Actuator Position Control Using Sensor Deviation Hold Logic
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Solution Overview
Problem
Existing actuator control systems with redundant position sensors fail to accurately diagnose and respond to faulty sensors, leading to erroneous control signals, increased wear, and costly maintenance due to inability to distinguish between healthy and faulty sensor readings.
Innovation Solution
A method that fixes the control signal to a constant value when the deviation between sensor signals exceeds a threshold, allowing for the detection of faulty sensors by monitoring their position intervals, thereby immobilizing the actuator and preventing further wear, and allowing for automatic fault detection without additional measurements or complex thermodynamic models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control signal is generated using feedback from position sensors, then the actuator position can be regulated, but when a sensor fails the system cannot detect which sensor is faulty leading to erroneous control
Solution Approach 1:
The system performs preliminary actions by immobilizing the actuator and establishing expected position intervals for each sensor before fault detection is needed. This allows the system to have a baseline understanding of what normal sensor readings should look like, enabling quick fault identification when deviations occur.
Solution Approach 2:
The system uses feedback by continuously monitoring sensor readings against expected intervals and comparing actual positions with commanded positions. When a sensor reading falls outside its expected interval or when the actuator position doesn't match the commanded position while immobilized, the system identifies the faulty sensor through this feedback mechanism.
2Productivity
If the system selects one measurement signal when deviation exceeds threshold, then control can continue, but the actuator undergoes rapid variations accelerating wear
Solution Approach 1:
The system takes preliminary action by immobilizing the actuator as soon as a sensor deviation is detected. This prevents the actuator from continuing to operate with erroneous feedback, thereby avoiding rapid variations and accelerated wear that would occur if control continued using the faulty sensor data.
Solution Approach 2:
The system converts the harmful effect of sensor failure into a beneficial outcome by using the deviation detection as an early warning signal. Instead of allowing the faulty sensor to cause continuous damage, the system immobilizes the actuator and identifies the faulty sensor, turning a potentially damaging situation into an opportunity for preventive maintenance.
3Reliability
If the system uses extreme values for control when deviation occurs, then safety is improved, but no diagnosis of the failure is carried out requiring costly maintenance
Solution Approach 1:
The system uses feedback to continuously monitor sensor readings and compare them against expected intervals. This feedback mechanism provides automatic diagnosis by identifying which sensor reading falls outside its expected range, eliminating the need for manual troubleshooting and reducing maintenance costs while maintaining safety.
Solution Approach 2:
The system performs self-diagnosis by automatically detecting and identifying faulty sensors through interval comparison. This self-service capability eliminates the need for external maintenance teams to perform time-consuming manual diagnostics, reducing both maintenance time and costs while maintaining system safety.
4Productivity
If the actuator operates with a faulty sensor signal, then control continues, but the measurement becomes noisy causing oscillations and degraded performance
Solution Approach 1:
The system takes preliminary action by immobilizing the actuator when sensor deviation is detected, preventing the propagation of noisy measurements. This preliminary action preserves measurement precision by stopping the system before faulty sensor data can cause oscillations and degraded performance.
Solution Approach 2:
The system converts the harmful noisy measurements into a beneficial diagnostic opportunity. By detecting the deviation that causes noise, the system identifies the faulty sensor and immobilizes the actuator, transforming a quality degradation problem into a fault detection opportunity that improves overall system reliability.
Data Source
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AI summary
The present invention relates to a method for controlling an actuator (4) comprising a mobile element (60), the method comprising steps of receiving a set-point signal (E) and two position-measurement signals (A, B) of the mobile element (60) acquired by different position sensors (7), calculating a deviation between the two position-measurement signals (A, B), generating (102) a control signal (S) for controlling a movement of the mobile element (60) on the basis of the set-point signal (E) and at least one of the position-measurement signals (A, B), the method being characterised in that when the deviation between the position-measurement signals (A, B) crosses (201) a predetermined threshold, said method comprises the following steps: setting (202) the control signal (S) to a constant value so as to immobilise the mobile element (60), for each of the two measurement signals (A, B), calculating an interval of positions associated with the measurement signal (A), and detecting an output of the value of a measurement signal (A) outside the associated interval while the control signal (S) is set to the constant value.