Tracking and vibration control of a free-floating space manipulator system with flexible links and joints

2021 ◽  
pp. 095441002110311
Author(s):  
Yuming Huang ◽  
Weidong Chen ◽  
Minqiang Shao
Keyword(s):  
Cross Sections ◽  
Coupled System ◽  
Joint Space ◽  
Momentum Conservation ◽  
Singular Perturbation Theory ◽  
Linear Quadratic ◽  
Space Manipulator ◽  
Hybrid Controller ◽  
System Method ◽  
Integral Manifolds

The problem of modeling and controlling of a free-floating space manipulator with flexures in both links and joints is addressed in this study. A mathematical model of the system is developed by combining Lagrange’s equations and momentum conservation. The finite element method is introduced to discretize multi-links with complex cross-sections. In order to reduce the dimensions and maintain the precision of a rigid-flexible coupled system, an iterated improved reduction system method is adopted. Then, a novel composite control scheme for the reduced system is presented that uses the concept of integral manifolds and singular perturbation theory. Finally, an augmented computed torque controller is applied to the under-actuated slow subsystem to realize trajectory tracking in joint space, while a linear-quadratic controller is designed to damp out the vibration of joints and links. Numerical simulation results verified that the proposed hybrid controller can successfully suppress vibration and track trajectory at the same time.

Robust Control for Coordinated Motion of Flexible Space Manipulator Based on the Augmentation Approach

2010 ◽  
Author(s):  
Zhiyong Chen ◽  
Li Chen
Keyword(s):  
Robust Control ◽  
A Priori ◽  
Joint Space ◽  
Momentum Conservation ◽  
Network Control ◽  
Coordinated Motion ◽  
Space Manipulator ◽  
Assumed Mode Method ◽  
Uncertainty Bound ◽  
Mode Method

In this paper, the coordinated control of a flexible space manipulator system with a front flexible link is discussed. With the assumed mode method and linear momentum conservation of the system, the dynamics of the manpulator is derived in Lagrangian formulation. By using the augmentation approach, a robust control scheme for the coordinated motion between the spacecraft’s attitude and arm’s joints of the flexible space manipulator with bounded external disturbances and uncertain parameters to track the desired trajectories in joint space is proposed. It is designed based on a priori knowledge about the uncertainty-bound and possesses the advantage that it can greatly reduce the calculation time needed by the adaptive or neural network control schemes. Simulation results show that the presented controller can stabilize the system to track the desired trajectories and keep the vibration amplitude of the flexible arm to be relatively low-level.

Multi-Objective Trajectory Optimization of Free-Floating Space Manipulator Using NSGA-II

2015 ◽  
Vol 713-715 ◽  
pp. 800-804 ◽  
Author(s):  
Gang Chen ◽  
Cong Wei ◽  
Qing Xuan Jia ◽  
Han Xu Sun ◽  
Bo Yang Yu
Keyword(s):  
Trajectory Optimization ◽  
Interpolation Method ◽  
Optimal Solution ◽  
Optimization Method ◽  
Joint Space ◽  
Motion Path ◽  
Objective Functions ◽  
Nsga Ii ◽  
Space Manipulator ◽  
Multi Objective

In this paper, a kind of multi-objective trajectory optimization method based on non-dominated sorting genetic algorithm II (NSGA-II) is proposed for free-floating space manipulator. The aim is to optimize the motion path of the space manipulator with joint angle constraints and joint velocity constraints. Firstly, the kinematics and dynamics model are built. Secondly, the 3-5-3 piecewise polynomial is selected as interpolation method for trajectory planning of joint space. Thirdly, three objective functions are established to simultaneously minimize execution time, energy consumption and jerk of the joints. At last, the objective functions are combined with the NSGA-II algorithm to get the Pareto optimal solution set. The effectiveness of the mentioned method is verified by simulations.

scholarly journals The Coupled Orbit-Attitude Dynamics and Control of Electric Sail in Displaced Solar Orbits

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Mingying Huo ◽  
He Liao ◽  
Yanfang Liu ◽  
Naiming Qi
Keyword(s):  
Linear Quadratic Regulator ◽  
Coupled System ◽  
Control Force ◽  
Attitude Dynamics ◽  
Voltage Distribution ◽  
Linear Quadratic ◽  
Displaced Orbit ◽  
Dynamics And Control ◽  
And Control ◽  
Small Torque

Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

scholarly journals A PROBLEM IN VIRTUAL GRAVITON EXCHANGES IN FLAT LARGE EXTRA DIMENSIONS

2010 ◽  
Vol 25 (23) ◽  
pp. 4511-4523
Author(s):  
HARUKA NAMATAME
Keyword(s):  
Cross Sections ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
High Energy ◽  
Momentum Conservation ◽  
More Care ◽  
High Energy Collider ◽  
The Cross ◽  
Shell Production ◽  
Kaluza Klein

It is pointed out in a class of models with large extra dimensions that the cross-section of processes with virtual Kaluza–Klein graviton exchanges becomes either much smaller or much larger by many orders of magnitude than what is expected from that of the on-shell production of the Kaluza–Klein gravitons. We demonstrate how the problem arises using a toy model. The cause of this new problem lies in the fact that we do not have momentum conservation in the extra dimensions. To search for the signal of the large extra dimensions with high energy collider experiments, we need more care in interpreting the earlier results on the cross-sections of these processes.

Dynamic Modeling and Vibration Control of a Space Flexible Manipulator Using Piezoelectric Actuators and Sensors

2011 ◽  
Vol 345 ◽  
pp. 46-52 ◽  
Author(s):  
Jun Qiang Lou ◽  
Yan Ding Wei
Keyword(s):  
Vibration Control ◽  
Dynamic Modeling ◽  
Vibration Suppression ◽  
Equations Of Motion ◽  
Linear Quadratic Regulator ◽  
Flexible Manipulator ◽  
Coupled Vibration ◽  
Linear Quadratic ◽  
Space Manipulator ◽  
Tip Mass

This paper concerns the dynamic modeling and vibration control of a space two-link flexible manipulator. Two types of PZT actuators, PZT shear actuator and torsional actuator, are used to suppress the bending-torsional-coupled vibration of the space manipulator. Using extended Hamilton’s principle and the finite element method, equations of motion of the space flexible manipulator with PZT actuators and tip mass are obtained. Based on modal analyze theory, the state space model of the system is then used to design the control system. A linear quadratic regulator (LQR) controller is designed to achieve vibration suppression of the space manipulator system. From the numerical results, we can get that the proposed controller has a suitable and efficient performance suppressing the bending-torsional-coupled vibration of the space two-link flexible manipulator.

scholarly journals Hybrid Controller Based on LQR Applied to Interleaved Boost Converter and Microgrids under Power Quality Events

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6909
Author(s):  
Gerardo Humberto Valencia-Rivera ◽  
Ivan Amaya ◽  
Jorge M. Cruz-Duarte ◽  
José Carlos Ortíz-Bayliss ◽  
Juan Gabriel Avina-Cervantes
Keyword(s):  
Renewable Energy Sources ◽  
Real Life ◽  
Linear Quadratic Regulator ◽  
Boost Converter ◽  
Optimal Operation ◽  
Gray Wolf ◽  
Linear Quadratic ◽  
Photovoltaic Array ◽  
Hybrid Controller ◽  
Interleaved Boost Converter

Renewable energy sources are an environmentally attractive idea, but they require a proper control scheme to guarantee optimal operation. In this work, we tune different controllers for an Interleaved Boost Converter (IBC) powered by a photovoltaic array using three metaheuristics: Genetic Algorithm, Particle Swarm Optimization, and Gray Wolf Optimization. We also develop several controllers for a second simulated scenario where the IBC is plugged into an existing microgrid (MG) as this can provide relevant data for real-life applications. In both cases, we consider hybrid controllers based on a Linear Quadratic Regulator (LQR). However, we hybridize it with an Integral action (I-LQR) in the first scenario to compare our data against previously published controllers. In the second one, we add a Proportional-Integral technique (PI-LQR) as we do not have previous data to compare against to provide a more robust controller than I-LQR. To validate our approach, we run extensive simulations with each metaheuristic and compare the resulting data. We focus on two fronts: the performance of the controllers and the computing cost of the solvers when facing practical issues. Our results demonstrate that the approach proposed for tuning controllers is a feasible strategy. The controllers tuned with the metaheuristics outperformed previously proposed strategies, yielding solutions thrice faster with virtually no overshoot and a voltage ripple seven times smaller. Not only this, but our controllers could correct some issues liaised to the IBC when it is plugged into an MG. We are confident that these insights can help migrate this approach to a more diverse set of MGs with different renewable sources and escalate it to real-life experiments.

scholarly journals Singularly Perturbed Modeling and LQR Controller Design for a Fuel Cell System

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2735
Author(s):  
Kliti Kodra ◽  
Ningfan Zhong
Keyword(s):  
Time Scales ◽  
Gas Flow ◽  
Proton Exchange Membrane ◽  
Controller Design ◽  
Linear Quadratic Regulator ◽  
Cell System ◽  
Proton Exchange ◽  
Singularly Perturbed ◽  
Singular Perturbation Theory ◽  
Linear Quadratic

Modeling and control of proton-exchange membrane fuel cells (PEMFC) has become a very popular research topic lately due to the increasing use of renewable energy. Despite this fact, most of the work in the current literature only studies standard dynamical models without taking into consideration possible parasitics such as small gas flow perturbations that could be available in the system. This paper addresses this issue by elaborating on time-scale modeling of an augmented eighteenth-order PEMFC-reformer system via singular perturbation theory. The latter captures time scales that arise in the model due to the presence of small perturbations. Specifically, a novel and efficient algorithm that helps identify the presence of different time-scales is developed. In addition, the method converts an implicit singularly perturbed model into an explicit equivalent where the time-scales are evident. Using this algorithm, a complete singularly perturbed dynamic model of the augmented eighteenth-order PEMFC-reformer system is obtained. Modeling of the PEMFC-reformer system is followed by linear quadratic regulator (LQR) design for the individual time-scales present in the system.

Hybrid-Trajectory Based Terminal Sliding Mode Control of a Flexible Space Manipulator with an Elastic Base

Robotica ◽  
2019 ◽  
Vol 38 (3) ◽  
pp. 550-563
Author(s):  
Xiaoyan Yu
Keyword(s):  
Sliding Mode ◽  
Angular Displacement ◽  
Momentum Conservation ◽  
Elastic Base ◽  
Control Force ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Space Manipulator ◽  
Attitude Error ◽  
Flexible Vibrations

SummaryA hybrid-trajectory based terminal sliding mode controller (TSMC) is addressed for a free-flying two-flexible-link space manipulator with an elastic base. In this system, there are unknown but bounded external disturbances and parameters. First, the Lagrange dynamic model of the manipulator was established by the momentum conservation. Second, a TSMC based on desired trajectory was proposed, by which the terminal trajectories were asymptotically tracked and periodic flexible vibrations were excited. Then based on virtual control force, hybrid trajectories were generated, in which the flexible variables, the joint angular displacement errors and the base’s attitude error were considered. Finally, a hybrid-trajectory TSMC was presented, by which the terminal trajectories were asymptotically tracked and the flexible vibrations were suppressed.

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