Weihong Wang

A novel extended state observer.

A novel extended state observer, which feeds back the output estimation error via both nonlinear and switching terms, is put forward for the first time in this paper. No longer neglecting the lumped uncertainty׳s first time derivative, the problem of disturbance observer design is transformed into the problem of state observer design in the presence of external disturbance. The switching term of the output estimation error is employed to counteract the adverse effect of external disturbance. The newly developed extended state observer provides an attractive solution to the issue of high precision motion control system. Both numerical simulation and experimentation on a speed turntable with temperature box are implemented to verify the performance of the proposed newly developed extended state observer.

A novel guidance law using fast terminal sliding mode control with impact angle constraints

This paper is concerned with the question of, for a missile interception with impact angle constraints, how to design a guidance law. Firstly, missile interception with impact angle constraints is modeled; secondly, a novel guidance law using fast terminal sliding mode control based on extended state observer is proposed to optimize the trajectory and time of interception; finally, for stationary targets, constant velocity targets and maneuvering targets, the guidance law and the stability of the closed loop system is analyzed and the stability of the closed loop system is analyzed, respectively. Simulation results show that when missile and target are on a collision course, the novel guidance law using fast terminal sliding mode control with extended state observer has more optimized trajectory and effectively reduces the time of interception which has a great significance in modern warfare.

Fast terminal sliding mode control based on extended state observer for swing nozzle of anti-aircraft missile

This paper concerns with achieving fast and accurate control in swing nozzle of anti-aircraft missile with nonlinear system. Firstly, swing nozzle servo institutions and their load torque has been modeled; secondly, a fast terminal sliding mode control based on extended state observer has been proposed to reduce the influence of large disturbance and system uncertainty; finally, the controller designed has been studied and the stability of the control algorithm has been proved. The computer simulation results show that on the condition of large disturbance and system uncertainty, the fast terminal sliding mode control with extended state observer has high control accuracy and fast performance for swing nozzle servo system, and can effectively reduce the chattering. The results are in agreement with experimental data, which verifies the validity of the algorithm.

Backstepping sliding-mode control for missile attitude using a linear extended state observer

On the basis of nonlinear dynamic inversion theory, a novel scheme combining sliding-mode control and backstepping is proposed for missile attitude control. In order to handle matched and unmatched uncertainties caused by unmodeled dynamics and variations of aerodynamic coefficients, a linear extended state observer (LESO) is introduced to estimate the uncertainties and the evaluated errors are compensated at each step of the backstepping design procedure. The stability of the closed-loop system is demonstrated based on Lyapunov theory. Simulation results show that the proposed scheme can guarantee the excellent tracking performance and the strong robustness against aerodynamic derivative variations.

Research on robot path planning based on fuzzy neural network and particle swarm optimization

In a certain evaluation standard, robot path planning is to find a collision-free path from the initial state to the target state in an environment with obstacles, which is one of the key research directions of intelligent mobile robots. The mathematical model of the surrounding environment is established by using the grid method. The obstacle avoidance strategy of the fuzzy neural network is proposed. The function of the obstacle avoidance is realized by searching the next feasible node by the fuzzy neural network. Aiming at the parameter optimization problem of fuzzy neural network, the improved particle swarm optimization algorithm is used to optimize the parameters of fuzzy neural network, which avoids the instability of the system caused by improper parameter selection. Simulation results verify the effectiveness of the method. The simulation results show that the path planning of mobile robot based on fuzzy neural network and particle swarm optimization achieves performance index of the minimum sum of the obstacle cost and the route cost.

Research on adaptive backstepping control method for a hex-rotor Unmanned Aerial Vehicle

This paper concentrates on attitude control and position control of the hex-rotor Unmanned Aerial Vehicle (UAV) to achieve fixed-point hover. First, based on the Newton-Euler equations, the equations of motion are established in the inertial coordinate system. Then according to the characteristics of the hex-rotor UAV model, adaptive backstepping mode controllers are designed to realize the attitude and position control. Using Lyapunov theory, the stability of system is proved. Finally, simulation results prove that the control system has strong robustness to both the disturbance and the parametric variation.

Nonlinear attitude control of tiltrotor aircraft based on dynamic surface adaptive backstepping

In this paper, the tiltrotor aircraft model is established based on the multi-body dynamics method, in order to further improve the modeling accuracy, an augmented Pitt-Peters dynamic inflow model was used to establish the induced velocity model of the rotor. Based on the presented model, aiming at the uncertainties of the nonlinear dynamics of aircraft, the dynamic surface adaptive backstepping control strategy is used to make the flight control system more adaptive and robust to the nonlinear, uncertain and unmodeled controlled objects with dynamic characteristics. The adaptive adjustment function is used to compensate the influence of system uncertainty, a robust term function is designed to solve the problem of approximation error, and the possible problem of controller singularity can be avoided by introducing projection operator. In the design of adaptive backstepping, the first-order filter is introduced to obtain the differentiation of the virtual control input by using the dynamic surface design method which eliminates the problem of “differential explosion” in the traditional backstepping design. The Lyapunov stability theorem guarantees the error uniformly bound. Simulation verification shows effectiveness of the design of attitude control.

Terminal angle constrained integrated guidance and control for missile pitch channel in the presence of input saturation

In this paper, in order to attack a fixed target and solve actuator saturation, an integrated guidance and control (IGC) scheme based on LESO and dynamic surface control algorithm with constrained terminal impact angle for missile pitch channel is proposed. Firstly, based on Coriolis theorem, an IGC model for pitch channel is established which does not assume that the initial velocity of the missile coincides with the line-of-sight (LOS) approximately. Then, an auxiliary system including a Nussbaum function is introduced to settle actuator saturation. The dynamic surface control algorithm with LESO which is used to estimate the disturbances of the system is designed to track the states of the system. Whats more, the stability of the closed-loop system is proved theoretically according to Lyapunov theorem. The simulation results show that the missile can hit the target in desired impact angle stably without input saturation, which reflects validity of the control scheme.

Duck pack algorithm — A new swarm intelligence algorithm for route planning based on imprinting behavior

In this paper, by studying the foraging behavior of ducks, a new bionic clustering intelligent algorithm — duck pack algorithm (DPA) is proposed and applied to route planning. The foraging behavior of the duck pack is dependent on imprinting behavior and food orientation, and this is why the ducks are different from other kinds of packs. To obtain the duck pack algorithm, the imprinting behavior and food orientation are abstracted into two operators and then the two operators are merged into an iterative process. Then the DPA is applied to route planning, and it can be found that DPA converges more quickly and the path generated by the DPA algorithm is smoother than that generated by the standard DE. This shows the reasonableness of the algorithm, and proves that the DPA algorithm is superior to the standard DE algorithm in stability and superiority.

L 1 adaptive output feedback controller for tilt-rotor aircraft

this paper considers application of L1 adaptive output feedback controller to tilt-rotor aircraft longitudinal autopilot design. The proposed adaptive controller has satisfactory performance which meets ADS-33E-PRF Military Rotorcraft handing qualities specifications in the presence of unknown time-varying nonlinearities. Simulations verify the controller.