Fan Coupling Control for Predictive Hunting Suppression
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Solution Overview
Problem
Fan coupling devices experience hunting, a repetitive increase and decrease in rotation speed due to response delays from characteristic variations and secular changes, which existing controllers fail to effectively restrain.
Innovation Solution
A controller for fan coupling devices that includes an acquisition unit, a control unit, a prediction unit, and a restraining unit, which predicts hunting occurrences based on acceleration and deviation parameters and adjusts feedback control gains to prevent hunting by lowering integral gain and increasing derivative gain when hunting is predicted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedback control is used to control the regulation mechanism, then the rotation speed of the fan can be controlled, but hunting (repetitive increase and decrease of rotation speed) may occur due to response delay
Solution Approach 1:
The prediction unit performs preliminary action by predicting hunting occurrence before it actually happens, based on the current operating point in the coordinate system. When the operating point falls within the predicted region, the system proactively adjusts control gains to prevent hunting, rather than reacting after hunting has already occurred.
Solution Approach 2:
The controller dynamically adjusts the integral gain and derivative gain of the feedback control based on the predicted hunting risk. The integral gain is lowered and derivative gain is increased when hunting is predicted to occur, creating a dynamic control strategy that adapts to changing operating conditions to maintain stability.
2Stability of the object's composition
If the integral gain is lowered and derivative gain is increased to restrain hunting, then hunting is suppressed, but the response speed and control precision may deteriorate
Solution Approach 1:
The controller applies different control gain settings in different regions of the operating space. In the predicted region where hunting is likely, lower integral gain and higher derivative gain are used for stability. In other regions, normal control gains are maintained for faster response. This local differentiation of control quality optimizes both stability and response speed.
Solution Approach 2:
The control gains are dynamically adjusted based on the real-time operating point. The system transitions between different control strategies (normal mode vs. hunting prevention mode) depending on the predicted hunting risk, allowing it to maintain fast response when safe and ensure stability when hunting is predicted.
Data Source
AI summary
A controller of a fan coupling device includes: an acquisition unit that acquires an acceleration parameter and a deviation parameter; a control unit that controls a regulation mechanism; a prediction unit that predicts that hunting occurs in the rotation speed of the fan, when an operating point of the fan expressed with the deviation parameter and the acceleration parameter belongs to a predicted region; and a restraining unit that executes, when the hunting is predicted to occur, a hunting restraining process of executing at least one of lowering an integral gain of a feedback control to be lower than when the hunting is not predicted to occur and increasing a derivative gain of the feedback control to be higher than when the hunting is not predicted to occur.