Variable stiffness robotic hand for stable grasp and flexible handling

Mahboubi, S; Davis, ST; Nefti-Meziani, S

Abstract

Robotic grasping is a challenging area in the field of robotics. When interacting with an object, the dynamic properties of the object will play an important role where a gripper (as a system), which has been shown to be stable as per appropriate stability criteria, can become unstable when coupled to an object. However, including a sufficiently compliant element within the actuation system of the robotic hand can increase the stability of the grasp in the presence of uncertainties. This paper deals with an innovative robotic variable stiffness hand design, VSH1, for industrial applications. The main objective of this work is to realise an affordable, as well as durable, adaptable, and compliant gripper for industrial environments with a larger interval of stiffness variability than similar existing systems. The driving system for the proposed hand consists of two servo motors and one linear spring arranged in a relatively simple fashion. Having just a single spring in the actuation system helps us to achieve a very small hysteresis band and represents a means by which to rapidly control the stiffness. We prove, both mathematically and experimentally, that the proposed model is characterised by a broad range of stiffness. To control the grasp, a first-order sliding mode controller (SMC) is designed and presented. The experimental results provided will show how, despite the relatively simple implementation of our first prototype, the hand performs extremely well in terms of both stiffness variability and force controllability.

• Journal Article Type: Article
• Acceptance Date: Oct 24, 2018
• Online Publication Date: Nov 5, 2018
• Publication Date: Nov 5, 2018
• Deposit Date: Nov 12, 2018
• Publicly Available Date: Nov 12, 2018
• Journal: IEEE Access
• Electronic ISSN: 2169-3536
• Publisher: Institute of Electrical and Electronics Engineers
• Volume: 6
• Pages: 68195-68209
• DOI: https://doi.org/10.1109/ACCESS.2018.2879633
• Publisher URL: https://doi.org/10.1109/ACCESS.2018.2879633
• Related Public URLs: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=6287639
• Additional Information: Funders : People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme; Projects : FP7/2007-2013/; Grant Number: 608022