Motor Speed Controller Out-of-Control Reverse Rotation Detection
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Solution Overview
Problem
Existing motor speed controllers using a single pulse signal cannot accurately detect the direction of rotational speed, leading to potential out-of-control reverse rotation due to measurement errors, especially when chattering occurs in the pulse signal, causing the motor to deviate from the target speed.
Innovation Solution
A motor speed controller incorporating a feedforward control section, feedback control section, and an out-of-control reverse rotation determining section, which uses a composite signal to identify and correct out-of-control reverse rotation by determining the control direction and strength of the signal, allowing for restoration to the target rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one kind of pulse signal is used from the motor, then the device complexity is reduced, but the measurement precision of rotational speed direction is lost
Solution Approach 1:
The patent implements feedback control by continuously monitoring the composite signal (combination of target instruction signal and compensation instruction signal) and comparing it with the target rotational speed. When the motor enters out-of-control reverse rotation, the feedback mechanism detects the deviation and generates corrective control signals to restore normal operation, thereby resolving the direction detection problem using only one pulse signal.
Solution Approach 2:
The patent introduces an intermediary mechanism - the out-of-control reverse rotation determining section - which acts as a mediator between the single pulse signal and the control system. This intermediary processes the pulse signal through feedforward and feedback control to infer rotational direction and detect abnormal states, enabling direction detection without requiring multiple pulse signals.
2Stability of the object's composition
If feedback control is applied to correct speed deviations, then the stability of rotational speed is improved, but out-of-control reverse rotation may occur due to measurement errors
Solution Approach 1:
The patent applies preliminary action by implementing feedforward control that anticipates potential speed deviations and prepares corrective measures in advance. The out-of-control reverse rotation determining section proactively monitors the composite signal and identifies abnormal trends before they lead to complete loss of control, allowing preventive correction rather than reactive response.
Solution Approach 2:
The patent implements beforehand cushioning by creating a safety mechanism that cushions against the harmful effect of out-of-control reverse rotation. The determining section continuously evaluates the composite signal and prepares to intervene when abnormal patterns are detected, providing a protective buffer that prevents measurement errors from causing catastrophic control failure.
3Measurement precision
If the target rotational speed is adjusted frequently to correct errors, then the measurement precision is improved, but the loss of time increases
Solution Approach 1:
The patent ensures continuity of useful action by implementing continuous monitoring of the composite signal through the out-of-control reverse rotation determining section. Rather than intermittent corrections, the system continuously evaluates the feedback signal and maintains optimal control, eliminating the need for frequent discrete adjustments while preserving high measurement precision.
Data Source
AI summary
A motor speed controller detects out-of-control reverse rotation of a motor even when the pulse signal obtained from the motor and synchronized with the rotation is of only one kind. A target instruction signal is generated on the basis of a target rotational speed ωT of the motor. A compensation instruction signal is generated on the basis of an error signal Ve that corresponds to a difference between the actual rotational speed ω and ωT. A composite signal is generated by combining above two instruction signals. A state in which the control direction of the composite signal with respect to ω is the reverse of the direction of ωT, and the strength of the composite signal exceeds a designated threshold continues for a designated period, is judged as a state of out-of-control reverse rotation, and restoration to the normal state is performed.