Articulated Robot Gas Spring Pressure Estimation via Motor Current
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Solution Overview
Problem
Conventional methods for estimating gas pressure decrease in gas springs of articulated robots require stopping the production line and operating under specific conditions, leading to a decline in operation rate due to the inability to estimate pressure decrease under different operating conditions.
Innovation Solution
A method that calculates a set current value based on the rotation angle of the arm at a stop position with no gas leakage, using a torque-current characteristic to estimate the gas pressure decrease by comparing actual and set current values, allowing for continuous operation without stopping the production line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference current value and target current value are acquired under the same operating condition (posture, speed), then the gas internal pressure decrease amount can be estimated accurately, but the robot must stop the production line to perform special operations, causing decline in operation rate
Solution Approach 1:
The invention changes the operating parameters (posture, speed) between acquiring the reference current value and target current value. The control unit acquires the reference current value at a reference posture and reference speed, then acquires the target current value at a different target posture and target speed. The system compensates for these parameter changes through calculation, allowing estimation of gas pressure decrease without requiring identical operating conditions.
Solution Approach 2:
The invention makes the operating conditions dynamic rather than static. Instead of requiring the robot to maintain the same posture and speed for both measurements, the system allows the robot to move to different positions and speeds, adapting the measurement process to the actual operational state while still enabling accurate gas pressure estimation through compensatory calculations.
2Productivity
If the robot operates continuously without stopping the production line, then the operation rate is maintained, but the gas internal pressure decrease cannot be estimated under different operating conditions
Solution Approach 1:
The system is designed to handle parameter changes by acquiring reference data at one set of operating conditions (reference posture, reference speed) and target data at different operating conditions (target posture, target speed). The control unit calculates the relationship between these different parameter sets to estimate gas pressure decrease, enabling continuous operation without requiring identical operating conditions for measurement.
Solution Approach 2:
The invention creates a universal estimation method that works across multiple operating conditions. The control unit can estimate gas internal pressure decrease regardless of changes in posture, speed, or other operational parameters, making the system adaptable to various operational scenarios while maintaining continuous production.
3Measurement precision
If a special operation is performed to acquire the target current value under the same operating condition as reference time, then the gas pressure decrease can be estimated, but the production line must be stopped, causing decline in operation rate
Solution Approach 1:
The invention eliminates the need for special operations by allowing parameter changes between reference and target measurements. The control unit acquires the reference current value at reference operating conditions and the target current value at different target operating conditions, then calculates the gas pressure decrease based on these different parameter sets, avoiding production line stoppage.
Solution Approach 2:
The system maintains continuous useful action by allowing the robot to operate normally without interruption. The current values are acquired during regular operation at different postures and speeds, eliminating the need to halt production for special measurement operations, thus preventing loss of time while still enabling accurate gas pressure estimation.
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
Enables continuous estimation of gas pressure decrease in articulated robots without halting operations, preventing a decline in operation rate and ensuring reliable gas spring functionality.
Implementation Method 1
a gas spring utilizing a reaction force against a piston due to an increase in the pressure of a gas compressed according to the movement of the piston as a spring
Implementation Method 2
the torque to be generated by the servo motor in order to stop the robot arm at a stop position while maintaining an energized state of the servo motor
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
This articulated robot (1) is provided with an arm (2, 3), a drive motor (9) for driving the arm (2, 3), a gas spring (5) for supporting a load acting on the arm (2, 3) to reduce a load of the drive motor (9), and a control unit (8) for controlling the drive motor (9). The control unit (8) has a function of estimating a decrease state of a gas sealed inside the gas spring (5) based on an actual current value of the drive motor (9) obtained at a stop position at which the drive motor (9) is operated and stopped in an energized state. Thus, the decrease state of the gas sealed inside the gas spring can be estimated based on the current value of a servo motor without causing decline in operation rate of the robot and the like.