scholarly journals Mathematical Modeling and Modal Switching Control of a Novel Tiltrotor UAV

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhiwei Kong ◽  
Qiang Lu
Keyword(s):  
Flight Control ◽  
Good Control ◽  
Numerical Results ◽  
Control Effect ◽  
Transition Mode ◽  
Control Approach ◽  
Flight Mode ◽  
Horizontal Flight ◽  
Nonlinear Control Law ◽  
Tiltrotor Aircraft

This paper concentrates on the flight control of a novel tiltrotor aircraft with fixed wings. This kind of aircraft has two flight modes and a transition mode. In the phase of vertical take off and landing (VTOL), the aircraft can operate as a quadrotor helicopter. And in the phase of horizontal flight, the aircraft is in the normal airplane mode. The transition mode is between these two flight modes. In this part of work, a novel tiltrotor aircraft was presented since transition mode is achieved by tilting the front dual tiltrotor (DTR) and the mathematical model was established. The classical PID method was used during the phase of VTOL and the numerical results were given and the simulation shows good control effect. A nonlinear control law based on backstepping was proposed to achieve a stable transition from vertical flight to horizontal flight. And the numerical results show that the flight mode could transit stably which shows the effectiveness of the control approach. Finally, the vertical flight experiment has been carried out on DTR aircraft and the attitude was stable.

scholarly journals Research on Dynamic Modeling and Transition Flight Strategy of VTOL UAV

2019 ◽  
Vol 9 (22) ◽  
pp. 4937
Author(s):  
Chunyang Wang ◽  
Zhou Zhou ◽  
Rui Wang
Keyword(s):  
Flight Simulation ◽  
Flight Performance ◽  
Research Focus ◽  
Transition Mode ◽  
Flight Mode ◽  
Horizontal Flight ◽  
Vtol Uav ◽  
Aerial Vehicle ◽  
Control Quantity ◽  
Transition Flight

A vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) can meet both VTOL and horizontal flight performance, but how to achieve a safe and stable transition is a research focus of this type of aircraft. According to the overall configuration characteristics of VTOL UAV, aerodynamic models of lift fan, lift duct and induced wing surface of VTOL UAV were established. Three flight modes of induced VTOL UAV are studied, including hover, transition and horizontal flight. The method of longitudinal flight balance of UAV in transition mode is also studied. Finally, a UAV is taken as an example to conduct the research of transition flight mode balancing and flight simulation with the method presented in this paper. The results show that the proposed method can reasonably give the control quantity and longitudinal attitude of UAV in the whole transition mode, so that the UAV can achieve a steady transition flight.

scholarly journals Taxiing Characteristic Analysis and Control for Full-Wing Solar-Powered Unmanned Aerial Vehicle

2019 ◽  
Vol 37 (1) ◽  
pp. 7-12
Author(s):  
Zhenyu Ma ◽  
Xiaoping Zhu ◽  
Zhou Zhou
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Good Control ◽  
Front Wheel ◽  
Control Effect ◽  
Characteristic Analysis ◽  
Control Approach ◽  
Disturbance Rejection Control ◽  
Aerial Vehicle ◽  
Solar Powered ◽  
Propeller Thrust

To solve the taxiing control problem of the full-wing solar-powered unmanned aerial vehicle (UAV) without front wheel steering servo and rudder, a control approach using differential propeller thrust to control the taxiing is proposed in this paper. Firstly, the taxiing mathematical models of two kinds of full-wing solar-powered UAVs with the front wheels turning freely or fixed are established. Meanwhile, the taxiing characteristics of full-wing solar-powered UAV in different taxiing speeds are analyzed. Secondly, based on the linear active disturbance rejection control (LADRC) theory, a yaw angle controller is designed by using differential propeller thrust as the control output. Finally, a straight line trajectory tracking scheme which is suitable for take-off and landing taxiing is designed on the base of improved vector field theory. Simulation results show that the designed controller has a good control effect on full-wing solar-powered UAV's take-off and landing taxiing periods, and better robustness.

Automatic Flight Control of Unmanned Helicopter Based on Nonlinear Model

2012 ◽  
Vol 472-475 ◽  
pp. 1492-1499
Author(s):  
Run Xia Guo
Keyword(s):  
Nonlinear Model ◽  
Flight Control ◽  
Attitude Control ◽  
Lyapunov Stability Theory ◽  
Test Results ◽  
Unmanned Helicopter ◽  
Control Laws ◽  
Control Approach ◽  
State Dependent ◽  
Compensation Technique

The Unmanned helicopter (UMH) movement was divided into two parts, namely, attitude and trajectory motion. And then a two-timescale nonlinear model was established. The paper improved and expanded state dependent riccati equation (SDRE) control approach, deriving analytical conditions for achieving global asymptotic stability with lyapunov stability theory. Proof was given. By combining improved SDRE control with nonlinear feed-forward compensation technique, the full envelop flight attitude control laws could be designed. On the basis of attitude control, trajectory controller was developed. Actual flight tests were carried out. Test results show that the control strategy is highly effective.

scholarly journals Tracking control and robustness study of shifting process

2018 ◽  
Vol 46 (2) ◽  
pp. 99-106
Author(s):  
Xin-xin Zhao ◽  
Chao Guan
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Tracking Control ◽  
Pid Controller ◽  
Automatic Transmission ◽  
Good Control ◽  
Simulation Software ◽  
Control Effect ◽  
Engine Torque ◽  
Shift Quality

Heavy dump vehicles are usually working with big load changes and bad work environment, thus change the friction performance of transmission clutches, as well as great affect the shift quality seriously, which influence the vehicle performance. Many researchers developed a lot to design a useful automatic transmission control system. Using PID tracking control and Monte Carlo method, the controller based on an dynamic model was set up to analyze the shifting process of automatic transmission and its robustness in this paper．The shift process was divided into four stages, low-gear phase, torque phase, inertia phase and high-gear phase. The model presents the process from the first gear to the second gear when the torque has big change．Since the jerk and the friction work of clutch are both related to the speed of clutch which was easier to control, it was chose as the target to control the oil pressure for satisfying the requirement of shift quality．The simulation software, Maplesim and Simulink, were used to build the vehicle model and shifting controller for simulation under different working conditions, and the maximum jerk was changed from 34 m/s3 to 12 m/s3 after the optimization. In this paper the Monte Carlo has been used to quantize and evaluate the robustness of the closed-loop system for the friction coefficients and output torque of turbine variation leading by the friction feature parameters and throttle angle changed. Monte Carlo method was used to analyze the effectiveness and robustness of PID controller, which proves that it has good control effect when the throttle is ongoing minor fluctuations. When the throttle is full opening, a quadratic optimal controller based on disturbance is designed by the method of multi-objective optimization. When it changes within 20 percent, PID controller was designed under the guidance of tracking thoughts. The results also show that the controller could still obtain better effect when the friction coefficient ranged from -40 % to 40 % as well as engine torque changed from -20 % to 20 %, which indicates the robustness of controller.

Investigation on All Digital Control System of Brushless DC Motor for Beam-Pumping Unit

2013 ◽  
Vol 336-338 ◽  
pp. 728-733
Author(s):  
Xi Zhu ◽  
Jian Guo Song ◽  
Qing Lu Zhang
Keyword(s):  
Pulse Width Modulation ◽  
Operation Mode ◽  
Good Control ◽  
Dc Motor ◽  
Brushless Dc Motor ◽  
Motor Speed ◽  
Control Effect ◽  
Brushless Dc ◽  
Speed Regulator ◽  
Pumping Unit

In order to drive beam-pumping unit with brushless DC motor (BLDCM), a kind of motor speed regulator was investigated. When pumping unit is in up stroke, BLDCM is power-driven; when in down stoke, pumping unit is braked by BLDCM. To meet the operation mode, PI double closed loops control strategy and Pulse Width Modulation (PWM) are applied. Simulation and test in field show that our design has good control effect and popularizing value.

scholarly journals The Time–Concentration–Mortality Responses of Western Flower Thrips, Frankliniella occidentalis, to the Synergistic Interaction of Entomopathogenic Fungus Metarhizium flavoviride, Insecticides, and Diatomaceous Earth

Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 93 ◽  
Author(s):  
Wenchao Ge ◽  
Guangzu Du ◽  
Limin Zhang ◽  
Zhengyue Li ◽  
Guanli Xiao ◽  
...  
Keyword(s):  
Diatomaceous Earth ◽  
Frankliniella Occidentalis ◽  
Synergistic Effects ◽  
Western Flower Thrips ◽  
Good Control ◽  
Invasive Pest ◽  
Control Effect ◽  
Metarhizium Flavoviride ◽  
Flower Thrips ◽  
Median Lethal Concentrations

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is a highly invasive pest which is harmful to many cash crops globally and resistant to various insecticides. Entomopathogenic fungi (EPF), as biological control agents, have demonstrated a good control effect on WFT. The aim of this study was to evaluate the synergistic and pathogenicity efficacy of the fungal strain Metarhizium flavoviride WSWL51721 when distributed with diatomaceous earth (DE) and the active ingredient imidacloprid using four bioassay methods against adult and second instar larvae of WFT. The data of the four bioassays have been fitted to the time–concentration–mortality (TCM) model. The corrected mortality ranges of WFT adults were 75–100%, 82.69–100%, 78.85–100%, and 92.31–100%, and the corrected mortality ranges of WFT second instar larvae were 72.22–100%, 85.19–100%, 77.77–100%, and 100% in the four bioassays at concentrations of 1.2 × 106 to 1.2 × 108 conidia/mL, respectively. At 1.2 × 108 conidia/mL, assays 2 (M. flavoviride with DE), 3 (M. flavoviride with imidacloprid), and 4 (M. flavoviride with DE and imidacloprid) had the shortest median lethal time (LT50), compared with that of assay 1 (M. flavoviride alone) for adults at 2.26 d, 2.06 d, and 1.53 d, and second instar larvae at 2.45 d, 1.70 d, and 1.41 d, respectively. The median lethal concentration (LC50) in the four bioassays decreased within 3–10 days of inoculation. On the third day, it was found that the lowest median lethal concentrations in assays 2, 3, and 4 were 1.58 × 107, 1.13 × 107, and 3.39 × 106 conidia/mL, respectively, which were significantly different from that in assay 1 for the adults. For the second instar larvae, assays 2, 3, and 4 also had the lowest lethal concentrations and were significantly different from those of assay 1. There were significant differences in sporulation between adults and second instar larvae under the four bioassays. Our results indicate that assays 2 (M. flavoviride with DE), 3 (M. flavoviride with imidacloprid), and 4 (M. flavoviride with DE and imidacloprid) demonstrate synergistic effects on the control of both adult and second instar larvae of WFT under laboratory conditions.

Application of Single Neuron Adaptive PID Control in Electro-Hydraulic Position Servo System

2012 ◽  
Vol 542-543 ◽  
pp. 563-566
Author(s):  
Chao Yong Yan ◽  
Yao Jun Yu
Keyword(s):  
Single Neuron ◽  
Linear Time ◽  
Servo System ◽  
Good Control ◽  
Response Speed ◽  
System Response ◽  
Control Effect ◽  
Time Varying Parameters ◽  
Position Servo ◽  
Adaptive Pid Control

Currently used electro-hydraulic position servo system has more serious non-linear, time-varying parameters and external load disturbance, through the establishment of the system's mathematical model, designed the single neuron adaptive PID controller. Simulation results show that the improved system response speed, steady-state error is small, you can adjust the PID parameters online in real time and good control effect.

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