Flexible Catheter Control Using Estimated Articulation Feedback
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Solution Overview
Problem
Existing systems face challenges in controlling flexible medical devices due to fault conditions that disrupt feedback signals from articulation sensors, leading to inaccurate control of the device's position and movement.
Innovation Solution
A control method that switches to an alternate feedback signal based on actuator sensor signals, processed through a simulation model to estimate the actual articulation, ensuring stable control during temporary sensor faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If articulation sensor signals are used for feedback control, then control accuracy is improved, but system reliability deteriorates when sensor faults occur
Solution Approach 1:
The patent introduces a simulation model as an intermediary that processes actuator sensor signals to generate estimated articulation signals. This intermediary bridges the gap between actuator movement and actual articulation, providing a reliable feedback source when direct articulation sensors fail. The simulation model acts as a mediator that translates actuator commands into expected articulation outcomes, maintaining control accuracy even when primary sensors are faulty.
Solution Approach 2:
The patent implements a dual feedback mechanism: primary feedback from articulation sensors and secondary feedback from actuator sensors processed through a simulation model. When articulation sensor signals are detected as abnormal, the system automatically switches to using actuator sensor signals with simulation-based articulation estimation. This feedback redundancy ensures continuous reliable control by providing alternative information pathways when primary sensing fails.
2Measurement precision
If articulation sensor signals are used directly, then control precision is improved, but control stability deteriorates during sensor faults
Solution Approach 1:
The patent implements dynamic signal selection that adapts the feedback source based on real-time sensor health status. The system continuously monitors articulation sensor signal quality and dynamically switches between direct articulation sensor feedback and simulation-based actuator feedback. This dynamic adaptation maintains control stability by preventing the use of corrupted sensor data while preserving the benefits of accurate feedback when sensors are functioning properly.
Solution Approach 2:
The simulation model serves as a stable intermediary that provides consistent articulation estimates based on actuator commands, regardless of articulation sensor status. When sensor faults occur, this intermediary maintains control stability by providing predictable, physics-based articulation estimates rather than relying on erratic sensor readings. The simulation model's deterministic nature ensures stable control behavior during fault conditions.
3Reliability
If the system switches to alternate feedback during sensor faults, then reliability is improved, but device complexity increases
Solution Approach 1:
The simulation model serves multiple functions: it normally operates as a background computational element and activates as a primary feedback source when articulation sensors fail. The actuator sensor signals serve dual purposes - both for controlling actuator movement and for generating articulation estimates through simulation. This multi-functionality reduces the need for separate redundant hardware systems, maintaining reliability improvement while limiting complexity increase.
Solution Approach 2:
The system uses its own actuator sensor signals and internal simulation model to generate articulation feedback when external articulation sensors fail. Rather than requiring separate redundant sensing hardware, the system serves its own feedback needs by processing commands it already issues through its control algorithms. This self-service approach improves reliability without adding external complexity.
Data Source
AI summary
A system includes a flexible catheter, an actuator disposed at a proximal portion of the flexible catheter and that actuates the flexible catheter along an articulation degree of freedom, an articulation sensor that provides articulation sensor signals representing articulation of the flexible catheter, an actuator sensor that provides actuator sensor signals representing movement of the actuator; and a controller that, based on detecting a change in a first articulation sensor signal that prevents or hinders the first articulation sensor signal from being used as a feedback signal for controlling the actuator transitions from: using the articulation sensor signals to control the actuator to: determining an articulation estimate of the flexible catheter, based on a relationship between the movement of the actuator and the resulting articulation of the flexible catheter, applied to a first actuator sensor signal obtained from the actuator sensor; and controlling the actuator based on the articulation estimate.