Steering Control Device Filtered Torque Disturbance Suppression
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Solution Overview
Problem
Conventional electric power steering systems face challenges in accurately estimating and compensating for disturbances from the road surface, as the accuracy of mathematical models used for disturbance estimation is affected by the dynamic characteristics of the steering system, leading to complex compensation processes.
Innovation Solution
A steering control device with a first torque command controller and a second torque command controller that uses a filter to suppress frequency regions corresponding to disturbances, allowing for parallel motor torque instruction based on the steering wheel operation, without relying on mathematical models for disturbance estimation, thereby simplifying the compensation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a disturbance observer using a mathematical model is used to estimate disturbance, then disturbance estimation can be performed, but accuracy of the mathematical model affects accuracy of disturbance estimation and makes disturbance compensation complicated
Solution Approach 1:
The patent extracts and removes the mathematical model from the disturbance estimation process. Instead of using a disturbance observer that relies on mathematical models of the steering system, the invention directly processes steering wheel operation signals through filtering to generate torque commands, eliminating the need for complex model-based disturbance estimation while reducing compensation complexity
Solution Approach 2:
The patent replaces the mechanical/mathematical modeling approach with a signal processing approach. By substituting the mathematical model-based disturbance observer with a filter-based signal processing method that operates directly on steering wheel operation signals, the system achieves disturbance suppression without requiring accurate dynamic characteristics of the steering system
2Device complexity
If a filter is used to suppress disturbance frequency regions in parallel torque command control, then disturbance suppression is achieved without mathematical models, but the system requires coordination between multiple torque command controllers
Solution Approach 1:
The patent segments the torque command generation into two parallel independent controllers: a first torque command controller that generates baseline torque commands from steering wheel operation, and a second torque command controller that applies filtering to suppress disturbance frequency regions. This segmentation allows each controller to perform its function independently while their outputs are combined, simplifying the overall control architecture
Solution Approach 2:
The second torque command controller serves multiple functions simultaneously: it processes the steering wheel operation signal, applies frequency-based disturbance suppression through filtering, and generates a torque command that can be combined with the first controller's output. This multi-functionality reduces the need for separate disturbance estimation and compensation mechanisms
Data Source
AI summary
A steering control device for controlling drive of a motor that drives a steering mechanism according to an operation amount of a steering wheel, includes a first torque command controller that instructs the motor on motor torque according to the operation amount of the steering wheel, and a second torque command controller that instructs the motor on the motor torque according to the operation amount of the steering wheel in parallel with the first torque command controller. The second torque command controller suppresses a frequency region corresponding to disturbance added to the steering mechanism with respect to the operation amount of the steering wheel with a filter.