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Organizers

• Yinoussa Adagolodjo, Research Engineer, Inria Lille
• Hugo Tablot, SOFA Consortium
• Damien Marchal, Senior Research Engineer, CNRS
• Félix Vanneste, PhD Student, Inria Lille
• Eulalie Coevoet, Research Engineer, Inria Lille
• Christian Duriez, Research Director, Inria Lille
  

 

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ABSTRACT

This workshop will provide a series of in-depth tutorials on how to use the open source simulation framework SOFA and the SoftRobots plugins made by the DEFROST research team to model, simulate and control deformable robots. At the end of the tutorial session, we expect attendees to be capable of modeling and controlling basic soft robots with SOFA including being able to precisely model contact with inverse control. A special moment will be allocated on the new SofaPython3 API, and how to upgrade previously done simulations.

 

The workshop can be done on-site and remotely. We will do our best for remote attendees so they have the best experience. The sessions will be streamed and recorded, and dedicated live visio-conference rooms will be created. For the “hands-on” sessions, additional members of the DEFROST team will be present online to support and guide remote participants in their modeling of soft-robots.  

 

SOFA is a modeling and simulation framework based on Finite Element Methods and providing state-of-the-art solutions to compute deformations and multi-contact response with friction in real-time. In recent years, the DEFROST team built on this framework to provide a new numerical platform dedicated to the community of soft robotics. These tools are made freely available to the community for research purposes. 

SoftRobot: is a plugin for SOFA that brings components dedicated for Soft Robotics among which: sensors, pressure and cable actuators, direct and inverse models for control as well as connectors for serial/arduino and ROS to access commonly used hardware.

DEFROST (DEFormable RObotics SofTware) is a research team (Inria / University of Lille in France) that develops a platform based on SOFA that gathers algorithms for modeling, simulation and control of soft robots.

 

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DESCRIPTION

This workshop will provide a series of in-depth tutorials on how to use the open source simulation framework SOFA and the SoftRobots plugin to model, simulate and control deformable robots. At the end of the tutorial session, we expect attendees to be capable of modeling and controlling basic soft robots with SOFA including being able to precisely model contact with inverse control. 

The covered topics includes:

• deformation modeling
• setting up the actuators
• real-time execution of the simulation with interactive control of the actuators
• extraction of the kinematic model of the robot
• taking into account collisions
• inverse modeling
• reducing the order of the model to speed up calculations
• control loop
• updating scenes to cope with recent SOFA version (python3)

Throughout the tutorial we will alternate between the theoretical aspects of the SOFA modeling and practical, “hands-on”, sessions. During these hands-on sessions, participants will have the opportunity to practice on the “Soft Tripod”. This “tripod” is an open-hardware learning platform available on https://handsonsoftrobotics.lille.inria.fr/ specifically designed for tutoring soft robotics.

Session 1: Modeling of soft robot on SOFA (1h30)

In the first 30 minutes of the session we will present the SOFA community and the SOFA concepts: SceneGraph, Object, Node, Data, Mapping and ForceField. Then the attendees will have the opportunity to model a very simple scene. During this session, we will model and simulate a soft robot tripod. This tripod is an open-hardware, cheap and easy to replicate for soft robot experiments that were designed specifically as a teaching platform. It is composed of three servo motors actuating and deforming an elastic deformable part. Attendees will learn how to model and simulate this robot through the step-by-step tutorial covering:  deformable mechanical modeling, constraints, coupling rigid and deformable parts and contact modeling. 

• 30 min: Presentation of SOFA & general concepts (presentation)
• 30 min: Modeling with FEM, placement of the servomotors (presentation and practice)
• 30 min: Deformable-Rigid coupling (presentation and practice)

 

 

Session 2: Real-time Simulation, inverse model and control (2h)

The second session will focus on connecting the simulation to the hardware, for introducing control of physical robots. We will then present how to add an inverse model for open loop inverse control. The session will terminate on closing the loop by using ROS to get real world robot’s positions from a LeapMotion tracker.

• 30 min: Constraint based modeling (presentation)
• 30 min: Contact modeling (presentation and practice)
• 30 min: Inverse Kinematic for open-loop control (practice)
• 30 min: Closed loop control and applications (practice)

Training a Neural Network for Soft-Robots control using the SOFA simulator

Tutorial requirements: Thanks to the support of the Sofa-consortium, ready to install packages packaged with our plugins will be made available for Linux, Windows and MacOS.

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