Surgical Tool Path Adjustment From Actual-State Deviation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Robotic surgical systems face inaccuracies and regenerative cutting errors due to delayed updates in positioning the end effector, which fail to account for near real-time actual positions and fast anatomy movements, exacerbated by the lag between tracking systems and robot response.
Innovation Solution
A surgical system that includes a manipulator and controllers to determine actual and commanded states of the surgical tool, detecting deviations and adjusting the feed rate or tool path in near real-time using raw or lightly filtered kinematic and navigation data to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tracking systems update robot positioning at high frequencies, then near real-time accuracy is improved, but system stability deteriorates due to positive feedback
Solution Approach 1:
The system performs preliminary filtering of tracking data at multiple levels (raw data filtering, commanded state filtering) before using the data for control. This anticipates the stability issue by preprocessing data to remove high-frequency noise that would cause positive feedback, while still maintaining near real-time responsiveness through selective filtering rather than aggressive low-pass filtering.
Solution Approach 2:
The system dynamically adjusts filtering intensity based on the specific data stream and control loop. Different filtering parameters are applied to different data streams (tracking data vs. commanded states), and filtering strength is modulated based on system state, allowing high-frequency response when safe and smooth control when needed.
2Speed
If robot responds quickly to tracking data, then responsiveness is improved, but cutting accuracy deteriorates due to regenerative errors
Solution Approach 1:
The system implements multi-loop feedback where actual states are continuously compared with commanded states, and deviations are fed back to adjust subsequent commanded states. This closed-loop feedback corrects regenerative cutting errors by detecting deviations early and compensating in near real-time, maintaining both speed and accuracy.
Solution Approach 2:
The system performs preliminary comparison and deviation detection on tracking data before executing corrective actions. By analyzing the difference between commanded and actual states in advance and planning corrections proactively, the system maintains responsiveness while preventing accuracy degradation from regenerative errors.
3Stability of the object's composition
If filtered data is used for control, then system stability is improved, but real-time accuracy deteriorates due to filtering delay
Solution Approach 1:
The system segments the data processing pipeline into distinct filtering stages with different purposes: raw data filtering for noise reduction, commanded state filtering for control smoothness, and actual state determination using minimally filtered data. Each segment handles filtering at the appropriate level, preventing any single filtering stage from introducing excessive delay while maintaining overall stability.
Solution Approach 2:
Different filtering characteristics are applied to different parts of the control system based on local requirements. Tracking data receives filtering tailored to its high-frequency nature, commanded states receive filtering appropriate for control smoothness, and actual states use minimal filtering to preserve real-time accuracy. This localized filtering strategy optimizes both stability and responsiveness in each subsystem.
Data Source
AI summary
A surgical system and method of operating the same. A manipulator supports and facilitates movement of a surgical tool along a tool path relative to a surgical site. Controller(s) determine commanded states and actual states of the surgical tool relative to the tool path for a plurality of time steps. The controller(s) detect at least one deviation between the commanded states and the actual states of the surgical tool for at least one of the plurality of time steps. The controller(s) respond to the deviation by modification of one or both of: a feed rate of the surgical tool; and the tool path.