Hand-Guided Robot Tracking With Kinematic Model Accuracy

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Solution Overview

Problem

Current methods for tracking hand-guided robots in medical minimally invasive interventions lack the necessary precision and accuracy, which is critical for the success of such procedures.

Innovation Solution

A method utilizing a kinematic and dynamic model of the manipulator, coupled with sensors to determine joint movements and calculate the absolute position of the end effector within the operational volume, allowing for precise tracking by accounting for mechanical properties like friction, flexibility, and backlash, and displaying deviation and error information to facilitate manual displacement along a target trajectory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a software-based kinematic and dynamic model is used to determine end effector position, then tracking accuracy is improved, but computational complexity and processing time increase

Engineering Contradiction:
Improvetracking accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores a lookup table of transformation matrices for all possible manipulator configurations before the intervention procedure. During tracking, the system only needs to query this pre-computed table based on measured joint positions, avoiding real-time complex calculations while maintaining high accuracy through the software-based kinematic and dynamic model

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex real-time mechanical computation with a software-based approach using pre-computed lookup tables. The transformation from joint space to operational space is achieved through software lookup rather than real-time mathematical computation, substituting computational complexity with memory storage and retrieval operations

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If frequent interventional imaging is performed to verify end effector position, then positioning accuracy is improved, but patient radiation exposure and procedure time increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpatient radiation exposure
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements continuous tracking feedback by measuring joint positions with sensors and using the pre-computed transformation matrices to calculate end effector position in real-time. This provides continuous positional feedback to the operator, reducing the need for frequent verification imaging and thereby reducing patient radiation exposure while maintaining positioning accuracy

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent creates a virtual copy of the physical manipulator through software-based kinematic and dynamic modeling. This virtual model replicates the manipulator's position and orientation based on joint measurements, providing accurate positional information without requiring frequent physical verification through imaging, thus reducing radiation exposure

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3444078B1Method for tracking a hand-guided robot, hand-guided robot, computer program, and electronically readable storage medium
Publication Date: 2023.07.05 SIEMENS HEALTHINEERS AG
  • EP3444078B1 patent drawingFigure 1~2
  • EP3444078B1 patent drawingFigure 3
  • EP3444078B1 patent drawingFigure 4

AI summary

Method for tracking a hand-guided robot (1) comprising a control unit (14) and at least one manipulator (6) coupled to an end effector (10), in which the manipulator (6) comprises a plurality of joints (7, 8) and links (9) and the end effector (10) is manually displaceable within an operational volume (11), characterized in that the control unit (14) determines at least one movement information of each joint (7, 8) during and/or after a manual or partially manual displacement of the end effector (10), and a position and orientation information of the end effector (10) inside the operational volume (11) during and/or after the displacement of the end effector (10) using the determined movement information of each joint (7, 8) and a software-based kinematic and dynamic model of the manipulator (6) stored in a memory (16) of the control unit (14).