Motor Vehicle Window Lift Force Control for Pinching Prevention
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Solution Overview
Problem
Existing methods for controlling motor vehicle adjusting devices, such as electric window lifters, fail to reliably adjust components while preventing trapping forces and ensuring safe operation, particularly during closing movements, as they often lead to damage or injury from excessive forces or sudden movements.
Innovation Solution
A method that adjusts the speed and force of the drive component based on setpoint values, which are stored and adaptable to temperature and ambient conditions, with a transition from speed to force control in case of trapping, ensuring safe operation by reducing forces and avoiding damage, and allowing for continuous adjustment without additional sensors or memory components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive speed is adjusted to a speed setpoint value during closing movement, then the adjustment reliability is improved, but trapping forces may occur causing damage or injury
Solution Approach 1:
The control method prepares for potential trapping situations by establishing a force setpoint value in advance before closing movement begins. This pre-established force limit serves as a safety threshold that prevents excessive trapping forces from developing, allowing the system to maintain reliable closing operation while having protective measures ready.
Solution Approach 2:
The monitoring of drive force during closing movement provides continuous feedback to detect trapping conditions. When the drive force exceeds the predefined force setpoint value, the system responds by reversing the drive, thereby eliminating harmful trapping forces while maintaining adjustment reliability through active control.
2Productivity
If the drive force is increased to overcome movement difficulties, then the adjustment speed is improved, but trapping forces increase causing damage risk
Solution Approach 1:
The control method dynamically adjusts the drive force during closing movement by continuously monitoring the actual drive force and comparing it to the force setpoint value. This dynamic control allows the system to optimize adjustment speed while preventing trapping forces from exceeding safe thresholds, as the force is actively regulated rather than fixed.
Solution Approach 2:
The system changes the drive force parameter in response to detected trapping conditions. When the drive force exceeds the force setpoint value, the control method reverses the drive, thereby changing the force parameter from a potentially harmful high value to a safe reversed value, eliminating trapping forces while maintaining adjustment functionality.
3Reliability
If additional sensors or memory components are added to detect trapping, then the safety is improved, but the device complexity increases
Solution Approach 1:
The control method utilizes the existing drive force monitoring capability of the adjusting device to detect trapping conditions. By evaluating the drive force that is already being controlled for normal operation, the system achieves safety functionality without requiring additional sensors or memory components, thereby maintaining simplicity while improving safety.
Solution Approach 2:
The drive force monitoring system serves multiple functions: it controls the normal operation of the adjusting device and simultaneously detects trapping conditions. This multi-functionality allows the same control mechanism to perform both adjustment and safety functions, eliminating the need for separate dedicated trapping detection components.
Data Source
AI summary
In order to control an adjusting device of a motor vehicle, in particular a window lift, having a motor-driven adjusting part, the speed of the drive is controlled to a desired speed value during normal operation at least in a sub-range of an adjustment travel and the driving force is controlled to a desired force value in the event of difficult motion for a first time period. After the first time period has ended, the adjusting part is reversed or the drive is at least stopped in the event of pinching. If the difficult motion is not an event of pinching, the speed of the drive is controlled anew to the desired speed value, wherein the driving force is first reduced to a first force and is increased to the desired force value within a second time period and/or a value realized during normal operation is used as a desired force value for the driving force.