scholarly journals Control of a Lightweight Flexible Robotic Arm Using Sliding Modes

10.5772/5798 ◽  
2005 ◽  
Vol 2 (2) ◽  
pp. 11 ◽  
Author(s):  
Victor Etxebarria ◽  
Arantza Sanz ◽  
Ibone Lizarraga
Keyword(s):  
Robust Control ◽  
Optimal Design ◽  
Closed Loop ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Robotic Arm ◽  
Sliding Modes ◽  
Flexible Link ◽  
Composite Approach ◽  
Control Scheme

This paper presents a robust control scheme for flexible link robotic manipulators, which is based on considering the flexible mechanical structure as a system with slow (rigid) and fast (flexible) modes that can be controlled separately. The rigid dynamics is controlled by means of a robust sliding-mode approach with well-established stability properties while an LQR optimal design is adopted for the flexible dynamics. Experimental results show that this composite approach achieves good closed loop tracking properties both for the rigid and the flexible dynamics.

A practical time-delay control scheme for aerial manipulators

2020 ◽  
pp. 095965182094651
Author(s):  
Yadong Ding ◽  
Yaoyao Wang ◽  
Bai Chen
Keyword(s):  
Time Delay ◽  
Unmanned Aerial Vehicles ◽  
Closed Loop ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode ◽  
Control Scheme

In recent years, aerial manipulators consist of unmanned aerial vehicles and robotic manipulators have been widely utilized in aerial operations. The complex dynamic coupling effects between unmanned aerial vehicles and robotic manipulators will bring some issues to the motion control. Therefore, the article proposes a new control scheme for aerial manipulators. The proposed method includes three elements, that is, time-delay estimation, backstepping design, and nonsingular terminal sliding mode. The time-delay estimation technique is adopted to estimate the complex system dynamics and to bring a model-free feature of the system. With the backstepping design, the proposed control strategy can ensure the asymptotic stability of the closed-loop system by recursive procedure. To deal with the unmodelling dynamics and disturbances, and to assure finite-time convergence of the system states, the nonsingular terminal sliding mode is adopted. By combining three elements, the tracking performance of aerial manipulators is improved under unmodelling dynamics and disturbances. Global stability of closed-loop control system is analyzed using Lyapunov stability theory. Finally, comparative simulations are conducted, and the results show that the proposed controller has better performance than a conventional proportional–derivative controller or a nonsingular terminal sliding mode controller.

A computationally efficient adaptive robust control scheme for a quad-rotor transporting cable-suspended payloads

2021 ◽  
pp. 095441002110136
Author(s):  
Nasim Ullah ◽  
Irfan Sami ◽  
Wang Shaoping ◽  
Hamid Mukhtar ◽  
Xingjian Wang ◽  
...  
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Adaptive Robust Control ◽  
Computationally Efficient ◽  
Control Scheme ◽  
Control Schemes ◽  
Adaptive Laws ◽  
Unknown Disturbances ◽  
The Stability

This article proposes a computationally efficient adaptive robust control scheme for a quad-rotor with cable-suspended payloads. Motion of payload introduces unknown disturbances that affect the performance of the quad-rotor controlled with conventional schemes, thus novel adaptive robust controllers with both integer- and fractional-order dynamics are proposed for the trajectory tracking of quad-rotor with cable-suspended payload. The disturbances acting on quad-rotor due to the payload motion are estimated by utilizing adaptive laws derived from integer- and fractional-order Lyapunov functions. The stability of the proposed control systems is guaranteed using integer- and fractional-order Lyapunov theorems. Overall, three variants of the control schemes, namely adaptive fractional-order sliding mode (AFSMC), adaptive sliding mode (ASMC), and classical Sliding mode controllers (SMC)s) are tested using processor in the loop experiments, and based on the two performance indicators, namely robustness and computational resource utilization, the best control scheme is evaluated. From the results presented, it is verified that ASMC scheme exhibits comparable robustness as of SMC and AFSMC, while it utilizes less sources as compared to AFSMC.

scholarly journals Robust Control of Underactuated Systems: Higher Order Integral Sliding Mode Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Sami ud Din ◽  
Qudrat Khan ◽  
Fazal ur Rehman ◽  
Rini Akmeliawati
Keyword(s):  
Robust Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Integral Manifold ◽  
Control Design ◽  
Underactuated Systems ◽  
Control Laws ◽  
Beam System ◽  
Integral Manifolds ◽  
Robust Control Design

This paper presents a robust control design for the class of underactuated uncertain nonlinear systems. Either the nonlinear model of the underactuated systems is transformed into an input output form and then an integral manifold is devised for the control design purpose or an integral manifold is defined directly for the concerned class. Having defined the integral manifolds discontinuous control laws are designed which are capable of maintaining sliding mode from the very beginning. The closed loop stability of these systems is presented in an impressive way. The effectiveness and demand of the designed control laws are verified via the simulation and experimental results of ball and beam system.

Load relief control of launch vehicle using aerodynamic angle estimation

2017 ◽  
Vol 232 (8) ◽  
pp. 1598-1605
Author(s):  
Gyeongtaek Oh ◽  
Jongho Park ◽  
Jeongha Park ◽  
Hongju Lee ◽  
Youdan Kim ◽  
...  
Keyword(s):  
Closed Loop ◽  
Sliding Mode ◽  
Dynamic Pressure ◽  
Launch Vehicle ◽  
Aerodynamic Load ◽  
Load Relief ◽  
Control Scheme ◽  
Potential Benefits ◽  
Aerodynamic Angle ◽  
Ascent Phase

A nonlinear closed-loop load relief scheme is proposed to reduce the aerodynamic load during the ascent phase of a launch vehicle. The proposed controller is designed based on a back-stepping and sliding-mode control scheme with aerodynamic angle feedback. A hybrid load-relief strategy using the load relief scheme around the period of the maximum dynamic pressure and the traditional minimum-drift scheme during the other period is proposed. An aerodynamic angle estimator is also developed using a Kalman filter for the feedback of the load relief control. Numerical simulation is conducted to demonstrate the performance of the proposed strategy as well as the potential benefits.

scholarly journals Sliding Mode Robust Active Disturbance Rejection Control for Single-Link Flexible Arm with Large Payload Variations

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2995
Author(s):  
Fan Wang ◽  
Peng Liu ◽  
Feng Jing ◽  
Bo Liu ◽  
Wei Peng ◽  
...  
Keyword(s):  
Robust Control ◽  
Disturbance Rejection ◽  
Sliding Mode ◽  
Active Disturbance Rejection Control ◽  
Outer Loop ◽  
Active Disturbance Rejection ◽  
Flexible Arm ◽  
Disturbance Rejection Control ◽  
Control Scheme ◽  
Single Link

This paper proposes a novel robust control scheme for tip trajectory tracking of a lightweight flexible single-link arm. The developed control scheme deals with the influence of tip payload changes and disturbances during the working process of the flexible arm, thus realizing the accurate tracking for the tip reference trajectory. The robust control scheme is composed of an inner loop and an outer loop. The inner loop adopts the traditional PD control, and an active disturbance rejection control (ADRC) with a sliding mode (SM) compensation is designed in the outer loop. Moreover, the sliding mode compensation is mainly used to cope with the disturbance estimation error from the extended state observer (ESO), by which the insensitivity to tip payload variations and strong disturbance resistance is achieved. Finally, some numerical simulations are performed to support the theoretical analysis. The results show that the system is more robust to the tip mass variations of the arm and more resistant to the external torque after adding the sliding mode robustness term to the ADRC.

scholarly journals Efficient and Novel voltage control method using DC-DC Cuk Converter under Load Variation

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
Syed Mujtaba Mahdi Mudassir ◽  
Faheem Ahmed Khan ◽  
Shaziya Sultana
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Sliding Mode ◽  
Loop System ◽  
Control Mode ◽  
System Response ◽  
Switching Function ◽  
Sliding Modes ◽  
Closed Loop System ◽  
Cuk Converter

A control system is a set of mechanical or electronic devices that regulates other devices or systems by way of control loops. Typically, control systems are computerized. The mode of operation in a Control System where controlling variables is a function of the system and the structure is changed knowingly according to set of rules, which are already declared: for example a sensor based  system, is called as sliding control mode where the feedback control system response is limited and revolves around surface in the space to a point of equilibrium. In this mode of schemes, a switching variable dictates which form of control is to be used at a given instant, depending on the position of the state from the surface. First a set of points for which the switching function is null is used called as sliding surface. Sliding Mode Control (SMC) is a very robust technique which can handle sudden and large changes in dynamics of the system which can be applied to many areas like controlling of motor, aircraft and spacecraft, process control and power systems. SMC is one of the best tool in the industry to design controllers for the systems which has variable values, and provides robust properties against matched uncertainties, However,this use of SMC can only be achieved after the occurrence of the sliding mode. Before the occurrence of the switching function as null i.e. during the reaching phase, the system is affected by even matched ones. Several first order SMC applications for linear and nonlinear systems can be found in the literature [1]. Hence to eliminate the reaching phase and to make sure the ruggedness of the system throughout the entire closed-loop system response Integral Sliding Modes are used. In this paper a design procedure for sliding mode controllers for better control of voltage is applied, and then the ideas implemented are extended to all integral sliding modes in order to ensure optimum operation of entire system response[2]. Necessary conditions for the existence of sliding modes are also given. The closed-loop system is also proved to be exponentially stable. Simulation and experimental tests using the prototype of controlled DC-DC  CUK converter were performed to validate the proposed control approach.

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