End-effector Trajectory Control in a Two-Link Flexible Manipulator Through Reference Joint Angle Values Modification by Neural Networks

2006 ◽  
Vol 12 (2) ◽  
pp. 101-117 ◽  
Author(s):  
Gülay Öke ◽  
Yorgo İstefanopulos
Keyword(s):  
Neural Networks ◽  
Joint Angle ◽  
Trajectory Control ◽  
Flexible Manipulator ◽  
End Effector

Stable Manipulator Trajectory Control Using Neural Networks

1997 ◽  
pp. 117-151 ◽  
Author(s):  
Yichuang Jin ◽  
Tony Pipe ◽  
Alan Winfield
Keyword(s):  
Neural Networks ◽  
Trajectory Control

scholarly journals A novel solution of inverse kinematic for 6R robot manipulator with offset joint based on screw theory

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092564
Author(s):  
Zhiwei Liao ◽  
Gedong Jiang ◽  
Fei Zhao ◽  
Xuesong Mei ◽  
Yang Yue
Keyword(s):  
Joint Angle ◽  
Screw Theory ◽  
Robot Manipulator ◽  
Inverse Kinematic ◽  
Transformation Matrix ◽  
Inverse Kinematic Problem ◽  
End Effector ◽  
Closed Form Solutions ◽  
Specific Configuration ◽  
Kinematic Approach

This article proposes a novel inverse kinematic approach with translation transformation matrix based on screw theory to solve the inverse kinematic problem for 6R robot manipulator with offset joint. The translation transformation matrix is introduced to convert the 6R robot manipulator with offset joint to a new configuration with intersecting axes, and the mapping relationship from the end effector to the joint angle is established along with the Paden–Kahan subproblems. The eight closed solutions of the specific configuration are deduced, which automatically eliminate the singularity solutions. Moreover, the precision and efficiency of the proposed method are verified through a numerical example. Unlike other approaches, the presented algorithm not only inherits the superior accuracy of the other geometric approaches but also exhibits an outperform efficiency. Finally, the method is generalized to other 6R robots, which has closed-form solutions to further verify its versatility. The presented study provides some basis for further investigations, such as trajectory planning and motion control, which provides a new tool on the analysis and application of this kind of robot manipulator.

Control of a two-link flexible manipulator using neural networks

2007 ◽  
Author(s):  
Minoru Sasaki ◽  
Haruki Murasawa ◽  
Satoshi Ito
Keyword(s):  
Neural Networks ◽  
Flexible Manipulator

Dynamic trajectory-tracking control method of robotic transcranial magnetic stimulation with end-effector gravity compensation based on force sensors

2018 ◽  
Vol 45 (6) ◽  
pp. 722-731
Author(s):  
ZeCai Lin ◽  
Wang Xin ◽  
Jian Yang ◽  
Zhang QingPei ◽  
Lu ZongJie
Keyword(s):  
Neural Networks ◽  
Trajectory Tracking ◽  
Tracking Control ◽  
Magnetic Stimulation ◽  
Control Method ◽  
Gravity Compensation ◽  
Trajectory Tracking Control ◽  
End Effector ◽  
Content Type ◽  
Dynamic Trajectory

Purpose This paper aims to propose a dynamic trajectory-tracking control method for robotic transcranial magnetic stimulation (TMS), based on force sensors, which follows the dynamic movement of the patient’s head during treatment. Design/methodology/approach First, end-effector gravity compensation methods based on kinematics and back-propagation (BP) neural networks are presented and compared. Second, a dynamic trajectory-tracking method is tested using force/position hybrid control. Finally, an adaptive proportional-derivative (PD) controller is adopted to make pose corrections. All the methods are designed for robotic TMS systems. Findings The gravity compensation method, based on BP neural networks for end-effectors, is proposed due to the different zero drifts in different sensors’ postures, modeling errors in the kinematics and the effects of other uncertain factors on the accuracy of gravity compensation. Results indicate that accuracy is improved using this method and the computing load is significantly reduced. The pose correction of the robotic manipulator can be achieved using an adaptive PD hybrid force/position controller. Originality/value A BP neural network-based gravity compensation method is developed and compared with traditional kinematic methods. The adaptive PD control strategy is designed to make the necessary pose corrections more effectively. The proposed methods are verified on a robotic TMS system. Experimental results indicate that the system is effective and flexible for the dynamic trajectory-tracking control of manipulator applications.

Analysis and Validation of a Flexible Planar Two Degrees-of-Freedom Parallel Manipulator With Structural Passive Compliance

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Genliang Chen ◽  
Zhuang Zhang ◽  
Lingyu Kong ◽  
Hao Wang
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Interaction Force ◽  
Flexible Manipulator ◽  
End Effector ◽  
Flexible Links ◽  
Wide Range ◽  
Pick And Place ◽  
Passive Compliance ◽  
Large Deflection Problem

Abstract Passive compliance plays an important role in robot pick-and-place manipulation where large interaction force will be produced in response to small misalignments. In this paper, the authors report on compliance analysis and validation of a novel planar pick-and-place parallel manipulator consisting of a flexible limb. In the proposed manipulator, a planar flexible parallelogram linkage, which is coupled with a rigid one, is introduced to connect the moving and the base platforms. Since the flexible parallelogram linkage is capable of producing large deformation in both the horizontal and the vertical directions, the end effector of the manipulator can generate wide-range motions because of the flexible links. An efficient approach to the large deflection problem of flexible links is used to precisely predict the kinetostatics of the manipulator. Then, a compensation algorithm to the structural deflection of the links can be developed to actively control the position of the parallel manipulator’s end effector. The merit of the proposed flexible manipulator is its intrinsic passive compliance while performing pick-and-place tasks. A prototype is fabricated to conduct experiments for the validation of the proposed idea. The results show that the prototype has acceptable positioning accuracy, even when a large external load is exerted on its end effector. The compliance properties of the proposed flexible manipulator have also been verified in both the horizontal and the vertical directions.

scholarly journals Adjustments in end-effector trajectory and underlying joint angle synergies after a target switch: Order of adjustment is flexible

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0238561
Author(s):  
Maureen B. G. Wissing ◽  
Laura Golenia ◽  
Joanne Smith ◽  
Raoul M. Bongers
Keyword(s):  
Joint Angle ◽  
End Effector

A Study on Vibrations of Hexarot-Based High-G Centrifugal Simulators

Robotica ◽  
2019 ◽  
Vol 38 (2) ◽  
pp. 299-316 ◽  
Author(s):  
Siamak Pedrammehr ◽  
Houshyar Asadi ◽  
Saeid Nahavandi
Keyword(s):  
Dynamic Model ◽  
Virtual Work ◽  
Viscous Friction ◽  
Stability Index ◽  
Flexible Manipulator ◽  
Kinematics And Dynamics ◽  
Principle Of Virtual Work ◽  
End Effector ◽  
Dynamic Formulation ◽  
Different Parts

SummaryThis paper investigates the vibrations of hexarot simulators. The generalized modeling of kinematics and dynamics formulation of a hexarot mechanism is addressed. This model considers the flexible manipulator with the base motion. The dynamic formulation has been developed based on the principle of virtual work. The dynamic model consists of the stiffness of the different parts of the mechanism, the effects of gravity and inertia, torque and force related to the joints viscous friction. Finally, the response of the end effector at various frequencies has been presented, and the vibrations of the mechanism and the dynamic stability index have been investigated.

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