OBOG Controller Gain Adjustment for Oxygen Response
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Solution Overview
Problem
Existing oxygen generating apparatuses on aircraft, such as OBOGs, face delays in responding to changing oxygen demand due to environmental factors like altitude and G-forces, leading to inconsistent oxygen supply, as they rely on conventional control methods that do not account for varying efficiency with environmental parameters.
Innovation Solution
A control method that senses oxygen concentration, determines instantaneous demand, and generates a control signal by compensating for environmental parameters like altitude, using a PI or PID algorithm with gain adjustment based on reference data to rapidly adjust the separation process, ensuring accurate oxygen concentration matching demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional control methods are used without environmental parameter compensation, then the control system is simple, but the response time is delayed and oxygen concentration cannot match instantaneous demand
Solution Approach 1:
The control system performs preliminary action by sensing environmental parameters (altitude, temperature, pressure) in advance and using these parameters to predict and compensate for changes in oxygen demand before the actual demand change occurs. This allows the OBOG to proactively adjust oxygen concentration rather than reactively responding after delays
Solution Approach 2:
The control system dynamically adjusts the gain factor in the control algorithm based on real-time environmental parameters. The gain is not fixed but varies with altitude, temperature, and pressure conditions, allowing the system to adapt its response characteristics to match changing environmental conditions and optimize response speed across different operating scenarios
2Speed
If the oxygen concentration control responds rapidly to changing demand, then the oxygen supply matches demand better, but the system becomes less stable due to cyclic charging/venting operations
Solution Approach 1:
The control system employs feedback mechanisms where the actual oxygen concentration is continuously sensed and compared with the target concentration derived from environmental parameters and demand signals. The error signal is fed back through a control algorithm that applies environmental compensation, allowing the system to self-correct while maintaining stability through proportional-integral control action
Solution Approach 2:
The system changes control parameters dynamically by adjusting the gain factor based on environmental conditions. This parameter adaptation allows the controller to be more aggressive when stability is less critical and more conservative when stability is paramount, optimizing both response speed and stability across different operating conditions
3Measurement precision
If environmental parameter compensation is implemented, then oxygen concentration matches demand more accurately, but the control algorithm complexity increases
Solution Approach 1:
The control algorithm incorporates environmental parameter compensation by dynamically adjusting the gain factor based on sensed altitude, temperature, and pressure. This single parameter adjustment (gain) simplifies the complexity increase compared to implementing full environmental modeling, while still achieving accurate oxygen concentration matching across varying conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the apparatus to produce oxygen at concentrations more closely matching instantaneous demand, reducing delays and improving system stability by accounting for environmental factors that affect separation efficiency.
Implementation Method 1
a bed of adsorption material therein, such as Zeolite, adsorbs primarily nitrogen from the air supply
Data Source
AI summary
A method of controlling an apparatus for separating product gas and non product gas from an air supply, the concentration of the product gas produced by the apparatus being variable depending on a control signal from a controller and the efficiency of the apparatus in producing product gas depending upon an environmental parameter, the method including sensing the oxygen concentration in the product gas produced by the apparatus, determining an instantaneous demand for oxygen concentration in the product gas, providing to the controller a process variable signal indicative of the sensed concentration of the oxygen in the product gas, and providing to the controller a demand input signal indicative of the demand, sensing the environmental parameter and providing an environmental parameter input signal to the controller, comparing the process variable signal and the demand signal to generate an error signal indicative of a change in oxygen concentration in the product gas required to match the instantaneous demand, conditioning the error signal to derive a control signal to control the apparatus to satisfy the demand, characterised in that the conditioning of the error signal is compensated to derive the control signal, depending upon the environmental parameter input signal.