Wiper Drive Torque Control via Adaptive Curves
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Solution Overview
Problem
Wiper drives, especially those used in motor vehicles, face significant loads during operation, particularly when encountering snow loads, wind loads, or jamming, which can lead to damage or failure due to the inability to adjust engine torque effectively, especially when the system becomes blocked.
Innovation Solution
A method for operating a wiper drive with a motor that involves reading and utilizing angle-dependent and direction-dependent torque characteristic curves to manage torque based on different wiping angles and directions, accounting for air resistance, inertia, and frictional forces, allowing for load-dependent torque control and reduced risk of damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor torque is reduced by voltage reduction to protect against damage during blocking, then the system protection is improved, but the wiper system cannot maintain the legally required minimum speed
Solution Approach 1:
The patent applies dynamics by making the torque characteristic curve adjustable and adaptable to different operating conditions. The control device can modify the torque characteristics dynamically based on detected blockage conditions, transitioning from a first torque characteristic curve during normal operation to a second torque characteristic curve during blockage detection, enabling the system to adapt its mechanical response in real-time
Solution Approach 2:
The patent changes the parameter of torque characteristics by using different torque characteristic curves. The control device stores multiple torque characteristic curves and selects appropriate curves based on operating conditions. During blockage, the system changes from one torque characteristic to another, modifying the torque-angle relationship to reduce peak torques while maintaining operational speeds
2Reliability
If the torque characteristic curve is modified to reduce peak torques during blocking, then the protection function is improved, but the wiper system may not be able to pull through at high wind speeds
Solution Approach 1:
The system dynamically adjusts torque characteristics based on real-time operating conditions. The control device monitors the operating point and can switch between different torque characteristic curves, making the torque output adaptive rather than fixed, allowing optimization for both protection and performance under varying conditions
Solution Approach 2:
The patent implements preliminary action by pre-calculating and storing multiple torque characteristic curves that account for different operating scenarios including blockage conditions. The system prepares appropriate torque characteristics in advance and selects the suitable curve based on current operating parameters, enabling proactive adaptation rather than reactive response
Data Source
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AI summary
The invention relates to a method for operating a direct wiper drive having a motor, in particular for a windshield wiper. The method comprises reading out at least one characteristic curve from a memory and operating the wiper direct drive at an angle- and direction-dependent torque, corresponding at a maximum to a value of the angle- and direction-dependent characteristic curve, wherein the characteristic curve comprises at least the following values: a first, maximum value for upward wiping at a first wiping angle between a lower turning location and an upper turning location; a second value for upward wiping at a second wiping angle between the first wiping angle and the upper turning location, wherein the second value for upward wiping at the second wiping angle is less than the first, maximum value for upward wiping at the first wiping angle; a first, maximum value for downward wiping at a wiping angle between the upper turning location and the lower turning location, wherein the first, maximum value for downward wiping is greater than the first, maximum value for upward wiping; and a second value for downward wiping corresponding to a wiper position at the second wiping angle, wherein the second value for downward wiping is greater than the second value for upward wiping.