WO2021056671A1 - 一种大型无人机uav的强自耦pi协同控制方法 - Google Patents
一种大型无人机uav的强自耦pi协同控制方法 Download PDFInfo
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
- G05D1/08—Control of attitude, i.e. control of roll, pitch, or yaw
- G05D1/0808—Control of attitude, i.e. control of roll, pitch, or yaw specially adapted for aircraft
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
- G05D1/10—Simultaneous control of position or course in three dimensions
- G05D1/101—Simultaneous control of position or course in three dimensions specially adapted for aircraft
Definitions
- the present invention relates to the technical field of the aircraft control field, and in particular to a strong auto-coupling PI (Enhanced Auto-Coupling Proportional-Integral, EAC-PI) collaborative control method for a large unmanned aerial vehicle (UAV).
- PI Enhanced Auto-Coupling Proportional-Integral, EAC-PI
- the controller gain also needs to change, and this is also a variety of improved PID Control methods such as the original motivation of adaptive PID, nonlinear PID, neuron PID, intelligent PID, fuzzy PID, expert system PID, etc.
- improved PIDs can improve the adaptive control ability of the system by optimizing and tuning the controller gain parameters online, the existing various PID controls are still powerless for the control problems of non-affine nonlinear uncertain systems, especially The anti-disturbance robustness is poor.
- the large unmanned aerial vehicle is a typical multi-input multi-output and input limited non-affine nonlinear strong coupling uncertain system
- the traditional PID and its various The improved PID control methods seem helpless, and the existing control methods mainly include: second-order non-singular dynamic terminal sliding mode control method, second-order non-singular terminal sliding mode control method based on the cerebellar model (CMAC) interference observer, and A second-order non-singular terminal sliding mode control method based on wavelet cerebellar model (WCMAC) interference observer.
- CMAC cerebellar model
- WCMAC wavelet cerebellar model
- the second-order non-singular dynamic terminal sliding mode control method is out of control; the second-order non-singular terminal sliding mode control method based on CMAC and the second-order non-singular terminal sliding mode control based on WCMAC
- CMAC Cost-to-envelope-to-envelope-to-envelope-to-envelope-to-envelope-to-envelope-to-envelope-to-envelope
- WCMAC the second-order non-singular terminal sliding mode control based on WCMAC
- the purpose of the present invention is to address the defects in the background technology and propose a strong autocoupling PI collaborative control method for large UAV UAVs, through a model structure that is simple, easy to set parameters, good dynamic quality, high control accuracy, and anti-disturbance
- a powerful control method can effectively improve the dynamic quality and steady-state performance of the UAV control system, reduce the amount of calculation, improve real-time performance, and enhance the stability of the control system.
- the present invention adopts the following technical solutions:
- Step A Measure and obtain the expected trajectory y dj and differential signal of the UAV UAV And the actual output y j of the UAV, and establish its tracking error e j and the integral e j0 of the tracking error;
- e j represents the tracking error
- e j0 represents the integral of the tracking error
- step B Obtain the tracking error e j of the UAV UAV according to step A, according to the tracking error e j , the integral of the tracking error e j0 and the derivative signal of the desired trajectory
- the creation of the EAC-PI cooperative control law u j specifically includes the use of the following formula to obtain the EAC-PI cooperative control law:
- z j represents the speed factor of the EAC-PI controller on the jth channel of the UAV, and z j >0;
- ⁇ j represents the dimensionless enhancement factor of the EAC-PI controller of the j- th UAV channel, ⁇ j >0;
- u j represents the output coordinated control power of the j-th channel EAC-PI coordinated controller.
- step C according to the EAC-PI cooperative control law model of the jth channel of UAV established in step B, and through the integrated control force of the jth channel And the coordinated control force u j are respectively limited in amplitude processing to avoid integral saturation in the dynamic process and meet the requirements of the input limited system;
- u jm represents the maximum amplitude of the coordinated control input of the j-th channel, and u jm >0.
- a strong auto-coupling proportional-integral (EAC-PI) control method of the present invention concentrates the respective advantages of the three mainstream controllers and eliminates their respective limitations, namely: It has the advantages of simple PID structure, good robust stability of SMC, and strong anti-disturbance ability of ADRC; it not only effectively avoids the difficulty of PID gain tuning, but also effectively solves the high frequency chattering and chattering of SMC. The problem of irreconcilability between anti-disturbance capabilities also effectively avoids the problems of too many ADRC gain parameters and too much calculation.
- the invention of the EAC-PI control method has enriched the control theory system for more than half a century, and has provided an effective technical guarantee for the technical upgrade of various PID controllers in operation.
- the invention has broad application prospects in the field of non-affine nonlinear uncertain control systems and aircraft control.
- Figure 1 is a framework diagram of the UAV UAV control system based on the EAC-PI controller of the present invention
- Fig. 2 is an airspeed tracking trajectory diagram in the tracking control result of the nominal UAV system of the present invention
- Fig. 3 is a track diagram of the track tilt angle in the tracking control result of the nominal UAV system of the present invention
- Fig. 4 is a track diagram of track and azimuth tracking in the tracking control result of the nominal UAV system of the present invention
- Figure 5 is a UAV system thrust control input diagram in the nominal UAV system tracking control result of the present invention.
- Figure 6 is a UAV system overload coefficient control input diagram in the nominal UAV system tracking control result of the present invention.
- Figure 7 is a UAV system roll angle control input diagram in the nominal UAV system tracking control result of the present invention.
- Fig. 8 is an airspeed tracking trajectory diagram in the tracking control result of the disturbed UAV system of the present invention.
- FIG. 9 is a track diagram of track tilt angle tracking in the tracking control result of the disturbed UAV system of the present invention.
- Fig. 10 is a track diagram of the track and azimuth angle in the tracking control result of the disturbed UAV system of the present invention.
- Figure 12 is a UAV system overload coefficient control input diagram in the tracking control result of the disturbed UAV system of the present invention.
- Fig. 13 is a UAV system roll angle control input diagram in the tracking control result of the disturbed UAV system of the present invention.
- V, ⁇ and ⁇ are the UAV's airspeed, track inclination angle and track azimuth angle respectively; T, n, ⁇ are engine thrust, overload coefficient and roll angle respectively; g is the acceleration due to gravity; M is the mass of the UAV ; D is resistance and is expressed as:
- the actual flight safety requirements of UAV should also be considered, that is, the roll angle ⁇ should meet:
- UAV is a three-input three-output non-affine nonlinear strong coupling system.
- the present invention first defines the non-affine nonlinear uncertain dynamics of each channel separately Is the sum of three disturbances, namely:
- the system (4) is a three-input three-output linear uncertain system which is completely equivalent to the UAV system (3), and the control of the system (4) is equivalent to the control of the UAV system (3).
- MIMO non-affine nonlinear uncertain systems can be expressed as MIMO linear uncertain systems (4), Has universal significance. Not only that, through the definition of total disturbance, all known or unknown uncertain factors are represented by total disturbance, and the idea of converting a non-affine nonlinear uncertain system into a linear uncertain system completely dilutes linearity and nonlinearity.
- b 1 g/M
- the error dynamic system of the j-th channel can be established as follows:
- the error system (8) is a second-order error dynamics system (EDS).
- EDS error dynamics system
- z j >0 and ⁇ j >0 are the speed factor and dimensionless enhancement factor of the EAC-PI controller of the jth channel of the UAV system
- b j is the control gain of the jth channel of the UAV
- b 1 g/M
- u j is not only the cooperative control force output of the j-th channel EAC-PI cooperative controller, but also the cooperative control force input of the j-th channel controlled object.
- the speed factor is not only an important link factor between the two gains k p and k i in the EAC-PI controller, but also an equivalent conversion factor of k p and k i.
- the main function of the enhancement factor is to adjust the control force of the proportional link. When 0 ⁇ j ⁇ 1, the control force of the proportional link is reduced, otherwise, the control force of the proportional link is enhanced.
- Theorem 1 Assuming that the comprehensive disturbance is bounded:
- ⁇ (j 1, 2, 3), then if and only when z j >0 and ⁇ j >0, the EAC-PI controller (9)
- the composed closed-loop control system is globally robust and stable, and the EAC-PI controller has good anti-disturbance robustness.
- the error system (11) is a dynamic system under the excitation of bounded disturbance
- the initial state Take the unilateral Laplace transform for the error dynamic system (11), then:
- the organized closed-loop control system is:
- the first term of the closed-loop control system (13) is a zero-input response
- the second term is a zero-state response.
- the system transfer function is:
- k 1 0.5( ⁇ j - ⁇ j )/ ⁇ j
- k 2 -0.5( ⁇ j + ⁇ j )/ ⁇ j .
- Theorem 1 shows that when z j >0 and ⁇ j >0, the gain tuning rule of formula (10) can ensure the global stability of the closed-loop control system composed of EAC-PI controller (9). Therefore, z j has Large setting margin.
- EAC-PI cooperative controller In order to make the EAC-PI cooperative controller have a fast response speed and strong anti-disturbance ability, it is required that the larger z j is, the better. However, if z j is too large, it may cause overshoot and oscillation due to integral saturation. Therefore, it is required to set the speed factor z j of EAC-PI reasonably.
- the specific method is as follows:
- k p> 0 is a non-independent property proportional gain
- T i is the integral time constant independent PI controllers.
- z j is the reciprocal of T i, i.e., z j dimension is / sec, so called speed factor.
- T i the time scale of the controlled object
- the speed factor z j of the EAC-PI controller is required to be larger, otherwise the opposite is true.
- the speed factor z j is not only the internal core coupling factor of the EAC-PI controller (9) and the equivalent conversion factor of the EAC-PI controller gain tuning rule (10), but also the scale ⁇ reflecting the speed of the controlled object.
- a definite external connection (21) is established. Therefore, the value range of the speed factor z j can be set according to the speed characteristics of the controlled object.
- u jm > 0 is the maximum amplitude of the control input of the j-th channel.
- Integral link control force limit
- the influence of factors such as the flight environment may cause problems such as uncertain aerodynamic parameters and failure of the actuator.
- problems such as uncertain aerodynamic parameters and failure of the actuator.
- n a (1-k n ) n between the expected overload coefficient n and the actual overload coefficient n a
- FIG. 8-13 show that when the UAV has uncertain parameters and actuator failures, the EAC-PI control method of the present invention not only still has fast response speed and high control accuracy, but also has good robustness and stability. It further shows that the strong autocoupling PI control method for large and small UAVs of the present invention is a globally stable and strong anti-disturbance control method.
- PID controllers, SMC and ADRC based on cybernetic strategies are currently the three mainstream controllers widely used in the field of control engineering, the limitations of traditional PID controllers are also very obvious.
- various improved PID controllers such as adaptive PID controller, nonlinear PID controller, parameter self-learning nonlinear PID controller, fuzzy PID controller, optimal PID controller, neuron PID controller, expert PID controllers have overcome the parameter tuning problems of traditional PID controllers to a large extent, and have certain non-linear control capabilities.
- the existing improved PID controllers have a large amount of calculation, and have poor real-time performance and resistance.
- the calculation amount of gain parameters and related nonlinear functions is too large, the control system structure is more complicated, and the stability of the control system cannot be analyzed theoretically.
- a strong auto-coupling proportional-integral (EAC-PI) control method of the present invention concentrates the respective advantages of the three mainstream controllers and eliminates their respective limitations, namely: It has the advantages of simple PID structure, good robust stability of SMC, and strong anti-disturbance ability of ADRC; it not only effectively avoids the difficulty of PID gain tuning, but also effectively solves the high frequency chattering and chattering of SMC. The problem of irreconcilability between anti-disturbance capabilities also effectively avoids the problems of too many ADRC gain parameters and too much calculation.
- the invention of the EAC-PI control method has enriched the control theory system for more than half a century, and has provided an effective technical guarantee for the technical upgrade of various PID controllers in operation.
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