Diplomingenieur (Dipl.-Ing.) The DLR Hand-Arm-System is the first component of a new humanoid robot which is as robust and anthropomorphic as possible. Each joint of the system has an adjustable spring mechanism, which enables to adjust the mechanical stiffness. Additionally, the springs increase the mechanical robustness of the system against impacts. In this thesis the compliance control of t...

Hypotonia, ligament laxity and motor alterations are characteristic for patients with Down syndrome (DS). The purpose of this study was the evaluation of typical gait pattern of subjects with Down syndrome and the quantification of their joint stiffness, connected with ligament laxity and hypotonia, as a possible compensation. 98 children with DS (mean age: 11.7 years; range: 6-15 years) and 30...

Pneumatic artificial muscles (PAMs) have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the fle...

Stiffness following surgery or injury to a joint develops as a progression of four stages: bleeding, edema, granulation tissue, and fibrosis. Continuous passive motion (CPM) properly applied during the first two stages of stiffness acts to pump blood and edema fluid away from the joint and periarticular tissues. This allows maintenance of normal periarticular soft tissue compliance. CPM is thus...

This paper presents a simple procedure that can be used to determine the stiffness matrix of 6R serial manipulator in selected points of the work space with joint stiffness coefficients taking into account. Elastokinematical model for the robot manipulator FANUC S-420F was considered as spatial and serial kinematical chain composed of six rigid links, connected by ideal revolute joint (without ...

A prototype of a variable stiffness prosthetic joint has been constructed and tested. The joint is based on two actuator subsystems arranged in an antagonistic configuration. Each actuator subsystem is composed of a small, high-speed electric motor, a single stage, worm-gear based transmission and a nonlinear stiffness element. Each nonlinear stiffness element is composed of a set of short sect...

Joints with variable stiffness are used to introduce modal disparity in a frame structure. The joint stiffness can be set at two distinct values and thus the structure can be characterized by two stiffness states. The placement of a small number of these joints on the structure is optimized to achieve a maximum measure of modal disparity. This allows the migration of vibration energy from modes...

A new vibration isolation system is proposed which uses zero-power magnetic suspension. Since a zero-power system behaves as if it has a negative stiffness, combining it with a normal spring can generate infinite stiffness against disturbances on the isolation table. It enables the system to have good performance both in reducing vibration transmitted from ground and in suppressing direct vibra...

Kuitunen, Sami Muscle and joint stiffness regulation during normal and fatiguing stretchshortening cycle exercise Jyväskylä: University of Jyväskylä, 2010, 76 p. (Studies in Sport, Physical Education and Health, ISSN 0356-1070; 149) ISBN 978-951-39-3969-4 (PDF), 978-951-39-3954-0 (nid.) Finnish summary Diss. The present series of studies were designed to investigate the regulation of leg stiffn...