Multi-joint Robot Gas Spring Pressure Estimation
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Solution Overview
Problem
Existing multi-joint robots with gas springs face issues of gas leakage leading to decreased inner pressure, which results in reduced torque output, necessitating costly pressure indicators and sensors that increase equipment size and leakage risks.
Innovation Solution
A controller system that calculates the decrease in inner pressure of the gas spring by comparing reference and object current values of the servomotor, allowing for precise estimation without additional pressure sensors, and visually or aurally alerts operators to potential gas leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure indicators and sensors are installed to monitor gas spring pressure, then measurement precision of gas pressure is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the servomotor's own current detection capability to infer gas spring pressure status. The control unit calculates pressure changes by comparing current values at different positions, allowing the servomotor to serve its own monitoring function without external pressure sensors.
Solution Approach 2:
The patent replaces mechanical pressure sensors and indicators with an electrical calculation method. By substituting direct pressure measurement with current-based inference, the system eliminates the need for additional mechanical monitoring devices while achieving the same monitoring objective.
2Measurement precision
If pressure indicators and connecting means are added to monitor gas pressure, then measurement precision is improved, but the possibility of gas leakage increases
Solution Approach 1:
The servomotor system monitors its own operational parameters (current consumption) to detect gas pressure changes. This self-monitoring approach eliminates the need for external connecting means that could become leakage points, maintaining system integrity while achieving monitoring goals.
Solution Approach 2:
The patent extracts the monitoring function from external pressure indicators and integrates it into the control unit through calculation. By removing physical pressure sensing components from the gas spring system, the potential leakage paths are eliminated while the monitoring capability is preserved through electrical measurements.
3Duration of action of moving object
If pressure control valves and compressors are installed to maintain gas pressure, then duration of action is improved, but device complexity and size increase
Solution Approach 1:
The control unit continuously monitors servomotor current values and calculates gas pressure status in real-time. This feedback mechanism allows the system to detect pressure degradation and alert operators, enabling timely maintenance without requiring complex active pressure control systems.
Solution Approach 2:
The system uses the existing servomotor and control unit to perform pressure monitoring, eliminating the need for separate compression systems. The servomotor's current characteristics serve as indirect pressure sensors, and the control unit performs calculations that would otherwise require dedicated pressure management hardware.
Data Source
AI summary
A multi-joint robot having a function for estimating an amount of decrease in inner pressure of a gas spring, by means of a simple and low-cost structure, and a method for estimating the amount of decrease in inner pressure of the gas spring. The gas pressure within a cylinder of the gas spring decreases in connection with the motion of a lower arm associated with the gas spring. In the present invention, an amount of decrease in inner pressure within the gas spring is estimated by using a current value of a servomotor, in view of the finding that the amount of decrease in inner pressure is generally proportional to an amount of decrease in torque, and the torque generated by the servomotor can be calculated based on the current value of the servomotor.