Workspace analysis of positioning discontinuities due to clearances in parallel manipulators

Altuzarra, Oscar; Aginaga, Jokin; Hernández, A.; Zabalza, Isidro

doi:10.1016/j.mechmachtheory.2011.01.005

Cited by 20 publications

(14 citation statements)

References 21 publications

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“…Chen et al [24] studied the planar parallel manipulators considering input uncertainties and joint clearance based on the theory of the envelope. Altuzarra et al [25] present a methodology for analyzing the location of the discontinuities produced by clearances within a 5R planar parallel mechanism. Hu and Li [26] performed the optimal design of parallel machines under uncertainties.…”

Section: Introductionmentioning

confidence: 99%

Kinematic performance of planar 5R symmetrical parallel mechanism subjected to clearances and uncertainties

Lara-Molina

Koroishi

Steffen

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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Parallel mechanisms are unavoidably subjected to uncertainties. These uncertainties produce a small variation of link lengths and joints position associated with the clearances. Therefore, this contribution aims at analyzing the effect of these uncertainties on the kinematic performance of the mechanism by examining the kinematic performance atlases. Initially, the complete kinematic model of the mechanism is formulated by considering the uncertainties thar are included in the modeled. The kinematic performance with the uncertainties is computed by using the Monte Carlo method. Then, the kinematic performance atlases based on workspace size and kinematic dexterity are analyzed including the uncertainties. Finally, the kinematic accuracy is evaluated for different link lengths in order to show the correspondent relationship with the kinematic performance atlases.

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Section: Introductionmentioning

confidence: 99%

Kinematic performance of planar 5R symmetrical parallel mechanism subjected to clearances and uncertainties

Lara-Molina

Koroishi

Steffen

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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show abstract

“…A procedure to calculate the positional error in parallel manipulators due to both clearances and elastic deformations was proposed [10]. For analysing the location of the discontinuities, a methodology was presented and the advantages of approach were analysed using a 5R planar mechanism [11]. The effect of joint flexibility on the dynamic performance of a serial spatial robot arm with rigid links was studied by using three developed models [12].…”

Section: Introductionmentioning

confidence: 99%

Effects of Joint Clearance on the Motion Accuracy of Robotic Manipulators

2018

SV-JME

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Accuracy is one of the key features that improves the quality of robotic manipulators for many industrial and medical applications. Even with an accurate design and manufacturing process, clearance problems in joints cannot be eliminated in articulated systems. This leads to a loss of accuracy in robotic manipulation. In this study, the effects of joint clearance in a robotic system are investigated. The need for the trajectory of end effector is considered to analyse the motion sensitivity. The kinematics and dynamics of a six-DOF robot with joint clearance are evaluated relative to a robot without joint clearance. Different scenarios for clearance values and working periods are performed to fulfil the required motion task. A neural model is also used to predict the trajectory deviations during the working process. The results show that clearance has a significant role in the motion sensitivity of robotic manipulations. Trajectory errors can also be determined by using a dynamic neural predictor with suitable input variables.

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“…Many authors have explored the error and accuracy of parallel mechanisms using different techniques. Altuzarra et al [21] provide a method to locate regions of the workspace with discontinuities for a planar parallel robot, addressing the error between the pin and the hub of a joint with clearance. Also, stiffness modelling method for overconstrained systems has been used to formulate workspaces as close as possible to a predefined velocity in flexible links [22].…”

Section: Introductionmentioning

confidence: 99%

Error Assessment Model for the Inverse Kinematics Problem for Stewart Parallel Mechanisms for Accurate Aerospace Optical Linkage

Hernández-Gómez

Medina

Miguel

et al. 2018

Mathematical Problems in Engineering

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In this work we develop a mathematical model to estimate the error for inverse kinematics problem for Gough-Stewart parallel mechanisms. We propose the estimation error method to include manufacture, assembly, backlash, and sensing errors. We provide the error transmission matrices for the length of each leg of the hexapod, which permits evaluation of the accuracy error in the position of each one, given a desired position and orientation of the mobile platform. We also present numerical modelling in order to estimate the accuracy of the methodology herein proposed, for specific attitude operations corresponding to performing a successful ground-LEO nanosatellite optical link. In such a case, we were able to provide the required tolerances for the actuators in order to guarantee an orientation precision requirement of the order of milliradians.

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Workspace analysis of positioning discontinuities due to clearances in parallel manipulators

Cited by 20 publications

References 21 publications

Kinematic performance of planar 5R symmetrical parallel mechanism subjected to clearances and uncertainties

Kinematic performance of planar 5R symmetrical parallel mechanism subjected to clearances and uncertainties

Effects of Joint Clearance on the Motion Accuracy of Robotic Manipulators

Error Assessment Model for the Inverse Kinematics Problem for Stewart Parallel Mechanisms for Accurate Aerospace Optical Linkage

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