scholarly journals FRACTIONAL-ORDER PASSIVITY-BASED ADAPTIVE CONTROLLER FOR A ROBOT MANIPULATOR TYPE SCARA

Fractals ◽  
2020 ◽  
Vol 28 (08) ◽  
pp. 2040008
Author(s):  
J. E. LAVÍN-DELGADO ◽  
S. CHÁVEZ-VÁZQUEZ ◽  
J. F. GÓMEZ-AGUILAR ◽  
G. DELGADO-REYES ◽  
M. A. RUÍZ-JAIMES

In this paper, a novel fractional-order control strategy for the SCARA robot is developed. The proposed control is composed of [Formula: see text] and a fractional-order passivity-based adaptive controller, based on the Caputo–Fabrizio and Atangana–Baleanu derivatives, respectively; both controls are robust to external disturbances and change in the desired trajectory and effectively enhance the performance of robot manipulator. The fractional-order dynamic model of the robot manipulator is obtained by using the Euler–Lagrange formalism, as well as the model of the induction motors which are the actuators that drive their joints. Through simulations results, the effectiveness and robustness of the proposed control strategy have been demonstrated. The performance of the fractional-order proposed control method is compared with its integer-order counterpart, composed of the PI controller and the conventional passivity-based adaptive controller, reported in the literature. The performance comparison results demonstrate the superiority and effectiveness of the fractional-order proposed control strategy for a SCARA robot manipulator.

Author(s):  
Amel Bouzeriba

In this chapter, the projective synchronization problem of different multivariable fractional-order chaotic systems with both uncertain dynamics and external disturbances is studied. More specifically, a fuzzy adaptive controller is investigated for achieving a projective synchronization of uncertain fractional-order chaotic systems. The adaptive fuzzy-logic system is used to online estimate the uncertain nonlinear functions. The latter is augmented by a robust control term to efficiently compensate for the unavoidable fuzzy approximation errors, external disturbances as well as residual error due to the use of the so-called e-modification in the adaptive laws. A Lyapunov approach is employed to derive the parameter adaptation laws and to prove the boundedness of all signals of the closed-loop system. Numerical simulations are performed to verify the effectiveness of the proposed synchronization scheme.


2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Xiangxiang Meng ◽  
Haisheng Yu ◽  
Herong Wu ◽  
Tao Xu

A novel method of disturbance observer-based integral backstepping control is proposed for the two-tank liquid level system with external disturbances. The problem of external disturbances can be settled in this paper. Firstly, the mathematical model of the two-tank liquid level system is established based on fluid mechanics and principle of mass conservation. Secondly, an integral backstepping control strategy is designed in order to ensure liquid level tracking performance by making the tracking errors converge to zero in finite time. Thirdly, a disturbance observer is designed for the two-tank liquid level system with external disturbances. Finally, the validity of the proposed method is verified by simulation and experiment. By doing so, the simulation and experimental results prove that the scheme of disturbance observer-based integral backstepping control strategy can suppress external disturbances more effective than the disturbance observer-based sliding mode control method and has better dynamic and steady performance of the two-tank liquid level system.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Fei-xiang Xu ◽  
Xin-hui Liu ◽  
Wei Chen ◽  
Chen Zhou ◽  
Bing-wei Cao

To improve the road feeling of the steer-by-wire (SBW) system, a fractional order PID (proportion-integral-derivative) method with a fault tolerant module is proposed in this paper. Firstly, the overall road feeling control strategy of the SBW system is introduced, and then the mathematical model of road feeling control is established. Secondly, a fractional order PID (FOPID) controller is designed to control torque of the road feeling motor. Furthermore, genetic algorithm (GA) is applied to tune the FOPID controller’s parameters. Thirdly, a fault tolerant module aiming at potential failures of the motor’s torque sensor is studied to improve the reliability of the system. Kalman Filter (KF) algorithm is utilized in the fault tolerant module so as to detect failures of the motor’s torque sensor, and then fault tolerant module reconfigures the motor’s torque estimated by KF as a substitute when the torque sensor fails. Finally, simulations based on MATLAB are performed with the proposed control strategy to identify its performance, and the results demonstrate that the proposed control method is feasible and accurate.


Author(s):  
Mohammed Ali ◽  
Charles K. Alexander

The tracking performance of a robot manipulator is controlled using nonlinear active disturbance rejection control (ADRC). The proposed method does not require the complete knowledge of the plant’s parameters, and external disturbances since it is based on the rejection and estimation of the unknown internal dynamics and external disturbances. The proposed method is simple and has minimal tuning parameters. The robustness of the proposed method is discussed against parameter uncertainties and disturbances. First, the mathematical model of the manipulator is developed. ADRC theory is explained. The manipulator is represented in ADRC form. ADRC’s tracking performance for the joints and end-effector is compared to the tracking performance of the robust passivity (RP) control. The simulations prove that the proposed control method achieves good tracking performance compared to RP control. It is shown that ADRC has a lower energy consumption compared to RP control by calculating the power in the input signals.


2017 ◽  
Vol 13 (1) ◽  
pp. 114-122
Author(s):  
Abdul-Basset AL-Hussein

A composite PD and sliding mode neural network (NN)-based adaptive controller, for robotic manipulator trajectory tracking, is presented in this paper. The designed neural networks are exploited to approximate the robotics dynamics nonlinearities, and compensate its effect and this will enhance the performance of the filtered error based PD and sliding mode controller. Lyapunov theorem has been used to prove the stability of the system and the tracking error boundedness. The augmented Lyapunov function is used to derive the NN weights learning law. To reduce the effect of breaching the NN learning law excitation condition due to external disturbances and measurement noise; a modified learning law is suggested based on e-modification algorithm. The controller effectiveness is demonstrated through computer simulation of cylindrical robot manipulator.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yilin Hao ◽  
Xiulan Zhang

In this article, the adaptive control of uncertain fractional-order time-delay systems (FOTDSs) with external disturbances is discussed. A Takagi-Sugenu (T-S) fuzzy model with if-then rules is adopted to characterize the dynamic equation of the FOTDS. Besides, a fuzzy adaptive method is proposed to stabilize the model. By utilizing the Lyapunov functions, a robust controller is constructed to stabilize the FOTDS. Due to the uncertainty of system parameters, some fractional-order adaptation laws are designed to update these parameters. At the same time, some if-then rules with linear structure based on the fuzzy T-S adaption concept are established. The designed method not only guarantees that the state of closed-loop system asymptotically converges to origin but also keeps the signal in the FOTDS bounded. Finally, the applicability of the control method is proved by simulation examples.


2019 ◽  
Vol 9 (20) ◽  
pp. 4449 ◽  
Author(s):  
Zhiping Cheng ◽  
Meng Gong ◽  
Jinfeng Gao ◽  
Zhongwen Li ◽  
Jikai Si

In order to improve the stability of direct current (DC) microgrid with constant power loads, a novel virtual inductive approach is proposed in this paper. It is known that the negative impedance characteristic of constant power loads will lead to DC bus voltage fluctuation, which will be more serious when they integrate into the DC microgrid though a large transmission line inductive. For the convenience of analysis, a simplified circuit model of the system is obtained by modeling the distributed resources. Unlike the existing control strategies, the proposed control strategy constructs a negative inductance link, which helps to counteract the negative effects of the line inductive between the power source and the transmission line. Detailed performance comparison of the proposed control and virtual capacitance are implemented through MATLAB/simulink simulation. Moreover, the improved performance of the proposed control method has been further validated with several detailed studies. The results demonstrate the feasibility and superiority of the proposed strategy.


2013 ◽  
Vol 694-697 ◽  
pp. 2134-2138
Author(s):  
Ying Hao ◽  
Hao Yuan ◽  
Feng Dong

The control of simulated beer production line is implemented based on a Q series PLC controller of Mitsubishi company. The mathematical modeling method and the self-adaptive control strategy are introduced. The Mitsubishi PX-Developer software is adopted to design, run and debug online the PID and self-adaptive PID controller. Performance comparison between the two kinds of control strategy is made. It is shown that the self-adaptive PID control algorithm has the superiority.


2021 ◽  
Author(s):  
Xiaolian Liu ◽  
Shaohua Wang ◽  
Ying Luo

Abstract In order to make robot manipulators work more compliantly when contacting with the environment, it is necessary to reduce the contact force caused by positioning errors. One effective way to solve this problem is impedance control, which makes the robot manipulator a second-order mass-spring-damping system in principle. In this paper, a position-based fractional-order impedance control design method is proposed for the robot manipulator force control. The end-effector/environment contact model is established, and the closed-loop system is analyzed with the reference force as input. A fractional-order impedance parameters design method is proposed for better force-control performance, which calculates and optimizes parameters through frequency-domain specifications (i.e., phase margin and gain crossover frequency) and time-domain specification (i.e., the minimum JITSE). With the Robotics ToolBox for MATLAB (RTB), the performance comparison between integer-order and fractional-order impedance controls is illustrated in simulation. The fractional-order impedance control system has a faster response, smaller overshoot, and better resistance to external disturbances from the environment.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yan Wang ◽  
Ling Liu ◽  
Chongxin Liu ◽  
Ziwei Zhu ◽  
Zhenquan Sun

In this paper, fractional calculus is applied to establish a novel fractional-order ferroresonance model with fractional-order magnetizing inductance and capacitance. Some basic dynamic behaviors of this fractional-order ferroresonance system are investigated. And then, considering noncommensurate orders of inductance and capacitance and unknown parameters in an actual ferroresonance system, this paper presents a novel fractional-order adaptive backstepping control strategy for a class of noncommensurate fractional-order systems with multiple unknown parameters. The virtual control laws and parameter update laws are designed in each step. Thereafter, a novel fractional-order adaptive controller is designed in terms of the fractional Lyapunov stability theorem. The proposed control strategy requires only one control input and can force the output of the chaotic system to track the reference signal asymptotically. Finally, the proposed method is applied to a noncommensurate fractional-order ferroresonance system with multiple unknown parameters. Numerical simulation confirms the effectiveness of the proposed method. In addition, the proposed control strategy also applies to commensurate fractional-order systems with unknown parameters.


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