Motor Drive Position Recognition via Optical Sensor
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Solution Overview
Problem
Existing drive systems for translational or rotational movements, such as sliding gates and revolving doors, rely on expensive and complex frequency control for asynchronous motors, and require end stops or limit switches to determine load position, which are prone to malfunction and increase costs.
Innovation Solution
A sensor system that measures the actual speed and rotational position of the electric motor's rotor, using a sensor transmitter and receiver to calculate phase control points, allowing the drive control to recognize the load's position and eliminate the need for end stops and limit switches by determining the position within the intended range of movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end stops and limit switches are used to determine load position, then the drive control can recognize the position of the moving load, but the gate construction becomes more expensive and the components are prone to malfunction due to weather and mechanical influences
Solution Approach 1:
The patent replaces mechanical end stops and limit switches with an optical sensor system. The sensor transmitter is mounted on the motor shaft and rotates with it, while the sensor receiver remains stationary. This optical measurement system eliminates the need for mechanical contact components, thereby reducing mechanical failures and improving reliability in outdoor environments.
Solution Approach 2:
The patent introduces a sensor transmitter as an intermediary element mounted on the motor shaft. This transmitter rotates with the shaft and works in conjunction with a stationary sensor receiver to determine the angular position of the shaft without requiring mechanical end stops or limit switches, thus simplifying the overall gate construction.
2Measurement precision
If frequency control is used to control the speed of asynchronous motors, then the speed control is precise, but the control system becomes complex and expensive
Solution Approach 1:
The patent replaces complex frequency control electronics with a simpler phase control system. By using a sensor to detect the angular position of the motor shaft and comparing it with the target position, the system calculates the required phase control point to achieve precise speed control without requiring complex frequency control circuitry.
Solution Approach 2:
The patent implements a feedback mechanism where the sensor continuously monitors the actual angular position of the motor shaft, and the control element compares this with the target position. Based on this comparison, the system adjusts the phase control points to maintain precise speed control, replacing the need for complex open-loop frequency control.
3Device complexity
If phase control is used to control the speed of electric motors, then the control system is simpler and less expensive, but the speed control precision is reduced
Solution Approach 1:
The patent uses preliminary action by pre-calculating the required phase control points based on the target angular position. The control element determines in advance what phase control points are needed to achieve the desired speed and position, allowing simple phase control to achieve precise results through proactive adjustment rather than reactive correction.
Solution Approach 2:
The patent introduces dynamics by continuously adjusting the phase control points based on the real-time angular position of the motor shaft. The system dynamically calculates the required phase control points to maintain precise speed control throughout the motor's operation, transforming static phase control into a dynamic, position-dependent control system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control of motor speed and position recognition, reducing costs and mechanical failures by eliminating the need for end stops and limit switches, while maintaining accurate positioning even after power failures.
Implementation Method 1
a sensor (18) is provided which serves to measure the actual speed and the rotational position of the rotor (16) of the electric motor (8) or of a sensor wheel connected to it for rotation
Data Source
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AI summary
The drive (7) has an electric motor (8) operated with alternating current, three-phase alternating current or pulsed direct current. A phase controlled modulator controls the number of revolutions of the electric motor. A sensor measures the actual number of revolutions and a turning position of a rotor or a driveshaft of the electric motor or sensor wheels rotatably connected with the motor, if required. A control element controls the electric motor to compare the actual number of revolutions with a predetermined target number of revolutions and to compute a required phase intersection point.