Surgical Tool Articulation Joint Hardstop Compensation
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Solution Overview
Problem
In minimally invasive surgery, robotic end effectors often encounter hardstops, either internal or external, which can lead to damage if the user is unable to identify them, especially when only visual feedback is available, causing unintended motor displacement and potential harm to the robot or external objects.
Innovation Solution
A robotically assisted surgical electro-mechanical system with a tool driver and processors that calculate articulation joint positions and torques to determine a torque ratio, allowing for adjustments to compensate for hardstops, ensuring safe movement without damaging the robotic system or external objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If robotic end effectors are used in minimally invasive surgery, then surgical precision and minimality are improved, but the risk of damage from hardstop collisions increases when visual feedback is insufficient
Solution Approach 1:
The system implements torque feedback sensing to detect hardstop collisions. The torque sensor measures the torque required to rotate the articulation joint, and when a hardstop is detected (excessive torque), the system provides feedback to the controller to adjust or terminate the motion, preventing damage to the robotic system or external objects.
Solution Approach 2:
The patent replaces purely visual feedback mechanisms with a torque-based sensing system. Instead of relying solely on visual detection of hardstops, the system uses mechanical torque sensing to detect collisions and calculate a torque ratio to determine appropriate responses, substituting visual reliance with tactile/mechanical sensing.
2Object-affected harmful factors
If articulation joint movements are allowed to compensate for hardstops, then damage prevention is improved, but control complexity increases due to torque ratio calculations
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by automatically calculating the torque ratio and determining appropriate articulation joint adjustments without external intervention. The controller autonomously processes torque sensor data, calculates compensation values, and adjusts joint movements to prevent damage, making the system self-sufficient in hardstop handling.
Solution Approach 2:
The patent changes the control parameter from direct position control to torque-ratio-based adjustment control. By calculating the torque ratio and using it to determine articulation joint adjustments, the system transforms the control approach to accommodate hardstop conditions while maintaining manageable complexity through mathematical modeling.
Data Source
AI summary
The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. One example system for handling hardstops includes one or more processors configured to calculate an articulation joint position for the articulation drive disk or the one or more corresponding rotary motors corresponding rotary motors, calculate an articulation joint torque for the articulation drive disk or the one or more corresponding rotary motors, determine a torque ratio based on the articulation joint position and the articulation joint torque, and adjust a commanded articulation joint position received from the user based on the torque ratio to compensate for collision involving the end effector.