Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (UMR5287)

Aquitaine Institute for Cognitive and Integrative Neuroscience

Université de Bordeaux

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CNRS Ecole Pratique des Hautes Etudes Université de Bordeaux

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Neurocampus Unitéde Formation de Biologie


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Home > Teams > HYBRID ( De RUGY) > Themes

Theme 3: Robotic Arm Control (REACHY)

by Loïc Grattier - published on , updated on

In collaboration with a developmental robotics team (FLOWERS, P-Y Oudeyer) and a startup in robotics (Pollen Robotics), we develop the 3D printed robotic platform REACHY as a testbed for prosthesis human-robot control strategies in our team on others (Mick et al, 2019).

Following the sharing philosophy of the broader Poppy Project, a family of robots for research, arts and education (, REACHY is fully open-source for both software and hardware resources. It is composed of 3D-printed plastic skeleton parts and off-the-shelf actuators (Dynamixel servomotors), mechanical components and electronics. The robot is controlled through a serial port with Pypot, a software base common to the whole Poppy-Reachy family of Dynamixel powered robots. Following an open-source approach, Pypot was entirely written in Python in order to enable crossplatform deployment. Pypot also includes features to control a virtual robot with the virtual robotic simulator V-REP, such that the same software can be used to control either a real or a simulated version of REACHY.

We established proofs of concept whereby REACHY is interfaced with various systems for easy control. In the first one (Fig2A), we used supervised learning with an artificial neural network to learn the mapping between the 7 joint angles of REACHY and the position of its hand in space, and use this mapping to resolve inverse kinematics and directly control the hand position. When the movements used to learn this mapping are produced by humans during free reaching, this strategy enables to encapsulate natural coordination within the network and exploits it for natural robot control. A short video of REACHY tele-operated from a unique marker on the hand illustrates that this method is effective at producing easy to control natural movements: (Fig2A). In a second proof of concept (Fig2B), we linked REACHY with gaze information and simple myoelectric signals, such that an operating subject looking at an object can trigger REACHY’s movement towards this object by simple arm muscle contraction. A video of this gaze-controlled REACHY is available at (Fig2B).

We recently used this platform in an experiment showing that the biological plausibility of arm posture influences the controllability of the robotic arm teleoperation (Mick et al., minor revision). This robotic platform is also designed to integrate control strategies developed in all other themes of Hybrid.

- Mick S, Lapeyre M, Rouanet P, Halgand C, Benois-Pineau J, Paclet F, Cattaert D, Oudeyer P-Y, de Rugy A (2019) Reachy, a 3D-printed human-like robotic arm as a test bed for prosthesis control strategies. Frontiers in NeuroRobotics 13: 65.
- Mick S, Badets A, Oudeyer P-Y, Cattaert D, de Rugy A (In Press) Biological plausibility of arm postures influences the controllability of robotic arm teleoperation. Human Factors.
- Mick S, Cattaert D, Paclet F, Oudeyer P-Y, de Rugy A (2017) Performance and Usability of various Robotic Arm Control Modes from Human Force Signals. Frontiers in NeuroRobotics. 11: 55.