Medical Robot Tool Guide Force Sensor Control
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Solution Overview
Problem
Current medical robotic systems for mini-invasive procedures rely heavily on practitioner skill, leading to variability in precision and increased radiation exposure for patients, with existing solutions like accelerometer-based trembling detection being complex and requiring additional sensors.
Innovation Solution
A medical robot with a robotized arm equipped with a force sensor and a control unit that adjusts displacement speed based on the practitioner's force, using a variable gain factor to ensure fluid movement at a distance and precise control near the patient, while preventing jerky movements and automatic release of instruments during unexpected patient movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the robotised arm is displaced manually by the practitioner, then the movement can be fluid and reactive when the tool guide is distant from the patient, but the movement must be controlled with precision and at low speed when the tool guide is close to the patient, creating a contradiction in movement speed requirements
Solution Approach 1:
The system dynamically adjusts the gain factor of the control unit based on the distance between the tool guide and the patient's anatomy. When the tool guide is distant, a higher gain factor enables fluid and reactive movement. When the tool guide is close, a lower gain factor ensures precise and controlled movement, thus resolving the contradiction between speed and precision requirements at different positions
Solution Approach 2:
The control unit changes the operational parameter (gain factor) according to the spatial position of the tool guide. This parameter adjustment allows the system to transition from high-speed reactive movement at distances to low-speed precise movement near the patient, simultaneously satisfying both speed and precision requirements
2Reliability
If an accelerometer is integrated into the medical robot to detect practitioner trembling, then trembling can be detected, but the system becomes relatively complex to implement
Solution Approach 1:
The force sensor, originally designed to measure forces exerted on the tool guide during normal operation, is also used to detect practitioner trembling. This multi-functional use of the force sensor eliminates the need for separate accelerometer hardware, reducing system complexity while maintaining reliable trembling detection capability
Solution Approach 2:
The existing force sensing capability of the robotised arm is leveraged to serve the additional function of trembling detection. The system uses its own inherent sensing resources rather than adding external dedicated sensors, thereby avoiding increased complexity while achieving the detection objective
3Ease of operation
If the practitioner manually displaces the robotised arm, then the arm can be positioned flexibly, but jerky movements caused by practitioner trembling may occur when the tool guide is close to the patient
Solution Approach 1:
The control unit continuously monitors the force sensor output and uses this feedback to adjust the robotised arm's movement in real-time. When trembling is detected through force variations, the control unit compensates by smoothing the movement, thereby maintaining ease of manual operation while eliminating jerky movements and ensuring reliable smooth operation near the patient
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
This solution enhances precision and safety during medical procedures by adapting movement speed according to the practitioner's force, reducing the risk of injury and radiation exposure, and enabling controlled, smooth arm displacement, even when trembling occurs.
Implementation Method 1
The tool guide is coupled to a force sensor. When the medical robot is used in a cooperative manual control mode, the control unit is configured to determine, by means of the force sensor, a force exerted by the practitioner on the tool guide
Data Source
AI summary
The invention relates to a medical robot for assisting a practitioner during a medical intervention on a relevant anatomical part of a patient. The medical robot comprises a robotic arm equipped, at one end, with a tool guide intended to guide a medical instrument. The medical robot also comprises a control unit configured to control the movement of the robotic arm. The tool guide is coupled to a force sensor. When the medical robot is used in a “cooperative manual control” mode, the control unit is configured to determine, using the force sensor, a force applied by the practitioner to the tool guide and to calculate a speed of movement of the tool guide on the basis of a gain factor applied to the determined force. Advantageously, the value of the gain factor is variable and is calculated on the basis of the determined force.