Parallel Robot Wrist Section with Orthogonal Axes
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Solution Overview
Problem
Existing parallel robots with a single orientation changing axis face difficulties in mounting workpieces to inclined surfaces due to the risk of singular states, where the robot movement for precise positioning and orientation cannot be unambiguously programmed.
Innovation Solution
A parallel robot with a wrist section having three degrees of freedom, featuring a first, second, and third rotary member with orthogonal rotation axes and an attachment surface inclined at a predetermined angle, allowing for three-axis orientation-changing motion and preventing singular states by ensuring the rotation axes are not parallel when the attachment surface is oriented horizontally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single orientation changing axis is used in the movable member, then the robot structure remains simple, but it cannot perform tasks on inclined surfaces and may encounter singular states
Solution Approach 1:
The orientation changing function is segmented into three separate rotary members (first, second, and third rotary members) with orthogonal rotation axes. Each rotary member handles a specific degree of freedom, dividing the complex orientation control into manageable segments. This allows the robot to achieve versatile orientation control for inclined surfaces while maintaining a structured and organized configuration.
Solution Approach 2:
The invention transitions from a single-axis orientation system to a three-axis orientation system by adding rotational capabilities in multiple dimensions. The orthogonal arrangement of rotation axes (fourth, fifth, and sixth axes) enables the wrist section to operate in three-dimensional space, providing the ability to perform tasks on inclined surfaces and eliminate singular states through multi-dimensional orientation control.
2Device complexity
If the attachment surface is oriented horizontally with rotation axes parallel, then the structure is simplified, but singular states occur where robot movement cannot be unambiguously programmed
Solution Approach 1:
The invention introduces asymmetry in the wrist section configuration by arranging the rotation axes of the three rotary members orthogonally to each other rather than in parallel. This asymmetric spatial arrangement ensures that the rotation axes are never parallel regardless of the attachment surface orientation, thereby eliminating singular states while maintaining a compact and efficient wrist section structure.
Solution Approach 2:
The orthogonal arrangement of rotation axes is designed in advance to prevent the occurrence of parallel axis configurations that would lead to singular states. By establishing the axes in orthogonal relationship from the beginning, the system proactively avoids the harmful condition of singularity, ensuring reliable robot movement control across all orientations without requiring additional correction mechanisms.
Data Source
AI summary
A parallel robot includes a movable-section drive mechanism, and a wrist-section drive mechanism. The wrist section includes a first rotary member supported on the movable section and rotatable about a fourth rotation axis different from axes of the three-axis translational motion of the movable section, a second rotary member connected to the first rotary member and rotatable about a fifth rotation axis orthogonal to the fourth rotation axis, and a third rotary member connected to the second rotary member and rotatable about a sixth rotation axis orthogonal to the fifth rotation axis. The third rotary member is provided with an attachment surface to which a tool is attached. The attachment surface is inclined with respect to the sixth rotation axis at a predetermined angle.