Steering Control Device Learning Control Constants at Vehicle Velocity
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Solution Overview
Problem
Existing steering control devices are unable to calculate the play amount when the vehicle velocity is higher than zero, leading to inefficiencies in steering angle and turning wheel displacement relationships.
Innovation Solution
A steering control device with a software processing unit that executes a sampling process, a turning angle calculation process, and a control constant learning process, allowing for the calculation of turning angles using yaw rates and vehicle velocities, and learning control constants based on steering angles and corresponding turning angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vehicle is moving (velocity higher than zero), then the steering control device cannot calculate the play amount using existing methods, but the device needs to learn control constants for accurate steering control at all velocities
Solution Approach 1:
The patent introduces yaw rate as an intermediary parameter to indirectly obtain turning angle information when the vehicle is moving. Instead of directly measuring turning angle at zero velocity, the system uses yaw rate sensor data combined with vehicle velocity to calculate turning angle through mathematical relationships, enabling control constant learning across all velocity ranges including moving conditions
Solution Approach 2:
The patent replaces direct mechanical measurement of turning angle (which fails at non-zero velocities) with a computational approach using yaw rate sensors and mathematical calculations. The turning angle is derived from integrating yaw rate over time and considering vehicle velocity, substituting physical direct measurement with sensor-based computational estimation
2Measurement precision
If the device rotates the electric power steering motor to learn play amount, then the device can detect steering angles, but the method fails when vehicle velocity is higher than zero
Solution Approach 1:
The patent transitions from a static learning method (rotating motor at stationary conditions) to a dynamic learning approach that operates during vehicle motion. The system continuously learns control constants by processing real-time steering angle and turning angle data while the vehicle is moving, making the learning process adaptive to different velocity conditions rather than restricted to stationary states
Data Source
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AI summary
A software processing device of a steering control device (60) is configured to execute a sampling process, a turning angle calculation process, and a control constant learning process. The sampling process is a process of sampling a steering angle and a yaw rate in synchronization. The turning angle calculation process is a process of calculating a turning angle of the turning wheel (40), using the yaw rate and a vehicle velocity as inputs. The control constant learning process is a process of learning a control constant based on a plurality of combinations each of which is constituted by the steering angle sampled by the sampling process and the turning angle corresponding to the steering angle. The control constant is a constant that indicates a rotational displacement of the turning wheel (40) with respect to a rotational displacement of the steering shaft (14).