Steering Controller Execution Ratio Adaptation
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Solution Overview
Problem
Conventional steer-by-wire steering systems face a significant load on the controller when executing both main and auxiliary processes, leading to increased costs and reduced utility, as they prioritize the failure diagnosis process over steering torque control.
Innovation Solution
The system adjusts the execution ratios of the main and auxiliary processes based on vehicle speed, decreasing the main process load and increasing the auxiliary process load when the vehicle is above a threshold speed, allowing for a high-performance steering system without excessive processing load on the controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the controller executes both main process (steering torque control) and auxiliary process (failure diagnosis) simultaneously, then the steering system can provide comprehensive functionality, but the processing load on the controller becomes excessive
Solution Approach 1:
The controller dynamically adjusts the execution ratio of main and auxiliary processes based on vehicle running speed. At low speeds, the execution ratio of the main process is increased while the auxiliary process execution ratio is decreased. At high speeds, the execution ratio of the main process is decreased while the auxiliary process execution ratio is increased. This dynamic adjustment resolves the contradiction by making the processing load distribution adaptable to different operating conditions rather than fixed
Solution Approach 2:
The controller changes the execution ratio parameters of different processes based on vehicle speed conditions. By using vehicle speed as a threshold parameter, the system switches between different execution ratio configurations, allowing the same controller to handle both comprehensive functionality and acceptable processing load through parameter-based adaptation
2Productivity
If a high-performance controller is used to handle both main and auxiliary processes, then the processing capacity is sufficient, but the cost of the steering system increases
Solution Approach 1:
The controller performs auxiliary processes partially by adjusting execution ratios based on vehicle speed. Instead of always executing auxiliary processes at full capacity, the system applies excessive action only when necessary (at high speeds where steering torque requirements are lower), and reduces auxiliary processing at low speeds where steering control is more critical. This partial execution approach allows using a standard controller rather than requiring an expensive high-performance controller
3Productivity
If the execution ratio of the main process is decreased at high vehicle speeds, then the execution ratio of the auxiliary process can be increased, but the steering control precision may be compromised
Solution Approach 1:
The controller applies different execution ratio configurations to different operating conditions (local conditions). At high vehicle speeds where steering precision requirements are lower, the auxiliary process execution ratio is increased. At low vehicle speeds where steering precision is critical, the main process execution ratio is increased. This local quality approach ensures that steering control precision is maintained where needed while allowing auxiliary process enhancement where less critical
Data Source
AI summary
A steering system of a vehicle, including an operation member to be operated by a driver, a steering device configured to steer a wheel, and a controller configured to control the steering system, wherein the controller is configured to parallelly execute a main process including a process in which the controller controls the steering device to perform steering of the wheel in accordance with an operation of the operation member and an auxiliary process relating to an operation of the steering system and configured to decrease an execution ratio of the main process and increase an execution ratio of the auxiliary process when a condition that a running speed of the vehicle is not lower than a threshold speed is satisfied.