Parallel Kinematic Mechanism Decoupling Rotational Motions
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Solution Overview
Problem
Existing minimally invasive surgical tools lack design characteristics for enhanced dexterity and intuitive control of multiple degrees of freedom, particularly in wrist-like rotations, due to complex mechanical transmission challenges and non-intuitive control schemes.
Innovation Solution
The implementation of parallel kinematic mechanisms with a constraint map focusing on articulation motion, allowing two orthogonal rotations between a handle and a frame, which separates and filters rotations into independent paths for easy transmission, using mechanical or electromechanical systems to correlate and transmit these rotations to an end effector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If serial kinematic mechanisms are used to transmit rotational motions, then the mechanical path is simple and direct, but the control of multiple degrees of freedom becomes non-intuitive and complex
Solution Approach 1:
The patent segments the rotational motion transmission by using separate mechanical paths for different degrees of freedom. The parallel kinematic mechanism divides the control of pitch and yaw rotations into independent transmission paths, allowing each degree of freedom to be controlled intuitively without complex coupled motion sequences required by serial mechanisms.
Solution Approach 2:
The patent transitions from serial (one-dimensional path) to parallel (multi-dimensional paths) kinematic architecture. By implementing multiple independent mechanical paths that converge at the end effector, the system enables intuitive control of multiple degrees of freedom simultaneously, resolving the contradiction between operational ease and mechanical complexity.
2Adaptability or versatility
If parallel kinematic mechanisms are implemented with multiple independent paths, then the control of multiple degrees of freedom becomes intuitive, but the mechanical design complexity increases
Solution Approach 1:
The patent employs universal joints and spherical connectors that can accommodate multiple rotational degrees of freedom within single components. These universal elements serve multiple functions by allowing independent rotation about different axes while maintaining mechanical connectivity, thereby reducing the overall number of separate components needed in the parallel kinematic mechanism.
Solution Approach 2:
The patent uses intermediate spherical bodies and universal joints as mediators between the input control mechanisms and the end effector. These intermediary elements simplify the mechanical design by providing standardized connection points that naturally handle complex rotational transformations, reducing the design complexity of the overall parallel kinematic system.
3Ease of operation
If multiple connectors allow rotation in different directions, then the degrees of freedom are achieved, but the mechanical transmission paths become complex
Solution Approach 1:
The patent applies local quality by giving each connector specific rotational characteristics tailored to its position in the kinematic chain. Each universal joint and spherical connector is designed to allow rotation about specific axes while constraining others, creating a distributed system where local rotational freedoms combine to achieve overall dexterity without requiring complex global coordination.
Data Source
AI summary
A parallel kinematic mechanism apparatus includes a frame, a handle and an input joint that connects having at least two independent and functionally parallel paths for transmission of motion coupling the handle to the frame. A first path includes a first intermediate body connected to the frame by a first connector and to the handle by a third connector while the second path that is independent from the first path includes a second intermediate body that is connected to the frame by a second connector and to the handle by a fourth connector. The first connector and the fourth connector both allow rotation in a first rotational direction and restrict rotation in a second rotational direction and the second and third connectors allow rotation in the second rotational direction and restrict rotation in the first rotational direction.