Symbitron ‒ BioRob ‐ EPFL

Project Description

Symbitron: Symbiotic man-machine interactions in wearable exoskeletons to enhance mobility for paraplegics

2013-10-01 to 2018-03-31 (ongoing project)

The goal of Symbitron is to enable individuals with paraplegia to regain mobility with a novel lower-limb exoskeleton and a bio-inspired controller. BioRob’s role is to develop and test a neuromuscular controller that can produce various walking gaits with resemblance to human kinematics, kinetics, and muscle activations with few sensors and no pre-defined reference patterns.

Neuromuscular Controller

For real world function, wearable devices to assist gait should be highly responsive to both the user and the environment. Users should also be able to interact with the device in an intuitive manner. This positive shared control between machine and human is especially important for individuals with spinal cord injuries, where active recruitment of their own neuromuscular system could promote motor recovery. Here we demonstrate the capability of a biologically-inspired neuromuscular controller (NMC) and its use in assisting the gait of SCI test pilots.

The NMC was based on a sagittal plane neuromechanical simulation developed by Hartmut Geyer, which generates walking by activating simulated muscle reflex loops stimulated by few sensory imputs. Only the foot contact states and joint angles are needed to activate the simulated reflex loops of the Hill-type muscle models. The stance reflexes loop provides weight bearing support during the stance phase, and the swing reflexes allow the leg to flex and swing freely. The muscle forces generated from the virtual muscle dynamics combine to produce knee and hip torque commands to the gait trainer. The advantages of this controller over other approaches include robustness, modularity, and adaptability. In particular, the controller does not require filtering of its inputs (as with myoelectric control), can be decomposed into relevant modules (e.g. only knee or hip control), and can generate walking at different speeds and on different terrains in simulation.

For implementation on hardware, we developed a NMC Simulink library with control modules that allowed for tailoring to specific exoskeleton devices. So far we have tested the NMC on three different devices. The ankle module was tested on powered ankle exoskeleton Achilles, and the knee and hip modules were tested with gait trainer LOPES (both devices are from UTwente). We are currently testing the ankle and knee module on our new wearable exoskeleton. To provide subject-specific control for the SCI subjects, the NMC modules were designed to provide asymmetric control between the right and left legs, between extension and flexion, and among different muscles.

Tests with Human Subjects

We evaluated our controller with both healthy and paraplegic subjects. The modular nature of our controller enables us to test it on several different types of lower limb assistive devices. We evaluated subjects’ walking kinematics and kinetics, muscle activation levels, and metabolic power when possible.

Ankle Control

We tested the ankle module of the neuromuscular controller with a powered ankle exoskeleton (UTwente’s Achilles) on healthy subjects and paraplegic test plots with some mobility. For the healthy subjects, we evaluated the mechanics and energetics of walking with such a device and controller. This controller was designed to mimic human reflex patterns during locomotion, which we hypothesized would lead to lower energetic costs compared to walking with the added mass of the device only. Preliminary tests found that healthy-like gait patterns remained intact, and metabolic costs were reduced compared to the transparent mode of the device. Muscle activity of the tibialis anterior and soleus were also reduced with the assistive push-off. Please see Dzeladini et al. 2016 under Publications for more information.

Knee and Hip Control

We evaluated the neuromuscular controller on a lower-limb knee and hip robotic gait trainer (UTwente’s LOPES) with seven pilots with paraplegia (four complete, two incomplete) and one healthy subject. We determined that the NMC could enable normal-like walking gait kinematics at various walking speeds. We found that SCI pilots could walk at a range of normal walking speeds– from 0.6 m/s to 1.4 m/s. Despite a few differences between NMC-produced torques and healthy biological torques, the SCI joint kinematics were similar to healthy kinematics. With few sensors and no predefined gait patterns for multiple speeds or different subjects, the NMC could produce various walking patterns based on subject interaction with the environment. Please see Wu et al. 2017 under publications for more information.

WE1: Ankle and Knee Control

Our consortium partners at Delft and UTwente have developed a new ankle and knee wearable exoskeleton. Tests of the NMC with this device on paraplegic pilots are currently ongoing at the Fondazione Santa Lucia, another one of our consortium partners. Since this exoskeleton only actuates the ankle and knee, these pilots already have some volitional control of their hip joint.

WE2: Lower Limb Control (ankle, knee, hip)

Tests of the full lower limb exoskeleton and neurmuscular controller will be conducted in early 2018. These tests will involve paraplegic pilots who do not have volitional control of their hip joints.

Media

S08_LNMC_Symbitron_Video.mp4

Symbitron_WE1_promo_video.mp4Promotion video for WE1 (knee and ankle actuation) in zero impedance mode

Student Projects

Related student projects:

S. Berger. Energy consumption optimization and stumbling corrective response for bipedal walking gait.

F. Dzeladini. Implementation of a human feedback-based locomotion and its control by means of a feedforward component inspired by central pattern generators

A. di Russo. Biomechanical analysis of slow walking and stepping behavior in healthy subjects on treadmill

Researchers

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Auke J. Ijspeert, Florin Dzeladini, Amy R. Wu

Publications

Field Guide to Northern Tree-related Microhabitats: Descriptions and size limits for their inventory in boreal and hemiboreal forests of Europe and North America

R. Bütler Sauvain; L. Larrieu; L. F. Lunde; M. Maxence; B. Nordén et al.

Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Switzerland, 2024.

Project Description

Neuromuscular Controller

Tests with Human Subjects

Ankle Control

Knee and Hip Control

WE1: Ankle and Knee Control

WE2: Lower Limb Control (ankle, knee, hip)

Media

Student Projects

Researchers

Publications

Field Guide to Northern Tree-related Microhabitats: Descriptions and size limits for their inventory in boreal and hemiboreal forests of Europe and North America

Data Champions Lunch Talks – Green Bytes: Data-Driven Approaches to EPFL Sustainability

Timelapse: Geneva Lake, in front of Chexbres – 2019

German Democratic Radio

Aesthetics of Conservation; Aesthetics of Extinction. The Chilean Pavilion at the 59th Art Biennale

Type and History

The Broadcasting House: Architecture, Type, and the Culture Industry

Infrastructures of Solidarity, Infrastructures of Totalitarism

Notes on Los Angeles

Comparison of Three Viral Nucleic Acid Preamplification Pipelines for Sewage Viral Metagenomics

How to Support Students to Develop Skills that Promote Sustainability

How to Support Students Giving Each Other Constructive Feedback, Especially When It Is Difficult to Hear

How teachers can use the 3T PLAY trident framework to design an activity that develops transversal skills

The conceptual foundations of innate immunity: Taking stock 30 years later

Radio-Activities: Architecture and Broadcasting in Cold War Berlin

No Last One

All That is Solid

Turba Tol – Hol Hol Tol

Echo’s Chambers by Joseph Clarke (Book Review)

Coming to Terms with Drawing

Drawing the Line

Learning to Learn: Review of ‘The University Is Now on Air: Broadcasting Modern Architecture

The House at the End of the World: On the Possibility of Architecture in Capitalist Ruins

Radio as Architecture: Notes toward the Redefinition of the Berlin Walls

Radio-Activities

The Ground as Forensic Evidence: Alfredo Thiermann in Conversation with Eyal Weizman

White on White

What Does an Invisible Architecture Look Like

Dynamics of the Void

Dynamics of the Void

Artefact Nr. I

Artefact Nr. I

Artefacto Nr. I

Artefact Nr. I.

Characterization of the gut-bone marrow axis through bile acid signaling

Studies of crystal collimation for heavy ion operation at the LHC

Engineering novel protein interactions with therapeutic potential using deep learning-guided surface design

Querying the Digital Archive of Science: Distant Reading, Semantic Modelling and Representation of Knowledge

Hybrid organic/metal-oxide shells on semiconductor nanocrystals via colloidal atomic layer deposition

Electrical and Optical Manifestations of Flat Band Physics in Van der Waals Materials

Plasmonically enhanced molecular junctions for investigation of atomic-scale fluctuations in self-assembled monolayers

Exact Obstacle Avoidance for Robots in Complex and Dynamic Environments Using Local Modulation

S-acylation and lipid exchange at the ER-Golgi membrane contact sites regulate pathogen entry in human cells

Serial Dependence in Human Visual Perception and Decision-Making

Data-Driven Methods for Controller Design in Atomic Force Microscopy

Aesthetics of Extinction, Aesthetics of Conservation: the Chilean Pavilion at the 59th Venice Art Biennale

Quantum-mechanical effects in photoluminescence from thin crystalline gold films

Quantifying the effects of rainfall temporal variability on landscape evolution processes

Towards a metabolic theory of catchments: scaling of water and carbon fluxes with size

Biohybrid Superorganisms—On the Design of a Robotic System for Thermal Interactions With Honeybee Colonies

Dataset to accompany publication “Quantum-mechanical effects in photoluminescence from thin crystalline gold films”

Impact of CO2-rich seawater injection on the flow properties of basalts

Material Reform: Building for a Post-Carbon Future

Architecture of a decentralised decision support system for futuristic beehives

Comment une situation d’investigation policière fait évoluer les conceptions d’élèves de troisième sur l’ADN

TSLAM: a tag-based object-centered monocular navigation system for augmented manual woodworking.

Water weakening and the compressive brittle strength of carbonates: Influence of fracture toughness and static friction

Integration of the Pilatus3 detector for soft X-ray diagnostics on TCV

Siloxide tripodal ligands as a scaffold for stabilizing lanthanides in the +4 oxidation state

High-Permittivity Polysiloxanes for Bright, Stretchable Electroluminescent Devices

An extension of the stochastic sewing lemma and applications to fractional stochastic calculus

A bridge between trust and control: computational workflows meet automated battery cycling

Capsizing due to friction-induced twist in the failure of stopper knots

A CTCF-dependent mechanism underlies the Hox timer relation to a segmented body plan

Gradient High-Q Dielectric Metasurfaces for Broadband Sensing and Control of Vibrational Light-Matter Coupling

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

Dielectric elastomer actuator-based valveless pump as Fontan failure assist device: introduction and preliminary study

Tree diversity reduces variability in sapling survival under drought

Probing structural and dynamic properties of MAPbCl3 hybrid perovskite using Mn2+ EPR