Parallel Link Robot Posture Control Beyond Singularity Zones
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Solution Overview
Problem
Articulated arm mechanisms become unstable when the posture of a control point approaches a singularity vicinity, leading to potential interference with other members and increased task completion time.
Innovation Solution
A robot system incorporating an articulated arm mechanism and a parallel link mechanism, where the control device adjusts the posture of the control point by moving the parallel link mechanism based on detection results from a detector, ensuring the posture remains outside the singularity vicinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feedback control is used to adjust the posture of the control point, then the task completion accuracy is improved, but the operation becomes unstable when approaching singularity vicinity
Solution Approach 1:
The patent introduces a parallel link mechanism as an intermediary device between the articulated arm mechanism and the end effector. This parallel link mechanism acts as a mediator that provides additional degrees of freedom and enables posture adjustment without requiring the articulated arm to operate in singular configurations, thus maintaining both accuracy and stability
Solution Approach 2:
The patent divides the posture control function into two separate mechanisms: the articulated arm mechanism for position control and the parallel link mechanism for posture control. This segmentation allows each mechanism to operate in its optimal range, avoiding the singularity issues that would occur if a single mechanism attempted to control both position and posture
2Adaptability or versatility
If the control point posture is adjusted at singularity vicinity, then the task flexibility is improved, but the arm mechanism or end effector may interfere with other members
Solution Approach 1:
The patent adds a new dimension of control by introducing the parallel link mechanism, which provides independent posture adjustment capability. This allows the system to achieve task flexibility through additional degrees of freedom rather than by maneuvering the articulated arm into singular configurations that cause interference
3Manufacturing precision
If feedback control adjusts posture at singularity vicinity, then the task precision is improved, but more time than normal is necessary for task completion
Solution Approach 1:
The patent separates position control and posture control into different mechanisms, allowing parallel execution of control operations. This segmentation eliminates the need for slow, cautious adjustments that would be required when operating near singularities, thus maintaining precision while improving task completion speed
Data Source
AI summary
A robot system according to an embodiment includes an arm mechanism that is articulated, a parallel link mechanism, an end effector, a detector, and a control device. The parallel link mechanism includes a fixed part mounted to a distal part of the arm mechanism, and a movable part that is mounted to the fixed part via multiple parallel links and is movable with respect to the fixed part. The end effector is mounted to the movable part. The detector is provided for detecting a position or orientation of a control point. The control device controls the arm mechanism and the parallel link mechanism. The control device performs a first operation of setting a posture of the control point to a first posture, and a second operation of setting the posture of the control point to a task posture in which the end effector performs a task.