Motor Startup Pinch Detection in Vehicle Open-Close Control
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Solution Overview
Problem
Existing open/close control systems for vehicles, such as power windows, face challenges in accurately determining pinching immediately after the motor is started due to unstable motor operations, leading to erroneous pinching prevention activations and delayed detection.
Innovation Solution
An open/close control system that computes an acceleration term based on the change in rotational period and load of the motor, adjusting the determination value by increasing it when a local maximum acceleration value exceeds a threshold during the motor's startup, to prevent false pinching detection and ensure timely detection of actual pinching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the determination value for pinching detection is increased to avoid false detection during motor startup, then false pinching prevention activations are reduced, but the detection timing of actual pinching is delayed
Solution Approach 1:
The determination value is made dynamic rather than fixed. The control device adjusts the determination value based on the motor operation state: using a first (lower) determination value during unstable startup period and a second (higher) determination value during stable operation period. This dynamic adjustment resolves the contradiction by allowing timely detection during startup while preventing false detections during stable operation.
Solution Approach 2:
The patent changes the parameter (determination value) based on operating conditions. By monitoring motor current and operation state, the system switches between different determination value settings. This parameter change approach allows the system to optimize detection accuracy for each operational phase, avoiding both false detections and delayed detection.
2Loss of time
If the determination value is kept low for timely pinching detection, then detection timing is improved, but false pinching prevention activations occur during unstable motor operation
Solution Approach 1:
The determination value transitions from static to dynamic based on motor startup phase. During the unstable startup phase, a lower determination value is used to enable timely detection, while during stable operation, a higher value prevents false activations. This dynamic behavior resolves the contradiction between timely detection and false activation prevention.
Solution Approach 2:
The system performs preliminary classification of motor operation state (startup vs. stable operation) before applying the appropriate determination value. By identifying the operational phase in advance, the system can pre-select the appropriate threshold, ensuring timely detection during startup while preventing false activations during stable operation.
Data Source
AI summary
An open/close control device which detects pinching by an open/close body due to driving of a motor, includes a computing unit configured to compute an acceleration term based on a change in a rotational period of the motor, and a load applied to the motor based on the acceleration term, based on a signal indicating the rotation period of the motor, a determination unit configured to determine that the pinching by the open/close body occurred, when the load computed by the computing unit exceeds a predetermined determination value, and a determination value adjusting unit configured to increase the determination value when a local maximum value of the acceleration term exceeds a predetermined threshold value, or the acceleration term becomes less than or equal to a predetermined reference value, or the acceleration term decrease by a predetermined value or more, during a certain period after starting the motor.