Ventilator PI Control for Adaptive Target Curve Tracking

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Solution Overview

Problem

Existing mechanical ventilation systems struggle to effectively apply ventilation variables according to desired target curves due to divergent anatomical conditions of patients, leading to inconsistent results.

Innovation Solution

A system and method for controlling ventilation variables using a controller with proportional and integral terms, adjusting the gain factor of the integral term based on control differences and zero crossings to track target curves, eliminating the need for patient anatomy data and allowing automated adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If patient anatomy data (resistance and expansion capacity) are used to parameterize the controller, then the control can be tailored to individual patients, but the determination of these parameters is complex and inaccurate

Engineering Contradiction:

Improveaccuracy of patient parameter determinationVSAvoidcomplexity of parameter determination

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for complex patient parameter determination (resistance and expansion capacity) by using a model-free control approach. The controller directly tracks the target curve using sensor feedback without requiring extraction or calculation of patient-specific anatomical parameters, thereby removing the source of inaccuracy and complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The control system performs self-adjustment by automatically modifying the integral term's gain factor based on real-time control difference integration. The system serves itself by adapting to divergent patient anatomical conditions without external parameter input, eliminating the need for complex and inaccurate patient parameter determination while maintaining effective control.

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If the gain factor of the integral term is increased to improve tracking accuracy, then the controller responds more strongly to control differences, but this may cause overshooting and instability

Engineering Contradiction:

Improvetracking accuracy of ventilation variableVSAvoidstability of control system

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent implements dynamic adjustment of the integral term's gain factor based on the accumulated control difference. The gain factor is not fixed but adapts in real-time: it is increased when the integral of the control difference exceeds a threshold (improving tracking accuracy) and decreased when zero crossings are excessive (preventing overshooting and maintaining stability). This dynamic adaptation resolves the contradiction between tracking accuracy and system stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system uses feedback from the integrated control difference to automatically adjust the integral term's gain factor. The feedback mechanism monitors the accumulation of control errors and modifies the controller's response strength accordingly, enabling the system to achieve high tracking accuracy while maintaining stability through self-regulation.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If a fixed controller parameterization is used, then the control system is simple to implement, but it cannot adapt to divergent patient anatomical conditions

Engineering Contradiction:

Improveadaptability to patient conditionsVSAvoidcomplexity of control system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The controller performs self-adjustment by automatically modifying the integral term's gain factor based on real-time control difference integration. This self-service capability enables the system to adapt to divergent patient anatomical conditions without requiring complex parameterization or external intervention, achieving high adaptability through a relatively simple automated mechanism.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent changes the controller parameter (gain factor of the integral term) dynamically based on the integrated control difference. This parameter adaptation allows the fixed-structure controller to achieve versatility across different patient conditions by modifying its operational parameters in real-time, balancing adaptability with implementation simplicity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260048214A1System for controlling a ventilation variable of a ventilator and ventilator

Publication Date: 2026.02.19 HAMILTON MEDICAL AG

AI summary

A system for controlling a ventilation variable of a ventilation device for tracking a target curve includes at least one sensor to detect instantaneous values of the ventilation variable; an actuator to adjust the ventilation variable of the ventilation device; a memory for storing the target curve for the ventilation variable for an inspiration and/or expiration phase; and a controller having a proportional term and an integral term and that calculates a control difference between the target curve and the instantaneous values, and that controls the actuator accordingly. The controller adjusts the gain factor of the integral term: (i) increasing it when the integral of the control difference for the inspiration and/or expiration phase exceeds a predetermined integral threshold value, or (ii) reducing it when a number of zero crossings of the control difference during the inspiration and/or expiration phase exceeds a predetermined zero-crossing threshold value.