Fluid Injector Gain Scheduling for Viscosity-Driven Resistance
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Solution Overview
Problem
Existing fluid injection systems face challenges in accurately controlling motor performance due to varying hydraulic resistance, particularly in conditions involving small bore catheters and highly viscous fluids, leading to motor overshooting or undershooting, which can compromise safety and delivery precision.
Innovation Solution
Implementing a system that determines hydraulic resistance scores based on fluid viscosity and adjusts motor controller gains using gain scheduling to improve motor control accuracy, ensuring precise fluid delivery and reducing the risk of pressure and flow rate deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motor controller gains are kept constant, then the control system is simple, but motor control accuracy deteriorates under varying hydraulic resistance
Solution Approach 1:
The patent implements dynamic adjustment of motor controller gains based on real-time hydraulic resistance scores. The system transitions from static, fixed gains to dynamic, adaptive gains that change with operating conditions. This resolves the contradiction by making the control system flexible enough to maintain accuracy under varying hydraulic resistance while only adding complexity when needed.
Solution Approach 2:
The patent changes the control parameter (motor controller gains) based on the hydraulic resistance score. By calculating the resistance score from fluid properties and catheter characteristics, the system adjusts gains to match actual operating conditions. This resolves the contradiction by using parameter adaptation to maintain precision without requiring a completely complex redesign of the control architecture.
2Manufacturing precision
If fixed motor controller gains are used, then the control system is easy to operate, but delivery precision deteriorates with varying fluid viscosity and catheter conditions
Solution Approach 1:
The system performs self-adjustment by automatically calculating hydraulic resistance scores and modifying motor controller gains without requiring manual intervention. The control system serves itself by adapting to changing conditions, which resolves the contradiction by maintaining high delivery precision while keeping the operation simple and automated.
3Reliability
If motor controller gains are adjusted dynamically, then motor control accuracy improves under varying hydraulic resistance, but device complexity increases
Solution Approach 1:
The patent calculates hydraulic resistance scores in advance based on known fluid properties and catheter characteristics before actual injection begins. This preliminary calculation allows the system to be pre-configured with appropriate controller gains, improving reliability from the start while avoiding the need for complex real-time adjustments during critical injection phases.
Data Source
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AI summary
A system for controlling a fluid injection system is disclosed. The system includes at least one processor programmed or configured to determine at least one characteristic of a power injection protocol, where the at least one characteristic of the power injection protocol is associated with a medical fluid involved in the power injection protocol, determine an estimated value of viscosity of the medical fluid based on the at least one characteristic of the power injection protocol, calculate a hydraulic resistance score based on the estimated value of viscosity of the medical fluid, and determine one or more motor controller gains of a motor of a powered fluid injector in the power injection protocol based on the hydraulic resistance score.