Turbofan Engine ADRC Control for Steady and Transition States
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Solution Overview
Problem
Current turbofan engine control systems are complex and inefficient, primarily focusing on steady state performance, with limited ability to manage transition states and lacking robust multi-variable control capabilities, leading to cumbersome design processes and suboptimal control strategies.
Innovation Solution
A steady state and transition state multi-variable control method based on Active Disturbance Rejection Control (ADRC) theory, which uniformly treats steady and transition states, uses total disturbance estimation for robustness, and includes a tracking differentiator, linear extended state observer, nonlinear PD module, and upper limit protection to optimize control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PID control algorithm with linear model identification is used for steady state control, then control stability is improved, but design complexity increases due to multiple linear models and parameter tuning
Solution Approach 1:
The patent transforms the complex PID control approach into a simplified ADRC approach by changing the control parameters and methodology. Instead of identifying multiple linear models and tuning numerous PID parameters, the system uses a single nonlinear ADRC controller with extended state observer that estimates total disturbance and compensates for it, reducing design complexity while maintaining control stability
Solution Approach 2:
The patent extracts the disturbance compensation function from the traditional PID control framework and implements it separately through the extended state observer in ADRC. This separation allows the controller to focus on steady-state error elimination while the observer handles disturbance estimation, simplifying the overall design process
2Stability of the object's composition
If traditional steady state controller is used, then steady state performance is ensured, but transition state performance cannot be optimized due to schedule limitations
Solution Approach 1:
The patent implements a universal ADRC controller that functions effectively in both steady state and transition state conditions. The extended state observer continuously estimates total disturbance regardless of operating condition, and the nonlinear PD controller adapts its response based on real-time error and disturbance information, providing consistent performance across all engine operating states without requiring separate control strategies
Solution Approach 2:
The patent introduces dynamic adaptation through the nonlinear PD controller and extended state observer that continuously adjust their behavior based on real-time system state and disturbance estimation. This dynamic response allows the controller to optimize performance for both steady state and transition state conditions, eliminating the need for static schedule-based control
3Ease of operation
If schedule-based control is used for accelerate/decelerate processes, then control authority is simplified, but control effect depends on preset schedules and lacks flexibility
Solution Approach 1:
The patent implements self-service control through the extended state observer that automatically estimates and compensates for disturbances without requiring preset schedules. The nonlinear PD controller autonomously adjusts control actions based on real-time error signals and disturbance estimation, providing flexible and adaptive control during accelerate/decelerate processes while maintaining simplified control authority
4Adaptability or versatility
If multiple manipulated variables are used for multi-variable control, then control optimization space increases, but control system complexity and decoupling requirements increase
Solution Approach 1:
The patent extracts the coupling effects and disturbance interactions from the multi-variable control system and consolidates them into a single total disturbance term estimated by the extended state observer. This approach allows multiple manipulated variables to be controlled without requiring complex decoupling mechanisms, as the observer compensates for all coupling effects collectively
Solution Approach 2:
The patent merges the control of multiple manipulated variables into a unified ADRC framework where the extended state observer estimates total disturbance affecting all variables, and the nonlinear PD controller coordinates their control actions. This unified approach simplifies the control system architecture while maintaining multi-variable optimization capabilities
Data Source
AI summary
A steady state and transition state multi-variable control method of a turbofan engine based on an active disturbance rejection control theory (ADRC) belongs to the technical field of aero-engine control. Firstly, multiple groups of manipulated variables and controlled variables of a turbofan engine are preliminarily selected, and then the manipulated variables and controlled variables with high correlation are further determined by a correlation analysis method. Each group of control instructions is planned as a tracking trajectory by using a tracking differentiator, and is used as the input of a nonlinear proportional-differential controller together with the current state estimated by the extended state observer to calculate the manipulated variables.