Surgical Robotic Arm Layout for Active RCM Positioning
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Solution Overview
Problem
Current robotic arms used in minimally invasive surgery face complexities in kinematics inverse operation and potential interference among multiple arms, which complicates the positioning of the active remote-center-of-motion point and increases operational complexity.
Innovation Solution
The robotic arm incorporates a spatial positioning mechanism, a planar motion mechanism, and a connection and rotation joint, allowing for precise positioning of the active remote-center-of-motion point through a wide range of motion without requiring the spatial positioning mechanism to move, thereby reducing collision risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mechanical fixed point based on parallelogram linkage mechanism is used, then the position of the fixed point is fixed relative to the base, but the clamping process requires strict matching relationship which brings high operational complexity and long preoperative preparation time
Solution Approach 1:
The patent replaces the mechanical fixed point system (parallelogram linkage) with an active remote-center-of-motion point system that uses control algorithms and kinematics constraints. This substitution eliminates the need for mechanical clamping structures and strict physical matching, thereby reducing device complexity while maintaining positioning precision through software-based control.
Solution Approach 2:
The patent changes the fundamental parameter from a mechanically fixed point to an actively controlled remote-center-of-motion point. This parameter change allows the system to achieve precise positioning through dynamic control rather than static mechanical constraints, reducing operational complexity while maintaining manufacturing precision.
2Manufacturing precision
If an active remote-center-of-motion point with universal industrial robot configuration is used, then the surgical instrument can be constrained to pass through a fixed point, but a relatively complex kinematics inverse operation is required and singularity may be easily introduced
Solution Approach 1:
The patent segments the robotic arm into a spatial positioning mechanism and a planar motion mechanism. This segmentation allows the complex kinematics problem to be divided into simpler sub-problems: the spatial mechanism handles the remote-center-of-motion constraint while the planar mechanism handles the surgical instrument motion, reducing the overall computational complexity of kinematics inverse operations.
Solution Approach 2:
The patent introduces dynamics by making the remote-center-of-motion point active rather than fixed. The planar motion mechanism dynamically adjusts the surgical instrument's position and orientation while maintaining the remote-center-of-motion constraint, allowing real-time adaptation without requiring complex inverse kinematics calculations for static configurations.
3Adaptability or versatility
If multiple arms are used in combination, then surgical operations can be performed with enhanced capability, but interference among the plurality of arms may be easily caused
Solution Approach 1:
The patent resolves arm interference by transitioning from two-dimensional planar motion to three-dimensional spatial positioning. The spatial positioning mechanism enables arms to operate in different spatial planes and depths, allowing multiple arms to share the same surgical field without interference by utilizing the third dimension (depth/spatial layering).
Data Source
AI summary
This application provides a robotic arm and a control method therefor. The robotic arm comprises a spatial positioning mechanism, a planar motion mechanism and a connection and rotation joint connecting the spatial positioning mechanism and the planar motion mechanism. The space positioning mechanism comprises a base, and a joint mechanism including multiple joints, with the joint at a head end thereof installed onto the base, and the joint at a tail end rotatably connected to the connection and rotation joint; a tail end of the planar motion mechanism is connected to a surgical instrument. Perpendicular line of a plane where the planar motion mechanism is located is perpendicular to rotation axis of the connection and rotation joint; and the intersection between the rotation axis and axis of the surgical instrument is an active remote-center-of-motion point, which facilitates setting of the active remote-center-of-motion point and reduces occurrence of multi-arm collision.