Steering System Hands-On Detection via Vibration Phase Analysis

The patent applies mechanical vibration by exciting the steering system with a vibration generator at a specific excitation frequency. The system responds with vibrations whose amplitude and phase characteristics change depending on whether hands are on the steering wheel. This vibration-based approach allows friction states to be distinguished without additional sensors, resolving the contradiction between avoiding complex sensor systems and maintaining detection accuracy.

The patent changes the parameter being measured from simple movement behavior to the phase difference between excitation and response vibrations. By monitoring how the phase difference changes with varying excitation frequencies and amplitudes, the system can distinguish between static and sliding friction states, thereby accurately detecting hands-on/hands-off conditions without additional sensors.

The patent employs dynamic excitation by varying the excitation frequency and amplitude according to a predefined sequence. Instead of using a fixed excitation signal, the system dynamically adjusts parameters to probe different friction regimes. This dynamic approach ensures that actual physical transitions between friction states are induced and reliably detected, resolving the contradiction between detection capability and reliability.

The system uses feedback by continuously monitoring the response vibration characteristics and comparing them against expected patterns for different friction states. The excitation parameters are adjusted based on the detected state, creating a closed-loop system that ensures reliable transition detection and maintains accurate hands-on/hands-off identification throughout operation.