Medical Instrument Compression Compensation via Positioning
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Solution Overview
Problem
Medical instruments with elongated shafts experience undesirable compression during pull wire-based movements, leading to inaccuracies in navigation and positioning within the body.
Innovation Solution
The use of an instrument positioning device, such as a robotic arm, to compensate for compression by determining the amount of compression through compression compensation parameters and adjusting the position of the medical instrument accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pull wires are actuated to articulate the elongated shaft, then the shaft can be steered and navigated within the patient, but axial compression of the shaft occurs causing positioning inaccuracy
Solution Approach 1:
The system continuously monitors the actual position of the elongated shaft using sensors (optical, electromagnetic, or acoustic) and compares it to the commanded position. A feedback loop calculates the compression-induced position error and automatically adjusts the instrument positioning device to compensate, ensuring accurate positioning despite pull wire actuation.
Solution Approach 2:
The system determines compression parameters (axial compression amount) based on pull wire characteristics (tension, displacement, actuator position) and uses these parameters to calculate compensation values. By changing the positioning parameters of the instrument positioning device based on these compression parameters, the system compensates for the compression effect.
2Strength
If the elongated shaft is compressed during articulation, then the shaft structure remains intact, but navigation precision is degraded
Solution Approach 1:
The system performs preliminary determination of compression parameters before final positioning is achieved. By calculating the compression amount in advance based on pull wire actuation characteristics, the system can pre-adjust the instrument positioning device to compensate for the compression, ensuring navigation precision is maintained throughout the articulation process.
Solution Approach 2:
Instead of relying solely on mechanical rigid connections that are susceptible to compression, the system uses sensor-based measurement (optical, electromagnetic, or acoustic fields) to detect the actual shaft position and substitutes mechanical precision with field-based measurement and computational compensation.
3Measurement precision
If compression compensation is implemented using sensor-based monitoring, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The instrument positioning device performs multiple functions: it positions the medical instrument, monitors compression through sensor integration, calculates compensation values, and executes corrective positioning. By making the positioning device multi-functional, the system avoids adding separate dedicated compression compensation hardware, thereby limiting the increase in device complexity.
Solution Approach 2:
The system uses the existing pull wire actuation characteristics and sensor data to automatically determine compression parameters and calculate compensation values without requiring external intervention. The instrument positioning device self-adjusts based on real-time compression monitoring, reducing the need for additional complex control systems.
Data Source
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AI summary
Certain aspects relate to systems and techniques for compensating for compression in elongated shafts of medical instruments. Medical instruments can include elongated shafts that may experience compression when articulated. The medical instruments can be attached to instrument positioning devices that are configured to move the medical instruments to compensate for this compression. For example, an instrument positioning device can advance a medical instrument to compensate for compression in an elongated shaft of the medical instrument. In some instances, the amount of compression is determined using a compression compensation parameter. The compression compensation parameter can be determined during a calibration process of the medical instrument.