Steering Motor Current Threshold for Obstacle Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steer-by-wire steering systems face challenges in accurately detecting wheel contact with obstacles during stationary steering, leading to potential overheating of the steering motor and incorrect current threshold determination, which can result in missed obstacle detection and inadequate resistance feedback to the driver.
Innovation Solution
A steering system with a controller that includes a limiting control circuit, determining circuit, and threshold computing circuit, which sets a current threshold below the limiting value to prevent overheating while accurately detecting obstacle contact by comparing the supplied current, and incorporates a limiting axial force into the steering reaction command to provide resistance feedback to the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current threshold is set to the limiting value to prevent overheating, then motor protection is improved, but obstacle detection accuracy deteriorates because the current value may not reach the threshold when current is limited
Solution Approach 1:
The patent changes the parameter relationship between the current threshold and limiting value. Instead of setting the current threshold equal to the limiting value, the patent sets the current threshold to a value higher than the limiting value. This parameter change allows the system to distinguish between normal current limiting conditions and abnormal obstacle contact conditions, resolving the contradiction between motor protection and obstacle detection accuracy
Solution Approach 2:
The patent introduces a dual-threshold mechanism as an intermediary solution. By setting both a current threshold and a limiting value, the system creates a layered detection approach where the current threshold serves as the primary detection criterion and the limiting value serves as a secondary confirmation criterion, enabling accurate obstacle detection while preventing false positives during normal current-limited operation
2Measurement precision
If the current threshold is set below the limiting value to ensure obstacle detection, then detection sensitivity is improved, but false positive determinations increase during normal current-limited operation
Solution Approach 1:
The patent introduces a dual-threshold mechanism as an intermediary solution. By setting both a current threshold and a limiting value, the system creates a layered detection approach where the current threshold serves as the primary detection criterion and the limiting value serves as a secondary confirmation criterion, enabling accurate obstacle detection while preventing false positives during normal current-limited operation
Solution Approach 2:
The patent applies dynamic judgment logic that adapts the detection criteria based on operating conditions. The controller dynamically evaluates whether the current threshold is exceeded in conjunction with the limiting value, allowing the system to differentiate between legitimate obstacle contact signals and normal operational variations, thereby reducing false positives while maintaining detection sensitivity
3Ease of operation
If excessive current is supplied to follow the steering angle when the steer wheel hits a curb, then steering angle tracking is improved, but motor overheating occurs
Solution Approach 1:
The patent applies preliminary anti-action by pre-setting the current threshold and limiting value before operation begins. These pre-configured parameters establish protective boundaries that automatically prevent excessive current supply when the steer wheel encounters an obstacle, eliminating the need for reactive current reduction and ensuring motor temperature remains within safe limits while maintaining steering angle tracking capability
Data Source
AI summary
A steering system includes a mechanism configured to turn a steer wheel of a vehicle, a motor configured to generate driving force that is applied to the mechanism, and a controller configured to control the motor according to a steering status. The controller includes a limiting control circuit configured to limit a current that is supplied to the motor to a limiting value, a determining circuit configured to determine whether the steer wheel is in contact with an obstacle by using at least a comparison between a value of the current that is supplied to the motor and a threshold, and a threshold computing circuit configured to compute the threshold that is used by the determining circuit, the threshold computing circuit being configured to compute a value less than the limiting value according to the limiting value as the threshold.