[robotics-worldwide] [meetings] ICRA 2018 workshop Soft Robotics for Rehabilitation Applications: Design, Material and Control

ernesto hernandez ernestoh_92 at hotmail.com
Thu Mar 22 10:38:41 PDT 2018


Advanced Robotic Manipulators (ARM) lab at University of Texas at San Antonio will organize:

ICRA 2018 workshop
Soft Robotics for Rehabilitation Applications:
Design, Material and Control

The current robotic rehabilitation systems are powerful and active but usually bulky and made of rigid elements, such as exoskeletons. This prevent fully exploiting the use of robotic systems in rehabilitation applications and sometime can even present danger to the patients.  Indeed, to guarantee safety of the human in any direct physical interaction, the softness should be intrinsic to the robot’s structure. The emerging field of soft robotics will present the foundation of future robotic systems with plethora of applications in human-robot interaction, locomotion, and especially in rehabilitation technologies.
Soft robotic systems have the potential of changing the lingering status-quo of bulky robotics, since they can easily deform and adapt to dynamic environments and human body.
However, the design of rehabilitation devices that are soft, light, wearable and powerful is a grand challenge. The new field of soft robotics, required substantially different design, material development and control approaches to deal with continues deformable body of these platforms in interaction with humans. This workshop will bring together globally recognized robotistics, material scientists and control engineers to discuss practical applications of soft robotics in robotic application from different perspectives of material, design and control.

Invited Speakers
1- Neville Hogan, Massachusetts Institute of Technology,
Challenges and opportunities of soft robotics for rehabilitation:
        Robotic assistance to recover after neurological injury depends critically on the robot’s ability to provide permissive-assistance-as-needed. Soft human-interactive robotics promise unprecedented ability to provide this capability while simultaneously accommodating the kinematic peculiarities of the human skeleton. However, this technology has drawbacks as well as advantages in this application arena. This presentation will show that, at least for lower-extremity rehabilitation after stroke, technology should reduce joint mechanical impedance rather than enhance it. This may be a challenge for many soft robotic actuator designs, which tend to increase mechanical impedance. Possible advantages of antagonistic tensile actuator designs, which may act to reduce mechanical impedance, will be reviewed. Conversely, the ability of soft robotics to selectively increase the mechanical impedance of individual joints may afford new approaches to therapy. It may provide a means to resolve the abnormal kinematic synergies that commonly accompany the abnormal muscle tone patterns resulting from neurological injury.

2- Carmel Majidi, Carnegie Mellon University
Cutting the Cord – Integrated Sensing, Actuation, and Robust Electronics for Soft Robot Autonomy
        Progress in soft lithography, additive manufacturing, biohybrid engineering, and soft materials integration have lead to extraordinary new classes of soft-matter sensors, circuits, and actuators.  These materials represent the building blocks of soft machines, robots, and bio-inspired systems that will exhibit the rich multifunctional versatility and robust adaptability of soft biological organisms.  While there are key challenges in materials and manufacturing that remain to be addressed, further progress in soft robotics now depends on accomplishing a new set of goals:  systems-level materials integration, untethered functionality, and robot autonomy.  In this talk, I will focus on this latter set of challenges and the new fundamental questions that emerge when exploring the interface of soft multifunctional materials, rigid microelectronics, and robot mobility.  In particular, I will report efforts by my lab to create an untethered soft robot capable of walking in a variety of environments, including rocky terrain and confined spaces.  I’ll also present recent work on mechanically robust and self-healing electronics that can withstand extreme loading and damage.  When used as internal circuit wiring within an electrically-powered soft robot, such materials enable autonomous response to tearing, puncturing, or material removal – damage modes that would be catastrophic for most other soft-bodied robots.  I will close by highlighting ongoing efforts to create new computational tools for modeling the motion and surface interactions of limbed soft robots.  Based on continuum mechanics, finite element analysis, and emerging techniques in computer graphics, these tools represent another critical requirement for soft robot autonomy by potentially enabling on-board computational intelligence and adaptive decision making.

3- Amir Jafari, University of Texas at San Antonio
Bilaterally adjusting the surface stiffness, a new rehabilitation approach
        Surface  stiffness  plays  an  important  role  in  human locomotion mechanics. This would affect both the energy expenditure  and  gait  of  the  human.  This  work  presents  the  design and  development  of  a  novel  Treadmill  with  adjustable  stiffness (TwAS) with the Ability to Regulate the Vertical Stiffness of the Ground. The novelty of the system is on its stiffness adjustment mechanism  which  allows  for  vertical  stiffness  of  the  surface  to change  quickly  (less  than  0.5  second)  from  almost completely  passive to  the structural  stiffness of the system,  with  minimum  energy  consumption, independent of the location of the person over the treadmill. The design  also  allows  for  bilateral  surface  stiffness  regulation  (i.e. both  legs,  independently)  that  is  an  extremely  helpful  criterion in  studying  the  locomotion  mechanics  and  eventually  gaining valuable  insights  into  best  rehabilitation  strategies  of  mobility impaired   patients.   In   order   to   show   the   proof   of   concept, we  present  experiments  to  show  the  effect  of  surface  stiffness regulation  on  the  metabolic  cost  and  gait  of  a  healthy  subject.

4- Houman Dallali, California State University

Locomotion Envelopes for Adaptive Control of Powered Ankle Prostheses
         In this presentation we combine Gaussian process regression and impedance control, to illicit robust, anthropomorphic, adaptive control of a powered ankle prosthesis. We learn the non-linear manifolds which guide how locomotion variables temporally evolve, and regress that surface over a velocity range to create a manifold. The joint set of manifolds, as well as the temporal evolution of the gait-cycle duration is what we term
a locomotion envelope. Current powered prostheses have problems adapting across speeds. It is likely that humans rely upon a control strategy which is adaptable, can become more robust and accurate with more data and provides a nonparametric approach which allows the strategy to grow with the number of observations. We demonstrate such a strategy in this study and successfully simulate locomotion well beyond our training data. The method we propose is based on common physical features observed in numerous human subjects walking at different speeds. Based on the derived locomotion envelopes we show that ankle power increases monotonically with speed among all subjects. We demonstrate our methods in simulation and human experiments, on a powered ankle foot prosthesis to demonstrate the
effectiveness of the method.
5- David Braun, Singapore University of Design and Technology,
Analytical theory of variable stiffness actuator design

Variable stiffness actuators used to drive prosthetic devices, orthotic devices, and wearable exoskeletons are analogous to biological muscles moving human limbs. Despite the theoretical appeal of using these actuators, and recent advances in controlling these actuators, their design remains experience-based and not well understood. This presentation will cover our effort in developing analytical and optimization-based frameworks for the design of efficient and mechanically minimalistic variable stiffness systems.

6- Ahmad Taha, University of Texas at San Antonio
Time-Varying Actuator Selection and Robust Control Methods for Dynamic Systems with Applications to Soft Robotics
                Many dynamic systems such as soft robotics include a large number of actuators. Recently, various studies have shown that these systems can be actuated with a subset of the available actuators, while still producing reasonable energy performance and robustness guarantees. In short, control algorithms can be developed to minimize the number of activated actuators while not incurring large control inputs. In this talk, the speaker presents new optimization-based methods that simultaneously solve for (a) the time-varying selection of actuators and (b) state-feedback control laws for the activated actuators. The methods are developed linear systems with unknown disturbances. The combinatorial nature of actuator selection methods often entails solving highly nonconvex optimization routines. To that end, convex relaxations and approximations are discussed to ensure scalability of the proposed methods. The developed approach is then applied to the control of artificial muscles with electromagnetic soft actuators. A mathematical model depicting the dynamic network of artificial muscles network is derived given unknown disturbances due to external forces and linearization errors. Then, a robust control and minimal actuator selection problem with logistic constraints and maximum voltage bounds is solved. Numerical tests are finally presented showcasing the presented computational approach.

Call for Papers
Contribution following the IEEE RAS paper template for addressing one of the workshop topics.
An accompanying video is optional and can also be provided as a weblink (e.g., youtube).
All contributions must be sent as a pdf file to
amir.jafari at utsa.edu<mailto:amir.jafari at utsa.edu>
Accepted contributions will be allocated in Soft Robotics for Rehabilitation book that will be published by Elsevier.

Important Dates
        Submission Deadline: March 25st, 2018
        Acceptance Notification: April 15th, 2018

More information about the robotics-worldwide mailing list