Piston Thrust Monitoring in Double-Acting Cylinders
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Solution Overview
Problem
Conventional actuator-operation detecting apparatuses face challenges in accurately monitoring piston operation due to limited air exhaust causing persistent negative differential pressure and microcomputer delays in information processing, especially in food factories where cleaning liquids can corrode sensors, and noise leads to false detection.
Innovation Solution
An actuator-operation detecting apparatus that calculates the thrust force on the piston based on pressures in the first and second pressure acting chambers and the piston's pressure-receiving area, using a differential amplifier circuit and microcomputer to determine the piston's operating state, regardless of operating takt speed, thereby accurately monitoring forward and backward movements and preventing information processing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetism detecting sensors are placed at the ends of the double-acting cylinder to detect piston position, then the piston operating state can be monitored, but the sensors and wires are susceptible to corrosion from cleaning liquids in food factories
Solution Approach 1:
The patent extracts the detection function from the physical sensors placed on the cylinder and relocates it to pressure sensors positioned remotely. By measuring pressure changes in the fluid supply lines and calculating thrust force, the system determines piston position without placing sensitive components in the corrosive environment, thus eliminating corrosion risk while maintaining detection capability.
2Object-affected harmful factors
If pressure sensors are used to detect thrust force for monitoring piston operation, then sensors are protected from corrosion, but information processing delays occur due to microcomputer calculation requirements
Solution Approach 1:
The patent performs preliminary calculation by pre-storing the pressure-receiving area of the piston and pre-establishing the relationship between pressure differential and thrust force. During operation, the microcomputer only needs to retrieve stored values and perform simple multiplication and subtraction operations rather than complex calculations, significantly reducing processing time while maintaining accuracy.
3Productivity
If the operating takt is slowed down by limiting air exhaust amount, then productivity is reduced, but the persistent negative differential pressure causes false detection in thrust force monitoring
Solution Approach 1:
The patent implements dynamic threshold adjustment for thrust force detection. The determination threshold is not fixed but adapts based on real-time operating conditions including air supply pressure, air exhaust pressure, and piston position. This dynamic approach allows the system to maintain reliable detection across varying operating speeds and load conditions, preventing false positives even when productivity is reduced.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus accurately monitors piston operation by determining the direction of movement based on the thrust force's sign and change rate, reducing false detections and information processing delays, ensuring reliable operation even with varying operating speeds and in corrosive environments.
Implementation Method 1
a first pressure sensor configured to detect pressure in the first pressure acting chamber; a second pressure sensor configured to detect pressure in the second pressure acting chamber
Implementation Method 2
calculate a thrust force acting on the piston based on a pressure-receiving area of the piston, a first pressure value detected by the first pressure sensor, and a second pressure value detected by the second pressure sensor
Data Source
AI summary
An actuator-operation detecting apparatus is configured to check the operating state of a piston of an actuator. The actuator includes a double-acting cylinder, the piston that partitions the cylinder into a first pressure acting chamber and a second pressure acting chamber, and a rod connected to an end face of the piston facing the second pressure acting chamber. The actuator-operation detecting apparatus includes a first pressure detector to detect the pressure in the first pressure acting chamber, a second pressure detector to detect the pressure in the second pressure acting chamber, a differential amplifier circuit to calculate a thrust force acting on the piston based on the pressures detected by the first and second pressure detectors and the pressure-receiving area of the piston, and a microcomputer to monitor the operation of the piston based on the thrust force.