Steer Torque Manager Bandwidth Scaling for ADAS
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Solution Overview
Problem
Current steer torque managers in advanced driver assistance systems face a contradiction between high bandwidth for accurate tracking of steering requests and low bandwidth for comfort, leading to pulsating torque sensations and potential car sickness, while high bandwidth can cause discomfort and low bandwidth may result in sluggish performance.
Innovation Solution
A steer torque manager that scales the bandwidth of the wheel angle controller based on driver activity, reducing bandwidth during high activity and increasing it during low activity, using a driver in the loop factor and vehicle traveling velocity to adapt the torque management, and employing integral action and scale tables for smooth control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high bandwidth is used in the wheel angle controller, then accurate tracking of steering requests is improved, but pulsating torque sensations and driver discomfort occur
Solution Approach 1:
The patent applies dynamics by making the bandwidth of the wheel angle controller variable rather than fixed. The controller dynamically adjusts its bandwidth based on detected driver activity levels - using high bandwidth when driver activity is low for accurate tracking, and reducing bandwidth when driver activity is high to eliminate pulsating torque sensations. This dynamic adaptation resolves the contradiction between tracking accuracy and driver comfort.
Solution Approach 2:
The patent changes the parameter of bandwidth from a constant value to a variable parameter that is adjusted based on driver activity. By monitoring driver activity signals and modifying the bandwidth parameter accordingly, the system achieves both high tracking accuracy when needed and smooth torque delivery when the driver is actively steering, thus resolving the technical contradiction.
2Object-affected harmful factors
If low bandwidth is used in the wheel angle controller, then driver comfort is improved, but sluggish tracking performance occurs
Solution Approach 1:
The system dynamically adjusts bandwidth based on real-time driver activity detection. When driver activity is detected as low, the controller uses high bandwidth to ensure fast and accurate tracking of steering requests. When driver activity increases, the bandwidth is reduced to provide smooth torque and maintain driver comfort. This dynamic behavior resolves the contradiction between comfort and tracking speed.
Solution Approach 2:
The patent implements feedback by continuously monitoring driver activity signals and using this information to adjust the bandwidth parameter of the wheel angle controller. The feedback loop ensures that the controller adapts its bandwidth - using high values for fast tracking when the driver is not active, and low values for comfort when the driver is active, thus resolving the contradiction between tracking speed and driver comfort.
3Object-affected harmful factors
If bandwidth is reduced to eliminate pulsating torque, then driver comfort is improved, but tracking accuracy deteriorates
Solution Approach 1:
The patent makes the bandwidth dynamic rather than static, adjusting it based on driver activity levels. When driver activity is low, high bandwidth is used to maintain accurate tracking of steering requests. When driver activity is high, bandwidth is reduced to ensure torque smoothness and eliminate pulsating sensations. This conditional dynamic adjustment resolves the contradiction between torque smoothness and tracking accuracy.
Solution Approach 2:
The system changes the bandwidth parameter based on detected driver activity conditions. By monitoring driver activity signals and modifying the bandwidth parameter accordingly - high when activity is low for accuracy, low when activity is high for smoothness - the patent resolves the contradiction between torque smoothness and steering request tracking accuracy.
Data Source
AI summary
A steer torque manager for an advanced driver assistance system of a road vehicle and a method therefor. The steer torque manager includes a driver in the loop functionality for determining when to hand over control to a driver, and a wheel angle controller for providing, from an advanced driver assistance system wheel angle request, an overlay torque request to be added to a torque request from an electrical power assisted steering. The steer torque manager is configured to receive an assistance torque related signal and arranged to scale, in a scaling functionality the bandwidth of the wheel angle controller based on a measure of driver activity, such that the bandwidth is reduced if the measure of driver activity indicates high driver activity and increased if the measure of driver activity indicates low driver activity.