Reconfiguration of a parallel kinematic manipulator with 2T2R motions for avoiding singularities through minimizing actuator forces

Valero, Francisco; Díaz‐Rodríguez, Miguel; Vallés, Marina; Besa, Antonio; Bernabeu, Enrique J.; Valera, Ángel

doi:10.1016/j.mechatronics.2020.102382

Cited by 9 publications

(8 citation statements)

References 19 publications

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“…These four DOFs are shown in Figure 1. In order to accomplish these requirements, a PR with 4-DOF has been designed, built [29], and optimized [30] at the Universitat Politècnica de València. The PR under study is named 3UPS+RPU due to its four-limb architecture.…”

Section: Ups+rpu Parallel Robotmentioning

confidence: 99%

Vision-Based Hybrid Controller to Release a 4-DOF Parallel Robot from a Type II Singularity

Pulloquinga

Escarabajal

Ferrándiz

et al. 2021

Sensors

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The high accuracy and dynamic performance of parallel robots (PRs) make them suitable to ensure safe operation in human–robot interaction. However, these advantages come at the expense of a reduced workspace and the possible appearance of type II singularities. The latter is due to the loss of control of the PR and requires further analysis to keep the stiffness of the PR even after a singular configuration is reached. All or a subset of the limbs could be responsible for a type II singularity, and they can be detected by using the angle between two output twist screws (OTSs). However, this angle has not been applied in control because it requires an accurate measure of the pose of the PR. This paper proposes a new hybrid controller to release a 4-DOF PR from a type II singularity based on a real time vision system. The vision system data are used to automatically readapt the configuration of the PR by moving the limbs identified by the angle between two OTSs. This controller is intended for a knee rehabilitation PR, and the results show how this release is accomplished with smooth controlled movements where the patient’s safety is not compromised.

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Section: Ups+rpu Parallel Robotmentioning

confidence: 99%

Vision-Based Hybrid Controller to Release a 4-DOF Parallel Robot from a Type II Singularity

Pulloquinga

Escarabajal

Ferrándiz

et al. 2021

Sensors

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“…Another considerable deficiency is performance evaluation of 3T1R PMs. The widely used performance evaluation indices in the lower-mobility PMs, such as 3T1R PMs, 12,16 3R1T PMs, [26][27][28] 2R2T PMs, 29,30 etc., are based on the Jacobian matrix, for example, manipulability 31 and local condition number index, 32 which reflect the dexterity of the manipulator. When the end effector of the PM contains translations and rotations, the Jacobian-based indices lose their physical meanings for inconsistency of the units.…”

Section: Introductionmentioning

confidence: 99%

2PPaRR-2PPaRU: Design, analysis, and optimization of a new 3T1R parallel manipulator with rotational pitch motion

Zhang

Wenxun

Dai

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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A new 3T1R parallel manipulator (PM) 2PPaRR-2PPaRU with rotational pitch motion is proposed in this paper. In such a mechanism, there are four limbs connected to the moving platform (MP) through several revolute joints and universal joints, and all actuated joints are prismatic joints with an axis along a vertical direction. Mobility and motion characteristics are verified by constraint screw theory. The inverse kinematic solutions and the singularity configurations are derived through kinematic analysis. Next, the workspace analysis and the connection between [Formula: see text] and the volume of the reachable workspace are performed. The local motion/force transmission index is selected to evaluate the local transmission performance of 2PPaRR-2PPaRU PM. Finally, the global motion/force transmission index and the volume of reachable workspace are considered simultaneously to optimize the structural parameters. The 2PPaRR-2PPaRU PM with improved local transmission performance and reachable workspace has been achieved after optimization.

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“…1 Robotic rehabilitation for lower limb by kinematic optimisation of the robot (Wang et al, 2010;Russo et al, 2018;Valero et al, 2020). In a singular configuration within the workspace of a PR, the end-effector could move despite the actuators being locked.…”

Section: Robotic Rehabilitation For Lower Limbmentioning

confidence: 99%

“…The Universitat Politècnica de València has designed, build, and optimised a 4-DOF PR for knee rehabilitation (Vallés et al, 2018;Valero et al, 2020). The 4-DOF PR for knee rehabilitation is named 3UPS+RPU due to its mechanical architecture.…”

Section: Robotic Rehabilitation For Lower Limbmentioning

confidence: 99%

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A New Index for Detecting and Avoiding Type II Singularities for the Control of Non-Redundant Parallel Robots

Zapata¹

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Reconfiguration of a parallel kinematic manipulator with 2T2R motions for avoiding singularities through minimizing actuator forces

Cited by 9 publications

References 19 publications

Vision-Based Hybrid Controller to Release a 4-DOF Parallel Robot from a Type II Singularity

Vision-Based Hybrid Controller to Release a 4-DOF Parallel Robot from a Type II Singularity

2PPaRR-2PPaRU: Design, analysis, and optimization of a new 3T1R parallel manipulator with rotational pitch motion

A New Index for Detecting and Avoiding Type II Singularities for the Control of Non-Redundant Parallel Robots

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