Design and Kinematical Performance Analysis of a 3-RUS/RRR Redundantly Actuated Parallel Mechanism for Ankle Rehabilitation

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Congzhe Wang ◽  
Yuefa Fang ◽  
Sheng Guo ◽  
Yaqiong Chen
Keyword(s):  
Performance Analysis ◽  
Conceptual Design ◽  
Parallel Mechanism ◽  
Structural Characteristics ◽  
Robotic System ◽  
Degree Of Freedom ◽  
Redundant Robot ◽  
Ankle Rehabilitation ◽  
Redundantly Actuated ◽  
Rehabilitation Exercise

In this paper, we present the design of a novel 3-RUS/RRR redundantly actuated parallel mechanism for ankle rehabilitation based on the principle from the conceptual design. The proposed mechanism can actualize 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, owing to the structural characteristics of the special constraint limb and platform. A new actuator redundancy scheme is used, which not only still maintains all inherent advantages from actuator redundancy but also possesses the kinematic partially decouple feature that improves the flexibility of the robotic system. Kinematic performances, such as dexterity, singularity and stiffness, are analyzed based on the computed Jacobian. Then simulation is performed. All the results show that the redundant robot has no singularity, better dexterity and stiffness within the prescribed workspace in comparison with the corresponding 3-RUS/RRR nonredundant robot, and is suitable for rehabilitation exercise.

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

Robotica ◽  
2014 ◽  
Vol 33 (2) ◽  
pp. 366-384 ◽  
Author(s):  
Congzhe Wang ◽  
Yuefa Fang ◽  
Sheng Guo ◽  
Changchun Zhou
Keyword(s):  
Degrees Of Freedom ◽  
Control Strategies ◽  
Structural Characteristics ◽  
Parallel Mechanisms ◽  
Spherical Mechanisms ◽  
Ankle Rehabilitation ◽  
Redundantly Actuated ◽  
Reconfigurable Capacity ◽  
Three Degrees Of Freedom ◽  
Rehabilitation Exercise

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.

Geometry and Kinematic Analysis of a Redundantly Actuated Parallel Mechanism for Rehabilitation

2007 ◽  
Author(s):  
Jody A. Saglia ◽  
Jian S. Dai
Keyword(s):  
Control System ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Jacobian Matrix ◽  
Forward Kinematics ◽  
Control System Design ◽  
Ankle Rehabilitation ◽  
Redundantly Actuated ◽  
Moving Platform

This paper presents the geometry and the kinematic analysis of a parallel manipulator developed for ankle rehabilitation, as the beginning of a control system design process. First the geometry of the parallel mechanism is described, secondly the equations for the inverse and the forward kinematics are obtained, then the forward kinematics is analyzed in order to define all the possible configurations of the moving platform. Finally the Jacobian matrix of the rig is obtained by differentiating the position equations and the singularities are investigated, comparing the non-redundant and redundant type of mechanism.

A High-performance Redundantly Actuated Parallel Mechanism for Ankle Rehabilitation

2009 ◽  
Vol 28 (9) ◽  
pp. 1216-1227 ◽  
Author(s):  
J.A. Saglia ◽  
N.G. Tsagarakis ◽  
J.S. Dai ◽  
D.G. Caldwell
Keyword(s):  
Parallel Mechanism ◽  
High Performance ◽  
Ankle Rehabilitation ◽  
Redundantly Actuated

Design of a Redundantly Actuated Asymmetric Linear DELTA Parallel Mechanism for Singularity-Free Mode Changes

2014 ◽  
Vol 575 ◽  
pp. 711-715 ◽  
Author(s):  
Takashi Harada
Keyword(s):  
Numerical Simulations ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Degree Of Freedom ◽  
Moving Plate ◽  
Mode Change ◽  
Redundantly Actuated ◽  
Free Mode ◽  
Linear Actuators ◽  
Three Degree Of Freedom

A novel parallel mechanism which enlarges the workspace by singularity-free mode change is proposed. The proposed mechanism is inherited the design of Linear DELTA which has three degree-of-freedom translational moving plate driven by three linear actuators, in addition, extended it by redundantly actuation by four linear actuators and asymmetric design. New criterions about redundancy and singularity of redundantly actuated parallel mechanism using summation and product of determinants of minor matrices of the transposed Jacobian matrix are proposed. Redundantly actuation and asymmetric design enables singularity-free mode changes with loss redundancy but maintain non-singularity, that are evaluated by the proposed criterions. Numerical simulations demonstrate the singularity-free mode changes of the proposed mechanism.

scholarly journals Control Method for Realistic Motion in a Construction Tele-robotic System with a 3-DOF Parallel Mechanism

2003 ◽  
Vol 15 (4) ◽  
pp. 361-368 ◽  
Author(s):  
Dingxuan Zhao ◽  
◽  
Yupeng Xia ◽  
Hironao Yamada ◽  
Takayoshi Muto
Keyword(s):  
Parallel Mechanism ◽  
Control Method ◽  
Robotic System ◽  
Degree Of Freedom ◽  
Experimental Result ◽  
Parallel Mechanisms ◽  
High Quality ◽  
Link Mechanism ◽  
Acceleration Sensors ◽  
Parallel Link

In this study, we developed a construction tele-robotic system, which can be widely used, for example, for restoration works in damaged areas. The system consists of a servo-controlled construction robot, two joysticks for operations of the robot from a remote place and a 3-degree-of-freedom (DOF) parallel mechanism. An important problem to be solved in such a system is how to convey adequate presence of working area in a high quality to the operator. In this paper, we propose a control method of a 3-DOF parallel link mechanism to simulate the motion of the construction robot by using three acceleration sensors. The validity of this method has been confirmed experimentally. According to the experimental result, each motion of roll, pitch and heave of the construction robot can be simulated accurately by the 3-DOF parallel mechanisms.

Conceptual design and dimensional synthesis of a novel parallel mechanism for lower-limb rehabilitation

Robotica ◽  
2018 ◽  
Vol 37 (3) ◽  
pp. 469-480 ◽  
Author(s):  
Hui Wang ◽  
Wen Li ◽  
Haitao Liu ◽  
Jianxin Zhang ◽  
Songtao Liu
Keyword(s):  
Conceptual Design ◽  
Lower Limb ◽  
Parallel Mechanism ◽  
Generalized Jacobian ◽  
Transmission Index ◽  
Redundantly Actuated ◽  
Kinematic Performance ◽  
Limb Rehabilitation ◽  
Local Transmission ◽  
Lower Limb Rehabilitation

SUMMARYThis paper introduces a novel 2R1T parallel manipulator redundantly actuated by pneumatic muscles for lower-limb rehabilitation. First, the conceptual design of the proposed 3-DOF parallel mechanism is presented. Then, the inverse kinematics and the generalized Jacobian analysis are carried out. Based on the generalized Jacobian and the constraint characteristics of the mechanism, the force/motion transmissibility of the redundantly actuated parallel mechanism is investigatedviafour individual cases without actuation redundancy, leading to a suitable local transmission index for the evaluation of kinematic performance of the proposed mechanism. Finally, the design variables are optimized by maximizing the mean value of the local transmission index with the aid of genetic algorithm. The numerical result shows that the proposed parallel mechanism can achieve a good kinematic performance in its task workspace.

Geometry and Kinematic Analysis of a Redundantly Actuated Parallel Mechanism That Eliminates Singularities and Improves Dexterity

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Jody A. Saglia ◽  
Jian S. Dai ◽  
Darwin G. Caldwell
Keyword(s):  
Condition Number ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Parallel Mechanisms ◽  
Rank Deficiency ◽  
Actuation Redundancy ◽  
Ankle Rehabilitation ◽  
Redundantly Actuated ◽  
Lower Mobility

This paper investigates the behavior of a type of parallel mechanisms with a central strut. The mechanism is of lower mobility, redundantly actuated, and used for sprained ankle rehabilitation. Singularity and dexterity are investigated for this type of parallel mechanisms based on the Jacobian matrix in terms of rank deficiency and condition number, throughout the workspace. The nonredundant cases with three and two limbs are compared with the redundantly actuated case with three limbs. The analysis demonstrates the advantage of introducing the actuation redundancy to eliminate singularities and to improve dexterity and justifies the choice of the presented mechanism for ankle rehabilitation.

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