جستجوی مقالات مرتبط با کلیدواژه « quadrotor » در نشریات گروه « مکانیک »

In this investigation, using the fractional calculus, a controller for trajectory control of a quadrotor is designed. As a matter of fact, one of the most important challenges in quadrotors is changing the mass of the quadrotor for carrying loads. In this paper, the controller is designed adaptive to show appropriate response in the presence of changing mass. For designing this controller, the sliding mode controller is utilized, which the sliding surfaces are considered as a fractional model. The results of this study demonstrate the effectiveness of the fractional-order controller for trajectory control of a quadrotor with changing the mass parameter. Moreover, simulations illustrate that by changing the fractional-order a new controller can be designed which can do the same mission with less control effort. Therefore, utilizing the fractional controller, the Dynamic Load Carrying Capacity (DLCC) of a quadrotor can be increased. The results show that by considering fractional-order = 0.275, the DLCC is maximized. The innovation of this work is the investigation of fractional order controllers in determining the DLCC, which shows that by setting a certain value, the DLCC can be increased by about two times compared to the classical sliding mode control.

n this paper, the use of PID controller to control a model of a quadrotor with nonlinear dynamics is investigated. In this regard, after presenting the designed nonlinear dynamic quadrotor model, four distinct methods for adjusting the parameters of this controller are examined and compared. These four techniques, which are classified into two categories, online and offline, include online techniques of neural network and fuzzy inference, and offline techniques of genetic and particle swarm optimization algorithms. Finally according to the results of numerical simulations and the results of comparing a predefined squared cost function calculated in each case, in the presence of a relatively large disturbance with amplitude and frequency that is selected in the whole time simulation affects the system, shown in general, the order online algorithms, especially despite the mentioned disturbance, have better performance in controlling the dynamics of the system because they update the control coefficients of the closed-loop system momentarily in each step of numerical simulation.

In this paper, a finite-time fault tolerant controller based on sliding mode algorithm, as a robust control method, is presented to control the attitude stabilization of the quadrotor system in the presence of actuator fault and uncertainty. The controller is designed based on the nonlinear model of a quadrotor and its stability analysis is performed according to the Lyapunov stability theorem. Also, regarding some weaknesses of MEMS sensors such as partly high noise and bias error, an extended Kalman filter is designed and implemented in order to merge sensors data and reduce the noise effect on the outputs. To validate the controller performance, the experimental tests is implemented on a full-scale quadrotor in real-time. The evaluation of the designed strategy is carried out in different scenarios, no fault in the actuators and a partial loss of effectiveness of an actuator as well as uncertainty in the quadrotor parameters. The experimental results reveal the superiority of the sliding mode tolerant strategy over feedback linearization in the presence of various faults and uncertainty effects.

Today, the use of drones to automate activities such as civil works, rescue operations, and military missions is expanding to increase speed and accuracy, retaining manpower and reducing costs. According to this approach, in this paper, hybrid control of position and force for a spherical inverted pendulum on top of a quadrotor whose motion is constrained in the vertical direction is studied to enable the quadrotor-spherical inverted pendulum system to perform operations such as painting and cleaning on high ceilings. In this regard, first using Newton-Euler laws, the equations of motion governing the quadrotor-inverted pendulum system in the constrained motion are extracted, and then by presenting a model for the constraint force, a hierarchical control system including position-force control loop, inverted pendulum orientation control loop and quadrotor orientation control loop is provided. Proposed Control laws for the inverted pendulum orientation control loop and the quadrotor orientation control loop are designed using some theorems of geometric control methods.  Finally, to study the performance of the proposed control method, some numerical simulations have been performed.

In this paper, an intelligent integral Back-step controller is used to control the position of the quadrotor. Using a new strong particle swarm optimization algorithm, the optimal system response is Achieved by changing constant design values in the controller. Then, the optimal path for the quadrotor is designed using the algorithmic method of particle swarm and considering the predetermined obstacles in the three-dimensional environment, which ensures safety flight. Also, the shortest path between the origin and destination as the optimal path is determined. Finally, the path generated by the algorithm as the optimal path of planning. Thus, in addition to optimizing the control parameters in the controller, the quadrotor path is also optimized using the algorithm to minimize energy consumption from source to destination. Finally, by simulating the system in MATLAB environment, the system response to the desired input in a limited time was plotted and investigated.

Liquid transport by unmanned aerial vehicles is a necessary task in autonomous firefighting and field spraying missions. On the other hand, transient and residual sloshing of the liquid during and after the movement can cause instability, increase position error and control effort, and create danger or damage if the liquid is flammable. Therefore, in this study, control of a liquid carrier quadrotor has been studied and a controller has been presented that, unlike previous studies, can provide stability in point-to-point transmission without the need to measure or estimate liquid states. For this purpose, a controller is first designed by linearizing the equations of motion of the system and assuming the liquid is rigid via pole placement. On the other hand, in order for the behavior of the system to be similar to the behavior of the design model and to maintain the stability of the system, the liquid sloshing must be reduced as much as possible. Therefore, a command smoother based on the natural frequencies of the liquid sloshing modes is used. The ability of the proposed control system has been investigated, validated, and compared with a similar study by simulation. Also, the simulation results show that the implementation of the designed command smoother can significantly reduce the amplitude of liquid sloshing, the deviation of the system states from the equilibrium state, and the control effort.

In this research, a novel nonlinear control strategy along with its simulation for a quadrotor helicopter is proposed. In the present work, a six-DOF dynamic equations of the quadrotor system subjected to unknown external disturbances based on the Newton-Euler equations is developed completely and without any simplification. Considering the under-actuated and strongly coupled characteristics of quadrotor helicopter, a nonlinear control method is designed using integral backstepping combined with the sliding mode control (integral BS-SMC) to stabilize the qudrotor attitude and to tracking the desired trajectory. The designed controllers based on the hierarchical control scheme can be used to control the rotational and translational movements and their stability are validated by the Lyapunov stability theorem. Using the proposed controller, the chattering phenomenon and discontinuousness of the control inputs faced by traditional sliding mode control (SMC) can be avoided. The feasibility and performance of the presented control approach is verified by the simulations under different scenarios. The results show that the proposed nonlinear control method not only has a better tracking performance than PID controller, but also has a higher robustness when unknown disturbances occur.

Quadrotor is an underactuated and nonlinear coupled system. in this paper for controlling the dynamic of the system, feedback linearization (FL) method is used to convert the nonlinear model to a simple linear one. Moreover, a combination of fractional order PID (FOPID) with FL is used to improve the tracking ability. Tuning the parameters of NFOPID, because of two more orders of integral and derivation is a complicated task; therefore neural networks (NNs) method is used to cope with this duty. Back propagation (BP) algorithm is used to train the weights of the NNs. Because of the flexibility and online learning of the NNs, the proposed controller can be robust against uncertainties and disturbances. The fractional order operator has infinite dimension and for practical implementation modified Oustaloup's method is used in this paper. and finally the results of the simulations also validate the effectiveness and robustness of the proposed scheme.

In this paper, a reference trajectory tracking control is designed for a typical quadrotor. For this purpose, two control ‎loops is proposed as follow: the inner loop is based on state feedback control technique and optimal control which ‎coefficients are obtained as a function of system states using the genetic algorithm. Then, optimal control coefficients ‎functions are extracted‏ ‏using the optimally stored data and least square method. The mentioned control function is ‎based on a linear relationship between system state space and control coefficients. In the outer control loop, the PID ‎control is utilized. Since, in this approach, the control coefficients are ‎obtained from the genetic algorithm, the ‎properties of the fitness function are considered. The ‎performance of the proposed controller is evaluated by a ‎comparative study especially to the PID ‎controller, which is widely used in the literature. The simulation results show ‎the effective performance of this technique in controlling Euler angles, reduction in summation of tracking error and ‎optimization in power consumption.‎

In recent decades, quadrotors are considered, because of the special missions and reducing the cost of flight operation. In this paper, three flight missions are defined to the quadrotor for shooting the special area. Attitude control of quadrotor is analyzed on basis of state-dependent Riccati equation. In the first mission, an experimental sample is taken in order to find the Euler angles for the implementation of routes. The sample quadrotor is on basis of the proportional–derivative controller. For this purpose, results of simulation base on proportional–derivative controller are conducted and the results are validated by state-dependent Riccati equation controller method. In the second and the third missions, the quadrotor is given maneuver by state-dependent Riccati equation method and flies in more complex routes such as square and round to cover more surface. Considering external wind fieldis the important parameter for the mention missions. The feasibility of these missions related to quadrotor stability and guaranteed security in wind field, for this purpose, the influence of force and moment of the wind field is applied to equations of motion of quadrotor. Dynamic performance of quadrotor is investigated for proportional–derivative, linear quadratic regulator and state-dependent Riccati equation methods encountering wind field.

Quadrotor is an unmanned aerial robot from multi-rotor drones group that has high maneuverability, vertical take-off, and landing and stationary flight capabilities. In the most practical applications, the quadrotor system is subjected to external disturbance forces due to wind and unbalanced weight or inertia of the payload. To maintain balance and hold the position, attitude stabilization of the quadrotor is necessary for the presence of disturbances and unbalanced forces. Using conventional controllers with constant gains is not very efficient to eliminate variable disturbances that affect quadrotor motion in different conditions. In this paper, an adaptive fuzzy proportional integral derivative controller is designed for quadrotor attitude stabilization in which controller gains are regulated continuously based on the adaptive laws and the fuzzy inference system. The performance of the proposed controller is examined in the disturbance rejection test and is compared to the conventional proportional integral derivative controller. Also, the performance of the proposed controller is approved by hardware in the loop experimental tests using a 3 degree of freedom pilot platform. The experimental results will show the effectiveness of the adaptive fuzzy proportional integral derivative controller compared with the conventional proportional integral derivative controller.

In this paper, by introducing a robust hybrid controller with an obstacle avoidance unit based on potential functions, the trajectory tracking control of quadrotors are discussed in the presence of obstacles. Quadrotors are underactuated systems and the design of a robust tracking controller has become one of the most challenging topics in recent researches. First, dynamic modeling of a quadrotor is considered using the Newton-Euler method by considering all its nonlinear terms. In the following, the system state space is represented. Then, a control method based on linear control algorithms is designed to control the outer loop and for the inner loop of the controller, the backstepping method is presented. The combination of the control methods is designed so that the best performance of the system is obtained in terms of convergence to the reference path, minimum steady-state errors and other transient response specifications of the system. In the following, an obstacle avoidance unit based on potential functions is designed to prevent the collision of the quadrotor with obstacles by creating a repulsive force between the system and the obstacles. Finally, trajectory tracking case studies are considered for a quadrotor in the presence of obstacles. Obtained results show the robust performance of the controller in tracking the trajectories and avoiding obstacles.

Quadrotor is one type of unmanned aerial vehicles which it's maneuverability and simple structure has extracted fascination. In spite of this, its highly non-linear behavior can be regarded as one of its disadvantages. The dynamic model of quadrotor is nonlinear with many sources of uncertainty, so in the controller design process, robust control methods such as sliding mode, are required in order to achieve good tracking and stabilization results. In contrast to the high capabilities of sliding mode control approach, high frequency switching of the control signal, is considered as one of its disadvantages, which can be reduced by using higher order techniques. In this paper the behavior of the both first order and second order sliding mode controllers in, trajectory tracking of the position and the yaw angle to their desired values and stabilization of the roll and pitch angles of the quadrotor, under high uncertain conditions, are investigated. The second order sliding mode control was designed based on super twisting algorithm. Considering high parametric uncertainty in quadrotor data, the comparison between the results of the two methods, shows the good performance of the second order sliding mode control, in terms of tracking, stabilization and chattering reduction.

Today, unmanned aerial vehicles are highly considered for both military and commercial fields due to low cost, high maneuverability, and good survival. One of the most important design challenges of multi-UAV systems is mission planning. In the broad class of unmanned aerial vehicles (UAV), Quadrotor is an important member. The capabilities of this vehicle in load transportation has attracted the attention of many research groups around the world. In this paper, path planning based on the minimum energy consumption is studied for load transportation. The purpose of the present study is to investigate the effect of proposed cost function in order to obtain optimal path for transporting loads based on reducing the energy consumption of quadrotors. The results indicate the 35.29% energy consumption of multi UAV compared to the energy consumption of an individual quadrotor. This also leads to an increase in load carrying capacity. On the other hand, the leader- follower formation is preserved until the end of the path based on the defined relationships. The simulation results illustrate the power and efficiency of the method to overcome the high nonlinearity nature of the problem such as path optimization of multi-rotor helicopters.

A vertical take-off and landing (VTOL) aircraft is one that can hover, take off, and land vertically. VTOL UAVs have high maneuverability and their users are after maintaining this maneuverability. This alongside with their extreme nonlinearities and under actuating control system rises the importance of the control of flight. In this paper, the effect of using stabilizing mechanisms in trajectory tracking of quad-rotor unmanned aerial vehicles under wind gusts is studied. Two mechanisms that are simulated and used in this paper are very rare and introduced their usage for first time in this study. The first one is a spherical pendulum stabilizer and the second one is a cross stabilizer. Also appropriate controller is designed for each stabilizer mechanism. The performance of the systems are investigated in the presence of disturbing forces. The results show that instead of using complicated nonlinear control methods, the proposed stabilizer mechanism yields a desired performance. Acceptable trajectory tracking shows the successful effectiveness of the proposed stabilizers.

In this paper, the integral backstepping sliding mode (IBSM) control with the extended Kalman-Bucy filter (EKBF) to control and state estimation of unmanned aerial vehicles (quadrotor) is provided. In the quadrotor system, the aerodynamic effects of the‏ dynamics of a system are considered, and dynamical equations are derived by the Newton-Euler method. Quadrotor's behavior, which is affected by forces and aerodynamic moments is non-linear, but the integral backstepping sliding mode control has been able to stabilize the system dynamically, without considering the system and measurement noises and assuming all the dynamic states of the system. Noise is immaterial in dynamic systems, and the measurement of all systems states in practice is very complex and expensive; for this purpose, the EKBF in the control structure is used as observer states of the system and noise reduction in these modes. Therefore, simultaneous use of the controller-observer is suggested for controlling and estimating quadrature states. The numerical simulation demonstrates the good performance of the proposed controller-observer so that they were able to estimate both the system's unobservable state and overcome system and measurement noise.

Quadrotors have high energy consumption due to their inherent structure, hence minimization of their energy consumption play a crucial role in terms of enhancing their operational range and flight time. In this paper, optimal control based on a minimum-energy trajectory planning algorithm of a quadrotor has introduced between two certain points to maximize operation time. To do this, first, dynamic equations of quadrotor and Brushless motor are derived. Energy consumption of quadrotor is introduced as a cost function and the minimum energy path is determined using optimal control theory. To satisfy constraints, all of them are combined with a Hamiltonian equation using Lagrange multiplier. Finally, simulation results are compared with results of conventional trapezoidal velocity profile which shows energy saving up to 4% compared with conventional trapezoidal velocity profile. Also, results reveal that the influence of operation time is far more than path length on energy consumption. In order to verify the validity of the simulation results, they are compared with the results of an experimental model which is consisting Brushless motor, sensor and, control board. As well as using simulation results in different situations, a mathematical equation was extracted among path length, operation time and energy consumption which can be useful to estimate the maximum flight range or operation time considering the amount of energy of the battery.