Steering Device Delay Compensation via Electric Motor Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic power steering devices experience delays in turning wheel response due to the slowness of the hydraulic mechanism, particularly when steering on S-curved roads, leading to a discrepancy between the driver's intended and actual turning angles.
Innovation Solution
A steering device connected to a turning mechanism with an electric motor, rotation angle detector, and steering control unit that estimates and corrects the target turning angle based on a delay model, using the detected rotation angle to output delay information and adjust the electric motor's operation to minimize this delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a hydraulic mechanism is used to apply turning force to the turning mechanism, then the steering device can provide hydraulic assist force, but the hydraulic mechanism responds slowly causing delay in turning wheel response
Solution Approach 1:
The steering control device estimates the delay amount based on the rotation angle of the electric motor and proactively corrects the target turning angle before the delay occurs. This preliminary correction action compensates for the inherent slowness of the hydraulic mechanism, ensuring the turning wheels reach the intended position on time despite the hydraulic response delay.
2Loss of time
If the number of torsion bars is decreased to reduce delay, then the phase difference can be reduced, but the steering device loses mechanical assist capability
Solution Approach 1:
The patent replaces the mechanical assist function of torsion bars with an electric motor that provides both mechanical assist force and rotational movement. The electric motor's rotation angle is detected and used by the control device to estimate and correct hydraulic response delay, thereby achieving both force assistance and delay compensation without relying on torsion bars.
3Speed
If a larger electric motor is used to compensate for hydraulic delay, then the turning response can be improved, but the device size and arrangement complexity increase
Solution Approach 1:
The steering control device continuously detects the rotation angle of the electric motor and uses this feedback to estimate the hydraulic mechanism's delay amount. Based on this real-time feedback, the control device dynamically corrects the target turning angle, enabling precise control without requiring an oversized motor. This feedback mechanism allows a smaller motor to achieve the desired response speed while maintaining arrangement flexibility.
Data Source
AI summary
A steering device is connected to a turning mechanism to which a part of a turning force is applied by a hydraulic mechanism. The steering device includes an electric motor, a rotation angle detector, and a steering control device. The steering control device is configured to acquire a target turning angle which is a target value of a turning angle of turning wheels, to control the electric motor such that a turning angle of the turning wheels reaches the target turning angle, to estimate a delay of an actual turning angle of the turning wheels with respect to the target turning angle based on a delay model with the detected rotation angle as an input, to output delay information, and to correct the target turning angle based on the delay information.