Conceptual mechanical design of antagonistic variable stiffness joint based on equivalent quadratic torsion spring

Design, development and scaling analysis of a variable stiffness magnetic torsion spring

In this paper we report on the design, modeling, experimental testing and scaling analysis of a novel MAgnetic Variable stiffnEess spRIng-Clutch (MAVERIC) device, which may be used as the elastic element of Variable Stiffness Actuators (VSAs). The device, comprising two co-axial diametrically magnetized hollow cylinders, has two degrees of freedom: a rotation of the two cylinders around the com...

Mechanical Influences on the Design of Actuators with Variable Stiffness

In the 1990s compliant joint actuation was introduced to robotics with the Series Elastic Actuator [1] and the Mechanical Impedance Adjuster [2]. Such concepts provide safer human-robot interaction, can store energy and decrease force control effort [1]. In the following decades, energy efficient actuation with such concepts had high impact in mobile applications such as bipedal robots, since t...

Friction Compensation and Stiffness Evaluation on a Variable Torsion Stiffness

With safety aspects due to closer human-robot interaction and increased requirements in energy effiency due to mobile applications, series elastic joint concepts receive high priority in contemporary robotics. Beyond making robots more safe and flexbile, such concepts can store energy and thus optimize the energetic efficiency of the robot’s motion. Therefore adjusting the stiffness is advantag...

A Stiffness Estimator for Agonistic-Antagonistic Variable-Stiffness-Actuator Devices

Safe Physical Human Robot Interaction, conservation of energy and adaptability are just the main robotic applications that prompted the development of a number of Variable Stiffness Actuators (VSA). Implemented in a variety of ways, they use various technologies, and feature the most diverse mechanical solutions, all of which share a fundamentally unavoidable nonlinear behavior. The control sch...

Energy Efficient Variable Stiffness Actuators: Conceptual Design and Implementation