Steering Control Device with Backup Clutch for Power Management
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Solution Overview
Problem
Conventional steer-by-wire systems do not recognize reduced power supply capacity as an abnormality, leading to reduced operability and responsiveness of steering reaction force and steered portion actuators.
Innovation Solution
A steering control device with a mechanical backup system that disconnects and reconnects the steering and steered portions via a backup clutch, using power supply capacity estimation to switch between steer-by-wire control and conventional EPS control when power supply capacity is reduced, thereby maintaining responsive steering performance and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If steer-by-wire control is used during reduced power supply capacity, then responsive steering performance is maintained, but power consumption exceeds available supply capacity
Solution Approach 1:
The system dynamically switches between steer-by-wire control and conventional EPS control based on real-time power supply capacity conditions. When power supply capacity is reduced, the control switching means transitions from high-performance SBW control to lower-power conventional EPS control, optimizing the balance between steering responsiveness and power consumption according to actual operating conditions
2Use of energy by moving object
If conventional steering control is used during reduced power supply capacity, then power consumption is reduced, but steering responsiveness deteriorates
Solution Approach 1:
The system changes the control parameter from steer-by-wire mode to conventional EPS mode when power supply capacity is reduced. The power supply capacity estimating means detects the reduced capacity condition, and the control switching means responds by switching to conventional EPS control, which consumes less power but provides reduced steering assistance, thus adapting to the changed power availability parameter
3Use of energy by moving object
If frequent switching between control modes occurs during power voltage changes, then power supply capacity is optimized, but steering operability becomes uncomfortable
Solution Approach 1:
The system prepares for potential mode switching by continuously monitoring power supply capacity conditions. When switching between SBW and conventional EPS control, the system ensures smooth transitions that cushion the impact on steering operability, preventing abrupt changes that would cause driver discomfort while still optimizing power consumption based on available capacity
Data Source
AI summary
A steering control device in which a steering portion including an electric steering reaction force actuator and a steered portion including an electric steered portion actuator are mechanically disconnectable and connectable via a backup connection. Steer-by-wire control disconnects the backup connection and uses control of the steered portion actuator to set a steered angle corresponding to the steering condition and using control of the steering reaction force actuator to add a steering reaction force corresponding to the steered condition. Steering assistance control connects the backup connection and adds a steering aid force using at least one of the steering reaction force actuator and the steered portion actuator. The power supply capacity of a steered vehicle is selectively estimated and if the estimated power supply capacity reaches a predetermined value or below during the steer-by-wire control, steering is switched to the steering assistance control.