Closing Device Pinch Protection via Stored Integrator Value
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Solution Overview
Problem
Conventional automatic closing devices, such as window lifters and sliding roofs, often fail to reliably prevent pinching forces from exceeding the maximum threshold during the closing process due to indirect measurement of current pinching forces, leading to potential injuries or damages when the electric motor is restarted.
Innovation Solution
The method involves determining the pinching force by integrating a measurement variable, such as a revolution rate gradient, and temporarily storing this value when the electric motor is stopped. Upon resuming operation, the integration starts from the stored value, allowing for accurate assessment and prevention of excessive pinching forces by adjusting the motor direction based on specified threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor is stopped and restarted during the closing process, then the closing operation can be resumed, but the pinching force may exceed the maximum threshold because the integration of the measurement variable starts from zero, leading to unreliable pinch protection
Solution Approach 1:
The integrator value is temporarily stored before restarting the electric motor, so that the integration of the measurement variable continues from the stored value rather than starting from zero. This preliminary action ensures that existing pinching forces are accounted for before resuming the closing operation, preventing the pinching force from exceeding the maximum threshold.
Solution Approach 2:
The control unit continuously monitors the integrator value during the closing process and uses this feedback to determine when to stop the motor and whether to resume operation. By comparing the integrator value against the maximum threshold, the system provides feedback control that ensures pinching forces remain within safe limits.
2Measurement precision
If the integration of the measurement variable starts from zero upon motor restart, then the control logic is simplified, but the pinching force assessment becomes inaccurate, allowing excessive pinching forces to occur
Solution Approach 1:
Before restarting the electric motor, the control unit temporarily stores the integrator value that was accumulated during the previous operation. When the motor restarts, the integration continues from this stored value rather than resetting to zero, ensuring accurate assessment of the current pinching force condition.
3Productivity
If the electric motor is restarted without checking the current pinching force, then the closing process can proceed quickly, but hazardous situations may occur where pinching forces exceed the maximum threshold
Solution Approach 1:
The control unit performs a preliminary check by retrieving the temporarily stored integrator value before restarting the electric motor. This quick check ensures that resuming the closing operation will not cause the pinching force to exceed the maximum threshold, allowing the operation to proceed safely and efficiently without unnecessary delays.
Solution Approach 2:
The system prevents harmful pinching forces by taking preliminary action to store and retrieve the integrator value before motor restart. This preliminary anti-action ensures that the closing operation is only resumed when it will not result in excessive pinching forces, thereby preventing hazardous situations before they can occur.
Data Source
AI summary
The invention relates to a method for operating a closing device (1), wherein with the aid of an electric motor (4) controlled by a control unit (7), a closing element (2) can be moved against a stop edge in a closing direction, the method comprising the following steps: detecting a pinching force on an object or on a body part between the closing element and the stop edge by integrating a measurement variable, wherein the pinching force is represented by a corresponding integrator value; signalling that a maximum permissible pinching force has been reached as a function of the integrator value; temporarily storing the integrator value after the electric motor has been stopped (4); and, when a resumption of an operation of the electric motor (4) in the closing direction is requested, starting the integration of the measurement variable beginning with the temporarily stored integrator value as a starting value.