Surgical Robot Error Detection with Split Tracking Data Paths

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Solution Overview

Problem

Surgical robotic systems face delays in detecting errors or loss of accuracy due to high-speed tracking data noise and control system stability issues, leading to potential damage during surgical procedures.

Innovation Solution

A surgical system comprising a manipulator, a navigation system with a tracker and localizer, and controllers that determine and combine transforms to detect errors in real-time, using data fusion and filtering techniques to ensure accurate positioning and prevent system instability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If low-pass filtering is applied to tracking data to reduce noise, then signal-to-noise ratio improves and robot movement becomes smoother, but error detection is delayed due to filtering processing time

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoiderror detection delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the tracking data processing into separate streams: one stream applies low-pass filtering for smooth robot control, while another stream processes raw or minimally filtered data for real-time error detection. This segmentation allows both noise reduction and timely error detection to occur simultaneously without compromising either function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary error detection mechanism that operates between the tracking system and the robot control system. This intermediary layer monitors transformed values from both filtered and unfiltered data streams, comparing them to detect errors before they affect robot operation, thus bridging the gap between noise reduction and real-time monitoring.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If tracking system operates at high speed to capture robot movement, then positioning accuracy improves, but control system stability deteriorates due to noise and excessive bandwidth

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcontrol system stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent applies different quality levels of data processing to different control functions: high-speed raw tracking data is used for error detection where speed is critical, while low-pass filtered data is used for robot control where smoothness and stability are prioritized. This local differentiation of data quality resolves the contradiction between positioning accuracy and control stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses partial filtering rather than complete filtering of tracking data. By applying low-pass filtering only to the control commands while maintaining access to unfiltered data for error detection, the system achieves sufficient noise reduction for stable control without completely eliminating high-frequency information needed for accurate positioning monitoring.

Inventive Principle:
Principle #16Partial or excessive action

3Speed

If outer positioning loop bandwidth is increased to improve response speed, then robot responsiveness improves, but system stability deteriorates

Engineering Contradiction:
Improverobot responsivenessVSAvoidsystem stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary error detection on tracking data before the filtered data is used for control. By checking transformed values from raw tracking data against expected ranges in advance, the system can identify and flag potential errors before they propagate through the control loop, enabling faster response to errors without compromising overall system stability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11844495B2Techniques for detecting errors or loss of accuracy in a surgical robotic system
Publication Date: 2023.12.19 MAKO SURGICAL CORP
  • US11844495B2 patent drawing
  • US11844495B2 patent drawing
  • US11844495B2 patent drawing

AI summary

Systems and methods for detecting an error in a surgical system. The surgical system includes a manipulator with a base and a plurality of links and the manipulator supports a surgical tool. The system includes a navigation system with a tracker and a localizer to monitor a state of the tracker. Controller(s) determine values of a first transform between a state of the base of the manipulator and a state of one or both of the localizer and the tracker of the navigation system. The controller(s) determine values of a second transform between the state of the localizer and the state of the tracker. The controller(s) combine values of the first transform and the second transform to determine whether an error has occurred relating to one or both of the manipulator and the localizer.