control of parallel manipulators presentation

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Control of ParallelManipulators

Eng. Ahmad Mohammed Ali El SheikhTeaching Assistant, Faculty of Engineering,

Minia University

Abstract

The Parallel manipulators are closed loopstructures. They consist of three mainparts; a base (static) plate, movingplatform, and a number of limbs (chains)connecting the base plate and movingplatform.

Why parallel manipulators?

The Parallel manipulators (PMs) possessseveral points of advantage overtraditional series manipulators. Thepayload capacity, rigidity, workspace, andaccuracy of positioning are all in the favorof PMs.

As a result,

The PMs have been applied widely inmany fields. Machine tools, CNCmachining, aerospace simulation, andunderground projects are clearexamples.

The objective is to……

The most crucial question in operation ofparallel manipulator is about the design ofit is controller. The perfect tool to control amanipulator is the dynamic analysis.

In this proposed study, the parallelmanipulator (PM) will be controlled throughthe investigation of the dynamic entities suchas torques and forces for actuated joints, andthe kinematic aspects as acceleration, velocity,and displacement

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How can this be achieved?

This will be contributed through theformulation of a control loop andfunction. This strategy of control is toreduce (eliminate) the error between theinputs and outputs of the control system

Those outputs and inputs are…

The dynamic properties such as actuatortorques and forces.

The kinematic parameters for instance,acceleration, velocity and orientation(displacement).

Something else……

To acquire the procedures of thisproposed research, it is necessary togenerate the trajectory of the moving topplatform, so that we can define the error ininput and output of the control system; thekinematic and dynamic parameters.

The Literature Review

The Dynamics and control of a planar 3-DOF parallel manipulator with actuationredundancy are studied.

Jun Wu, Jinsong Wang, Liping Wang, Tiemin Li (2008)," Dynamics and control of a planar 3-DOF parallel manipulator with actuationredundancy", Institute of Manufacturing Engineering, Department of Precision Instruments, Tsinghua University, Beijing 100084, PRChina.

This research deals with the dynamics and control of a planar 3-DOF parallelmanipulator with actuation redundancy


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The Control scheme of the redundantly actuated parallelmanipulator


The Dynamic modeling and control of a 3-DOFCartesian parallel manipulator

The Dynamic modeling is the basic elementfor controller design of mechanisms. Inthis paper, an effective dynamic equationof a 3-DOF translational parallelmanipulator for control purpose has beenderived by the Lagrange-D’Alembertformulation

Ping-Lang Yen, Chi-Chung Lai (2008), "Dynamic modeling and control of a 3-DOF Cartesian parallel manipulator", Institute ofAutomation Technology, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Road, Taipei 106, Taiwan.


The Computed-torque method for theCPM


Force computation and continuous pathtracking for hydraulic parallel manipulators

Machine tools, robots and parallelmanipulators are useful platforms inmanufacturing. For parallel manipulators,developing contour tracking ability andclarifying the role of force computation areof significance.

Jih-Hua China, Yen-His Suna, and Yuan-Ming Chengb (2007)," Force computation and continuous path tracking for hydraulic parallelmanipulators", Department of Mechanical Engineering, National Chiao-Tung University, Hsinchu, 300, Taiwan, ROC and Departmentof Mechanical and Automation Engineering, Kao Yuan University, Kaohsiung County, 821, Taiwan, ROC.


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Experimental hydraulic manipulatorsystem


The Cascade control of a hydraulically driven 6-DOF(spatial) parallel robot manipulator based on a slidingmodeA cascade-control algorithm based on a sliding

mode in the leg space is proposed to realizethe trajectory tracking control of ahydraulically driven six degrees of freedom(6-DOF) parallel robot manipulator.

HongBo Guo (a,c) YongGuang Liu (a), GuiRong Liu (b), HongRen Li (c) (2007)," Cascade control of a hydraulically driven 6-DOFparallel robot manipulator based on a sliding mode", (a) Department of Electromechanical Engineering, School of AutomationScience and Electrical Engineering, BeiHang University, Beijing 100083, People’s Republic of China, (b) Department of Education,School of Education Science and Technology, Harbin Normal University, Harbin 150080, People’s Republic of China, (c) Departmentof Mechanical Engineering and Automation, School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001,People’s Republic of China.

The Prototype of a hydraulically driven 6-DOF parallelrobotic manipulator


Structure block diagram of the cascade control based onthe sliding mode


The Motor-mechanism dynamic modelbased neural network optimized computedtorque control of a high speed parallelmanipulator

Yang Zhiyong, Wu Jiang, Mei Jiangping (2007)," Motor-mechanism dynamic model based neural network optimized computedtorque control of a high speed parallel manipulator" School of Mechanical Engineering, Tianjin University, Tianjin, China.

There are wide applications of the parallel manipulators inthe industry field because of the high speed and accuracy,but difficulties are also unavoidable in the controllingprocess for the systematic time-varying and couplingcharacteristics.


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Therefore, the approaches for bettercontrol performance are vital to theapplication of parallel manipulator



Control block diagram of the system


The Robust learning control of a high precision planarparallel manipulator.

The learning control of a precision manipulator.End-point positioning accuracy and fastsettling time are essential in the motionsystem aimed at semiconductor packagingapplications

Jacob W.F. Cheung (a,b), Y.S. Hung (b) (2008), " Robust learning control of a high precision planar parallel manipulator", MotionControl and Systems Laboratory, Research and Development Department, ASM Assembly Automation Ltd., 3/F Watson Centre, 16Kung Yip Street, Kwai Chung, New Territories, Hong Kong, b Department of Electrical and Electronic Engineering, The University ofHong Kong, Pokfulam Road, Hong Kong.

Experimental setup of the planar parallelmanipulator


Block diagram of the robust learningcontroller


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A Force–Impedance ControlledIndustrial Robot using An ActiveRobotic Auxiliary Device

Anto´ nio Lopes, Fernando Almeida (2007)," A force–impedance controlled industrial robot using an active robotic auxiliary device",Faculdade de Engenharia da Universidade do Porto, DEMEGI/IDMEC, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.

In this research paper:

A strategy to improve the performance ofcurrent commercial industrial robots ispresented in this paper. This strategyinvolves cooperation of two roboticmanipulators: the robotic controlledimpedance device (RCID) and a commercialindustrial robot.


Photography (left), Serial combination of the RCID and anindustrial manipulator (right)


Block diagram of the inner acceleration loop controller,and controlled system


The study procedures are:

Defining the applicationand Structural Design

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• Workspace analysis• Making The Kinematic Analysis

• Making The Dynamic Analysis• The Design of the of the ControlSystem and Function

• Applying the compensationtechniques to avoid or to reduce thedesired out value and the actualvalue of it.

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Finally, we come to:

The Results and Discussions

And

The Conclusions and Recommendations

Thank you for your attention!

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control of parallel manipulators presentation

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