A Robot Gripper With Variable Stiffness Actuation for Enhancing Collision Safety

2020 ◽  
Vol 67 (8) ◽  
pp. 6607-6616
Author(s):  
Amirhossein H. Memar ◽  
Ehsan Tarkesh Esfahani
Keyword(s):  
Variable Stiffness ◽  
Robot Gripper ◽  
Collision Safety ◽  
Variable Stiffness Actuation

Design and Analysis of New Haptic Joysticks for Enhancing Operational Skills in Excavator Control

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Meera C S ◽  
Pinisetti Swami Sairam ◽  
Vineeth Veeramalla ◽  
Adarsh Kumar ◽  
Mukul Kumar Gupta
Keyword(s):  
User Interfaces ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Variable Stiffness ◽  
Significant Drop ◽  
Innovative Method ◽  
Resistive Torque ◽  
Kinesthetic Feedback ◽  
Variable Stiffness Actuation ◽  
Design Perspective

Abstract The design perspective of interfaces has strong implications on operator intuition and safety. Haptics enabled user interfaces can enhance operator skills and enhance interactivity. In this paper, an innovative method of haptic feedback in joysticks is presented for excavator control. Haptic illusion in the device is generated with the concept of the variable stiffness actuation mechanism. The force feedback (FFB) is rendered through “haptic links,” based on the effect of digging force at each joint. The stiffness in the device varies dynamically with the load and restricts the operator motion with a resistive torque in the range of 0–0.9 Nm. The haptic joystick aims to render high-fidelity kinesthetic feedback that can help to mitigate the operator error in loading operations. The user evaluation with the joystick showed an improvement of 40% in the volume of material removed and a significant drop in error rate related to force patterns and collisions.

Application of a Biphasic Actuator in the Design of a Robot Gripper for Garment Handling

2014 ◽  
Author(s):  
Loan Le ◽  
Matteo Zoppi ◽  
Michal Jilich ◽  
Han Bo ◽  
Dimiter Zlatanov ◽  
...  
Keyword(s):  
Hydraulic System ◽  
Degrees Of Freedom ◽  
Mechanical Design ◽  
Variable Stiffness ◽  
Robot System ◽  
Robot Gripper ◽  
Task Requirements ◽  
Grasping And Manipulation ◽  
Variable Stiffness Actuator

The paper describes a novel robot gripper for garment handling. The device has been designed, developed, prototyped, and tested within the CloPeMa European Project creating a robot system for automated manipulation of clothing and other textile items. The gripper has two degrees of freedom and includes both rigid and flexible elements. A variable-stiffness actuator has been implemented to add controlled compliance in the gripper’s operation allowing the combining of various grasping and manipulation tasks. First, we analyze the specific application-determined task requirements, focusing on the need for adaptive flexibility and the role of compliant elements in the design. The chosen solution is a simple planar mechanism, equipped with one standard and one variable-stiffness actuator. The mechanical design of the gripper, including the hydraulic system used in the biphasic actuator, is outlined, and the control architecture, using sensor feedback, is described.

Bidirectional antagonistic variable stiffness actuation: Analysis, design & Implementation

2010 ◽  
Author(s):  
Florian Petit ◽  
Maxime Chalon ◽  
Werner Friedl ◽  
Markus Grebenstein ◽  
Alin Albu-Schaffer ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Variable Stiffness Actuation ◽  
Analysis Design

scholarly journals Output-Based Control of Robots with Variable Stiffness Actuation

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Gianluca Palli ◽  
Claudio Melchiorri
Keyword(s):  
Degrees Of Freedom ◽  
State Feedback ◽  
Joint Stiffness ◽  
Variable Stiffness ◽  
Cascade System ◽  
Work Space ◽  
Consequent Reduction ◽  
Variable Stiffness Actuation ◽  
Feedback Techniques ◽  
Selection Of

The output-based control of a redundant robotic manipulator with relevant and adjustable joint stiffness is addressed. The proposed controller is configured as a cascade system that allows the decoupling of the actuators dynamics from the arm dynamics and the consequent reduction of the order of the manipulator dynamic model. Moreover, the proposed controller does not require the knowledge of the whole robot state: only the positions of the actuators and of the joints are necessary. This approach represents a significant simplification with respect to previously proposed state feedback techniques. The problem of controlling simultaneously the position trajectory and the desired stiffness in both the joint and work space is investigated, and the relations between the manipulator redundancy and the selection of both the joint and work space stiffness of the manipulator are discussed. The effectiveness of the proposed approach is verified by simulations of a 3 degrees of freedom planar manipulator.

Design of a 2D Haptic System With Passive Variable Stiffness Using Permanent Magnets for Upper-Limb Rehabilitation

2017 ◽  
Author(s):  
Sri Sadhan Jujjavarapu ◽  
Amirhossein H. Memar ◽  
Ehsan T. Esfahani
Keyword(s):  
Upper Limb ◽  
Permanent Magnets ◽  
Variable Stiffness ◽  
End Effector ◽  
Upper Limb Rehabilitation ◽  
Actuation System ◽  
Rehabilitation System ◽  
Variable Stiffness Actuation ◽  
Active Rehabilitation ◽  
Limb Rehabilitation

This paper presents a design of variable stiffness actuation system based on on the force interactions caused by permanent magnets. The system is designed for rehabilitation of the upper limb with the goal to enhance rehabilitation in both clinical and home environments. The proposed active rehabilitation system is composed of a lightweight 6-axes robotic arm to move the patients hand in the desired trajectory. The interaction stiffness is controlled by the mechanism attached to the end-effector. For this purpose, repelling magnet pairs in linear antagonistic configuration are used to control the stiffness of the handle. Stiffness in the mechanism can be controlled via adjusting the distance between the magnets. A mathematical model is presented to analyze the range of adjustable variable stiffness for this mechanism.

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