fuzzy-pid controller

Proportional-Integral-Derivative (PID) controllers have been regarded as one of the most prevalent and successful techniques for controlling dynamic systems. However, in the presence of uncertainties and complicated systems, their operation may be undesirable. The major purpose of this research is to assess and improve the performance of the PID controller in the variable load crop spraying quadcopter navigation system using fuzzy-based approaches. At first, the PID controller parameters are fixed and then are tuned based on a look-up table according to the quadcopter load changes. The simulations reveal that the PID controller with fixed parameters or based on the lookup table does not have its expected performance, in the presence of uncertainties such as load variations, and hence it is required to tune the parameters more correctly. Therefore, here the fuzzy systems are utilized for online parameter tuning of the PID controller in the parameters in the variable load spraying quadcopter navigation system. The proposed fuzzy-based PID controller achieves higher accuracy and more stable navigation compared with the fixed-parameter PID controller or look-up table.

Shape memory alloys (SMAs) are a special kind of smart materials with an intrinsic shape memory effect. This characteristic brings up SMAs as an actuator in dynamical mechanisms. These materials can recover their initial length under special thermal operations. This paper deals with fuzzy-PID control of contrary mechanisms actuating with a pair of SMA wires. The Brinson model combining with the Elahinia’s conditions are employed to describe the phase transformation models. By combining the Newton second law, transformation models, heat transfer and strain relations, the governing equations of the contrary mechanism is derived. Due to nonlinear behavior of SMA actuators, the non-model-based controllers are preferred compared with the model-based ones. Therefore, the fuzzy-PID control method is employed to control the position of the closed-loop system. The fuzzy rules are defined such that the coefficients of the PID controller are tuned according to the system response. Both numerical and experimental results are provided to illustrate the effectiveness of the proposed approach. It will be shown that under the proposed method, the tracking error will converge to zero asymptotically.

This paper dealing with a novel algorithm based on features of Fuzzy-PID controllers to estimate heat flux on the inverse heat conduction problems. The main structure of Fuzzy-PID is a PID controller in which the proportionalو integrator and the derivative gains are obtained online by fuzzy system. The input of the algorithm is the measured temperatures within the model. In each time-step, the smart controller calculates the proper heat flux in order to adjust the measured temperature with desired input temperature. The model studied a flat plate with an insulated surface and an active level that affects the variable heat flux at the time. The variation of heat flux with time can be considered to be constant, step, and triangular. The measured temperatures are obtained at the active and inactive surface with numerical simulation. The effect of noise level at the measurement temperatures on the accuracy of the proposed method is investigated. The estimations and error analysis indicate that this algorithm is very successful in estimating the different forms of heat flux with different amounts of noise and the different thermocouple positions in the wall.

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.

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.