Adaptive Dead Band Control for Actuator Wear Reduction
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Solution Overview
Problem
The use of a dead band element upstream of linear dynamic controllers in closed-loop control devices leads to reduced actuator movements and energy consumption but impairs control quality due to offset deviations and frequent interventions, especially during sudden desired value changes, resulting in suboptimal steady-state accuracy and increased wear and energy consumption.
Innovation Solution
A closed-loop control device that temporarily deactivates the dead band element during large control deviations, reactivating it when the control deviation undershoots a second threshold value, allowing the controlled variable to stabilize in the center of the dead band, thereby reducing actuator interventions and improving control behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dead band element is activated upstream of the controller, then actuator movements and energy consumption are reduced, but control quality deteriorates due to offset deviations and frequent interventions
Solution Approach 1:
The dead band element transitions from a static, constantly active component to a dynamic element that adaptively changes its state based on process conditions. The monitoring module continuously evaluates control behavior characteristics and automatically switches the dead band between active and inactive states, optimizing the trade-off between energy savings and control quality in real-time
Solution Approach 2:
The system changes the operational parameters of the dead band element based on monitored control behavior. When control deviations are small and stable, the dead band is activated with specific width parameters to reduce actuator interventions. When control quality deteriorates or large deviations occur, the dead band is deactivated or its parameters are adjusted, ensuring control precision is maintained
2Duration of action of moving object
If a dead band element is activated upstream of the controller, then actuator wear is reduced, but control precision deteriorates due to steady-state deviations from desired value
Solution Approach 1:
A monitoring module continuously observes control behavior characteristics including control deviations, actuator intervention frequency, and process stability. This feedback mechanism enables the system to detect when the dead band is causing unacceptable control precision deterioration and automatically responds by deactivating or adjusting the dead band parameters, thus maintaining both actuator protection and control accuracy
3Loss of energy
If a wide dead band is selected to minimize actuating interventions, then energy consumption is reduced, but control response deteriorates during sudden desired value changes
Solution Approach 1:
The system dynamically adapts the dead band configuration based on process conditions. During normal operation with small deviations, a wide dead band minimizes interventions and energy consumption. During sudden desired value changes or disturbances, the monitoring module detects the changed control behavior and automatically deactivates or reduces the dead band width, enabling fast control response when needed
Data Source
AI summary
A closed-loop control device for a process, in which a dead band element is connected upstream of a linear dynamic controller to reduce actuating interventions in the steady control state. If a control deviation (e) of the control loop exceeds a first threshold value (s1), then the dead band element is automatically deactivated, where a control deviation (e1) passed via the dead band element is uninfluenced by a set dead band in the inactive state. If the control deviation (e) then undershoots a second threshold value that is less than the first threshold value, then the dead band element is automatically re-activated. This reduces the energy consumption and wear of an actuator and improves the control behavior with regard to steady-state accuracy and the control behavior of the control loop.