Attitude Control of Five Degrees of Freedom Air-Bearing Platform Based on Fractional Order Sliding Mode

Author(s):  
Deng Liwei ◽  
Song Shenmin ◽  
Guo Yong
Author(s):  
Yaoyao Wang ◽  
Bai Chen ◽  
Hongtao Wu

For the multi-degrees of freedom control problem of underwater hydraulic manipulators with non-ignorable valve deadband and strong lumped nonlinearities and uncertainties, a practical continuous fractional-order nonsingular terminal sliding mode control design together with a deadband compensator is presented and studied. The presented method contains three parts a time delay estimation utilized to nearly estimate and compensate the extremely complicated system dynamics, a continuous fractional-order nonsingular terminal sliding mode used to ensure high control performance against the strong lumped nonlinearities and uncertainties, and a valve deadband compensator used to compensate for the non-ignorable valve deadband. The proposed method is model-free thanks to the time delay estimation, and can ensure satisfactory control performance thanks to the continuous fractional-order nonsingular terminal sliding mode and deadband compensator. Stability of the closed-loop control system including the deadband compensator is proved rigorously. Finally, practical 2-degrees of freedom experiments are performed, and corresponding results effectively demonstrate the superiorities of the newly presented controller with deadband compensator.


2013 ◽  
Vol 284-287 ◽  
pp. 2296-2300 ◽  
Author(s):  
Kuang Shine Yang ◽  
Chi Cheng Cheng

The quadrotor helicopter is designed to easily move in particular environments because it can take off and land in limited space and easily hover at a fixed location. For this reason, a robust adaptive sliding mode controller is developed to control of a quadrotor helicopter in the presence of external disturbances and parameter uncertainties. The quadrotor helicopter system is a typical underactuated system, which has fewer independent control actuators than degrees of freedom to be controlled. The main contribution here is to afford simulation and verification for the quadrotor helicopter flight controller under the assumption of unknown parameters. By utilizing the Lyapunov stability theorem, we can achieve asymptotic tracking of desired reference commands for the quadrotor helicopter, which is subject to both external disturbances and parametric uncertainties. From the simulation results, the controller was sufficient to achieve position and attitude control of the quadrotor helicopter system, which permits possible real time applications in the near future.


Author(s):  
Ahmet Dumlu

In this study, trajectory tracking control of six–degrees of freedom robotic manipulator has been performed using the proposed fractional-order adaptive integral sliding mode control scheme. The proposed method is first composed by fractional-order and adaptive integral sliding mode control to achieve the finite-time convergence, chattering-free control inputs, better tracking performance and robustness for the robotic manipulator. Furthermore, an adaptive method has been utilized to evaluate and compensate the uncertain and unknown dynamics of the system without relying on the prior knowledge of the upper bounds. To illustrate the efficiency of the proposed fractional-order adaptive integral sliding mode control method, the real-time experimental studies have been performed for the six–degrees of freedom industrial robot manipulator. The experimental outcomes strongly verified that the proposed controller gives quite well trajectory tracking response and faster convergence compared with the classical integral sliding mode control under the external payload.


2021 ◽  
Author(s):  
milad alipour ◽  
Maryam Malekzadeh ◽  
alireza ariaei

Abstract In this article, a novel multi-purpose modified fractional-order nonsingular terminal sliding mode (MFONTSM) controller is designed for the flexible spacecraft attitude control and appendages passive vibration suppression, assuming the control torque saturation in the system dynamics. Furthermore, an active FONTSM controller is proposed separately to perform active vibration suppression of the flexible appendages using piezoelectric actuators. The fixed-time stability of the closed-loop system for both the passive and active controllers is analyzed and proved using the Lyapunov theorem. Finally, the performance of the proposed controllers has been tested in the presence of uncertainties, external disturbances, and the absence of the damping matrix in order to study the effectiveness of the proposed method.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Jianghui Liu ◽  
Haiyang Li ◽  
YaKun Zhang ◽  
Jianyong Zhou ◽  
Lin Lu ◽  
...  

The control of body-fixed hovering over noncooperative target, as one of the key problems of relative motion control between spacecrafts, is studied in the paper. The position of the chaser in the noncooperative target’s body coordinate system is required to remain unchanged, and the attitude of the chaser and the target must be synchronized at the same time. Initially, a six-degrees-of-freedom-coupled dynamic model of a chaser relative to a target is established, and relative attitude dynamics is described through using modified Rodrigues parameters (MRP). Considering the model uncertainty and external disturbances of the noncooperative target system, an adaptive nonsingular terminal sliding mode (NTSM) controller is designed. Adaptive tuning method is used to overcome the effects of the model uncertainty and external disturbances. The upper bounds of the model uncertainty and external disturbances are not required to be known in advance. The actual control law is continuous and chatter-free, which is obtained by integrating the discontinuous derivative control signal. Finally, these theoretical results are verified by numerical simulation.


2013 ◽  
Vol 706-708 ◽  
pp. 1393-1396
Author(s):  
Yan Bin Li ◽  
Ren Song Zou ◽  
Tong Jiang

To improve the accuracy of attitude determination and control stabilization when simulating attitude motion of satellites in the space, the finite element model of the platform of 3-DOF spacecraft attitude control simulator was founded. Gravity field of air bearing testbed and formula for platform’s moment of inertia on the action of gravity was induced The result shows platform’s attitude accuracy error exist because of main principal axis of inertia change of direction.on the action of gravity, The more large value it is, the more error is .Error of inertia main axis changes as sine curve with the change of two horizontal Euler angle.


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