A new high-speed 4-DOF parallel robot synthesis and modeling issues

Marquet, F.; Pierrot, François

doi:10.1109/tra.2003.810232

Cited by 88 publications

(42 citation statements)

References 12 publications

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“…Although the matrix J x is a non-square matrix, its condition number can be still accessed through using Eqs. (17) and (18). Hence, through computing the eigenvalues of the matrix J T…”

Section: Singularity Analysismentioning

confidence: 99%

Design and kinematic analysis of redundantly actuated parallel mechanisms for ankle rehabilitation

et al. 2014

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Link to this article: http://journals.cambridge.org/abstract_S0263574714000241How to cite this article: Congzhe Wang, Yuefa Fang, Sheng Guo and Changchun Zhou (2015). Design and kinematic analysis of redundantly actuated parallel mechanisms for ankle rehabilitation. Robotica, 33, pp 366-384 SUMMARYIn this paper, we present the design of two serial spherical mechanisms to substitute for a single spherical joint that is usually used to connect the platform with the base in three degrees of freedom parallel mechanisms. According to the principle derived from the conceptual design, through using the two serial spherical mechanisms as the constraint limb, several redundantly actuated parallel mechanisms are proposed for ankle rehabilitation. The proposed parallel mechanisms all can perform the rotational movements of the ankle in three directions while at the same time the mechanism center of rotations can match the ankle axes of rotations compared with other multi-degree-of-freedom devices, due to the structural characteristics of the special constraint limb and platform. Two special parallel mechanisms are selected to analyze their kinematical performances, such as workspace, dexterity, singularity, and stiffness, based on the computed Jacobian. The results show that the proposed scheme of actuator redundancy can guarantee that the redundantly actuated parallel mechanisms have no singularity, better dexterity, and stiffness within the prescribed workspace in comparison with the corresponding non-redundant parallel mechanisms. In addition, the proposed mechanisms possess certain reconfigurable capacity based on control strategies or rehabilitation modes to obtain sound performance for completing ankle rehabilitation exercise.

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“…Although the matrix J x is a non-square matrix, its condition number can be still accessed through using Eqs. (17) and (18). Hence, through computing the eigenvalues of the matrix J T…”

Section: Singularity Analysismentioning

confidence: 99%

Design and kinematic analysis of redundantly actuated parallel mechanisms for ankle rehabilitation

et al. 2014

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“…Eventually, this workspace is limited to a (300 × 300 × 300)mm 3 centered cube: work will be done within this workspace. More details can be found in Pierrot et al [6] and Company, Marquet, and Pierrot [12]. The analytical forward geometric model of a parallel robot is more difficult to compute.…”

Section: A Geometric and Kinematics Modelingmentioning

confidence: 99%

Improving the Robustness of a Parallel Robot Using Predictive Functional Control (PFC) Tools

Maalouf

2006

Proceedings of the 45th IEEE Conference on Decision and Control

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Heuristically, it was claimed in the literature that increasing the time-constant 'T ref ' of the reference trajectory in Predictive Functional Control (PFC) improves the closed-loop stability because the controller will be able to tolarate model mismatch which is difficult for a zero time-constant reference trajectory (a pure set-point) to tolerate. On the other hand, PFC uses 'T ref ' as the main tuning parameter. Smaller time constants demand more aggressive control, while larger time constants result in less aggressive action. One may start with 'T ref ' equal to the open-loop time constant of the control variable, then refine the tuning based on performance/robustness trade-offs. In this paper, the author investigates these issues analytically for an H4 robot. The analysis done shows that the system obtained is of type MGS defined in [3] for which it is possible by using PFC tools to find analytically a stable equilibrium point for the system and track at the same time a reference trajectory with a gain margin that increases as 'T ref ' increases, improving that way the relative stability of the closed-loop system. The author notes that, the study done in this paper for the H4 robot could be applied to any robot whose linearised model is of MGS type defined in [3]. The author notes as well that the plots illustrated in this paper were obtained by simulation using Matlab/Simulink.

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“…However, the serially added device may become a weak point and may lead to the lack of stiffness and short service life [14][15][16]. To avoid this disadvantage, Pierrot et al [1,[17][18][19][20] proposed a new family of 4-DOF, doubleplatform parallel robots called H4. The rotary output of H4 is realized by the relative movement of the two platforms.…”

Section: Introductionmentioning

confidence: 99%

Conceptual design and kinematic analysis of a novel parallel robot for high-speed pick-and-place operations

2017

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This paper deals with the conceptual design, kinematic analysis and workspace identification of a novel four degrees-of-freedom (DOFs) high-speed spatial parallel robot for pick-and-place operations. The proposed spatial parallel robot consists of a base, four arms and a 1½ mobile platform. The mobile platform is a major innovation that avoids output singularity and offers the advantages of both single and double platforms. To investigate the characteristics of the robot's DOFs, a line graph method based on Grassmann line geometry is adopted in mobility analysis. In addition, the inverse kinematics is derived, and the constraint conditions to identify the correct solution are also provided. On the basis of the proposed concept, the workspace of the robot is identified using a set of presupposed parameters by taking input and output transmission index as the performance evaluation criteria.

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A new high-speed 4-DOF parallel robot synthesis and modeling issues

Cited by 88 publications

References 12 publications

Design and kinematic analysis of redundantly actuated parallel mechanisms for ankle rehabilitation

Design and kinematic analysis of redundantly actuated parallel mechanisms for ankle rehabilitation

Improving the Robustness of a Parallel Robot Using Predictive Functional Control (PFC) Tools

Conceptual design and kinematic analysis of a novel parallel robot for high-speed pick-and-place operations

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