Dynamic Modelling and Control Strategies of Space Manipulators

1993 ◽  
Vol 46 (11S) ◽  
pp. S165-S172
Author(s):  
A. Ercoli-Finzi ◽  
P. Mantegazza
Keyword(s):  
Numerical Simulations ◽  
Control Strategies ◽  
Equations Of Motion ◽  
Dynamic Modelling ◽  
Mixed Control ◽  
Space Manipulators ◽  
Pick And Place ◽  
Manipulator Arm ◽  
And Control

In this work the dynamics of a manipulator arm is analyzed by Maggi’s formulation and by automatic development of the equations of motion. Two control strategies, that is an adaptive and a standard one, are taken into account in order to satisfactory perform pick and place maneuvers. Numerical simulations emphasize performance qualities and limits of the two choices and suggest a possible implementation of mixed control strategies.

ESTIMATION OF CONTROL ENERGY AND CONTROL STRATEGIES FOR COMPLEX NETWORKS

2015 ◽  
Vol 18 (07n08) ◽  
pp. 1550018 ◽  
Author(s):  
DINGJIE WANG ◽  
SUOQIN JIN ◽  
FANG-XIANG WU ◽  
XIUFEN ZOU
Keyword(s):  
Complex Networks ◽  
Numerical Simulations ◽  
Energy Cost ◽  
Control Strategies ◽  
Energy Costs ◽  
Theoretical Derivation ◽  
Complete Control ◽  
Undirected Network ◽  
Normal Networks ◽  
And Control

The controlling of complex networks is one of the most challenging problems in modern network science. Accordingly, the required energy cost of control is a fundamental and significant problem. In this paper, we present the theoretical analysis and numerical simulations to study the controllability of complex networks from the energy perspective. First, by combining theoretical derivation and numerical simulations, we obtain lower bounds of the maximal and minimal energy costs for an arbitrary normal network, which are related to the eigenvalues of the state transition matrix. Second, we deduce that controlling unstable normal networks is easier than controlling stable normal networks with the same size. Third, we demonstrate a tradeoff between the control energy and the average degree (or the maximum degree) of an arbitrary undirected network. Fourth, numerical simulations show that the energy cost is negatively correlated with the degree of nodes. Moreover, the combinations of control nodes with the greater sum of degree need less energy to implement complete control. Finally, we propose a multi-objective optimization model to obtain the control strategy, which not only ensures the fewer control nodes but also guarantees the less energy cost of control.

Dynamic Modelling of Wind Farm Grid Interaction

2002 ◽  
Vol 26 (4) ◽  
pp. 191-210 ◽  
Author(s):  
Anca D. Hansen ◽  
Poul Sørensen ◽  
Frede Blaabjerg ◽  
John Becho
Keyword(s):  
Power System ◽  
Wind Farm ◽  
Control Strategies ◽  
Dynamic Modelling ◽  
Normal Operation ◽  
Simulation Tool ◽  
Power System Simulation ◽  
Collection System ◽  
Wind Model ◽  
And Control

This paper describes a dynamic model of a wind farm and its nearest utility grid. It is intended to use this model in studies addressing the dynamic interaction between a wind farm and a power system, both during normal operation of the wind farm and during transient grid fault events. The model comprises the substation where the wind farm is connected, the internal power collection system of the wind farm, the electrical, mechanical and aerodynamic models for the wind turbines, and a wind model. The integrated model is built to enable the assessment of power quality and control strategies. It is implemented in the commercial dedicated power system simulation tool DIgSILENT.

scholarly journals Modelling, Simulations and Analysis of the First and Second COVID-19 Epidemics in Beijing

2021 ◽  
Author(s):  
Lequan Min
Keyword(s):  
Numerical Simulations ◽  
Prevention And Control ◽  
Control Strategies ◽  
Equation Model ◽  
Control Measures ◽  
Disease Spreading ◽  
Prevention And Control Measures ◽  
Asymptomatic Individuals ◽  
Reported Data ◽  
And Control

AbstractTo date, over 130 million people on infected with COVID-19. It causes more 2.8 millions deaths. This paper introduces a symptomatic-asymptomatic-recoverer-dead differential equation model (SARDDE). It gives the conditions of the asymptotical stability on the disease-free equilibrium of SARDDE. It proposes the necessary conditions of disease spreading for the SARDDE. Based on the reported data of the first and the second COVID-19 epidemics in Beijing and simulations, it determines the parameters of SARDDE, respectively. Numerical simulations of SARDDE describe well the outcomes of current symptomatic and asymptomatic individuals, recovered symptomatic and asymptomatic individuals, and died individuals, respectively. The numerical simulations suggest that both symptomatic and asymptomatic individuals cause lesser asymptomatic spread than symptomatic spread; blocking rate of about 90% cannot prevent the spread of the COVID19 epidemic in Beijing; the strict prevention and control strategies implemented by Beijing government is not only very effective but also completely necessary. The numerical simulations suggest also that using the data from the beginning to the day after about two weeks at the turning point can estimate well or approximately the following outcomes of the two COVID-19 academics, respectively. It is expected that the research can provide better understanding, explaining, and dominating for epidemic spreads, prevention and control measures.

scholarly journals Modelling, Simulations and Analysis of the First COVID-19 Epidemic in Shanghai

2021 ◽  
Author(s):  
Lequan Min
Keyword(s):  
Numerical Simulations ◽  
Prevention And Control ◽  
Control Strategies ◽  
Equation Model ◽  
Control Measures ◽  
Differential Equation Model ◽  
Blocking Rate ◽  
Prevention And Control Measures ◽  
Asymptomatic Individuals ◽  
And Control

To date, over 178 million people on infected with COVID-19. It causes more 3.8 millions deaths. Based on a previous symptomatic-asymptomatic-recoverer-dead differential equation model (SARDDE) and the clinic data of the first COVID-19 epidemic in Shanghai, this paper determines the parameters of SARDDE. Numerical simulations of SARDDE describe well the outcomes of current symptomatic individuals, recovered symptomatic individuals, and died individuals, respectively. The numerical simulations suggest that both symptomatic and asymptomatic individuals cause lesser asymptomatic spread than symptomatic spread; blocking rate of about 95.5\% cannot prevent the spread of the COVID19 epidemic in Shanghai. The strict prevention and control strategies implemented by Shanghai government is not only very effective but also completely necessary. The numerical simulations suggest also that using the data from the beginning to the day after about 19 days at the turning point can estimate well the following outcomes of the COVID-19 academic. It is expected that the research can provide better understanding, explaining, and dominating for epidemic spreads, prevention and control measures.

Trajectory control of a mobile manipulator in the presence of base disturbance

SIMULATION ◽  
2018 ◽  
Vol 95 (6) ◽  
pp. 529-543 ◽  
Author(s):  
RV Ram ◽  
PM Pathak ◽  
SJ Junco
Keyword(s):  
Mobile Robot ◽  
Dynamic Models ◽  
Control Strategies ◽  
Effective Control ◽  
Mobile Manipulator ◽  
Dynamic Interactions ◽  
Additional Task ◽  
Manipulator Arm ◽  
And Control ◽  
Base Disturbance

A mobile manipulator is typically an assembly of a mobile robot base and an on-board manipulator arm. As the manipulator arm is mounted over the mobile robot base, the controller has the additional task of taking care of the disturbances of the mobile robot due to the dynamic interactions between the mobile robot base and manipulator arm. In the present work, dynamic models for the manipulator arm and an omni-wheeled mobile robot base were developed separately and then both were combined. Two control strategies, namely only manipulator arm control (OMAC) and simultaneous manipulator and base control (SMBC) were developed for the effective control of tip trajectory. In both strategies, an amnesia recovery coupled with classical proportional integral and derivative (PID) control was used. The bond graph methodology was used for the development of the dynamic model and control for the mobile manipulator. Simulation results are presented to illustrate the efficacy of the two control strategies.

Flight mechanics of a free-wing tilt-body aircraft

2008 ◽  
Vol 112 (1137) ◽  
pp. 625-640
Author(s):  
K. Ro ◽  
J. W. Kamman ◽  
J. B. Barlow
Keyword(s):  
Mathematical Model ◽  
Incidence Angle ◽  
Equations Of Motion ◽  
Dynamic Modelling ◽  
Flight Simulation ◽  
The Body ◽  
Flight Mechanics ◽  
Short Takeoff And Landing ◽  
And Control ◽  
The Mathematical Model

Abstract The free-wing tilt-body aircraft refers to a vehicle configuration in which the wing, fuselage, and empennage are in a longitudinally articulated connection. This allows the main wing to freely rotate relative to the body, while the empennage, which is in the form of a long twin boom connected to the rear of the body, changes its incidence angle relative to the body in response to external commands. The principal advantages claimed for the configuration are short takeoff and landing capability, and reduced gust sensitivity. The aerodynamics of the free-wing tilt-body configuration has been previously studied, but analysis of its flight mechanics is limited. In this paper we present derivations of the flight dynamic equations of motion using multi-body dynamic modelling techniques, and combine the resulting equations of motion with experimental aerodynamic data to achieve a nonlinear mathematical model for flight simulation of a generic free-wing tilt-body vehicle. The mathematical model is suitable for the study of detailed dynamic characteristics as well as for model based control law synthesis. Key flight performance, and stability and control characteristics of a generic configuration are obtained from the mathematical model.

Free-flying robots in space: an overview of dynamics modeling, planning and control

Robotica ◽  
2007 ◽  
Vol 25 (5) ◽  
pp. 537-547 ◽  
Author(s):  
S. Ali A. Moosavian ◽  
Evangelos Papadopoulos
Keyword(s):  
Control Strategies ◽  
Equations Of Motion ◽  
Experimental Studies ◽  
Robotic Manipulators ◽  
Microgravity Environment ◽  
Dynamics Modeling ◽  
Planning And Control ◽  
Fixed Base ◽  
And Control ◽  
Flying Robots

SUMMARYFree-flying space manipulator systems, in which robotic manipulators are mounted on a free-flying spacecraft, are envisioned for assembling, maintenance, repair, and contingency operations in space. Nevertheless, even for fixed-base systems, control of mechanical manipulators is a challenging task. This is due to strong nonlinearities in the equations of motion, and consequently different algorithms have been suggested to control end-effector motion or force, since the early research in robotic systems. In this paper, first a brief review of basic concepts of various algorithms in controlling robotic manipulators is introduced. Then, specific problems related to application of such systems in space and a microgravity environment is highlighted. Basic issues of kinematics and dynamics modeling of such systems, trajectory planning and control strategies, cooperation of multiple arm space free-flying robots, and finally, experimental studies and technological aspects of such systems with their specific limitations are discussed.

Dynamic Modelling and Control of an Underactuated Quasi-Omnidireccional Hexapod

2020 ◽  
pp. 377-400
Author(s):  
Edgar Alonso Martinez-Garcia ◽  
José A. Aguilera
Keyword(s):  
Numerical Simulations ◽  
Mechanical Design ◽  
Dynamic Control ◽  
Dynamic Modelling ◽  
Control Law ◽  
Proposed Model ◽  
Tripod Gait ◽  
Walking Mechanism ◽  
The Right ◽  
And Control

This chapter presents the mechanical design, dynamic model, and walking control law of an insect-like, asymmetric hexapod robot. The proposed model is an original walking mechanism designed with three actuators to provide quasi-omnidirectionality. One of the motivational aims is to reduce the number of actuators preserving similar holonomy as compared to popular 18-servo redundant hexapods with three servos per leg. This work includes the Klann mechanism as limb, two-drive differential robot's control, one per lateral triplet of legs. The legs of a triplet are synchronized in speed with different rotary angles phase. In addition, the six limbs are synchronized with bidirectional yaw motion. The proposed mechanical design has one servo for limbs yawing, one for the right limbs triplet and one motor for the left triplet. Thus, quasi-omnidirectional mobility is achieved. Furthermore, a dynamic control law that governs the robot's mechanisms motion is deduced, with an Euler-Lagrange approach. Kinematic and dynamic results are validated through numerical simulations using a tripod gait.

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