Steering Actuator Torque Compensation for Haptic Feedback
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Solution Overview
Problem
Existing haptic feedback systems in vehicles, such as lane departure warning systems, cause a drop in steering torque and friction during steering wheel vibration, leading to a lighter steering feel and potentially involuntary movements, compromising driving comfort.
Innovation Solution
An actuator applies an alternating torque to the steering grip, with a compensating torque counteracting the average total steering torque at the onset of haptic feedback, maintaining the original steering feel by adjusting and gradually reducing the compensating torque during and after the vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If haptic feedback is generated by applying alternating torque to the steering wheel, then the driver receives warning feedback, but the steering torque decreases causing lighter steering feel and potential involuntary movements
Solution Approach 1:
The control unit applies a compensating torque in advance or simultaneously with the alternating torque for haptic feedback. This compensating torque counteracts the friction reduction effect, preventing the steering feel from becoming too light and avoiding involuntary steering movements while maintaining reliable haptic feedback delivery.
Solution Approach 2:
The system dynamically adjusts the steering torque parameter by superimposing a compensating torque component when haptic feedback is active. This parameter change compensates for the friction decrease caused by vibration, maintaining consistent steering characteristics throughout the feedback delivery period.
2Loss of information
If alternating torque is applied to generate steering wheel vibration, then lane departure warning is provided, but the friction in steering system decreases
Solution Approach 1:
The system converts the harmful effect of reduced friction during vibration into a beneficial compensating torque application. By detecting the friction decrease caused by alternating torque, the control unit applies an opposing compensating torque that restores the original friction level, ensuring both effective warning delivery and stable steering force characteristics.
3Reliability
If support motor is used to generate vibration for lane departure warning, then haptic feedback is achieved, but steering torque varies during vibration
Solution Approach 1:
The control unit continuously monitors steering torque and friction conditions during haptic feedback delivery. Based on this feedback, it dynamically adjusts and applies a compensating torque to counteract variations caused by the alternating torque, maintaining consistent steering torque characteristics throughout the warning feedback period.
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
Prevents the perceived lightness and discomfort associated with haptic feedback, ensuring consistent steering torque and reducing the risk of involuntary movements, thereby enhancing driving comfort.
Implementation Method 1
an alternating torque is applied, via which the support motor causes the steering system to vibrate
Implementation Method 2
the natural damping or friction in the steering system, which normally constantly opposes the driver's steering action, decreases
Data Source
AI summary
A method and a device generate haptic feedback for a vehicle driver, the haptic feedback being generated by applying an additional torque, which alternates about an average total steering torque, to a steering grip of a vehicle by way of an actuator. When the present haptic feedback is recognized and/or simultaneously when haptic feedback occurs, the actuator is actuated such that the magnitude of the average total steering torque is increased by a compensation torque.