Teleoperated Surgical Instrument Ratcheting for Master-Slave Alignment
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Solution Overview
Problem
Existing teleoperated minimally invasive surgical systems, such as the da Vinci® surgical system, require powered master tool manipulators for aligning the master grip with the slave surgical instrument tip, leading to delays and the need for costly components, which can slow down surgical procedures.
Innovation Solution
A ratcheting system within the teleoperation servo control system continuously improves the alignment between the master grip and the slave surgical instrument tip in a common coordinate frame without autonomous motion, using a ratcheting system that includes a control loop error controller and roll-joint limit controller to seamlessly adjust the alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a powered master tool manipulator with motors in the gimbal assembly is used to align the master grip with the slave surgical instrument tip, then the alignment accuracy is improved, but the system complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical motor-driven alignment system with a software-based ratcheting control system. The ratcheting mechanism uses control algorithms to gradually adjust the slave instrument orientation to match the master grip orientation, eliminating the need for complex powered master manipulators with motors in the gimbal assembly.
Solution Approach 2:
The patent creates a virtual model of the master grip orientation and uses this copied information to guide the alignment of the slave surgical instrument. The ratcheting system continuously compares the master orientation with the slave orientation and adjusts accordingly, allowing alignment without direct mechanical coupling or powered actuators in the master manipulator.
2Measurement precision
If a powered master tool manipulator is used to perform master alignment, then the alignment precision is improved, but the time required for alignment increases
Solution Approach 1:
The ratcheting system performs alignment continuously during the teleoperation setup process rather than requiring a separate powered alignment step. The control system continuously reduces orientation errors between master and slave, allowing alignment to occur seamlessly as part of the normal operation initialization without adding time to the surgical procedure.
3Measurement precision
If powered master tool manipulator components are used for alignment, then the alignment capability is improved, but the cost of the system increases
Solution Approach 1:
The patent replaces expensive, complex powered master manipulator components with simpler, less costly hardware combined with software-based ratcheting control. The master grip can be a simpler mechanical device without motors in the gimbal assembly, reducing manufacturing costs while maintaining alignment capability through control algorithms.
4Measurement precision
If the system waits for powered alignment to complete before allowing following mode, then the alignment accuracy is ensured, but the productivity decreases
Solution Approach 1:
The ratcheting system performs preliminary alignment adjustments automatically as the surgeon begins teleoperation, rather than requiring completion of alignment before operation. The control system continuously refines the alignment in the background, allowing the surgeon to enter following mode immediately while the system ensures alignment accuracy is achieved through ongoing ratcheting adjustments.
Data Source
AI summary
Techniques for ratcheting an alignment between an input means and an instrument include a teleoperated system comprising a robotic means configured to support an instrument, an input means configured to be manipulated by an operator to command motion of the instrument, and a ratcheting means. The ratcheting means is configured to determine first rotation values describing an orientation of the input means; determine second rotation values describing an orientation of the instrument; determine, based on the first rotation values and the second rotation values, an orientation error between the orientation of the input means and the orientation of the instrument; generate, based on the orientation error, a motion command for the instrument to reduce the orientation error by increasing an alignment between the input means and the instrument; and command the robotic means to move in accordance with the motion command.