Motor Controller Back-EMF End Position Detection
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Solution Overview
Problem
Traditional motor control methods for reaching a mechanical end position often supply excessive energy, leading to mechanical stress and increased costs due to unnecessary energy consumption and bumping, which existing technologies fail to address effectively.
Innovation Solution
A motor controller that measures back electromotive force (EMF) to detect changes in acceleration and deceleration, allowing precise control of energy supply to prevent excessive energy delivery and reduce mechanical stress, without relying on starting position or speed integration, and adjusts energy based on EMF measurements and temperature considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a preconfigured amount of energy is supplied to the motor to reach the end position, then the motor can reliably reach the end position, but excessive energy is consumed and mechanical stress increases
Solution Approach 1:
The system continuously monitors back EMF measurements from the motor and uses this feedback to detect when the motor has reached the end position. The control unit adjusts the energy supply in real-time based on the detected motor state, stopping energy supply when the end position is reached, thereby eliminating excessive energy consumption while maintaining reliable end position achievement
Solution Approach 2:
The control system dynamically adjusts the energy supply to the motor based on real-time back EMF measurements. Instead of providing a fixed preconfigured energy amount, the system modulates the energy supply according to the motor's actual state and position, optimizing energy efficiency while ensuring the motor reaches the end position reliably
2Reliability
If a preconfigured amount of energy is supplied to the motor, then the motor can reach the end position, but mechanical stress and bumping increase
Solution Approach 1:
The control unit monitors back EMF measurements to detect the motor's approach to the end position and reduces or stops energy supply before the motor reaches the mechanical limit, thereby reducing mechanical stress and bumping while still ensuring the motor reaches the end position reliably
Solution Approach 2:
The system takes preliminary action by detecting the motor's proximity to the end position through back EMF measurements and preemptively reducing energy supply before the motor reaches the mechanical end position, preventing excessive mechanical stress and bumping from occurring in the first place
3Measurement precision
If current monitoring is implemented using a series resistor, then motor current can be measured, but energy loss increases due to voltage drop
Solution Approach 1:
Instead of directly measuring current through a series resistor, the system uses back EMF measurements as an intermediary indicator to infer motor state and position. This indirect measurement approach eliminates the need for power-dissipating series resistors while still providing the necessary information for precise motor control and end position detection
Solution Approach 2:
The system replaces the physical current measurement method (series resistor) with an electrical field-based measurement method (back EMF sensing). This substitution eliminates the mechanical/power loss associated with resistive current sensing while maintaining the ability to monitor and control motor operation precisely
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
This solution enables efficient motor control by detecting the mechanical end position accurately, reducing energy consumption, minimizing mechanical stress, and conserving energy, thus lowering costs and improving the reliability of motor assemblies in applications like electronic locks.
Implementation Method 1
A motor controller that measures back electromotive force (EMF) to detect changes in acceleration and deceleration
Data Source
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AI summary
It is presented a motor controller configured to control movement of a motor to a mechanical end position. The motor controller comprises: a motor output configured to control an amount of energy being supplied to the motor; a motor input configured to measure a back electromotive force, EMF, voltage over the motor; and a control unit being configured to control the amount of energy being supplied on the motor output based on back EMF measurements from the motor input when the motor output is in a state of not supplying energy to the motor wherein the control unit is configured to detect an end position of the motor based on changes of back EMF measurements.