A manoeuvre control strategy for flexible-joint manipulators with joint dry friction

Robotica ◽  
2009 ◽  
Vol 28 (4) ◽  
pp. 621-635 ◽  
Author(s):  
H. Salmasi ◽  
R. Fotouhi ◽  
P. N. Nikiforuk
Keyword(s):  
Singular Perturbation ◽  
Trajectory Tracking ◽  
Control Strategy ◽  
Integral Manifold ◽  
Tracking Error ◽  
Singular Perturbation Theory ◽  
Singular Perturbation Method ◽  
Flexible Joint ◽  
Perturbation Theorem ◽  
Joint Friction

SUMMARYA new control strategy based on the singular perturbation method and integral manifold concept is introduced for flexible-joint manipulators with joint friction. In controllers so far developed based on the singular perturbation theory, the dynamics of actuators of flexible-joint manipulators are partially modelled, and the coupling between actuators and links is ignored. This assumption leads to inaccuracy in control performance and error in trajectory tracking which is crucial in high-precision manipulation tasks. In this paper, a comprehensive dynamic model which takes into account the coupling between actuators and links is developed and a composite controller is then designed based on the singular perturbation theorem and integral manifold concept. To overcome the joint friction, a novel method is introduced in which a linear feed-forward torque is designed using the principle of work and energy. Finally, the experimental set-up of a single rigid-link flexible-joint manipulator in the Robotics Laboratory at the University of Saskatchewan is used to verify the proposed controller. Experimental results employing the new controller show that the trajectory tracking error during and at the end of the motion of the robot manipulator is significantly reduced.

scholarly journals A Novel Trajectory Tracking Control Strategy for Underactuated Quadrotor UAV with Uncertainties and Disturbances

2020 ◽  
Author(s):  
Jiang Han ◽  
Siyang Yang ◽  
Lian Xia ◽  
Ye-Hwa Chen
Keyword(s):  
Trajectory Tracking ◽  
Control Strategy ◽  
Tracking Control ◽  
Tracking Error ◽  
Uniform Boundedness ◽  
Trajectory Tracking Control ◽  
Quadrotor Uav ◽  
Uniform Ultimate Boundedness ◽  
Position Controller ◽  
Aerial Vehicle

Abstract In this research, a novel position trajectory tracking control architecture has been constructed for an underactuated quadrotor unmanned aerial vehicle (UAV) with uncertainties and disturbances. Primarily, we divide the whole dynamic system into an underactuated position subsystem and a fully-actuated attitude subsystem. For the position subsystem, we have transformed it into a fully-actuated system by constructing a virtual PD controller, and this controller can render the position tracking error asymptotically stable. Besides, based on the position controller designed for quadrotor UAV, the desired attitudes, i.e. roll, pitch and yaw angles, will be derived. Next, as for the attitude subsystem which is sensitive to uncertainties and external disturbances, a novel robust attitude constraint-following controller is proposed for this aircraft, this attitude controller can not only guarantee the uniform boundedness and uniform ultimate boundedness of constraint deviation, but also does not requiring more information of uncertainties and disturbances except their bounds. Eventually, the simulations have demonstrated a sound tracking performance of our proposed control strategy for quadrotor UAV even in the presence of uncertainties and disturbances.

Robust Trajectory Tracking Control of Elastic Robot Manipulators

1997 ◽  
Vol 119 (4) ◽  
pp. 727-735 ◽  
Author(s):  
Yoshifumi Morita ◽  
Hiroyuki Ukai ◽  
Hisashi Kando
Keyword(s):  
Trajectory Tracking ◽  
Control Strategy ◽  
Tracking Control ◽  
Robot Manipulators ◽  
Integral Manifold ◽  
Design Procedure ◽  
Trajectory Tracking Control ◽  
Composite Control ◽  
Structured Uncertainty ◽  
Nonlinear Mechanical

In this paper, a robust control strategy is proposed for the trajectory tracking control of multi-link elastic robot manipulators. The robustness against both of the structured uncertainty caused by the nonlinear mechanical structure and the unstructured one caused by elasticity of links is taken into account in designing controllers. For this purpose the model of elastic robot manipulators is decomposed into the slow model and the fast model by using an integral manifold approach. The slow controller, which is robust against the structured uncertainty, is designed for the slow model on the basis of VSS theory. On the other hand, the fast controller, which is robust against the unstructured uncertainty, is designed for the fast model on the basis of H∞ control theory. Then the composite control is constructed with the slow controller and the fast controller. Some results of numerical simulations are presented to show the effectiveness of this design procedure.

scholarly journals Path Planning and Trajectory Tracking Strategy of Autonomous Vehicles

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Peng Han ◽  
Bingyu Zhang
Keyword(s):  
Control System ◽  
Trajectory Tracking ◽  
Control Strategy ◽  
Public Transportation ◽  
Tracking Error ◽  
Transportation System ◽  
Path Generation ◽  
Articulated Vehicle ◽  
Public Transportation System ◽  
Feasible Path

With the development of global urbanization and the construction of regional urbanization, residents around urban cities are increasingly making demands on urban public transportation system. A new kind of modern public transportation vehicle named Multi-Articulated Guided Vehicle based on Virtual Track (MAAV-VT) with the advantages of beautiful, smart energy conservation and environmental protection is proposed in this paper, which aims at optimizing the public transportation system between and within urban areas. Therefore, concentrating on the general design and control strategy, the main contents of this paper are as follows. At first, the design concepts and key technologies of MAAV-VT are introduced. It is the fusion of urban rail transit operation mode and advanced automotive technologies, which have the characteristics of 100% low-floor, medium to high velocity, medium to big capacity, and low construction cost. Then, as the core subsystem, to guarantee the properties of self-guiding and trajectory tracking of the new vehicle, this paper is focused on the control system based on the dynamics and kinematics model of the whole multi-articulated vehicle. The multi-trace-points cooperative trajectory tracking control strategy on the basis of the circulation of feasible path generation method is proposed and the lateral controller is designed for trajectory tracking. The process of feasible path generation is conducted once the tracking error exceeded. A simulation platform is built considering the mechanical properties of each vehicle element and the characteristic of articulated mechanism. Finally, the function of control system is validated. The tracking error of each vehicle elements would be reduced to make sure the whole multi-articulated vehicle moves along the preset virtual track.

scholarly journals Trajectory Tracking of Flexible-Joint Robots Actuated by PMSM via a Novel Smooth Switching Control Strategy

2019 ◽  
Vol 9 (20) ◽  
pp. 4382 ◽  
Author(s):  
Yue Wang ◽  
Haisheng Yu ◽  
Jinpeng Yu ◽  
Herong Wu ◽  
Xudong Liu
Keyword(s):  
Trajectory Tracking ◽  
Control Strategy ◽  
Sliding Mode ◽  
Gaussian Function ◽  
Switching Control ◽  
Switching Function ◽  
Flexible Joint ◽  
Hybrid Controller ◽  
Hierarchical Sliding Mode ◽  
Smooth Switching

This paper presents the trajectory tracking control of a flexible-joint manipulator driven by permanent magnet synchronous motor (PMSM). Combining the PMSM electrical equation and mechanical equation of robotic manipulators, a novel smooth switching control scheme is proposed. Firstly, the position loop controller of the system is designed, with an improved hierarchical sliding mode control (IHSMC) algorithm proposed to further the response speed of the system, additionally, a robust interconnection and damping assignment passivity-based controller (IDA-PBC) is designed to improve the steady state performance of the system. Then, the IDA-PBC control strategy is leveraged to design the current loop controller of the system, on which basis a hybrid controller with smooth switching is designed. Furthermore, Gaussian function is applied as the smooth switching function of the hybrid controller to promote the switching performance. As a result, the hybrid controller has both good dynamic and steady performance. The simulation results verify the effectiveness of the algorithms.

Development of Analytical Solution for a Two-Phase Stefan Problem in Artificial Ground Freezing Using Singular Perturbation Theory

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Minghan Xu ◽  
Saad Akhtar ◽  
Ahmad F. Zueter ◽  
Victor Auger ◽  
Mahmoud A. Alzoubi ◽  
...  
Keyword(s):  
Analytical Solution ◽  
Singular Perturbation ◽  
Stefan Problem ◽  
Underground Structure ◽  
Computational Cost ◽  
Singular Perturbation Theory ◽  
Singular Perturbation Method ◽  
Two Phase ◽  
Ground Freezing ◽  
Artificial Ground Freezing

Abstract Artificial ground freezing (AGF) has historically been used to stabilize underground structure. Numerical methods generally require high computational power to be applicable in practice. Therefore, it is of interest to develop accurate and reliable analytical frameworks for minimizing computational cost. This paper proposes a singular perturbation solution for a two-phase Stefan problem that describes outward solidification in AGF. Specifically, the singular perturbation method separates two distinct temporal scales to capture the subcooling and freezing stages in the ground. The ground was considered as a porous medium with volume-averaged thermophysical properties. Further, Stefan number was assumed to be small, and effects of a few site-dependent parameters were investigated. The analytical solution was verified by numerical results and found to have similar conclusions yet with much lesser computational cost. Keywords: artificial ground freezing, Stefan-like problems, singular perturbation, porous media, outward solidification.

Impedance control of a two degree-of-freedom planar flexible link manipulator using singular perturbation theory

Robotica ◽  
2005 ◽  
Vol 24 (2) ◽  
pp. 221-228 ◽  
Author(s):  
G. R. Vossoughi ◽  
A. Karimzadeh
Keyword(s):  
Singular Perturbation ◽  
Sliding Mode ◽  
Impedance Control ◽  
Singular Perturbation Theory ◽  
Flexible Link ◽  
Singular Perturbation Method ◽  
Flexible Links ◽  
Assumed Mode Method ◽  
Mode Method ◽  
Flexible Link Robots

In this article, impedance control of a two link flexible link manipulators is addressed. The concept of impedance control of flexible link robots is rather new and is being addressed for the first time by the authors. Impedance Control provides a universal approach to the control of flexible robots, in both constrained and unconstrained maneuvers. The initial part of the paper concerns the use of Hamilton's principle to derive the mathematical equations governing the dynamics of joint angles, vibration of the flexible links and the constraining forces. The approximate elastic deformations are then derived by means of the Assumed-Mode-Method (AMM). Using the singular perturbation method, the dynamic of the manipulator is decomposed into fast and slow subsystems. The slow dynamic corresponds to the rigid manipulator and the fast dynamic is due to vibrations of flexible links. The sliding mode control (SMC) theory has been used as the means to achieve the 2nd order target impedance for the slow dynamics. A controller based on state feedback is also designed to stabilize the fast dynamics. The composite controller is constructed by using the slow and fast controllers. Simulation results for a 2-DOF robot in which only the 2nd link is flexible confirm that the controller performs remarkably well under various simulation conditions.

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