Decentralized and Hierarchical Control of a Class of Robot Manipulators

1994 ◽  
Vol 208 (3) ◽  
pp. 139-148 ◽  
Author(s):  
J H S Osman ◽  
P D Roberts
Keyword(s):  
Control Strategy ◽  
Robot Manipulators ◽  
Hierarchical Control ◽  
Reference Trajectory ◽  
Deterministic Approach ◽  
Ultimate Boundedness ◽  
Uniform Ultimate Boundedness ◽  
Tracking Controller ◽  
System Output ◽  
System Uncertainties

This paper is concerned with the design of robust controllers for uncertain non-linear robot manipulators based on a deterministic approach. A decentralized tracking controller is presented in which the controller is designed for each subsystem based only on its local states. For the cases in which the interconnection functions between the subsystems are large, a two-level hierarchical control strategy is proposed. In designing the controllers, only the bounds on the system uncertainties are assumed to be known. It is shown theoretically and through computer simulations that the proposed controllers guarantee uniform ultimate boundedness of the error between the reference trajectory and the system output.

scholarly journals An adaptive output feedback motion tracking controller for robot manipulators: Uniform global asymptotic stability and experimentation

2013 ◽  
Vol 23 (3) ◽  
pp. 599-611 ◽  
Author(s):  
Antonio Yarza ◽  
Victor Santibanez ◽  
Javier Moreno-Valenzuela
Keyword(s):  
Asymptotic Stability ◽  
Output Feedback ◽  
Global Asymptotic Stability ◽  
Motion Tracking ◽  
Robot Manipulators ◽  
Reference Trajectory ◽  
Feedback Controllers ◽  
Tracking Controller ◽  
Noisy Signals ◽  
First Time

Abstract This paper deals with two important practical problems in motion control of robot manipulators: the measurement of joint velocities, which often results in noisy signals, and the uncertainty of parameters of the dynamic model. Adaptive output feedback controllers have been proposed in the literature in order to deal with these problems. In this paper, we prove for the first time that Uniform Global Asymptotic Stability (UGAS) can be obtained from an adaptive output feedback tracking controller, if the reference trajectory is selected in such a way that the regression matrix is persistently exciting. The new scheme has been experimentally implemented with the aim of confirming the theoretical results.

Hierarchical energy management strategy considering switching schedule for a dual-mode hybrid electric vehicle

2021 ◽  
pp. 095440702110297
Author(s):  
Hui Liu ◽  
Rui Liu ◽  
Riming Xu ◽  
Lijin Han ◽  
Shumin Ruan
Keyword(s):  
Fuel Consumption ◽  
Energy Management ◽  
Control Strategy ◽  
Power Distribution ◽  
Hybrid Electric Vehicle ◽  
Hierarchical Control ◽  
Management Problem ◽  
Energy Management Strategy ◽  
Dual Mode ◽  
Hybrid Electric

Energy management strategies are critical for hybrid electric vehicles (HEVs) to improve fuel economy. To solve the dual-mode HEV energy management problem combined with switching schedule and power distribution, a hierarchical control strategy is proposed in this paper. The mode planning controller is twofold. First, the mode schedule is obtained according to the mode switch map and driving condition, then a switch hunting suppression algorithm is proposed to flatten the mode schedule through eliminating unnecessary switch. The proposed algorithm can reduce switch frequency while fuel consumption remains nearly unchanged. The power distribution controller receives the mode schedule and optimizes power distribution between the engine and battery based on the Radau pseudospectral knotting method (RPKM). Simulations are implemented to verify the effectiveness of the proposed hierarchical control strategy. For the mode planning controller, as the flattening threshold value increases, the fuel consumption remains nearly unchanged, however, the switch frequency decreases significantly. For the power distribution controller, the fuel consumption obtained by RPKM is 4.29% higher than that of DP, while the elapsed time is reduced by 92.53%.

Identification-Free Adaptive Separate Layer Water Injection Control Based on Expert Amendment

2010 ◽  
Vol 44-47 ◽  
pp. 1470-1475
Author(s):  
Feng Shan Wang ◽  
De Li Jia ◽  
Shu Jin Zhang ◽  
Chong Jiang Liu ◽  
De Kui Xu
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Water Injection ◽  
Strong Nonlinearity ◽  
Separate Layer ◽  
Injection Control ◽  
System Output ◽  
Adaptive Control Strategy ◽  
Injection Effect ◽  
Injection Technology

An identification-free adaptive control strategy based on expert amendment is proposed in this paper to solve the problem that it is difficult to establish mathematical model of water injection regulating process due to large time delay, strong nonlinearity and time variation in the flow control of separate layer water injection technology. In this control strategy, according to the past and current process information of water injection, the system output and trend can be estimated based on expert rules to amend the output of the identification-free adaptive control. The simulation result shows that this control strategy has perfect control performance and strong adaptability and it provides a feasible means for improving water injection effect.

Predictive Control of a Cable-Stayed Bridge under Multiple-Support Excitations

2011 ◽  
Vol 66-68 ◽  
pp. 268-272
Author(s):  
Gui Yun Yan ◽  
Zheng Zhang
Keyword(s):  
Predictive Model ◽  
Predictive Control ◽  
Control Strategy ◽  
Prediction Error ◽  
Actual System ◽  
Time Step ◽  
Cable Stayed Bridge ◽  
System Output ◽  
Multiple Support ◽  
Active Control Strategy

This paper presents a predictive control strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this active control strategy, a multi-step predictive model is built to estimate the seismic dynamics of cable-stayed bridge and the effects of some complicated factors such as time-varying, model mismatching, disturbances and uncertainty of controlled system, are taken into account by the prediction error feedback in the multi-step predictive model. The prediction error is that the actual system output is compared to the model prediction at each time step. Numerical simulation is carried out for analyzing the seismic responses of the controlled cable-stayed bridge and the results show that the developed predictive control strategy can reduce the seismic response of benchmark cable-stayed bridge efficiently.

scholarly journals A Novel Hierarchical Control Strategy for Low-Voltage Islanded Microgrids Based on the Concept of Cyber Physical System

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1835 ◽  
Author(s):  
Qiuxia Yang ◽  
Dongmei Yuan ◽  
Xiaoqiang Guo ◽  
Bo Zhang ◽  
Cheng Zhi
Keyword(s):  
Control Strategy ◽  
Physical System ◽  
Reactive Power ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Physical Layer ◽  
Cyber Physical System ◽  
Droop Control ◽  
Control Effect ◽  
Consensus Control

Based on the concept of cyber physical system (CPS), a novel hierarchical control strategy for islanded microgrids is proposed in this paper. The control structure consists of physical and cyber layers. It’s used to improve the control effect on the output voltages and frequency by droop control of distributed energy resources (DERs), share the reactive power among DERs more reasonably and solve the problem of circumfluence in microgrids. The specific designs are as follows: to improve the control effect on voltages and frequency of DERs, an event-trigger mechanism is designed in the physical layer. When the trigger conditions in the mechanism aren’t met, only the droop control (i.e., primary control) is used in the controlled system. Otherwise, a virtual leader-following consensus control method is used in the cyber layer to accomplish the secondary control on DERs; to share the reactive power reasonably, a method of double virtual impedance is designed in the physical layer to adjust the output reactive power of DERs; to suppress circumfluence, a method combined with consensus control without leader and sliding mode control (SMC) is used in the cyber layer. Finally, the effectiveness of the proposed hierarchical control strategy is confirmed by simulation results.

Predictive Control and Simulation for Variable-Pitch Wind Turbines

2012 ◽  
Vol 562-564 ◽  
pp. 1012-1015
Author(s):  
S.X. Wang ◽  
Z.X. Li ◽  
D.X. Sun ◽  
X.X. Xie
Keyword(s):  
Neural Network ◽  
Predictive Control ◽  
Small World ◽  
Modeling Method ◽  
Reference Trajectory ◽  
System Delay ◽  
Variable Pitch ◽  
Electricity Grid ◽  
System Output ◽  
The Impact

In order to avoid the limitations of traditional mechanism modeling method, a neural network (NN) model of variable - pitch wind turbine is built by the NN modeling method based on field data. Then considering that from wind turbine’s startup to grid integration, the generator speed must be controlled to rise to the synchronous speed smoothly and precisely, a neural network model predictive control (NNMPC) strategy based on the small-world optimization algorithm (SWOA) is proposed. Simulation results show that the strategy can forecast the change of generator rotational speed based on the wind speed disturbance, making the controller act ahead to eliminate the impact of system delay. Furthermore, the system output can track the reference trajectory well, making sure that the system can connect the electricity grid steadily.

Saturated output feedback control of uncertain nonholonomic wheeled mobile robots

Robotica ◽  
2014 ◽  
Vol 33 (1) ◽  
pp. 87-105 ◽  
Author(s):  
Khoshnam Shojaei
Keyword(s):  
Mobile Robots ◽  
Output Feedback ◽  
Actuator Saturation ◽  
Output Feedback Control ◽  
Robust Tracking ◽  
Velocity Measurements ◽  
Ultimate Boundedness ◽  
Wheeled Mobile Robots ◽  
Uniform Ultimate Boundedness ◽  
The Cost

SUMMARYMany research works on the control of nonholonomic wheeled mobile robots (WMRs) do not consider the actuator saturation problem and the absence of velocity sensors in practice. The actuator saturation deteriorates the tracking performance of the controller, and the use of velocity sensors increases the cost and weight of WMR systems. This paper simultaneously addresses these problems by designing a saturated output feedback controller for uncertain nonholonomic WMRs. First, a second-order input–output model of nonholonomic WMRs is developed by defining a suitable set of output equations. Then a saturated adaptive robust tracking controller is proposed without velocity measurements. For this purpose, a nonlinear saturated observer is used to estimate robot velocities. The risk of actuator saturation is effectively reduced by utilizing saturation functions in the design of the observer–controller scheme. Semi-global uniform ultimate boundedness of error signals is guarantied by the Lyapunov stability analyses. Finally, simulation results are provided to show the effectiveness of the proposed controller. Compared with one recent work of the author, a comparative study is also presented to illustrate that the proposed saturated controller is more effective when WMR actuators are subjected to saturation.

Periodic solutions to functional differential equations

1985 ◽  
Vol 101 (3-4) ◽  
pp. 253-271 ◽  
Author(s):  
O. A. Arino ◽  
T. A. Burton ◽  
J. R. Haddock
Keyword(s):  
Differential Equations ◽  
Functional Differential Equations ◽  
Sufficient Conditions ◽  
Uniform Boundedness ◽  
Continuous Functions ◽  
Ultimate Boundedness ◽  
Space Of Continuous Functions ◽  
Uniform Ultimate Boundedness ◽  
Functional Differential ◽  
Image Position

SynopsisWe consider a system of functional differential equationswhere G: R × B → Rn is T periodic in t and B is a certain phase space of continuous functions that map (−∞, 0[ into Rn. The concepts of B-uniform boundedness and B-uniform ultimate boundedness are introduced, and sufficient conditions are given for the existence of a T-periodic solution to (1.1). Several examples are given to illustrate the main theorem.

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