Robot Control Device Suppressing Vibration via Angular Velocity Ratio
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Solution Overview
Problem
Double-arm robots experience difficulty in attenuating vibration due to transmission of vibration from the trunk to the robot arms, making it challenging to suppress the vibration of both the trunk and the robot arms simultaneously.
Innovation Solution
A robot control device is implemented with inertial sensors at the trunk and robot arms, controlling the actuation of the robot system to ensure the ratio of angular velocity amplitudes before and after target position reaches satisfies specific conditions (B/A < 0.27 and D/C < 0.27), enhancing the stiffness of the trunk and effectively suppressing vibrations of the first and second robot arms and the trunk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If vibration attenuation methods are applied to robot arms, then robot arm vibration is reduced, but trunk vibration transmission prevents effective suppression
Solution Approach 1:
The patent divides the vibration control system into separate control loops for the trunk and robot arms. Inertial sensors are independently installed on the trunk and each robot arm to detect vibrations separately, allowing independent control strategies to be applied to each segment without interference from vibration transmission between them.
Solution Approach 2:
The patent applies different control parameters and damping characteristics to different parts of the system. The trunk control uses specific damping ratios while robot arm controls use different damping ratios, allowing each component to have optimized vibration suppression characteristics suited to its specific function and vibration characteristics.
2Productivity
If the robot arm moves quickly to reduce positioning time, then productivity increases, but vibration amplitude increases
Solution Approach 1:
The patent applies periodic damping control where the damping ratio is dynamically adjusted during the motion cycle. The control system modifies damping characteristics at different phases of the robot arm movement, applying higher damping during high-speed phases to suppress vibration while maintaining speed, and adjusting damping during positioning phases to ensure stability.
Solution Approach 2:
The patent dynamically changes control parameters including damping ratio and stiffness based on the robot arm's position, velocity, and acceleration. This allows the system to optimize between speed and vibration suppression by adjusting parameters in real-time according to the current operational state, enabling quick positioning while controlling vibration amplitude.
Data Source
AI summary
A robot control device controls the operation of a robot including a trunk that is rotatable around an axis, first and second robot arms that are provided at the trunk and rotatable with respect to the trunk, and first, second, and third inertial sensors. In an operation in which the second robot arm is brought into a stationary state and the first robot arm is rotated around the axis from the stationary state and moved to a target position, the robot control device makes B/A<0.27 satisfied when a maximum value of the amplitude of the angular velocity of the trunk around the axis before the first robot arm reaches the target position is defined as A, and a maximum value of the amplitude of the angular velocity of the trunk around the axis after the first robot arm has reached the target position first is defined as B.