Medical Manipulator Torque Sensing for Tissue Separation Control
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Solution Overview
Problem
Medical manipulators face challenges in detecting unexpected separation from body tissue, leading to potential rapid displacement and contact with surrounding tissue, especially due to the difficulty in providing force sensors at every joint, which complicates control and torque management.
Innovation Solution
A medical manipulator equipped with a torque detecting unit and a torque reducing unit that monitors torque changes to detect unexpected separation from body tissue, reducing torque transmission to prevent abrupt displacement and contact with surrounding tissue, eliminating the need for force sensors on the tip by using a combination of an electric motor, control unit, and operation input unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors are provided at every joint of the medical manipulator to detect unexpected separation, then detection accuracy is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent extracts the detection function from the tip of the manipulator and relocates it to the base end motor. By monitoring torque changes at the motor, the system can detect unexpected separation events without requiring force sensors at the manipulator tip or joints, thus simplifying the overall device structure while maintaining detection capability
Solution Approach 2:
The patent uses torque as an intermediary parameter to indirectly detect contact state. Instead of directly measuring contact force with sensors at the tip, the system monitors torque variations at the motor, which serve as a mediator to infer the contact status between the manipulator and body tissue
2Reliability
If force sensors are installed at every joint to detect separation, then reliability is improved, but ease of manufacture deteriorates due to increased complexity
Solution Approach 1:
The motor at the base end serves multiple functions: it provides driving torque for manipulator movement and simultaneously acts as a detection point for monitoring contact state through torque sensing. This multi-functionality eliminates the need for separate force sensors, improving manufacturability while maintaining reliability
Solution Approach 2:
The motor's own torque detection capability is utilized to serve the dual purpose of actuation and sensing. The system leverages the motor's inherent properties to detect unexpected separation events, making the manipulator self-diagnostic without requiring additional specialized sensors
3Power
If the manipulator applies force to body tissue, then treatment effectiveness is improved, but the risk of rapid displacement upon unexpected separation increases
Solution Approach 1:
The system continuously monitors torque at the motor and provides feedback to the control unit. When unexpected separation is detected through torque change analysis, the control unit immediately responds by adjusting motor output, creating a closed-loop feedback system that prevents harmful rapid displacement while allowing effective treatment force application
Solution Approach 2:
The system proactively detects separation events before they can cause harmful effects. By monitoring torque variations and identifying separation patterns in advance, the control unit can preemptively adjust motor torque to prevent rapid manipulator displacement and potential damage to surrounding tissue
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
Effectively detects and prevents unexpected separation from body tissue, suppressing abrupt displacement and avoiding contact with surrounding tissue by reducing torque transmission, ensuring precise control and safety during medical procedures without the need for force sensors on the manipulator's tip.
Implementation Method 1
The electric motor includes a current sensor or a torque detecting unit for detecting the torque of the motor
Data Source
AI summary
Embodiments of the technology disclosed herein is directed to a medical manipulator capable of detecting an instant when a tip of the medical manipulator is unexpectedly separated from a body tissue and thus avoid making contact with surrounding body tissues. The technology disclosed eliminates the needs for providing a force sensor located on the tip of the medical manipulator. The medical manipulator includes a movable unit at one end and an electric motor, a control unit, and an operation input unit at opposed end thereof. The movable unit includes a treating unit for treating the body tissue. The electric motor is configured to operate the movable unit. The electric motor includes a current sensor or a torque detecting unit for detecting the torque of the motor. The control unit includes a torque reducing unit for reducing the torque transmitted to the movable unit from the electric motor.