Incremental actuator with feedback control diagnostics
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Solution Overview
Problem
HVAC actuators face challenges with accurate position feedback, leading to drift issues and increased costs due to the need for additional wiring and higher expenses associated with proportional actuators, which are not effectively addressed by existing systems.
Innovation Solution
A controller system that uses a position sensor, such as a potentiometer, to receive voltage values indicative of the actuator's position, performs fault correction processes to calculate an updated stroke range, and implements periodic overdrive sequences to resynchronize the actuator, thereby correcting for drift and ensuring accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If incremental actuators are used without feedback control, then cost and wiring complexity are reduced, but position accuracy deteriorates due to drift
Solution Approach 1:
The patent implements feedback control by having the controller continuously monitor the actual position of the actuator through position feedback and compare it with the commanded position. When drift is detected (difference between actual and commanded position exceeds a threshold), the controller automatically initiates a recalibration process to correct the position error, thereby maintaining position accuracy without requiring complex additional hardware.
2Measurement precision
If proportional actuators are used to improve position accuracy, then position feedback is achieved, but cost and wiring requirements increase
Solution Approach 1:
The patent enables the incremental actuator to perform self-calibration and self-correction of position drift automatically. The controller monitors position feedback, detects drift conditions, and autonomously executes recalibration sequences without requiring external intervention or complex proportional control wiring, thus achieving measurement precision with minimal additional system complexity.
Solution Approach 2:
The patent performs preliminary calibration actions during system initialization and periodically during operation to establish accurate position reference points before normal operation begins. This preliminary positioning ensures that subsequent position measurements and corrections are based on accurate reference data, improving measurement precision without requiring continuous complex control wiring.
3Reliability
If automatic fault correction is implemented, then position accuracy is maintained, but processing time and computational load increase
Solution Approach 1:
The patent implements periodic monitoring of position feedback at predetermined intervals during normal operation. Instead of continuous real-time correction, the system checks position accuracy periodically and only initiates fault correction processes when drift is detected, thereby maintaining position accuracy while minimizing unnecessary processing time and computational overhead during normal operation.
Solution Approach 2:
The patent applies partial correction by only recalibrating the actuator position when drift exceeds a predetermined threshold, rather than continuously adjusting position. This selective correction approach maintains position accuracy while reducing the frequency and duration of fault correction processes, thereby minimizing loss of time during operation.
Data Source
AI summary
A controller for controlling operation of an actuator in an HVAC system is shown. The controller includes a processing circuit configured to receive, via a position sensor communicatively coupled to the actuator, a first voltage value, the first voltage value indicative of a first position of the actuator. The processing circuit is further configured to provide a control signal to the actuator to move to a second position. The processing circuit is further configured to, in response to the actuator moving to the second position, determine that the actuator is located in a different position than the second position based on a second voltage value via the position sensor. The processing circuit is further configured to automatically perform a fault correction process to calculate an updated stroke range of the actuator.