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

The Effect of Rivers on Energy Balance at the Neighborhood Scale. A comparative analysis of four Rhodanian sites in France and Switzerland

S. Aguacil Moreno; S. Formery; M. Laprise; E. Rey

2024-06-28. 37th Passive and Low Energy Architecture PLEA 2024 Conference, Wroclaw, Poland, June, 25-28, 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

The Effect of Rivers on Energy Balance at the Neighborhood Scale. A comparative analysis of four Rhodanian sites in France and Switzerland

Isogeny Problems with Level Structure

Echoing Swiss Coloniality. Land, Archive and Visuality between Brazil and Switzerland.

Teacher-Mediated and Student-Led Interaction with a Physics Simulation: Effects on the Learning Experience

An adaptive phase field approach to 3D internal crack growth in rocks

Timelapse: Rhone mouth in Geneva Lake – 2022

Timelapse: Rhone mouth in Geneva Lake – 2023

Remote wide angle view broad wavelength viewing system compatible with D-T operations in JET

Influence of wind direction on flow over a cliff and its interaction with a wind turbine wake

AI-Driven Workflows for Unlocking Switzerland’s Collective Memory: Distant listening of the RTS Archive

An improved statistical wake meandering model

Generative AI-Enabled Conversational Interaction to Support Self-Directed Learning Experiences in Transversal Computational Thinking

An improved statistical wake meandering model

Improvements to the dynamic wake meandering model by incorporating the turbulent Schmidt number

Industrial European regions at risk within the Fit for 55: How far implementing CBAM can mitigate?

Bactericidal effect of tetracycline in E. coli strain ED1a may be associated with ribosome dysfunction

Systematic mapping of antibiotic cross-resistance and collateral sensitivity with chemical genetics

Droit de superficie sur terrains privés: Une « solution à tenter » pour des projets d’utilité publique ?

Re-design of EU DEMO with a low aspect ratio

S’engager et transmettre en féministe : pour une éthique du care à l’université

Estrogenic, Genotoxic, and Antibacterial Effects of Chemicals from Cryogenically Milled Tire Tread

SC-TPTP: An Extension of the TPTP Derivation Format for Sequent-Based Calculus

Analyse de l’utilisation d’un outil de visualisation dans une situation d’entretien-conseil pédagogique dans l’enseignement supérieur

Wave-momentum shaping for moving objects in heterogeneous and dynamic media

Inversing the actuation cycle of dielectric elastomer actuators for a facial prosthesis

Highly anisotropic carbon fiber electrodes for DEAs and their dynamic non-monotonic conductive properties

An artificial urinary sphincter based on dielectric elastomer technology

Frequency response of fiber reinforced DEAs

Photo-doping of spiro-OMeTAD for highly stable and efficient perovskite solar cells

Carbon based printed electrodes for DEAs: study of pad, inkjet, and stencil printing

Prototyping and Experimental Analysis of Active Offloading Footwear for Patients With Diabetes Using an Array of Magnetorheological Fluid–Based Modules

A Review of Modeling, Design and Performance Assessment of Linear Electromagnetic Motors for High-Speed Transportation Systems

Impact of intercepted and sub-canopy snow microstructure on snowpack response to rain-on-snow events under a boreal canopy

Degradable and Printed Microstrip Line for Chipless Temperature and Humidity Sensing

Designing for Intimate Wellbeing: Aidee, a Qualitative Approach To Urine Home Monitoring

Author Correction: Fully co-factor-free ClearTau platform produces seeding-competent Tau fibrils for reconstructing pathological Tau aggregates

Distinct ultrastructural phenotypes of glial and neuronal alpha-synuclein inclusions in multiple system atrophy

Data for Paper “Scalable Semantic 3D Mapping of Coral Reefs with Deep Learning”

WildCLIP: Scene and animal attribute retrieval from camera trap data with domain-adapted vision-language models

From PV to EV: Mapping the Potential for Electric Vehicle Charging with Solar Energy in Europe

Validation of artificial intelligence for epileptic seizure detection: Moving from research into the clinic

Termination Analysis in a Higher-Order Functional Context

Quartiers rhodaniens en transition

DC Power Distribution Networks with Direct Current Transformers

Machine Learning for Modeling Stock Returns

Probabilistic and Deterministic Wellposedness for Low Regularity Dispersive Equations

Randomized low-rank approximation and its applications

Anomalous dissipation and other non-smooth phenomena in fluids

Topics in statistical physics of high-dimensional machine learning

Turbulence and Heat exchange in the Near-Surface Boundary Layer over Patchy Snow

Good enough: Intermediate complexity atmospheric models improve the representation of processes affecting seasonal snow

Electron-beam based nanoscale quantum controls

Development of Hyphenated Analytical Techniques using spICP-MS for Online Characterization of Metallic Nanoparticles in Aerosols

Study of flexible operating conditions in variable-speed hydraulic turbines : advanced models and experimental validation

Probing and modulating inter-areal coupling in the cortical visual motion processing pathway with non-invasive brain stimulation

New Applications of 1,3,2-Diazaphospholenes in Catalysis

HaloTag-Based Tools for Live-Cell Imaging and Elucidation of Organellar Redox Biology

Applications of the thawed Gaussian approximation to electronic spectroscopy.

Performing and Detecting Backdoor Attacks on Face Recognition Algorithms

Biophysically accurate and machine learning-based surrogate models to optimize neuroprosthesis design and operation

Fair real-time control of energy storage systems in active distribution networks in the presence of uncertainties

Drug Screening in C. elegans to identify new pharmacological mitochondrial stress inducers

Geometric Learning: Leveraging differential geometry for learning and control

Development of tools and methods for protein identification: From single molecules to in vivo applications.

Content Moderation in Online Platforms

Advancing Cell-Free Synthetic Biology: From sustained PURE protein synthesis to an isothermal one-pot DNA replication system

Engineering hydrogel microenvironments for epithelial organoid culture

Quand le Collège de France explorait le corps

A hybrid physics-based and data-driven model for intra-day and day-ahead wind power forecasting considering a drastically expanded predictor search space