Fluid-Powered Master-Slave Actuation for MRI-Safe Continuous Rotation
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Solution Overview
Problem
Current MRI-compatible mechatronics face challenges in maintaining zero interference during MRI operations, particularly in achieving bidirectional continuous rotation and positional control without electromagnetic interference.
Innovation Solution
A fluid-powered transmission system using a pair of cylinders connected via a long tube with a rolling diaphragm for low-friction transmission, allowing for infinite and continuous rotary motion with positional and torque control, and minimizing interference by using MR-safe materials and configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic actuation systems are used in MRI environments, then precise control and positioning can be achieved, but electromagnetic interference with MRI imaging occurs
Solution Approach 1:
The patent replaces electromagnetic actuation systems with a fluid-powered mechanical transmission system consisting of master and slave cylinders connected by fluid lines. This substitution eliminates electromagnetic interference with MRI imaging while maintaining precise control capability through hydraulic or pneumatic pressure transmission from the master cylinder to the slave cylinder.
Solution Approach 2:
The patent employs pneumatic or hydraulic fluid transmission to connect the master cylinder (positioned outside the MRI scanner) with the slave cylinder (positioned inside the MRI scanner). The fluid pressure changes in the master cylinder are transmitted through the fluid lines to actuate the slave cylinder, providing precise positioning control without any electromagnetic components in the MRI environment.
2Object-affected harmful factors
If fluid-powered transmission systems are used for MRI-compatible actuation, then electromagnetic interference is eliminated, but achieving bidirectional continuous rotation and infinite motion becomes challenging
Solution Approach 1:
The patent employs a rolling diaphragm seal that dynamically adapts to the piston movements within the slave cylinder. The rolling diaphragm can accommodate bidirectional piston motion and translate it into continuous rotational motion of the output shaft, enabling infinite motion range in both directions while maintaining fluid pressure sealing throughout the entire motion cycle.
Solution Approach 2:
The patent uses a flexible rolling diaphragm made of thin film material to seal the fluid pressure while allowing bidirectional piston movement. The diaphragm's flexibility enables it to roll back and forth with the piston, converting linear bidirectional motion into continuous rotational motion without compromising the fluid seal, thus achieving unlimited motion range.
3Loss of energy
If rolling diaphragm seals are used in fluid transmission, then friction is reduced and motion efficiency improves, but achieving tight sealing over long transmission distances becomes difficult
Solution Approach 1:
The patent employs a rolling diaphragm constructed from flexible thin film material that maintains effective sealing contact with the piston surface throughout the entire stroke length. The thin film's flexibility allows it to conform to the piston contours while rolling, ensuring tight sealing even over long transmission distances, and the rolling mechanism minimizes friction between the seal and piston surface.
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
The system enables MR-safe actuation in MRI-guided procedures, providing continuous bidirectional motion and precise control, reducing imaging interference and ensuring safety and efficiency in MRI environments.
Implementation Method 1
a rolling diaphragm configured to seal the pressurized fluid inside the tube
Implementation Method 2
The tubes are preferably filled with pressurized fluid and said pressurized fluid is retained inside the tubes
Data Source
AI summary
Systems and methods for an effective solution to MR safe actuation in all MRI-guided (robot-assisted) procedures are provided. The present integrated hydraulic transmission method or system uses piston-based cylinders (101,102,201,308(C1), 309(C2), 310(C3), 402, 501) to provide continuous bi-lateral rotation with unlimited range in an MRI environment. Positional and torque control can also be achieved. The system includes a master unit and a slave unit each comprising: a plurality of cylinders (101,102,201,308(C1), 309(C2), 310(C3), 402, 501), a piston (105,301,302,303,401,502) inserted within the bottom surface of each cylinder (101,102,201,308(C1), 309(C2), 310(C3), 402, 501), a seal positioned with each cylinder (101,102,201,308(C1), 309(C2), 310(C3), 402, 501) between the piston (105,301,302,303,401,502) and the top surface of the cylinder (101,102,201,308(C1), 309(C2), 310(C3), 402, 501) to inhibit a fluid from passing across the seal, and a plurality of tubes (103) connecting the master unit cylinders and slave unit cylinders (402).