Cable-Driven Surgical Tool Disengagement Detection by Tension Monitoring
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Solution Overview
Problem
Current surgical robotic systems lack effective detection mechanisms for disengagement, breakage, or failure of cables driving surgical tools, which can lead to unexpected movements and compromised surgical precision.
Innovation Solution
The implementation of a control unit that monitors motor operating parameters, such as torque, current, and position sensors to detect mechanical engagement and disengagement of tool disks with drive disks, using a combination of sensors and feedback loops to ensure proper alignment and engagement of surgical tool disks with their respective drive disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cable driven mechanisms are used in surgical tools, then flexibility and minimally-invasive access are improved, but detection of disengagement or breakage becomes more difficult
Solution Approach 1:
The system continuously monitors motor operating parameters (current, torque, speed) and compares them against expected values during cable-driven tool operation. When deviations indicate cable disengagement or breakage, the control unit generates alerts to notify the operator, enabling real-time detection without compromising the flexible cable-driven mechanism.
Solution Approach 2:
The patent replaces direct mechanical engagement detection with electrical parameter monitoring. Instead of using mechanical switches or physical contact sensors to detect cable status, the system uses electrical measurements (current, torque, speed) from the motor control system to infer cable integrity, thereby maintaining flexibility while enabling detection.
2Reliability
If real-time monitoring of motor parameters is implemented, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The control unit performs multiple functions: it controls motor operation, monitors operating parameters, detects cable disengagement or breakage, and generates alerts. By consolidating these functions into a single control unit rather than adding separate detection hardware, the system improves reliability without proportionally increasing device complexity.
Solution Approach 2:
The motor control system monitors its own operating parameters (current, torque, speed) to detect cable issues. The system uses its existing sensors and control infrastructure for self-diagnosis, eliminating the need for separate detection hardware and reducing overall system complexity while maintaining high detection reliability.
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 detecting disengagement of a surgical tool, includes an end effector connected to and driven by cables of a tool driver, sensors configured to detect forces associated with the cables, and one or more processors. The one or more processors identify cable tensions derived from forces detected by the sensors, compare the tension to a threshold tension value, calculate a velocity norm value based on a vector including the velocity value for each of the cables, compare the velocity norm value to a statistic velocity threshold, and identify a disengagement of at least one of the plurality of cables based on the first comparison and the second comparison.