Medical Robot Force Feedback for Safe Surgical Trajectory Control
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Solution Overview
Problem
Current medical robots in spinal surgery, particularly in cutting operations, lack the ability to correct operator misoperations in master-slave control modes, leading to potential nerve injuries and inefficiencies due to reliance on operator precision and incomplete anatomical fixation.
Innovation Solution
A medical robot system that includes an operator force acquisition unit, a robot force acquisition unit, a control module, and a driving module, which determines the desired velocity of the robot tip based on both operator and robot forces to maintain correct trajectory and region, using a multi-dimensional force sensor, joint torque detection, and regional constraint strategies to enhance safety and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If master-slave control mode is used for robotic assistance in cutting operations, then position precision is improved, but operator misoperations cannot be corrected and safety deteriorates
Solution Approach 1:
The patent implements force feedback control where the robot acquires operating force information from the operator and generates corrective force feedback to prevent misoperations. The control module continuously monitors the robot tip's position and force, comparing it against the pre-planned trajectory and dangerous region boundaries, then applies corrective forces to guide the tool back to the safe trajectory, thereby maintaining safety while preserving operator control.
Solution Approach 2:
The system performs preliminary safety planning by pre-defining the desired trajectory and identifying dangerous regions before the cutting operation begins. The control module uses these pre-established safety parameters to proactively prevent misoperations by generating opposing force when the tool approaches dangerous zones or deviates from the planned path, thus preventing harm before it occurs.
2Measurement precision
If simple position instruction control is used, then position precision is improved, but information exchange of operating force is lost and dependency on operator precision increases
Solution Approach 1:
The patent implements bidirectional force feedback control where the robot not only receives position instructions but also continuously acquires and processes operating force information from the operator through force sensors. This force information is fed back to the control module which adjusts the robot's motion accordingly, enabling natural force interaction between operator and robot while maintaining high position precision through continuous force-based trajectory correction.
3Measurement precision
If anatomical structure movement due to incomplete fixation is present, then registration precision errors increase, but the robot cannot adapt to dynamic changes
Solution Approach 1:
The patent transitions from static position control to dynamic force control by implementing continuous force-based trajectory adjustment. The control module continuously monitors the robot tip's position and operating force during the procedure, dynamically adjusting the trajectory in real-time to compensate for anatomical structure movement caused by incomplete fixation or physiological changes, thereby maintaining registration precision despite dynamic conditions.
Data Source
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AI summary
A medical robot and control method thereof. A movement speed of an end portion of a robot is determined jointly by the operation force of an operator and the operation force of the robot. When the operation of the operator makes the end portion of the robot deviate from a desired movement track or enter into a high-risk area, the operation force of the robot will be generated to ensure the end portion of the robot is kept on the correct track and in the correct area at all time. The medical robot and control method thereof change the master-slave (operator-robot) control mode in the prior art to enable information exchange between the operator and the robot, thus greatly improving the safety and accuracy of medical robot operation.