Steerable Catheter Rigidity Control During Retraction and Steering
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Solution Overview
Problem
Existing robotic systems for minimally invasive medical procedures lack effective mechanisms to dynamically adjust the rigidity of steerable instruments in response to movement and user input, potentially leading to tissue damage or instrument misalignment during retraction and insertion.
Innovation Solution
A robotic system that monitors movement and user input to adjust the rigidity of elongate devices, such as catheters, by maintaining, increasing, or decreasing rigidity based on predefined profiles associated with operation modes, prioritizing retraction over steering to ensure safe and controlled instrument movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rigidity of the elongate device is increased to improve steering control, then the precision of instrument movement is improved, but the risk of tissue damage during insertion and retraction increases
Solution Approach 1:
The system dynamically adjusts the rigidity of the elongate device based on the operational phase. During insertion and retraction, the rigidity is increased to provide structural support and control. During steering operations, the rigidity is decreased to allow flexible navigation. This temporal variation in rigidity resolves the contradiction by having high rigidity only when needed for precision movement while allowing low rigidity when flexibility is needed to avoid tissue damage.
Solution Approach 2:
The system changes the physical parameter of rigidity in response to detected movement and user input. When rapid movement or retraction is detected, the rigidity parameter is increased. When steady-state steering is detected, the rigidity parameter is decreased. This dynamic parameter adjustment allows the device to optimize between precision and safety based on real-time operational conditions.
2Reliability
If the rigidity of the elongate device is decreased to reduce tissue damage risk, then patient safety is improved, but the control and precision of instrument movement deteriorates
Solution Approach 1:
The system employs dynamic rigidity adjustment where the rigidity is decreased during steering phases to enhance patient safety by reducing tissue damage risk, and increased during insertion and retraction phases to maintain control and precision. This temporal separation of rigidity requirements resolves the contradiction by providing low rigidity (safety) when needed and high rigidity (precision) when needed.
Solution Approach 2:
The control system modifies the rigidity parameter based on real-time monitoring of device movement and user input. When the device is in a steady steering state, rigidity is reduced for safety. When acceleration or retraction is detected, rigidity is increased for control. This dynamic parameter change strategy ensures both safety and precision are maintained at appropriate times.
3Reliability
If the system continuously monitors movement and user input to dynamically adjust rigidity, then safety and control are enhanced, but the device complexity increases
Solution Approach 1:
The system implements a feedback control mechanism where sensors continuously monitor device movement and user input, and the control system adjusts rigidity based on this feedback. The feedback loop detects operational phases (insertion, retraction, steering) and automatically adjusts rigidity accordingly. This feedback-based approach enhances safety and control while keeping the control logic relatively simple by relying on automatic detection rather than complex manual control systems.
Solution Approach 2:
The control system operates autonomously by self-monitoring device movement and user input, then self-adjusting the rigidity parameter without requiring external intervention. The system serves itself by detecting its own operational state and making appropriate rigidity adjustments, which simplifies the overall control architecture compared to systems requiring external control inputs for each adjustment.
4Adaptability or versatility
If the rigidity is adjusted at different rates during different operational intervals, then the adaptability to operational conditions is improved, but the control system complexity increases
Solution Approach 1:
The system implements dynamic rigidity adjustment with different rates for different operational phases. During insertion, rigidity increases at a controlled rate. During retraction, rigidity increases more rapidly. During steering, rigidity decreases to a lower level. This phased approach with different adjustment rates provides high adaptability to operational conditions while maintaining relatively simple control logic based on detected operational phase.
Solution Approach 2:
The control system applies periodic adjustments to rigidity based on the operational cycle of the device. Different adjustment profiles are applied during different periods of the operational cycle (insertion period, steering period, retraction period). This periodic action with phase-dependent parameters provides adaptability while using a systematic approach that avoids excessive complexity.
Data Source
AI summary
Systems and methods for controlling an elongate device are provided herein. In some embodiments, a robotic system may comprise a manipulator assembly configured to drive an elongate device and a control device configured to receive user input commanding the elongate device. The robotic system may also comprise a control system communicatively coupled to the manipulator assembly and the control device. The control system may be configured to monitor movement of the elongate device during a plurality of intervals, monitor user input received by the control device during the plurality of intervals, and adjust a property of the elongate device based on at least one of the monitored movement or the monitored user input.