Arrangement and method for feedback control of a gas flow in a breathing assist apparatus
First Claim
1. A feedback controller for regulating respiratory gas in a mechanical breathing assist apparatus, said feedback controller comprising:
- a measurement unit which measures a value of a gas parameter associated with respiratory gas;
a comparator supplied with said value of said gas parameter, and with a target value for said gas parameter, said comparator periodically generating, in a current breathing cycle, an error signal representing a difference between said value of said gas parameter and said target value of said gas parameter;
a control signal generator supplied with said error signal for processing said error signal using a control function having a control parameter with a variable value, to generate a control signal for regulating said respiratory gas; and
an adaptation unit connected to said control signal generator for varying said value of said control parameter dependent on said error signal, by determining, for said current breathing cycle, an extreme value of said error signal and for varying said value of said control parameter for a next breathing cycle dependent on a rate of change of said extreme error signal relative to said value of said control parameter in said current breathing cycle.
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Accused Products
Abstract
A feedback controller for regulating respiratory gas in a mechanical breathing aid system has a comparator means for periodically generating, in a current breathing cycle, an error signal representing the difference between a value of a gas parameter measured for gas within the system and a target value of the gas parameter, and a control signal generator for processing the error signal in accordance with a control function to generate a control signal usable in the regulation of the respiratory gas. The controller has a variable value integral gain stage which provides an input to an integrator element. An adaption unit determines, for the current breathing cycle an extreme value of the periodically generated error signal and varies the value of the integral gain used in the integral gain stage for a next breathing cycle dependent on a rate of change of the value of the extreme error signal with value of the integral gain.
46 Citations
10 Claims
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1. A feedback controller for regulating respiratory gas in a mechanical breathing assist apparatus, said feedback controller comprising:
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a measurement unit which measures a value of a gas parameter associated with respiratory gas;
a comparator supplied with said value of said gas parameter, and with a target value for said gas parameter, said comparator periodically generating, in a current breathing cycle, an error signal representing a difference between said value of said gas parameter and said target value of said gas parameter;
a control signal generator supplied with said error signal for processing said error signal using a control function having a control parameter with a variable value, to generate a control signal for regulating said respiratory gas; and
an adaptation unit connected to said control signal generator for varying said value of said control parameter dependent on said error signal, by determining, for said current breathing cycle, an extreme value of said error signal and for varying said value of said control parameter for a next breathing cycle dependent on a rate of change of said extreme error signal relative to said value of said control parameter in said current breathing cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for regulating gas in a ventilator, comprising the steps of:
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periodically determining a current error value in a current breathing cycle as a difference between a value of a parameter measured for gas within a breathing assist system and a predetermined target value;
periodically executing a control function dependent on said error value for regulating said gas, said control function having a control parameter with a variable value, and varying said value of said control parameter dependent on said current error value and an error value generated in a previous breathing cycle, by determining, in said current breathing cycle, an extreme value of said current error signal and determining a rate of change of said extreme value relative to said control parameter and calculating said control parameter dependent on said rate of change for a next breathing cycle. - View Dependent Claims (9, 10)
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Specification