Robot Arm Mechanism Eliminating Singular Postures
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Solution Overview
Problem
Conventional robot arm mechanisms experience uncontrollable singular point postures due to lost degrees of freedom, leading to rapid joint movement and uncontrollable conditions, which are typically addressed by avoiding these points or sacrificing hand movement speed.
Innovation Solution
The robot arm mechanism incorporates a linear motion joint that extends or contracts along a third axis perpendicular to the other joints, allowing for offset distances between axes to prevent alignment and thus eliminate singular point postures by structurally arranging joints such that the axis of the third joint is offset from the second joint, preventing the alignment of revolute joints in a straight line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional rotational joints are used for all three root axes, then the robot arm can achieve full six-degree-of-freedom movement, but singular point postures occur causing uncontrollable joint movement and loss of degree of freedom
Solution Approach 1:
The patent changes the type of joint at the third root axis from rotational to linear motion, fundamentally altering the kinematic parameters of the system. This parameter change eliminates the singularity condition that occurs when all bending joints are at zero degree, as the linear motion joint cannot achieve the same rotational alignment that causes singularities in conventional robotic arms.
2Device complexity
If the third joint is positioned close to the second joint to reduce complexity, then device complexity is reduced, but singular point postures cannot be eliminated
Solution Approach 1:
The patent introduces a linear motion dimension along the third axis, perpendicular to the plane formed by the first two rotational joints. This dimensional change allows the third joint to move in a direction that prevents alignment of all three root axes, thereby eliminating singular point postures while maintaining a compact joint arrangement.
Data Source
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Figure 5A~6B
AI summary
The object of the present invention is to provide a robot arm mechanism capable of structurally eliminating or reducing singular point postures within a movable range. The robot arm mechanism has a plurality of joints J1-J6. Of the plural joints, a first joint J1 is a rotational joint that rotates on a first axis RA1, a second joint J2 is a rotational joint that rotates on a second axis RA2, and a third joint J3 is a linear motion joint that moves along a third axis RA3. The second axis RA2 is perpendicular to the first axis RA1 and is a first distance L1 away from the first axis RA1. The third axis RA3 is perpendicular to the second axis RA2 and is a second distance L2 away from the second axis RA2.