Surgical Robot Force Estimation via Arm-Mounted Detector
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Solution Overview
Problem
Existing surgical robot systems face challenges in reducing the size of the distal end of surgical instruments while improving the accuracy of external force measurement, which affects comfort and safety for subjects undergoing endoscopic surgery.
Innovation Solution
A surgical robot system is designed with a detector positioned at the arm device, not at the distal end of the surgical instrument, to detect forces and torques acting on the instrument. This system calculates the first external force from the trocar and the second external force from other objects based on detected values and resistance forces, allowing for precise control of the instrument's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detector is arranged at the distal end of the surgical instrument, then the measurement accuracy of external force is improved, but the size of the distal end increases
Solution Approach 1:
The patent introduces the arm device as an intermediary component that carries the detector. Instead of placing the detector directly at the distal end of the surgical instrument, the detector is mounted on the arm device which holds and positions the instrument. This mediator approach allows force measurement while keeping the instrument's distal end compact and suitable for minimally invasive surgery.
2Volume of moving object
If the detector is arranged at the arm device, then the distal end size is reduced, but the measurement accuracy of external force decreases
Solution Approach 1:
The patent implements a feedback mechanism where the controller calculates external forces based on detector readings from the arm device, resistance force information, and positional data. The system continuously monitors and adjusts control signals to the arm device based on calculated external forces, improving measurement accuracy through active compensation and feedback control.
Solution Approach 2:
The patent replaces direct mechanical force measurement at the distal end with a computational approach. Instead of mechanically measuring forces at the instrument tip, the system uses detectors at the arm device combined with resistance force calculations and control algorithms to determine external forces, substituting mechanical measurement with a hybrid mechanical-computational system.
3Measurement precision
If the surgical instrument includes resistance force between trocar and shaft, then the external force calculation accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent makes the system self-sufficient by calculating resistance force between the trocar and shaft using information already available in the system (detector readings, positional data, and control signals). The controller computes resistance force as part of the external force calculation process, eliminating the need for separate resistance force sensors or additional measurement devices.
Data Source
AI summary
A surgical robot system includes a surgical instrument including a shaft to be inserted through a trocar placed in a subject, an arm device that holds the surgical instrument and moves the surgical instrument with respect to the subject, a detector arranged at the arm device and configured to detect values of forces and torques acting on the surgical instrument; and a controller that calculates a value of a first external force that the surgical instrument receives from the trocar and a value of a second external force that is received from an object other than the trocar and that is abuttable on the surgical instrument, based on the values of forces and torques, and controls the arm device to move the surgical instrument, based on the value of the first external force and the value of the second external force.