Articulated Robot Gas Spring Leakage Detection via Dynamic Current
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Solution Overview
Problem
The existing methods for estimating the reduced state of gas in a gas spring of an articulated robot suffer from inaccuracies due to variations in static friction forces when the arm is stopped, leading to fluctuations in torque and current values of the drive motor, which compromise the precision of gas leakage detection.
Innovation Solution
An articulated robot system that determines whether the rotary arm is rotating or at rest to acquire actual current values, comparing them to theoretical values to estimate the reduced state of gas in the gas spring, thereby avoiding static friction-related inaccuracies and allowing for precise gas leakage detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the arm is stopped to acquire current values for gas spring estimation, then the robot can maintain position, but static friction force variations cause torque and current value fluctuations that reduce estimation accuracy
Solution Approach 1:
The patent transitions from static measurement (arm stopped) to dynamic measurement (arm rotating) to eliminate static friction effects. By acquiring current values during rotation, the system avoids the friction-induced variability that plagues stopped-state measurements, thereby improving both measurement stability and accuracy simultaneously.
Solution Approach 2:
The patent changes the operational state parameter from stopped to rotating to acquire current values. This parameter change fundamentally alters the measurement conditions, eliminating static friction effects and enabling more reliable gas spring reduced state estimation through the relationship between rotational current values and gas pressure.
2Measurement precision
If the arm rotates to avoid static friction effects, then estimation accuracy improves, but the robot cannot maintain position during measurement
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the arm's rotational state and adjusts the acquisition timing of current values accordingly. By synchronizing measurement with rotational phases and using feedback from position sensors, the system maintains position stability while capturing accurate dynamic current values for estimation.
Solution Approach 2:
The patent performs preliminary determination of the arm's rotational state before acquiring current values. The controller pre-judges whether the arm is rotating or stopped and selectively acquires current values only during rotational phases, ensuring measurement accuracy is achieved without compromising position stability during normal operation.
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
This approach enables highly precise estimation of the reduced state of gas in the gas spring by eliminating static friction-related errors, ensuring accurate detection of gas leakage and reducing the load on the drive motor, thus preventing excessive load and potential malfunctions.
Implementation Method 1
The gas spring generates a balancing force which reduces the load of the drive motor by a pressure of gas enclosed in the gas spring
Implementation Method 2
the torque generated by the servomotor can be calculated based on the current value of the servomotor
Implementation Method 3
In this stopped state of the arm, a static friction force acts on the arm
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A robot 2 includes an arm supporting part 12, a rotary arm 14 rotatably supported by the arm supporting part 12, a drive motor configured to rotate the rotary arm 14, a gas spring 8 configured to reduce a load of the drive motor by supporting a load acting on the rotary arm 14 and a controller 10. The controller 10 determines that the rotary arm 14 rotates, and estimates a reduced state of gas in the gas spring 8 based on a comparison between an actual current value and a theoretical current value of the drive motor when the rotary arm 14 rotates.