Showing 9 results for Pid Controller
Adel Rabie, Maryam Malekzadeh, Majid Abnili,
Volume 15, Issue 3 (5-2015)
Abstract
This paper talked about spacecraft formation flying control. Leader-flower structure is used in formation flying. A non-linear PID controller is designed based on predictive control. The formation relative equation is obtained from nonlinear Hill equation. First, the frequency control is achieved with the using of predictive control algorithm. In control frequency, disturbances have been replaced from disturbance observer. Equations are rewritten in the form of PID gains. Stability of the closed-loop system is proven by closed-loop error dynamics. Nonlinear PID controller performance in the pursuit of desired arrangement has been tested in simulations. Also effects of various factors on the quality of controller results are studied. It is shown that choosing predictive horizon time and disturbance observer gains have the most effect on system response. It is shown that if predictive time increase the settling time increase and the control effort decrease. if disturbance observer gain increase from a limit, it has no effect on settling time but control effort increase. As shown in simulation, the tracking response show the controller method ability. the simulation show the ability of this nonlinear control method in tracking.
Ali Reza Rarivar, Mohammad Reza Zakerzadeh,
Volume 15, Issue 7 (9-2015)
Abstract
The purpose of this paper is design, construction and the control of a two-wheel self-balancing robot. For this purpose firstly, a literature study is carried out on the history of manufactured self-balancing robots and the researches which have been done so far in this area are reported. In addition, the robot chassis with consideration of the size and material is analyzed; and the dynamic equations of the robot are computed according to the designed chassis. Then, the robot inertial parameters are measured through different experimental tests and these parameters are used in the equations. Also, the derived equations are simplified and the transfer functions are evaluated for considering the stability of the robot. In this self-balancing robot, the simplified Kalman and complementary filters are used for identifying of the bias angle from the vertical position by combination of data obtained from accelerometer and gyroscope sensors. The PID controller and the robot transfer functions are simulated in MATLAB software. Then, the controller gains are obtained for the stability of the constructed robot. These gains are computed by PID tuning toolbox of MATLAB software as well as theoretically, and the results in each method have been compared with each other. Finally, the robot control electronic circuit is designed for analyzing the results through AVR microcontroller, while angle identification sensor is used.
Mahdi Fakoor, Alireza Sattarzadeh, Majid Bakhtiari,
Volume 16, Issue 4 (6-2016)
Abstract
In the present study, a new attitude stabilization concept has been investigated for a satellite considering failure in one or more reaction wheels. In this approach control torques could be generated using only one thruster mounted on a two axis gimbal mechanism. In the other word, in the absence of reaction wheel(s), control torques are generated by applying a thruster rotating mechanism which can be turned around two axes by thruster vector. If any failure happened in reaction wheels, gimbal angles mechanisms will be added to the system as input controlling. Controller algorithm based on dynamic and kinematic equations of the satellite’s motion, has been developed in the presence of disturbances. Three-axis stabilization of the attitude in a LEO orbit satellites under disturbances has been executed by applying three reaction wheel actuators to produce torque in each direction. Disturbance torques that are commonly applied to the satellites are gravity gradient, solar radiation pressure and aerodynamics. For training the intelligent neuro-fuzzy controller, PID controller is employed. Numerical simulations show that, the recommend controlled method have acceptable results (in the presence of disturbances) and adding of a thruster actuator to the system as a redundancy, could enhance the space missions reliability and if any fault happened in the operation of reaction wheels, thruster mechanisms come in to control system , accurately, and sustained satellite stability at desirability attitude.
Sara Moghadaszadeh Bazaz, Vahid Bohlouri, Seyed Hamid Jalali Naini,
Volume 16, Issue 8 (10-2016)
Abstract
In this paper, the performance of a single-axis attitude control with pulse-width pulse-frequency (PWPF) modulation is enhanced using a modified proportional-integral-derivative (PID) controller for a rigid satellite with on-off thruster actuators. For this purpose, the well-known observer-based PID approach is utilized. The on-off thruster actuator is modeled with a constant delay followed by a second-order binomial transfer function. The modulator update frequency is limited to 40 Hz as an input to the on-off thruster actuators. In this study, the design criteria of pointing accuracy, overshoot of the attitude response, fuel consumption, and the number of thruster firings are considered for a step external disturbance (with different values). The parameters of the observer-based PID controller are tuned using parametric search method. Simulation results show that the fuel consumption and settling time of the observer-based approach are considerably decreased with respect to those of PID controller with PWPF modulator. Moreover, the overshoot of the observer-based approach is omitted. Finally, the robustness of the observer-based modified PID controller is investigated in presence of uncertainties in satellite moment of inertia and thrust level of on-off actuators.
Vahid Tikani, Hamed Shahbazi,
Volume 16, Issue 9 (11-2016)
Abstract
This paper presents a completely practical control approach for quadrotor drone. Quadrotor is modelled using Euler-Newton equations. For stabilization and control of quadrotor a classic PID controller has been designed and implemented on the plant and a fuzzy controller is used to adjust the controller parameters. Considering that quadrotor is a nonlinear system, using classic controllers for the plant is not effective enough. Therefor using fuzzy system which is a nonlinear controller is effective for the nonlinear plant. According to the desire set point, fuzzy system adjusts the controller gain values to improve the performance of quadrotor and it leads to better results than classical PID controller. To study the performance of fuzzy PID controller on attitude control of the system, a quadrotor is installed to the designed stand. The system consists of accelerometer and gyroscope sensors and a microcontroller which is used to design fuzzy PID attitude controller for the quadrotor. Considering that the experimental data has lots of errors and noises, Kalman filter is used to reduce the noises. Finally using the Kalman filter leads to better estimation of the quadrotor angle position and the fuzzy PID controller performs the desired motions successfully.
Mohsen Ekramian, Mohammad Danesh, Ahmad Kamali,
Volume 17, Issue 3 (5-2017)
Abstract
A nonlinear model for Autonomous Underwater Vehicles is proposed. In order to describe a more precise dynamic behavior, the nonlinear model for both Lateral and Longitudinal subsystems is derived based on all applied forces and moments. The proposed model can be explained as an extended linear model for AUV in depth and azimuth motions where some nonlinearities are taken into account. Due to some practical issues as well as the form of proposed model, the identification problem based on Least Square method is formulated to achieve the system parameters. By considering unstable dynamic of system, the open loop system cannot be excited. In this case, the PID regulators with simple tuning parameters are proposed in both Lateral and Longitudinal subsystems and the identification problem by utilizing sinusoidal inputs is followed within a feedback loop. Based on measurable variables i.e. linear moments, angular velocities and Euler angles, and utilizing some dynamic filters, the Least Square method is then applied to estimate the model parameters. The effectiveness of proposed nonlinear model as well as the parameter identification approach are finally demonstrated through some numerical simulations.
Kamran Daneshjou, Hasan Keshavarzian,
Volume 17, Issue 12 (2-2018)
Abstract
In unmanned aerial vehicle (UAV) classes, the control of quadrotor has attracted many researchers from around the world in recent years. In this type of rotary wing, it is attempted to achieve stability in hover and motion flight modes using the forces, produced by propellers. Quadrotor has nonlinear and time-varying behavior and the aerodynamic forces almost always disturb it. In near the ground, the wake of quadrotor interacting with the ground surface causes perturbation to the flow near the blades and frame. These perturbations have significant effect on quality and stability of flight. Most of the related researches were only studied hover and landing operation and the ground effect was considered as constant coefficient in dynamic equations. In this paper, a comprehensive nonlinear model is developed for variety modes of quadrotor flight in near the ground in space state, and the ground effect is as function of state variables in equation. Then, according to the proposed model, the PID controller is designed and the effect of the ground effect on controller performance is investigated. The results of simulation indicate that, the flight stability and trajectory tracking have improved significantly by using of the model and designed controller.
M. Mokhtari, M. Taghizadeh, M. Mazare,
Volume 19, Issue 12 (12-2019)
Abstract
Reference trajectory tracking and guarding against system disturbances and uncertainties are the important factors in the realm of lower limb exoskeleton robots control. Sliding mode PID is one of the robust controllers, which has a sliding manifold in the form of the PID controller. Chattering is the substantial predicament of the PIDSMC so that boundary layer around the sliding manifold is applied to eliminate the phenomenon. In this step, not only the chattering phenomenon is not eliminated but the robustness of the controller is also mitigated. In this study, supper twisting PID sliding mode controller (STPIDSMC) was used to eradicate the chattering phenomenon and enhancing controller robustness. The STPIDSMC robustness is protected indigenously and without defining the boundary layer, and the chattering phenomenon is reduced. Furthermore, to meet the external disturbances and uncertainties with unlimited amplitude, adaptive active force control method is combined by STPIDSMC as a modifying input control loop. In the active force control approach, the control input is online modified based on the estimation of moment inertia of the robot links. In order to accomplish maximum performance, control parameters were optimized using harmony search algorithm. In the optimal state, the performance of the proposed controller has been compared with PIDSMC and STPIDSMC that revealed the priority of the proposed controller rather than other controllers. The results indicate that the three error criteria, ITAE, ITASE, and IASE experience significant reduction about 39, 48, and 66 percent respectively compared to STPIDSM.
Alireza Basohbat Novinzadeh, Zahra Arabtelgerd,
Volume 21, Issue 9 (9-2021)
Abstract
In this paper, the mathematical modeling, construction, control, and implementation of a one-degree-of-freedom cube dynamic system with a reaction wheel actuator will be discussed. The innovation of this paper is the implementation of the proportional-integral-derivative controller on the experimental system of one degree of freedom with a reaction wheel. First, equations of system are expressed, then the system is analyzed in time and frequency domain. Then, the proportional-integral-derivative controller will be designed and implemented on the constructed system. The system response is compared in six steps for different control gains. The control gains of the best answer are proportional gain of -20, integral gain of -30 and derivative gain of 3- in system theory answers it has 1 degree of superiority and in experimental answer it has 7 degrees of overshoot. The steady-state error is zero for both experimental and theoretical system. The rise time of the simulation theory is 10 time steps, each time step is equal to 0.001 seconds, and the experimental response of the system is 10 time steps. The simulation session time is 180 time steps and the experimental response is 100 time steps.. In the next step, the stability of the control designed with the selected gains from the previous step is tested by inserting the perturbation, and the system is stabilized by 4 degrees overshoot. By changing the angle of the bottom plane, the response will have 3 degrees overshoot, but the system will remain stable.
