Miniaturized Pneumatic Artificial Muscles Actuating a Bio-Inspired Robot Hand

2013 ◽  
Author(s):  
Thomas E. Pillsbury ◽  
Ryan M. Robinson ◽  
Norman M. Wereley
Keyword(s):  
Degrees Of Freedom ◽  
Full Scale ◽  
Constitutive Relationship ◽  
Force Density ◽  
Human Hand ◽  
Artificial Muscles ◽  
Specific Work ◽  
Robotic Hand ◽  
Robot Hand ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are used in robotics applications for their light-weight design and superior static performance. Additional PAM benefits are high specific work, high force density, simple design, and long fatigue life. Previous use of PAMs in robotics research has focused on using “large,” full-scale PAMs as actuators. Large PAMs work well for applications with large working volumes that require high force and torque outputs, such as robotic arms. However, in the case of a compact robotic hand, a large number of degrees of freedom are required. A human hand has 35 muscles, so for similar functionality, a robot hand needs a similar number of actuators that must fit in a small volume. Therefore, using full scale PAMs to actuate a robot hand requires a large volume which for robotics and prosthetics applications is not feasible, and smaller actuators, such as miniature PAMs, must be used. In order to develop a miniature PAM capable of producing the forces and contractions needed in a robotic hand, different braid and bladder material combinations were characterized to determine the load stroke profiles. Through this characterization, miniature PAMs were shown to have comparably high force density with the benefit of reduced actuator volume when compared to full scale PAMs. Testing also showed that braid-bladder interactions have an important effect at this scale, which cannot be modeled sufficiently using existing methods without resorting to a higher-order constitutive relationship. Due to the model inaccuracies and the limited selection of commercially available materials at this scale, custom molded bladders were created. PAMs created with these thin, soft bladders exhibited greatly improved performance.

scholarly journals Flatness-Based Control of a Two Degrees-of-Freedom Platform With Pneumatic Artificial Muscles

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
David Bou Saba ◽  
Paolo Massioni ◽  
Eric Bideaux ◽  
Xavier Brun
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Sliding Mode ◽  
Feedforward Control ◽  
Volume Ratio ◽  
Open Loop ◽  
Control Technique ◽  
Artificial Muscles ◽  
Two Degrees Of Freedom ◽  
Pneumatic Artificial Muscles

Pneumatic artificial muscles (PAMs) are an interesting type of actuators as they provide high power-to-weight and power-to-volume ratio. However, their efficient use requires very accurate control methods taking into account their complex and nonlinear dynamics. This paper considers a two degrees-of-freedom platform whose attitude is determined by three pneumatic muscles controlled by servovalves. An overactuation is present as three muscles are controlled for only two degrees-of-freedom. The contribution of this work is twofold. First, whereas most of the literature approaches the control of systems of similar nature with sliding mode control, we show that the platform can be controlled with the flatness-based approach. This method is a nonlinear open-loop controller. In addition, this approach is model-based, and it can be applied thanks to the accurate models of the muscles, the platform and the servovalves, experimentally developed. In addition to the flatness-based controller, which is mainly a feedforward control, a proportional-integral (PI) controller is added in order to overcome the modeling errors and to improve the control robustness. Second, we solve the overactuation of the platform by an adequate choice for the range of the efforts applied by the muscles. In this paper, we recall the basics of this control technique and then show how it is applied to the proposed experimental platform. At the end of the paper, the proposed approach is compared to the most commonly used control method, and its effectiveness is shown by means of experimental results.

scholarly journals Virtualization of Robotic Hands Using Mobile Devices †

Robotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 81
Author(s):  
Santiago T. Puente ◽  
Lucía Más ◽  
Fernando Torres ◽  
and Francisco A. Candelas
Keyword(s):  
Degrees Of Freedom ◽  
Robotic Hand ◽  
Robot Hand ◽  
Real Time Control ◽  
Robotic Hands ◽  
Robot Operating System ◽  
Server Side ◽  
Time Control ◽  
Unity 3D ◽  
Real Robot

This article presents a multiplatform application for the tele-operation of a robot hand using virtualization in Unity 3D. This approach grants usability to users that need to control a robotic hand, allowing supervision in a collaborative way. This paper focuses on a user application designed for the 3D virtualization of a robotic hand and the tele-operation architecture. The designed system allows for the simulation of any robotic hand. It has been tested with the virtualization of the four-fingered Allegro Hand of SimLab with 16 degrees of freedom, and the Shadow hand with 24 degrees of freedom. The system allows for the control of the position of each finger by means of joint and Cartesian co-ordinates. All user control interfaces are designed using Unity 3D, such that a multiplatform philosophy is achieved. The server side allows the user application to connect to a ROS (Robot Operating System) server through a TCP/IP socket, to control a real hand or to share a simulation of it among several users. If a real robot hand is used, real-time control and feedback of all the joints of the hand is communicated to the set of users. Finally, the system has been tested with a set of users with satisfactory results.

Model-Based Feedforward Control of a Robotic Manipulator With Pneumatic Artificial Muscles

2012 ◽  
Author(s):  
Ryan M. Robinson ◽  
Norman M. Wereley ◽  
Curt S. Kothera
Keyword(s):  
Control Algorithm ◽  
Controller Design ◽  
Feedforward Control ◽  
Artificial Muscles ◽  
Specific Work ◽  
Pneumatic Actuators ◽  
Precise Control ◽  
Model Based ◽  
Pneumatic Artificial Muscles ◽  
Dynamics Simulations

Pneumatic artificial muscles (PAMs) are lightweight, flexible actuators capable of higher specific work than comparably-sized hydraulic actuators at the same pressure and electric motors. PAMs are composed of an elastomeric bladder surrounded by a helically braided sleeve. Lightweight, compliant actuators are particularly desirable in portable, heavy-lift robotic systems intended for interaction with humans, such as those envisioned for patient assistance in hospitals and battlefield casualty extraction. However, smooth and precise control remains difficult because of nonlinearities in the dynamic response. The objective of this paper is to develop a control algorithm that satisfies accuracy and smooth motion requirements for a two degree-of-freedom manipulator actuated by pneumatic artificial muscles and intended for interaction with humans, such as lifting a human. This control strategy must be capable of responding to large, abrupt variations in payload weight over a high range of motion. In previous work, the authors detailed the design and construction of a proof-of-concept PAM-based manipulator. The present work investigates the feasibility of combining output feedback using proportional-integral-derivative control or fuzzy logic control with model-based feedforward compensation to achieve improved closed-loop performance. The model upon which the controller is based incorporates the internal airflow dynamics, the geometric parameters of the pneumatic actuators, and the arm dynamics. Simulations were performed in order to validate the control algorithm, guide controller design, and predict optimal gains. Using real-time interface software and hardware, the controller was implemented and experimentally tested on the manipulator. Performance was evaluated for several trajectories, and different payload weights. The effect of varying the feedforward gain was also analyzed. Model refinement further improved performance.

Contractile Pneumatic Artificial Muscle Configured to Generate Extension

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Benjamin K. S. Woods ◽  
Shane M. Boyer ◽  
Erica G. Hocking ◽  
Norman M. Wereley ◽  
Curt S. Kothera
Keyword(s):  
Compressive Loading ◽  
Compressive Force ◽  
Artificial Muscle ◽  
Specific Power ◽  
Artificial Muscles ◽  
Specific Work ◽  
Operational Characteristics ◽  
Pneumatic Artificial Muscles ◽  
High Specific Power ◽  
Internal Mechanism

Pneumatic artificial muscles (PAMs) are comprised of an elastomeric bladder surrounded by a braided mesh sleeve. When the bladder is inflated, the actuator may either contract or extend axially, with the direction of motion dependent on the orientation of the fibers in the braided sleeve. Contractile PAMs have excellent actuation characteristics, including high specific power, specific work, and power density. Unfortunately, extensile PAMs exhibit much reduced blocked force, and are prone to buckling under axial compressive loading. For applications in which extensile motion and compressive force are desired, the push-PAM actuator introduced here exploits the operational characteristics of a contractile PAM, but changes the direction of motion and force by employing a simple internal mechanism using no gears or pulleys. Quasi-static behavior of the push-PAM was compared to a contractile PAM for a range of operating pressures. Based on these data, the push-PAM actuator can achieve force and stroke comparable to a contractile PAM tested under the same conditions.

Optimized Fingertip Mapping:A General Algorithm for Robotic Hand Teleoperation

1993 ◽  
Vol 2 (3) ◽  
pp. 203-220 ◽  
Author(s):  
Robert N. Rohling ◽  
John M. Hollerbach ◽  
Stephen C. Jacobsen
Keyword(s):  
General Algorithm ◽  
Human Hand ◽  
Robotic Hand ◽  
Robot Hand ◽  
Mapping Strategy ◽  
Robot Hands ◽  
A Priority ◽  
Dextrous Hand

An optimized fingertip mapping (OFM) algorithm has been developed to transform human hand poses into robot hand poses. It has been implemented to teleoperate the Utah/MIT Dextrous Hand by a new hand master: the Utah Dextrous Hand Master. The keystone of the algorithm is the mapping of both the human fingertip positions and orientations to the robot fingers. Robot hand poses are generated by minimizing the errors between desired human fingertip positions and orientations and possible robot fingertip positions and orientations. Differences in the fingertip workspaces that arise from kinematic dissimilarities between the human and robot hands are accounted for by the use of a priority based mapping strategy. The OFM gives first priority to the human fingertip position goals and the second to orientation.

A Modular Approach for Lightweight Humanoid Hand Design Using High Torque Density Electric Actuators

2018 ◽  
Author(s):  
Haotian Cui ◽  
Shuangyue Yu ◽  
Xunge Yan ◽  
Shuo-Hsiu Chang ◽  
Gerard Francisco ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Human Hand ◽  
Average Weight ◽  
Robot Hand ◽  
Electric Motors ◽  
Robotic Hands ◽  
Torque Density ◽  
High Torque ◽  
Humanoid Hand

The human hand has extraordinary dexterity with more than 20 degrees of freedom (DOF) actuated by lightweight and efficient biological actuators (i.e., muscles). The average weight of human hand is only 400g [1]. Over the last few decades, research and commercialization effort has been dedicated to the development of novel robotic hands for humanoid or prosthetic application towards dexterous and biomimetic design [2]. However, due to the limitations of existing electric motors in terms of torque density and energy efficiency, the design of humanoid hands has to compromise between dexterity and weight. For example, commercial prosthetic terminal devices i-Limb [3] and Bebionic [4] prioritize the lightweight need (450g) and use 5-DOF motors to under-actuated 11 joints, which is only able to realize a few basic grasp postures. On the other hand, some humanoid robot hand devices like DLR-HIT I & II hands [5] prioritize the dexterity need (15 DOF), but weigh more than four times than their biological counterpart (2200g and 1500g, respectively).

Kinematic Analysis of an Anthropomorphic Robot Hand

2012 ◽  
Vol 187 ◽  
pp. 293-297
Author(s):  
Pramod Kuma Parida ◽  
Bibhuti Bhusan Biswal ◽  
Dhirendra Nath Thatoi
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Industrial Applications ◽  
Human Hand ◽  
Robot Hand ◽  
Orthopedic Rehabilitation ◽  
Robot Hands

There has been a continuous effort by researchers to develop multi-fingered robot hands for variety of applications. Some of these hands are meant for industrial applications while thers are used for orthopedic rehabilitation of humans. However the degree of success to develop an anthropomorphic robot hand in close resemblence with a typical human hand has not been satisfactory. In the present work an attempt has been made to design a robot hand having five fingers with 25 degrees of freedom by closly following the anatomy of human hand.The kinematic analysis of the hand offers confirmative results for effective graspingand manipulating objects.

Design and testing of a high-specific work actuator using miniature pneumatic artificial muscles

2012 ◽  
Vol 23 (3) ◽  
pp. 365-378 ◽  
Author(s):  
Robert D. Vocke ◽  
Curt S. Kothera ◽  
Anirban Chaudhuri ◽  
Benjamin K.S. Woods ◽  
Norman M. Wereley
Keyword(s):  
Angular Rate ◽  
Active Material ◽  
Small Scale ◽  
Artificial Muscles ◽  
Prototype System ◽  
Specific Work ◽  
Pneumatic Actuators ◽  
Actuation System ◽  
Angular Deflection ◽  
Pneumatic Artificial Muscles

Micro-air vehicle (MAV) development is moving toward smaller and more capable platforms to enable missions such as indoor reconnaissance. This miniaturization creates challenging constraints on volume and energy generation/storage for all systems onboard. Actuator technologies must also address these miniaturization goals. Much research has focused on active material systems, such as piezoelectric materials and synthetic jets, but these advanced technologies have specific, but limited, capability. Conventional servo technology has also encountered concerns over miniaturization. Motivation has thus been established to develop a small-scale actuation technology prototype based on pneumatic artificial muscles, which are known for their lightweight, high-output, and low-pressure operation. The miniature actuator provides bidirectional control capabilities for a range of angles, rates, and loading conditions. Problems addressed include the scaling of the pneumatic actuators and design of a mechanism to adjust the kinematic load-stroke profile to suit the pneumatic actuators. The kinematics of the actuation system was modeled, and a number of bench-top configurations were fabricated, assembled, and experimentally characterized. Angular deflection and angular rate output of the final bench-top prototype system are presented, showing an improvement over conventional servo motors used in similar applications, especially in static or low-frequency operation.

scholarly journals Smart Materials and Their Application in Robotic Hand Systems: A State of the Art

2021 ◽  
Vol 6 (2) ◽  
pp. 401-426
Author(s):  
Paola Andrea Castiblanco ◽  
José Luis Ramirez ◽  
Astrid Rubiano
Keyword(s):  
Upper Limb ◽  
Human Body ◽  
Smart Materials ◽  
State Of The Art ◽  
The State ◽  
Soft Robotics ◽  
Human Hand ◽  
Artificial Muscles ◽  
Robotic Hand ◽  
Robotic Devices

The use of soft robotics and smart materials for the design of devices that help the population in different tasks has gained a rising interest. Medicine is one of the fields where its implementation has shown significant advances. However, there are works related to applications, directed to the human body especially in replacement of devices for the upper limb. This document aims to explore the state of the art relating to the study of soft robotics, the implementation of smart materials, and the artificial muscles in the design or construction of hand prostheses or robotic devices analogous to the human hand.

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