4-DOF parallel mechanism and parallel 4-DOF needle insertion device using the same

4-DOF Parallel Needle Insertion Device with Singularity Avoidance via Asymmetric Arrangement of Active and Passive Prismatic Links

This technology is a 4-DOF parallel mechanism consisting of a base and a platform connected by four active prismatic links and one passive prismatic link. The passive prismatic link constrains translational motion in two directions, while the four active prismatic links are arranged asymmetrically to prevent singularities, enabling three rotational degrees of freedom and one translational degree of freedom.

Existing serial robots suffer from cumulative error issues, while 6-DOF parallel mechanisms are inefficient due to excessive degrees of freedom and structural complexity. Specifically, control instability arises from singularities encountered when implementing the 4 degrees of freedom (3 rotation, 1 translation) required for needle insertion.

This technology uses one passive prismatic link to constrain two translational degrees of freedom and arranges four active prismatic links asymmetrically to prevent singularities. Independent and simultaneous control of the four active prismatic links via actuators allows for precise needle positioning and insertion. Applicable to precision surgical robots, needle insertion procedures, and medical automation, it ensures control stability for parallel manipulators by eliminating singularities.

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Key Features:

• A 4-DOF parallel mechanism comprising a base and a platform positioned at a distance from the base.
• Four active prismatic links, each with one end and the other end rotatably connected to the base and platform, respectively, and featuring a 1-DOF active prismatic joint.
• A passive prismatic link with one end connected to the base via a 3-DOF joint and the other end fixed to the platform, featuring a 1-DOF passive prismatic joint.
• A structure that achieves 4 degrees of freedom by constraining translational motion in two directions using the passive prismatic link.

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This invention was developed with support from the Ministry of Commerce, Industry and Energy's 2008 research project on the optimization of high-efficiency motor systems.