EPS Signal-Based Driver Grip Detection for Steering Control
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Solution Overview
Problem
Advanced driver assistance systems (ADAS) face challenges in detecting when a driver intends to take control of a vehicle, particularly in scenarios where the driver's hands are off the steering wheel, requiring a timely and intuitive method to communicate driver intervention.
Innovation Solution
A system comprising a driver torque estimation module and a grip detection module that estimates a driver torque state based on electric power steering signals, determining a grip level, hands-on wheel flag, and transition blending factor to facilitate a transition from position control mode to torque control mode in the power steering system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driver hand contact detection is implemented using traditional sensors, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The EPS system uses its own existing signals (motor current, position, velocity) to detect driver hand contact, making the detection system self-sufficient without requiring external sensors. The controller leverages data already being collected for steering assistance to simultaneously determine driver intent.
Solution Approach 2:
The patent replaces physical contact sensors with a signal-based detection method using electrical and computational means. Instead of mechanical or capacitive sensors that detect hand presence, the system uses motor current analysis and control signal processing to infer driver contact status.
2Reliability
If driver intervention detection is delayed, then system stability is maintained, but responsiveness to driver intent deteriorates
Solution Approach 1:
The system continuously monitors EPS signals and pre-calculates driver torque estimates before actual hand contact occurs. By maintaining readiness to detect driver intent through continuous signal analysis, the system can immediately respond when the driver applies torque, eliminating detection delay while maintaining stability through gradual transition blending.
Solution Approach 2:
The patent implements dynamic transition blending between position control and torque control modes based on real-time driver torque estimates. The transition blending factor continuously adjusts the control mode mix, allowing smooth adaptation to driver intent rather than abrupt switches, thereby maintaining system stability during mode transitions.
3Extent of automation
If position control mode is used exclusively, then automation level is improved, but driver control responsiveness deteriorates
Solution Approach 1:
The system dynamically adjusts the transition blending factor based on detected driver torque, continuously varying the mix between position control and torque control modes. When driver torque exceeds a threshold, the system gradually increases torque control contribution, enabling smooth handover from automated to manual control without abrupt transitions.
Solution Approach 2:
The patent changes the control parameter from pure position control to a blended control mode that incorporates torque control elements. By modifying the control parameter (transition blending factor) based on driver intent detection, the system adapts its control characteristics to balance automation and driver responsiveness.
Data Source
AI summary
A system for detecting handwheel control comprises a driver torque estimation module that estimates a driver torque state based on a plurality of electric power steering signals; and a grip detection module that determines one of a grip level, a hands-on wheel flag, and a transition blending factor from the driver torque state, the grip level is used to control a driver assist power steering system.