Instrument Support Device Passive Joint Decoupling
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Solution Overview
Problem
Conventional instrument carrier devices for robotic surgical systems are prone to failure due to complex structures and require significant space, limiting mobility and increasing the risk of collisions between manipulators, while also exerting unnecessary biomechanical stress on tissues during minimally invasive surgeries.
Innovation Solution
The instrument carrier device incorporates a passive second rotation joint in addition to a thrust joint, allowing the instrument holder to be freely rotatable and decoupling the instrument's longitudinal axis from the pivot point, enabling unforced guidance through the tissue without lateral forces and reducing the need for complex compensating movements, thus minimizing collisions and tissue stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional instrument carrier devices use complex structures to position instruments, then positioning precision is improved, but device reliability deteriorates and device complexity increases
Solution Approach 1:
The patent changes the kinematic parameters of the instrument carrier device by introducing a passive rotational degree of freedom around the instrument's longitudinal axis. This parameter change allows the instrument to freely rotate and align with the pivot point without requiring complex active control mechanisms, thereby maintaining positioning precision while improving reliability through mechanical simplicity
Solution Approach 2:
The patent implements a dynamic configuration where the instrument holder can passively rotate around the longitudinal axis of the instrument rod. This dynamic capability allows the system to adapt to tissue movement and positioning requirements without complex control systems, resolving the contradiction between positioning precision and reliability
2Adaptability or versatility
If conventional instrument carrier devices use complex structures with multiple joints, then positioning capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the complex active control mechanisms from the instrument carrier device and replaces them with a passive rotational joint. The instrument holder is decoupled from the third arm segment through this passive joint, allowing independent rotational movement without requiring additional actuators or control systems, thus maintaining positioning capability while reducing device complexity
Solution Approach 2:
The patent segments the instrument carrier device into distinct functional components: the active three-link arm for positioning, and the passive instrument holder for final alignment. This segmentation allows each component to perform its specific function with appropriate complexity, resolving the overall device complexity issue
3Measurement precision
If conventional instrument carrier devices require significant space for complex mechanisms, then positioning precision is improved, but the area occupied by the device increases
Solution Approach 1:
The patent changes the spatial parameters of the instrument carrier device by eliminating the need for complex compensating mechanisms through the passive rotational joint. This allows the device to achieve the same positioning precision with a more compact structure, reducing the area occupied by the device
4Ease of operation
If conventional instrument carrier devices use complex compensating movements, then instrument guidance through pivot point is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-aligning mechanism where the passive rotational joint automatically allows the instrument to align with the pivot point through its own weight and geometry. The instrument holder freely rotates around the longitudinal axis without requiring external control or complex compensating movements, resolving the contradiction between ease of operation and device complexity
Data Source
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Figure 3a~3b
AI summary
The invention relates to an instrument support device (3) for a manipulator (1) of a robotic surgical system, comprising a three-element arm in the form of an end piece of an open kinematic chain with a first, second, and third arm element (3.1, 3.2, 3.3), an interface for connecting the first arm element (3.1) to the manipulator (1) via an interface rotational joint (GS), a torsional joint (G3.1) which connects the first arm element (3.1) to the second arm element (3.2), a first rotational joint (G3.2) which connects the second arm element (3.2) to the third arm element (3.3), and a sliding joint (G3.3) which connects the third arm element (3.3) to an instrument mounting (3.4) for receiving a surgical instrument (4, 5, 18, 19) with an instrument longitudinal axis (I). The instrument support device (3) also comprises a controller for driving the torsional joint (G3.1), the first rotational joint (G3.2), and the sliding joint (G3.3) in order to move the arm elements (3.1, 3.2, 3.3) and the instrument mounting (3.4) relative to one another. In such an instrument support device (3), the instrument mounting (3.4) is connected to the third arm element (3.3) via a second passive rotational joint (G3.4) and can be freely rotated about the rotational axis of the instrument mounting. The rotational axes of the first and second rotational joint (G3.2, G3.4) are parallel to each other, whereby the instrument longitudinal axis (I) can be guided by a pivot point (PP) without exerting a force, said pivot point lying on the rotational axis of the torsional joint in an extension from the second arm element (3.2).