Joystick Steering Reaction Force Control for Reduced Driver Burden
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The application of reaction torque based on joystick operation in steer-by-wire systems places a burden on the driver by requiring continuous force application, leading to discomfort.
Innovation Solution
A steering control device with a reaction force command value calculation unit that switches between normal and keeping state calculation modes, reducing the reaction force when the joystick operation is constant, and incorporating a dead band in the keeping state mode to alleviate driver discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reaction torque is applied according to the amount of joystick operation, then steering control precision is improved, but driver burden increases due to continuous force application requirement
Solution Approach 1:
The patent applies dynamics by making the reaction torque characteristic changeable based on operating conditions. The control device dynamically adjusts the reaction torque calculation mode between normal mode and keeping state mode according to whether the operation amount is being maintained constant, allowing the system to adapt its torque characteristics to the current operational phase
Solution Approach 2:
The patent changes the parameter of reaction torque magnitude based on the operational state. In keeping state mode, the reaction force command value is reduced compared to normal mode, and a dead band is introduced where reaction torque does not change with operation amount, effectively changing the torque-parameter relationship to reduce driver burden during constant positioning
2Ease of operation
If reaction force command value is reduced in keeping state mode, then driver comfort is improved, but steering responsiveness may be degraded
Solution Approach 1:
The system dynamically switches between normal calculation mode and keeping state calculation mode based on detected operational conditions. When the joystick operation amount is determined to be kept constant (keeping state), the system activates the reduced reaction force mode with dead band, otherwise it uses normal mode, thereby dynamically optimizing both comfort and responsiveness based on real-time operational context
Data Source
AI summary
A steering control device is configured to calculate a reaction force command value to reflect a reaction force component calculated based on an operation amount of an operating lever, and generate a control signal based on the reaction force command value. The steering control device is configured to execute a keeping state determination process for determining whether a keeping condition for the operation amount is satisfied, and a calculation mode switching process for switching a calculation mode of the reaction force command value to a keeping state calculation mode when the keeping condition is satisfied. The keeping state calculation mode is configured such that a dead band that is a range in which the reaction force component does not change with respect to the operation amount is larger than a dead band in a normal state calculation mode.