Robotic Surgical Assembly With Macro-Micro Positioning Precision
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Solution Overview
Problem
Current robotic surgical assemblies face challenges in achieving precise kinematic control and miniaturization, with existing solutions often requiring complex motion strategies that result in kinematic inaccuracies and limited accessibility within the surgical workspace, and they lack the versatility and ease of use needed for various surgical procedures.
Innovation Solution
A robotic surgical assembly with a macro-positioning arm and multiple micro-positioning devices, each with motorized degrees of freedom, allowing for precise translational and rotational movements, and a tendon-driven system that minimizes friction and enables extreme miniaturization while maintaining precision and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plurality of independent movements are coordinated simultaneously for small motions of the surgical instrument, then the surgical instrument can access the operating work-field, but the control of kinematic accuracy becomes difficult and the operating work-field becomes inaccessible due to encumbrance
Solution Approach 1:
The robotic assembly is divided into a macro-positioning arm for coarse positioning and micro-positioning devices for fine adjustments. This segmentation allows independent control of large-scale positioning and precision movements, resolving the conflict between accessing the work-field and maintaining kinematic accuracy.
Solution Approach 2:
A master interface device serves as an intermediary between the surgeon's hand and the robotic system, providing intuitive control while a separate computer controls the multi-joint arms. This intermediary approach simplifies the control complexity for the surgeon while maintaining precise kinematic control through automated coordination.
2Adaptability or versatility
If multiple joints are articulated further away from the instrument tip to enable reorientation, then the instrument can be oriented in a large spatial cone, but the encumbrance in the operating field increases significantly
Solution Approach 1:
The micro-positioning devices are integrated within or adjacent to the macro-positioning arm structure, with joints nested along the arm's length. This nesting allows the robotic system to achieve multi-axis reorientation without adding external encumbrance to the operating field, as the joints are contained within the arm's structural envelope.
Solution Approach 2:
The robotic arm utilizes vertical movement along the patient's body as an additional dimension for positioning, rather than requiring all reorientation joints to be located at the distal end. This dimensional approach allows the instrument tip to reach various orientations while keeping the joint structure compact and minimally intrusive in the operating field.
3Length of moving object
If a tendon-driven system is used for miniaturization, then extreme miniaturization is enabled, but friction must be minimized to maintain precision
Solution Approach 1:
The tendon-driven mechanical system is supplemented with magnetic actuation mechanisms that can drive the miniaturized joints with minimal friction. This substitution of pure mechanical tendon actuation with magnetic field-based actuation maintains precision while enabling extreme miniaturization of the robotic end-effector.
Solution Approach 2:
The system employs variable stiffness mechanisms and adaptive friction compensation through controlled magnetic forces. By dynamically adjusting the magnetic field strength and tendon tension, the system maintains precise control despite the friction inherent in miniaturized tendon-driven joints, effectively changing the operational parameters to overcome scaling challenges.
Data Source
AI summary
A robotic surgical assembly includes a support, one macro-positioning arm, connected to the support and having a plurality of degrees of freedom. The macro-positioning arm includes a support member, at least two micro-positioning devices, each having a plurality of motorized degrees of freedom, connected in cascade to the support member of the macro-positioning arm, and at least two medical instruments. Each instrument is connected in cascade to each of the micro-positioning devices and includes a jointed device having a plurality of motorized degrees of freedom including a plurality of rotational joints. Each of the at least two medical instruments has a shaft, suitable for distancing the jointed device from the micro-positioning devices by a predetermined distance in a shaft direction (X-X).