Surgical Tool Roll Disk Engagement Without Mechanical Hardstops
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Solution Overview
Problem
Surgical robotic systems face challenges in engaging and synchronizing surgical tools with actuators due to the lack of mechanical hardstops, leading to difficulties in detecting engagement and ensuring safe operation, particularly in scenarios with unlimited range of motion and complex mechanical designs that exhibit backlash and compliance.
Innovation Solution
A method and apparatus for engaging the driving motor of a rotary actuator with a surgical instrument's roll tool disk without hardstops, using torque thresholds and synchronization of coupled motors to ensure safe and precise engagement, and a calibration and control mechanism to account for backlash and compliance in the mechanical design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If mechanical hardstops are removed to enable unlimited range of motion, then the range of motion is improved, but the difficulty of detecting engagement increases
Solution Approach 1:
The patent replaces mechanical hardstop-based engagement detection with an optical sensing system. Optical sensors detect the presence and position of the surgical tool relative to the robotic arm, enabling engagement detection without physical contact stops. This substitution allows unlimited range of motion while maintaining reliable engagement detection through optical fields rather than mechanical constraints.
Solution Approach 2:
The patent introduces optical sensors as intermediary detection elements between the surgical tool and the robotic arm control system. These sensors act as mediators that detect engagement status through optical signals (such as reflection, interruption, or position detection) without requiring mechanical hardstops. This intermediary sensing layer enables engagement detection while preserving the full range of motion capability.
2Adaptability or versatility
If mechanical hardstops are removed to enable unlimited range of motion, then the adaptability is improved, but the reliability decreases
Solution Approach 1:
The patent implements feedback control through optical sensors that continuously monitor the position and engagement status of the surgical tool. The control system receives real-time optical feedback and adjusts actuator commands accordingly, ensuring safe operation even without mechanical hardstops. This closed-loop feedback mechanism provides reliability by detecting engagement status and preventing unsafe movements through software-based constraints rather than physical stops.
3Measurement precision
If torque thresholds and time windows are used for engagement detection, then the measurement precision is improved, but the complexity of the detection system increases
Solution Approach 1:
The patent uses parameter changes in optical sensor readings (such as light intensity, position coordinates, or reflection patterns) to detect engagement. By monitoring changes in optical parameters before, during, and after tool attachment, the system achieves precise engagement detection. The torque threshold and time window concepts are applied to the optical signal analysis, where specific parameter thresholds and temporal windows identify engagement events accurately without requiring complex additional hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable and safe engagement of surgical tools with actuators, ensuring precise motion control and position tracking, even in designs without mechanical hardstops, thereby improving the operational reliability and safety of surgical robotic systems.
Implementation Method 1
determining whether a measured torque of the rotary motor exceeds a preset torque threshold
Data Source
AI summary
The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. A tool driver is coupled to a distal end of a robotic arm and includes a roll drive disk driven by a rotary motor. One or more processors are configured to detect an attachment of a surgical tool to the tool driver. The surgical tool includes a roll tool disk to be engaged with the roll drive disk of the tool driver, actuate of the roll drive disk through the rotary motor, determine that a measured torque of the rotary motor exceeds a preset torque threshold for a preset period of time since the actuation, and report a successful engagement between the roll drive disk and the roll tool disk.