Windshield Wiper Motor Control Circuit Using Angle-Based Speed Set Point
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Solution Overview
Problem
Existing windshield wiper motor control systems are inefficient at low rotation speeds, consume excessive power, and are bulky and complex, making them unsuitable for applications requiring high torque and aerodynamic considerations.
Innovation Solution
A control circuit for electric motors that adjusts angular speed using a continuous function of the motor angle, reducing power consumption and torque, and allowing for closed-loop feedback control to optimize motor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a motor operates in open-loop mode at maximum torque, then it can achieve high torque output, but its operating efficiency at low rotation speeds is reduced
Solution Approach 1:
The patent implements closed-loop control by measuring the actual rotational speed of the motor and comparing it with the reference speed. Based on the speed deviation, the controller adjusts the torque output to maintain optimal efficiency while achieving the required torque. This feedback mechanism allows the motor to operate at efficient points even during low-speed operations.
Solution Approach 2:
The control system dynamically adjusts the torque reference based on the measured speed and operational requirements. Rather than operating at fixed maximum torque, the system modulates torque in real-time to match actual needs, improving efficiency during low-speed phases while maintaining high torque capability when required.
2Ease of operation
If a connecting rod and crank system is used to convert rotary movement into back-and-forth movement, then the conversion is achieved, but the device becomes expensive, complex, bulky, and heavy
Solution Approach 1:
The patent replaces the traditional mechanical connecting rod and crank conversion system with an electronic control approach. The motor directly drives the windshield wiper through electronic speed and torque control, eliminating the need for intermediate mechanical conversion components. This substitution dramatically reduces device complexity, size, and weight while maintaining the required back-and-forth movement capability.
Solution Approach 2:
The invention extracts and removes the connecting rod and crank mechanism from the system, retaining only the essential motor and control electronics. By taking out the unnecessary mechanical conversion components, the system achieves the same functional outcome with significantly reduced complexity and weight.
3Ease of operation
If a connecting rod and crank system is used for movement conversion, then the rotary to back-and-forth conversion is achieved, but the device requires sufficient space and has non-negligible weight
Solution Approach 1:
The patent replaces the heavy mechanical connecting rod and crank system with a lightweight electronic control system. The motor directly actuates the windshield wiper through controlled electromagnetic forces, eliminating the need for heavy mechanical conversion components. This substitution significantly reduces the weight of the moving parts while maintaining full movement conversion capability.
4Ease of operation
If electrical power switches are used to control motor direction, then the windshield wiper direction changes are controlled, but the device is not suited for applications requiring high torque and aerodynamic considerations
Solution Approach 1:
The patent implements closed-loop speed control that continuously monitors motor performance and adjusts torque output accordingly. This feedback mechanism enables the system to deliver high torque when needed (during startup, against aerodynamic loads, or on heavy windshields) while maintaining precise direction control through the same control architecture that manages speed and torque.
Solution Approach 2:
The control system dynamically changes operational parameters including torque reference, speed reference, and current limits based on real-time conditions. This allows the motor to adapt its torque capability to match aerodynamic requirements and load conditions, overcoming the limitations of fixed-switch control systems.
Data Source
AI summary
The invention relates to a control circuit (3) for an electric motor, in particular for driving a windshield wiper, including a control means (16) comprising an output for controlling the electric motor, the control means being capable of varying the angle of the motor between a given minimum value and maximum value. In particular, the control means (16) comprises an input for receiving a speed set point and is capable of controlling the angular speed of the motor according to the speed set point, the control circuit likewise including a set point means (14) comprising an input for receiving values of the angle of the motor and an output for providing a speed set point to the control means, the set point means (14) being capable of determining the speed set point from a continuous function of the motor angle. The invention likewise relates to a driving mechanism (2) for producing an alternating rotary motion comprising a circuit (3) such as described previously and an electric drive motor (4), as well as to a windshield wiper device (I) including at least one driving mechanism (2) such as described previously and an windshield wiper arm (5) driven by the driving mechanism.