Workshop on modeling, simulation and control
of deformable robots on SOFA framework.
- Christian Duriez, Research Director, Inria Lille
- Damien Marchal, Senior Research Engineer, CNRS
- Eulalie Coevoet, Research Engineer, Inria Lille
- Maxime Thieffry, PhD Student, University of Valenciennes & Inria Lille
- Margarth Koeler, PhD Student, Stanford University
- Hugo Talbot, SOFA Consortium
- Alexandre Kruszewski, Assistant Professor, Centrale Lille
- Olivier Goury, Research Scientist, Inria Lille
- Felix Vanneste, PhD Student, Inria Lille
This workshop will provide a series of in-depth tutorial on how to use the open source simulation framework SOFA and the SoftRobots plugins to model, simulate and control deformable robots. At the end of the day we expect attendees to be capable of modeling and controlling basic soft robots with SOFA including precise contact modeling and inverse control. For that, throughout the day we will alternate between the theoretical aspects of the SOFA modeling and very practical sessions. During these practical sessions the attendees will have the opportunity to practice on the “Soft Tripod” an open-hardware learning platform available at https://handsonsoftrobotics.lille.inria.fr/.
The last session of the day will focus on providing examples of applications and use-cases from Soft-Robotics community of user.
Tutorial schedule (tentative)
Morning session 1 : Modeling and simulation (1h30), H. Talbot & D. Marchal
In the first 45 minutes of the session we will presents 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. Understanding the core sofa concepts it important to make high quality models but their manipulating can be cumbersome and verbose. To solve this problem the SOFA community is now providing plugins that contains ‘prefabricated elements’ (called Prefabs) to facilitate the development of new scenes and favore reusability. One of this plugins is the STLIB. During the last 45 minutes, attendees, with the help of presenters, will follow the “First-steps” tutorial on using the STLIB.
9:00 am to 9:45 am: Presentation of SOFA & general concepts (presentation)
9:45 am to 10:30 am: first-steps tutorial (practice)
Morning session 2 : SoftRobots Modeling and Simulation (2h00), D. Marchal & C. Duriez
Keywords: Deformable material & FEM, Actuators modeling, Interactive control, Deformable-Rigid coupling, Contact modeling.
During this session, we will follow a tutorial that presents how to model and simulate a soft tripod robot. The content is available on the website https://handsonsoftrobotics.lille.inria.fr/. This tripod is an open-hardware, cheap and easy to replicate for soft robots designed. It is composed of three servo motors actuating and deforming an elastic deformable part. Attendees will be learn how to model and simulate this robot through the step by step tutorial: deformable mechanical modeling, constraints, coupling rigid and deformable parts and contact modeling.
11:00 am to 11:30 am: Objectives of the tutorial and theoretical concepts (presentation)
11:30 am to 12:00 am: Modeling with FEM, placement of the servomotors (practice)
12:00 am to 12:30 am: Deformable-Rigid coupling (practice)
12:30 am to 1:00 pm: Contact modeling (practice)
Afternoon session 1 : Connecting Simulation to Real Hardware and Control (2h00), E. Coevoet & M. Thieffry
Keywords: Hardware, Inverse Kinematic, ROS, Open-loop control, Closed-loop control
The session will continue the session of the morning on the tripod robot, but focussing on connecting the simulation to the hardware, in particular for control. We will then see how to add inverse kinematic simulation of the deformable for open/close loop control.The session will terminate on closing the loop by using ROS to get the real world robot position position from a LeapMotion allowing to close the loop.
2:00 pm to 2:30 pm: Interfacing simulation with hardware (practice)
2:30 pm to 3:00 pm: Inverse Kinematic for open-loop control (presentation & practice)
3:00 pm to 3:30 pm: Interfacing simulation to a camera with ROS (practice)
4:30 pm to 4:00 pm: Closed loop control (presentation)
Afternoon session 2 : Use cases & Applications (1h30)
- Christian Duriez (INRIA) Model Order Reduction in SOFA. Presentation of the Model Order Reduction plugin (see https://project.inria.fr/modelorderreduction/). This plugin, allows to provide huge speed-up for the simulation of FEM models.
- Robert Katzschmann (MIT) & Maxime Thieffry (INRIA) Dynamically Closed-Loop Controlled Soft Robotic Arm using a Reduced Order Finite Element Model with State Observer
- Margaret Koehler (Stanford) Stiffness control of soft-robot using SOFA
- Carine Rognon (EPFL/Stanford) & Margaret Koehler (Stanford). Design of a soft haptic device to render the sensation of flying like a drone with the assistance of simulation.
- Damien Marchal (CNRS) Using SOFA simulation to train AI based controllers.
SOFA is based on Finite Element Methods and provide state-of-the-art solution to compute deformations and multi-contact response with friction in real-time.
In the last years, the presenters have been part of the DEFROST research team (Inria / University of Lille in France). They are developing a platform based on SOFA that gathers algorithms for modeling, simulation and control of soft robots. The team released several plugins for soft robotics, including SoftRobots (https://project.inria.fr/softrobot/), and ModelOrderReduction (https://project.inria.fr/modelorderreduction/). These tools are made either open-source or freely available to the community for research purposes.