Compared with conventional mechanisms, tensegrity mechanisms have many attractive characteristics such as light weight, high ratio of strength to weight, and accuracy of modeling. In this paper, the kinematics, singularity, and workspaces of a planar 4-bar tensegrity mechanism have been investigated. Firstly, the analytical solutions to the forward and inverse kinematic problems are found by using an energy based method. Secondly, the definition of a tensegrity mechanism&#x2019;s Jacobian is introduced. As a consequence, the singularity analysis of the planar 4-bar tensegrity mechanism has been completed. Thirdly, the actuator and output workspaces are mapped. Finally, some attractive characteristics of the mechanism are concluded.

Zhifei Ji

Tuanjie Li

Min Lin

Kinematics, Singularity, and Workspaces of a Planar 4-Bar Tensegrity Mechanism

A study of the inverse kinematics for a five-degree-of-freedom (DOF) spatial parallel micromanipulator is presented here below. The objective of this paper is the introduction of a structural and geometrical model of a novel five-degree-of-freedom spatial parallel micromanipulator, analysis of the effective and useful workspace of the micromechanism, presentation of the obtained analytical solutions of the microrobot&#x2019;s inverse kinematics tasks, and verification of its correctness using selected computer programs and computation environments. The mathematical model presented in this paper describes the behaviour of individual elements for the applied 2-DOF novel piezoelectric actuator, resulting from the position and orientation of the microrobot&#x2019;s moving platform.

Daniel Prusak

Konrad Kobus

Grzegorz Karpiel

Kinematics Analysis of a Novel Five-Degree-of-Freedom Spatial Parallel Micromanipulator

Kazuhiko Terashima

Shigeyuki Suzuki

Oliver Sawodny

Ryojyun Ikeura

Ken'ichi Yano

Ryo Saegusa

Rehabilitation Robotics 2013

Two mechatronics prototypes, useful for robotic neurotreatments and new clinical trainings, are here presented. P.I.G.R.O. (pneumatic interactive gait rehabilitation orthosis) is an active exoskeleton with an electropneumatic control. It imposes movements on lower limbs in order to produce in the patient&#x2019;s brain proper motor cortex activation. Bra.Di.P.O. (brain discovery pneumatic orthosis) is an MR-compatible device, designed to improve fMRI (functional magnetic resonance imaging) analysis. The two devices are presented together because both are involved in the study of new robotic treatments of patients affected by ictus or brain stroke or in some motor learning experimental investigations carried out on healthy subjects.

Guido Belforte

Gabriella Eula

Silvia Sirolli

Paolo Bois

Elisabetta Geda

Federico D'Agata

Franco Cauda

Sergio Duca

Marina Zettin

Roberta Virgilio

Giuliano Geminiani

Katiuscia Sacco

Bra.Di.P.O. and P.I.G.R.O.: Innovative Devices for Motor Learning Programs

Physiologically and biomechanically, the human body represents a complicated system with an abundance of degrees of freedom (DOF). When developing mathematical representations of the body, a researcher has to decide on how many of those DOF to include in the model. Though accuracy can be enhanced at the cost of complexity by including more DOF, their necessity must be rigorously examined. In this study a planar seven-segment human body walking model with single DOF joints was developed. A reference point was added to the model to track the body&#x2019;s global position while moving. Due to the kinematic instability of the pelvis, the top of the head was selected as the reference point, which also assimilates the vestibular sensor position. Inverse dynamics methods were used to formulate and solve the equations of motion based on Newton-Euler formulae. The torques and ground reaction forces generated by the planar model during a regular gait cycle were compared with similar results from a more complex three-dimensional OpenSim model with muscles, which resulted in correlation errors in the range of 0.9&#x2013;0.98. The close comparison between the two torque outputs supports the use of planar models in gait studies.

Alaa Abdulrahman

Kamran Iqbal

Gannon White

Improving Inverse Dynamics Accuracy in a Planar Walking Model Based on Stable Reference Point

Stress signal is difficult to obtain in the health monitoring of multibody manipulator. In order to solve this problem, a soft sensor method is presented. In the method, stress signal is considered as dominant variable and angle signal is regarded as auxiliary variable. By establishing the mathematical relationship between them, a soft sensor model is proposed. In the model, the stress information can be deduced by angle information which can be easily measured for such structures by experiments. Finally, test of ground and wall working conditions is done on a multibody manipulator test rig. The results show that the stress calculated by the proposed method is closed to the test one. Thus, the stress signal is easier to get than the traditional method. All of these prove that the model is correct and the method is feasible.

Wu Ren

Yunxin Wu

Zhaowei Zhang

Fan Hu

A Large-Scale Multibody Manipulator Soft Sensor Model and Experiment Validation

A current trend in robotics is fusing different types of sensors having different characteristics to improve the performance of a robot system and also benefit from the reduced cost of sensors. One type of robot that requires sensor fusion for its application is the service robot. To achieve better performance, several service robots are preferred to work together, and, hence, this paper concentrates on swarm service robots. Swarm service mobile robots operating within a fixed area need to cope with dynamic changes in the environment, and they must also be capable of avoiding dynamic and static obstacles. This study applies sensor fusion and swarm concept for service mobile robots in human services and rehabilitation environment. The swarm robots follow the human moving trajectory to provide support to human moving and perform several tasks required in their living environment. This study applies a reference control and proportional-integral (PI) control for the obstacle avoidance function. Various computer simulations are performed to verify the effectiveness of the proposed method.

Tresna Dewi

Naoki Uchiyama

Shigenori Sano

Hiroki Takahashi

Swarm Robot Control for Human Services and Moving Rehabilitation by Sensor Fusion

About this journal

Journal of Robotics publishes original research articles as well as review articles on all aspects of automated mechanical devices, from their design and fabrication, to testing and practical implementation.

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Chief Editor&nbsp;Professor Yangmin Li is based at The Hong Kong Polytechnic University, Hong Kong. His research interests include robotics, mechatronics, control and automation.

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Journal of Robotics - Table of contents 2014

title

Journal of Robotics publishes original research articles as well as review articles on all aspects of automated mechanical devices, from their design and fabrication, to testing and practical implementation.

Journal of Robotics