Robotic Surgical Articulation Limits Around the Remote Center of Motion
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Solution Overview
Problem
Robotic surgical systems face limitations in instrument articulation control due to abrupt changes in joint constraints and the distance of surgical instruments from the Remote Center of Motion (RCM), leading to collisions and reduced range of motion.
Innovation Solution
A system and method that selectively bind articulation limits to surgical instruments based on their distance from the RCM, allowing for real-time control of articulation by detecting linear movements and assigning binding or non-binding limits, which can change shape based on linear, quadratic, or power curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical RCM is used to ensure surgical instruments do not move beyond fixed entry points, then surgical safety is improved, but the range of motion is reduced and collisions between robotic arms occur
Solution Approach 1:
The patent replaces the mechanical RCM constraint system with a software-based virtual constraint system. The mechanical connection between the robotic arm and surgical portal is substituted with software-defined articulation limits that are calculated and enforced through control algorithms, allowing the instrument to move freely within safe boundaries without physical constraints.
Solution Approach 2:
The patent implements dynamic articulation limits that are continuously adjusted based on the instrument's position, orientation, and distance from the RCM. The binding/non-binding articulation limits are not fixed but are dynamically modified in real-time during surgical procedures, allowing the system to adapt to changing surgical conditions and maximize range of motion while maintaining safety.
2Reliability
If binding articulation limits are applied to prevent instrument movement beyond safe boundaries, then surgical safety is improved, but abrupt changes in joint constraints occur reducing operational flexibility
Solution Approach 1:
The system implements dynamic switching between binding and non-binding articulation limits based on real-time instrument position and surgical conditions. The articulation limits are not static but are continuously evaluated and adjusted, allowing smooth transitions between constrained and unconstrained motion states without abrupt changes that would disrupt surgical workflow.
Solution Approach 2:
The patent changes the parameter of articulation limit enforcement from a fixed binding state to a variable state that can switch between binding and non-binding based on calculated distances and surgical needs. This parameter change allows the system to maintain safety boundaries while providing operational flexibility when conditions permit.
3Ease of operation
If the distance of the distal portion of the surgical instrument from the RCM increases, then range of motion is improved, but abrupt changes in joint constraints occur due to limitations in the surgical site
Solution Approach 1:
The system continuously monitors the instrument's position, orientation, and distance from the RCM, and uses this feedback to dynamically adjust articulation limits. The control system receives real-time data about instrument configuration and surgical site conditions, processes this information, and automatically modifies binding/non-binding limits to maintain safety while maximizing range of motion.
Solution Approach 2:
The patent dynamically changes articulation limit parameters based on the calculated distance between the instrument's distal portion and the RCM. As the instrument moves farther from the RCM, the system adjusts the binding/non-binding nature of articulation limits to account for increased leverage and potential safety risks, without requiring complex manual constraint management.
Data Source
AI summary
A robotic surgical system and method of selectively binding articulation limits to a surgical instrument includes detecting a proximal or a distal linear movement of the surgical instrument, calculating a distance between a tool center point of the surgical instrument after the proximal or the distal linear movement and a remote center of motion, assigning and binding an articulation limit to the surgical instrument based on the calculated distance when the detected linear movement is distal linear movement, and assigning a non-binding articulation limit to the surgical instrument based on the calculated distance when the detected linear movement is proximal a linear movement.