Multi-Axis Robot Vibration Suppression via Orthogonal Joint Sensors
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Solution Overview
Problem
Existing multi-axis robots face challenges in effectively suppressing vibration due to the complexity of calculation required for vibration suppression techniques, which leads to slow response speeds and potential increases in vibration, especially when acceleration sensors are placed at the tip of the arm and require coordinate axis transformation, and when rotation axes are parallel, failing to account for mixed rotational components.
Innovation Solution
The implementation of inertia sensors installed on each arm to detect angular velocities and accelerations, with control units that feed back correction components derived from these measurements to drive sources, allowing for orthogonal or parallel rotation axes to be treated as simple rotational components, thereby simplifying calculations and avoiding singular points, ensuring reliable vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acceleration sensors are installed at the tip portion of the arm and coordinate axis transformation (Jacobi's transformation) is performed to convert acceleration detected by the acceleration sensor into those for the respective joint portions, then vibration suppression capability is improved, but the amount of calculation becomes huge and response speed becomes slow
Solution Approach 1:
The patent replaces the complex computational approach (Jacobi's transformation with matrix calculations) with a sensor placement strategy. By installing acceleration sensors directly at the joint portions instead of at the arm tip, the system directly obtains acceleration data for each joint without requiring coordinate transformation calculations, thus substituting a mechanically simple sensor distribution approach for a computationally complex transformation approach
Solution Approach 2:
The patent extracts the vibration detection function directly at the joint portions by placing acceleration sensors there, rather than detecting vibration at the arm tip and transforming the data. This extraction of the detection function to the exact location where it's needed eliminates the need for coordinate axis transformation and reduces calculation burden
2Reliability
If coordinate axis transformation calculation is performed to suppress vibration, then vibration suppression capability is improved, but calculation precision may decline and control performance may be impaired
Solution Approach 1:
The patent substitutes the complex coordinate transformation calculation system with a direct sensing system. By placing acceleration sensors at the joint portions, the system directly measures the physical quantities needed for control without requiring mathematical transformation, thereby avoiding precision loss from complex calculations
3Device complexity
If rotation axes of the arms are made parallel to each other and angular velocity sensors are provided on the arms, then device complexity is reduced, but different rotational components cannot be properly handled and vibration suppression capability cannot be satisfied
Solution Approach 1:
The patent applies local quality by making each arm's rotation axis orthogonal to the others, creating locally optimized rotational components for each arm. This orthogonal arrangement allows each angular velocity sensor to measure independent rotational components without interference, enabling proper handling of different rotational directions while maintaining manageable device complexity
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 configuration enhances the accuracy and speed of vibration suppression, reduces the need for high-speed computing, and prevents vibration increases, allowing for more precise control of multi-axis robots operating in three-dimensional spaces.
Implementation Method 1
a first angular velocity sensor that detects an angular velocity of the first arm rotating around the first rotation axis
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A robot (1) includes a base (11), a first arm (12), a second arm (13), a drive source (401) of the first arm (12), a drive source (402) of the second arm (13), a first inertia sensor (31), a second inertia sensor (32), a first angle sensor (411), and a second angle sensor (412). A rotation axis for the rotation of the first arm (12) and a rotation axis for the rotation of the second arm (13) are made orthogonal to each other. The first inertia sensor (31) is installed at the first arm (12), and the second inertia sensor (32) is installed at the second arm (13). The first angle sensor (411) is installed at the drive source (401) of the first arm (12), and the second angle sensor (412) is installed at the drive source (402) of the second arm (13). Angular velocities obtained from the detection of the first inertia sensor (31) and the first angle sensor (411) are fed back to a first drive source control unit (201). Angular velocities obtained from the detection of the second inertia sensor (32) and the second angle sensor (412) are fed back to a second drive source control unit (202).