Steering Handle Feedback Torque Adjustment for Hands-Free Detection
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Solution Overview
Problem
Steer-by-wire steering systems lack precise methods for determining hands-free operation, leading to unexpected vehicle behavior due to incomplete interruption of feedback torque generation.
Innovation Solution
A method that adjusts feedback torque based on sensory detection of contact between the driver and the steering handle, reducing the torque in hands-free operation only if it would otherwise move the steering handle away from the neutral position, using a combination of capacitive contact sensors and torque sensors to determine manual steering torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the feedback torque is completely interrupted during hands-free operation, then self-steering is prevented, but unexpected vehicle behavior occurs from the driver's perspective
Solution Approach 1:
Instead of completely interrupting the feedback torque during hands-free operation, the patent applies a reduced but non-zero feedback torque. This partial action prevents self-steering while avoiding the harmful effect of completely removing feedback, which causes unexpected vehicle behavior. The control unit reduces the feedback torque to a lower magnitude rather than setting it to zero.
Solution Approach 2:
The patent changes the parameter of feedback torque from a binary state (on/off) to a continuous adjustment where the torque magnitude is modified based on detection signals. When hands-free operation is detected, the feedback torque parameter is adjusted to a reduced non-zero value, smoothly transitioning between states to maintain predictable vehicle behavior.
2Device complexity
If simple methods are used to determine hands-free operation, then device complexity is reduced, but detection precision is insufficient
Solution Approach 1:
The patent combines multiple detection approaches (contact sensors on the steering handle and torque sensors detecting steering torque) into a unified hands-free detection system. This merging of detection methods improves measurement precision by cross-validating signals while maintaining reasonable device complexity through integrated control unit processing.
Solution Approach 2:
The control unit performs multiple functions: it controls the feedback torque actuator, processes contact sensor signals, analyzes torque sensor data, and determines hands-free operation status. This multi-functionality allows the system to achieve precise hands-free detection without adding separate dedicated detection hardware, thus balancing precision and complexity.
3Reliability
If the feedback torque is reduced to zero during hands-free operation, then self-steering is eliminated, but driver reaction time is reduced
Solution Approach 1:
The patent applies a reduced but non-zero feedback torque during hands-free operation instead of completely eliminating it. This partial action maintains enough feedback to provide the driver with tactile information about steering state, preserving reaction time while still preventing self-steering through the reduced torque magnitude.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides reliable detection of hands-free operation, reducing the risk of unexpected steering movements by maintaining a non-zero feedback torque, thus enhancing driver reaction time and preventing self-steering issues.
Implementation Method 1
using a combination of capacitive contact sensors and torque sensors to determine manual steering torques
Data Source
Figure 1~2
AI summary
The invention relates to a method for adjusting a feedback torque (MFF) on a steering handle (2) of a vehicle (14), wherein, in normal operation in which a driver grips the steering handle (2), a feedback torque (MFF) on the steering handle (2) is adjustable according to a steering angle (ϕL) specified by means of the steering handle (2); and wherein the method comprises: - determining whether hands-free operation is present, in which the driver does not grip the steering handle (2), based on a sensor detection of any contact between the driver and the steering handle (2), and if hands-free operation is present: - generating a feedback torque (MFF) that is non-zero and has a lower value than in normal operation. The invention further relates to a steering system (1) and a vehicle (14).