Actuator Abnormality Detection Using Piston Travel Time
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Solution Overview
Problem
Existing methods for detecting abnormalities in actuators, such as faults, are cumbersome and costly, requiring precise setting of conditions like takt time thresholds, which can vary by device and usage conditions, making them difficult to implement effectively.
Innovation Solution
An abnormality detecting system that uses input from external sources to monitor the travel time and number of operations of a movable actuator portion, employing sensors and a control device to calculate travel time and total distance, allowing for real-time detection of abnormalities without stopping the equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow sensor detection is used to examine pressurized fluid leakage, then abnormality detection capability is provided, but detection results vary depending on tube conditions, pressure values, pulsation, and temperature making it difficult to set conditions
Solution Approach 1:
The abnormality detecting device autonomously performs detection using internally stored statistical data without requiring external condition setting or calibration. The device self-serves by comparing actual operational data against pre-stored statistical thresholds, eliminating the need for manual condition setup and ensuring consistent detection across varying operational parameters.
2Reliability
If lowest working pressure examination is used to detect abnormalities, then abnormality detection capability is provided, but the actuator must be at rest and travel rate varies depending on bore size and stroke making condition setting difficult
Solution Approach 1:
The abnormality detection operates continuously during actuator operation without requiring the actuator to be stopped or held at rest. The system continuously monitors and accumulates operational data (stroke, pressure, time) throughout the actuator's working cycle, enabling real-time abnormality detection while maintaining continuous production flow and eliminating downtime for inspection.
3Extent of automation
If statistical data storage and takt time threshold detection are used, then abnormality detection is automated, but device-specific and condition-specific threshold settings are required increasing complexity
Solution Approach 1:
The abnormality detecting device employs universal statistical methods that can be applied across different actuator types and operating conditions. By using standardized statistical parameters (mean, standard deviation, coefficient of variation) rather than device-specific thresholds, the system achieves broad applicability and reduces complexity. The same detection algorithm works universally regardless of actuator bore size, stroke, or operational conditions.
Data Source
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AI summary
An abnormality detecting system (10) and an abnormality detecting method acquires a stroke of a piston (50) as input from outside, calculates a travel time of the piston (50) based on the results of sensing obtained by a first sensor (18) and a second sensor (22), calculates a total travel distance of the piston (50) using the number of operations and the stroke of the piston (50), and detects an abnormality of the actuator (14) based on the travel time and the number of operations or the total travel distance of the piston (50).