Study and enumeration of singular configurations for the kinematic model of human arm

Abstract In this paper, a seven degree-of-freedom anthropomorphic arm model defined by zero-position notation is used to study the kinematically singular configurations of human arm. The three findings of this study are: (1) A relationship is shown between the rank of Jacobian matrix J and the number of corresponding reciprocal screws for singular configurations of any three dimensional manipulator arm. (2) By investigating the geometrical positions of this model, its various singular configurations are identified and illustrated. (3) The determinant and cofactor matrix of JJT, and the sub-determinants of J are also examined to help a better understanding of the singularity conditions and characteristics for the seven degree-of-freedom anthropomorphic arm.

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Mechanical Design and Kinematic Modeling of a Cable-Driven Arm Exoskeleton Incorporating Inaccurate Human Limb Anthropomorphic Parameters

Sensors ◽

10.3390/s19204461 ◽

2019 ◽

Vol 19 (20) ◽

pp. 4461 ◽

Cited By ~ 1

Author(s):

Weihai Chen ◽

Zhongyi Li ◽

Xiang Cui ◽

Jianbin Zhang ◽

Shaoping Bai

Keyword(s):

Mechanical Design ◽

Kinematic Model ◽

Light Weight ◽

Skeletal System ◽

Kinematic Modeling ◽

Modeling And Control ◽

Arm Rehabilitation ◽

Human Arm ◽

Human Limb ◽

And Control

Compared with conventional exoskeletons with rigid links, cable-driven upper-limb exoskeletons are light weight and have simple structures. However, cable-driven exoskeletons rely heavily on the human skeletal system for support. Kinematic modeling and control thus becomes very challenging due to inaccurate anthropomorphic parameters and flexible attachments. In this paper, the mechanical design of a cable-driven arm rehabilitation exoskeleton is proposed to accommodate human limbs of different sizes and shapes. A novel arm cuff able to adapt to the contours of human upper limbs is designed. This has given rise to an exoskeleton which reduces the uncertainties caused by instabilities between the exoskeleton and the human arm. A kinematic model of the exoskeleton is further developed by considering the inaccuracies of human-arm skeleton kinematics and attachment errors of the exoskeleton. A parameter identification method is used to improve the accuracy of the kinematic model. The developed kinematic model is finally tested with a primary experiment with an exoskeleton prototype.

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Functional Design of a 6-DOF Platform for Micro-Positioning

Robotics ◽

10.3390/robotics9040099 ◽

2020 ◽

Vol 9 (4) ◽

pp. 99

Author(s):

Matteo-Claudio Palpacelli ◽

Luca Carbonari ◽

Giacomo Palmieri ◽

Fabio D’Anca ◽

Ettore Landini ◽

...

Keyword(s):

Kinematic Model ◽

High Accuracy ◽

Functional Design ◽

Spatial Motion ◽

Precise Positioning ◽

Singular Configurations ◽

Physical Prototype ◽

Parallel Kinematic ◽

Parallel Platform ◽

Accuracy And Repeatability

Parallel kinematic machines (PKMs) have demonstrated their potential in many applications when high stiffness and accuracy are needed, even at micro- and nanoscales. The present paper is focused on the functional design of a parallel platform providing high accuracy and repeatability in full spatial motion. The hexaglide architecture with 6-PSS kinematics was demonstrated as the best solution according to the specifications provided by an important Italian company active in the field of micro-positioning, particularly in vacuum applications. All the steps needed to prove the applicability of such kinematics at the microscale and their inherent advantages are presented. First, the kinematic model of the manipulator based on the study’s parametrization is provided. A global conditioning index (GCI) is proposed in order to optimize the kinetostatic performance of the robot, so that precise positioning in the required platform workspace is guaranteed avoiding singular configurations. Some numerical simulations demonstrate the effectiveness of the study. Finally, some details about the realization of a physical prototype are given.

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Kinematic Model for Determination of Human Arm Reachable Workspace

Meccanica ◽

10.1007/s11012-005-3067-0 ◽

2005 ◽

Vol 40 (2) ◽

pp. 203-219 ◽

Cited By ~ 36

Author(s):

Nives Klopčar ◽

Jadran Lenarčič

Keyword(s):

Kinematic Model ◽

Reachable Workspace ◽

Human Arm

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Optimal Design and Singularity Analysis of a Spatial Parallel Manipulator

Symmetry ◽

10.3390/sym11040551 ◽

2019 ◽

Vol 11 (4) ◽

pp. 551 ◽

Cited By ~ 1

Author(s):

Xiaoyong Wu

Keyword(s):

Optimal Design ◽

Mechanism Design ◽

Parallel Manipulator ◽

Screw Theory ◽

Kinematic Model ◽

Singularity Analysis ◽

Singular Configurations ◽

Simulation Results ◽

Optimal Configurations

Optimal design and singularity analysis are two important aspects of mechanism design, and they are discussed within a spatial parallel manipulator in this work. Resorting to matrix transformation, the parametric kinematic model is established, upon which the inverse position and Jacobian are analyzed. As for optimal design, dexterity and payload indices are taken into consideration. From the simulation results, two optimal configurations are obtained, namely, the star-shaped one and the T-shaped one, and they respectively own the best payload performance and the best dexterity performance. Moreover, the concept of shape singularity is introduced and generalized, which is a special type of singularity that will lead to the singularity in all configurations. The shape singularity of the proposed manipulator is indicated by dexterity index and identified by screw theory. A case study is presented to demonstrate the implication of the shape singularity. Both optimal and singular configurations are useful, and new devices can thus be envisaged for this type of application.

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An innovative equivalent kinematic model of the human upper limb to improve the trajectory planning of exoskeleton rehabilitation robots

Mechanical Sciences ◽

10.5194/ms-12-661-2021 ◽

2021 ◽

Vol 12 (1) ◽

pp. 661-675

Author(s):

Qiaolian Xie ◽

Qiaoling Meng ◽

Qingxin Zeng ◽

Hongliu Yu ◽

Zhijia Shen

Keyword(s):

Upper Limb ◽

Trajectory Planning ◽

Wrist Joint ◽

Kinematic Model ◽

Human Motion ◽

Upper Limb Exoskeleton ◽

Rehabilitation Robots ◽

Proposed Model ◽

Human Arm ◽

Human Upper Limb

Abstract. Upper limb exoskeleton rehabilitation robots have been attracting significant attention by researchers due to their adaptive training, highly repetitive motion, and ability to enhance the self-care capabilities of patients with disabilities. It is a key problem that the existing upper limb exoskeletons cannot stay in line with the corresponding human arm during exercise. The aim is to evaluate whether the existing upper limb exoskeleton movement is in line with the human movement and to provide a design basis for the future exoskeleton. This paper proposes a new equivalent kinematic model for human upper limb, including the shoulder joint, elbow joint, and wrist joint, according to the human anatomical structure and sports biomechanical characteristics. And this paper analyzes the motion space according to the normal range of motion of joints for building the workspace of the proposed model. Then, the trajectory planning for an upper limb exoskeleton is evaluated and improved based on the proposed model. The evaluation results show that there were obvious differences between the exoskeleton prototype and human arm. The deviation between the human body and the exoskeleton of the improved trajectory is decreased to 41.64 %. In conclusion, the new equivalent kinematics model for the human upper limb proposed in this paper can effectively evaluate the existing upper limb exoskeleton and provide suggestions for structural improvements in line with human motion.

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A KINEMATIC MODEL OF THE UPPER LIMB WITH A CLAVICLE-LIKE LINK FOR HUMANOID ROBOTS

International Journal of Humanoid Robotics ◽

10.1142/s0219843608001327 ◽

2008 ◽

Vol 05 (01) ◽

pp. 87-118 ◽

Cited By ~ 5

Author(s):

BERTRAND TONDU

Keyword(s):

Upper Limb ◽

Humanoid Robot ◽

Frontal Zone ◽

Kinematic Model ◽

Shoulder Girdle ◽

Humanoid Robots ◽

Biomechanical Study ◽

The Body ◽

Human Arm ◽

Shoulder Complex

Starting from a biomechanical study of the shoulder complex, the relevance of a serial nine d.o.f. kinematic model of the human arm, including a clavicle-like link, was analyzed. It is shown that this partial biomimetic joint model of the upper limb is able to mimic the ability of the natural arm to practically eliminate internal and bound singularities over a large frontal zone, so as to maintain its elbow laterally to the body. In this sense, it appears to be an advanced solution for increasing the dexterity of humanoid robot upper limbs, thus replacing classical seven d.o.f. anthropomorphic arms where a device mimicking the shoulder girdle mechanism is absent.

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Development of a biomechanically accurate kinematic model for the human arm and hand

10.26678/abcm.cobem2021.cob2021-2180 ◽

2021 ◽

Author(s):

Leonardo de la Roca ◽

Gabriel Luc Rodrigues ◽

José Ribeiro ◽

Americo Cunha Jr ◽

Gabriel de Araújo

Keyword(s):

Kinematic Model ◽

Human Arm

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Human arm kinematics for robot based rehabilitation

Robotica ◽

10.1017/s0263574705002304 ◽

2005 ◽

Vol 24 (3) ◽

pp. 377-383 ◽

Cited By ~ 30

Author(s):

Matjaž Mihelj

Keyword(s):

Virtual Reality ◽

Kinematic Model ◽

Inverse Kinematic ◽

Hand Position ◽

Empirical Validation ◽

Upper Arm ◽

Radial Acceleration ◽

Rehabilitation Robots ◽

Human Arm ◽

Position And Orientation

The paper considers a technique for computation of the inverse kinematic model of the human arm for robot based rehabilitation that uses measurements of the hand position and orientation and radial acceleration of the upper arm. Analytical analysis and empirical validation of the method are presented. The algorithm enables estimation of human arm angles, which can be used in trajectory planning for rehabilitation robots, evaluation of motion of patients with movement disorders, and generation of virtual reality environments.

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