Anti-Pinch Force Detection Using Motor Current and Obstacle Stiffness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anti-pinch detection methods based on motor speed fail to meet S5 regulations and often result in false detections due to inconsistent force measurements across obstacles with different stiffness, leading to potential failure in closing closure components.
Innovation Solution
An anti-pinch detection method that determines a first and second current change rate to identify obstacles, calculates stiffness, and adjusts the anti-pinch detection threshold based on obstacle stiffness, using a controller to reverse the motor when the pinch force exceeds a preset threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If motor speed-based anti-pinch detection is used, then detection speed is maintained, but measurement consistency across different obstacle stiffness fails
Solution Approach 1:
The patent changes the detection parameter from motor speed to motor current. By monitoring current changes during motor operation, the system can detect obstacles and calculate their stiffness. This parameter change enables consistent force measurements across different obstacle stiffness values while maintaining fast detection response, as current changes occur immediately when the closure component contacts an obstacle.
2Device complexity
If a fixed anti-pinch detection threshold is used, then detection simplicity is maintained, but false detections occur across different obstacle stiffness
Solution Approach 1:
The patent implements a dynamic anti-pinch detection threshold that adapts to different obstacle stiffness values. When an obstacle is detected, the system calculates its stiffness based on current change rates and uses this information to determine an appropriate threshold. This dynamic approach prevents false detections across different stiffness conditions while maintaining system reliability, as each obstacle type receives a customized detection threshold.
Solution Approach 2:
The system uses feedback from current measurements to continuously adjust the detection threshold. By monitoring the actual current response when the closure component contacts an obstacle, the system learns the obstacle's stiffness characteristics and adjusts the threshold accordingly. This feedback mechanism eliminates false detections while maintaining simple operation, as the threshold automatically adapts without requiring manual intervention.
3Measurement precision
If current change rate detection is implemented, then force measurement consistency is improved, but calculation complexity increases
Solution Approach 1:
The patent segments the current change rate calculation into two distinct components: a first current change rate for stiffness determination and a second current change rate for obstacle detection. This segmentation allows the system to use different calculation approaches for different purposes, simplifying the overall complexity while maintaining measurement precision. The first rate focuses on characterizing the obstacle, while the second rate focuses on detecting the contact event.
Solution Approach 2:
The system calculates current change rates over different time periods using the formula ΔI/Δt, where Δt can represent different durations (e.g., one control cycle or multiple cycles). This partial action approach allows flexible calculation based on specific detection needs without requiring complete recalculation of all parameters, thereby reducing computational complexity while maintaining precision.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The present invention provides an anti-pinch detection method and system. The method comprises: determining a first current change rate according to a current collected in the present current collection period and a current collected in a previous current collection period; determining a second current change rate according to the current collected in the present current collection period and a current collected in a target current collection period, there being N collection periods between the target current collection period and the present current collection period; detecting whether a closure component encounters an obstacle according to the second current change rate, and if yes, determining the stiffness of the obstacle according to the first current change rate; determining a real-time obstacle compression distance according to a contact position zero point and a motor position collected in real time; and determining a real-time anti-pinch force according to the stiffness of the obstacle and the real-time obstacle compression distance, and controlling a motor to reverse when the real-time anti-pinch force is greater than a preset anti-pinch detection threshold. The anti-pinch detection method provided in the present invention can satisfy S5 regulations, and the detection effect is good.