A new variable stiffness design: Matching requirements of the next robot generation

Abstract

Abstract-Facing new tasks, the conventional rigid design of robotic joints has come to its limits. Operating in unknown environments current robots are prone to failure when hitting unforeseen rigid obstacles. Moreover, safety constraints are a major aspect for robots interacting with humans. In order to operate safely, existing robotic systems in this field are slow and have a lack of performance. To circumvent these limitations, a new robot joint with a variable stiffness approach (VS-Joint) is presented. It combines a compact and highly integrated design with high performance actuation. The VSJoint features a highly dynamic stiffness adjustment along with a mechanically programmable system behavior. This allows an easy adaption to a big variety of tasks. A benefit of the joint is its intrinsic robustness against impacts and hard contacts, which permits faster trajectories and handling. Thus, it provides excellent attributes for the use in shoulder and elbow joints of an anthropomorphic robot arm.

Compliant Robotics and Automation with Flexible Fluidic Actuators and Inflatable Structures

“…This concept is referred to as series elastic actuation and has been carried out in many various forms [24,121,138,140]. Other drives with more or less inherent compliance are piezo-drives, shape-memory-actuators (SMA), electrorheological drives, and polymeric actuators.…”

Exploiting Variable Stiffness in Explosive Movement Tasks

“…From the perspective of mechanical design, VSAs are often developed with an antagonistic architecture [10,19], but have also been developed using more practical (technical) objectives [21,25]. Typically, this introduces additional complexity to the dynamics in the form of non-linearities, coupling of stiffness and motion characteristics, and increased dimensionality of the control input.…”

Small-Sized Variable Stiffness Actuator Module Based on Adjustable Moment Arm

“…두 개의 모터가 비 선형성의 탄성요소로 연결되어 장력을 조절하는 방식을 채택한 MACCEPA, (6) VSA-II (7) 및 VSAJoint, (2) 판 스프링을 활용한 VSJ, (8) 가변 모멘트 팔 기반의 HDAU, (9) AwAS, (10) AwAS-II (11) 및 vsaUT-II (12) …”