sensed signals and quantization noise, which existing methods struggle to completely eliminate without degrading system performance.
Innovation Solution
A method and apparatus that dynamically modify controller parameter values based on steering system signals to reduce dither noise by adjusting the motor control system's bandwidth, using a dither noise manager to filter out noise frequencies while maintaining system stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional motor control is used in EPS systems, then the system can provide steering assist functionality, but dither noise propagates through the system causing operator discomfort
Solution Approach 1:
The patent applies preliminary action by modifying controller parameters before the dither noise can propagate through the motor control system. The dither noise manager dynamically adjusts controller parameters based on operating conditions to prevent noise amplification at its source, rather than attempting to filter noise after it has already propagated through the system.
Solution Approach 2:
The patent implements parameter changes by dynamically modifying controller parameters (such as current control bandwidth, PI controller gains, or filter coefficients) based on operating conditions. This allows the system to adapt the control characteristics to minimize dither noise propagation while maintaining steering assist functionality across different operating scenarios.
2Object-affected harmful factors
If controller parameters are modified to reduce dither noise, then operator comfort improves, but system performance and stability may be compromised
Solution Approach 1:
The patent applies dynamics by implementing real-time, conditional modification of controller parameters based on operating conditions. The dither noise manager continuously monitors system state and dynamically adjusts parameters only when necessary to reduce dither noise, while maintaining optimal performance and stability characteristics under different operating conditions. This dynamic approach ensures system reliability is preserved while reducing noise.
3Object-affected harmful factors
If existing noise reduction methods are applied, then some dither noise is attenuated, but the noise cannot be completely eliminated without degrading system performance
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting controller parameters based on operating conditions to achieve complete dither noise elimination. The dither noise manager modifies parameters such as current control bandwidth, filter coefficients, or PI controller gains in real-time, allowing the system to eliminate noise across different operating scenarios while maintaining optimal steering assist performance.
Solution Approach 2:
The patent applies feedback by implementing a dither noise manager that monitors operating conditions and system response, then adjusts controller parameters accordingly. This closed-loop approach ensures that noise reduction actions are taken only when and where necessary, preventing performance degradation while achieving complete noise elimination across various operating conditions.
Data Source
AI summary
Technical solutions are described for attenuating dither noise in a steering system. An example method includes computing a torque command based on an input torque, and generating a current command corresponding to the torque command. Further, the method includes determining an adjustment parameter based on a plurality of steering system signals. Further, the method includes reducing dither noise of the steering system by dynamically modifying a controller parameter value using the adjustment parameter. Further, the method includes generating a voltage command using the current command and the modified controller parameter value, the voltage command used to generate torque by a motor.