Positioning Actuator Backlash Detection Using Pressure Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing diagnostic methods for positioning devices in process plants, such as nuclear power plants, are unreliable due to the complexity and potential failure of multiple components, which can lead to safety risks in safety-critical applications when detecting backlash in torque couplings.
Innovation Solution
A diagnostic method that uses a single measurement signal, such as a pressure or position measurement signal, to detect rotational backlash in a torque coupling, eliminating the need for additional displacement sensors and reducing system complexity, and generates a warning signal when a predetermined threshold is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple displacement sensors and evaluation devices are used to detect backlash, then measurement capability is improved, but system complexity and failure risk increase
Solution Approach 1:
The invention extracts the backlash detection function from the complex multi-sensor system and implements it using a single existing pressure sensor. By monitoring pressure changes in the actuator chamber during shaft reversal, the system detects backlash without requiring additional displacement sensors or complex evaluation devices, thus resolving the contradiction between measurement capability and system complexity
Solution Approach 2:
The pressure sensor, originally intended for actuator control, is made multi-functional by also using it for backlash detection. The same sensor serves dual purposes: controlling actuator operation and detecting mechanical backlash through pressure change analysis during shaft reversal, eliminating the need for dedicated diagnostic sensors
2Reliability
If multiple sensors and evaluation components are installed, then diagnostic capability is improved, but system reliability deteriorates due to more potential failure points
Solution Approach 1:
The system uses its own existing pressure sensor and control mechanisms to perform self-diagnosis for backlash detection. No external or additional diagnostic components are required - the actuator's own pressure system provides the diagnostic information, reducing component count and potential failure points while maintaining reliability
Solution Approach 2:
Pressure changes in the actuator chamber serve as an intermediary indicator of backlash. Instead of directly measuring mechanical clearance between shafts, the system uses pressure variations during shaft reversal as a mediator to indirectly detect backlash, simplifying the diagnostic approach
3Measurement precision
If additional displacement sensors are added for backlash detection, then measurement accuracy is improved, but cost and system complexity increase
Solution Approach 1:
The invention extracts diagnostic information from the existing pressure field in the actuator system, eliminating the need to add displacement sensors. By analyzing pressure changes during shaft reversal, the system obtains backlash measurement data without increasing sensor quantity
Solution Approach 2:
The system monitors changes in pressure parameters during shaft reversal to detect backlash. Instead of measuring mechanical position directly with additional sensors, the invention uses pressure parameter variations as a proxy indicator, reducing the number of sensors required
Data Source
AI summary
In a diagnostic method for a positioning device of a process plant, such as a chemical plant, a food processing plant or the like, which includes an actuator (e.g. pneumatic or electric actuator) with a drive shaft and a positioning armature, such as an actuator valve, with a positioning shaft, the drive shaft and the positioning shaft being connected to each other in a rotationally fixed manner (e.g. by a detachable coupling interface and/or a positive-locking torque coupling, such as a claw coupling), wherein a first measurement signal is detected during a movement of the drive shaft, and the first measurement signal or a derivative of the first measurement signal is evaluated with respect to a step-like change in order to detect a rotational backlash.