Surgical Instrument Calibration Fixture for Accurate Tool Tip Tracking
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Solution Overview
Problem
Existing computer-assisted surgical instruments face challenges in accurately tracking the position of the tool tip due to the inability to mount a trackable marker on the tool tip, affecting the precision and compliance with the predetermined surgical plan.
Innovation Solution
A calibration device and method for calibrating the kinematic state of a robotically controlled manipulator, utilizing a stabilization mechanism and connection sensing mechanism to ensure accurate tracking of the tool tip by defaulting the kinematic state of the manipulator, enabling precise surgical operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a trackable marker is mounted on the tool tip, then the position tracking precision is improved, but the device complexity and surgical procedure complexity increase due to retrofitting requirements
Solution Approach 1:
The patent introduces an intermediary calibration device that couples to the manipulator at a accessible location rather than directly on the tool tip. This calibration device serves as a mediator that allows indirect tracking of the tool tip position through mathematical transformation, avoiding the need to physically attach markers to the tool tip itself.
Solution Approach 2:
The patent replaces the mechanical approach of directly mounting physical trackable markers on the tool tip with a computational approach. The system uses a calibration device with known geometry and mathematical models to calculate tool tip position based on tracked positions of the calibration device, substituting direct mechanical attachment with indirect computational determination.
2Measurement precision
If a trackable marker is mounted on the tool tip, then the measurement precision is improved, but the ease of operation deteriorates due to additional retrofitting steps
Solution Approach 1:
The patent performs calibration as a preliminary action before actual surgical operations. The calibration device is coupled to the manipulator once during setup, establishing transformation relationships that enable subsequent direct tracking without requiring repeated attachment or modification steps during surgery.
Solution Approach 2:
The calibration device acts as an intermediary that simplifies operation by providing a standardized coupling interface. This mediator allows the system to track the manipulator through the calibration device rather than requiring direct modification of each surgical tool, streamlining the operational workflow.
3Manufacturing precision
If the kinematic state of the manipulator is calibrated, then the manufacturing precision and measurement precision are improved, but the loss of time increases due to the calibration process
Solution Approach 1:
The calibration process is performed as a preliminary setup step before clinical use. Once calibrated, the transformation relationships are stored and reused for subsequent operations, amortizing the initial time investment across multiple surgical procedures and reducing the effective time cost per operation.
Solution Approach 2:
The calibration process determines specific kinematic parameters (translation distances, rotation angles) that characterize the manipulator's geometry. By measuring and storing these parameters once, the system transforms the time-consuming repeated measurement problem into a simple parameter retrieval operation for subsequent use.
Data Source
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AI summary
A calibration device for a computer-assisted surgical instrument includes a rigid body, stabilization members, and references structurally or mechanically complementary to the stabilization members and disposed on opposite sides of a manipulator of the instrument. Kinematic state of the manipulator is defaulted when the calibration device is connected to the instrument by the stabilization members passing through the rigid body and removably attaching to the references. A calibration method for a computer-assisted surgical instrument implemented by a computer system includes the steps of: prompting a user to connect the calibration device to the instrument; determining if the calibration device is properly connected to the instrument; and generating default kinematic information of the manipulator of the instrument if the calibration device is properly connected to the instrument. The calibration device and method effectively improve accuracy and precision of computer-assisted surgeries.