Training of deep neural networks for the generation of dynamic movement primitives.

Journal: Neural networks : the official journal of the International Neural Network Society
Published Date:

Abstract

Dynamic movement primitives (DMPs) have proven to be an effective movement representation for motor skill learning. In this paper, we propose a new approach for training deep neural networks to synthesize dynamic movement primitives. The distinguishing property of our approach is that it can utilize a novel loss function that measures the physical distance between movement trajectories as opposed to measuring the distance between the parameters of DMPs that have no physical meaning. This was made possible by deriving differential equations that can be applied to compute the gradients of the proposed loss function, thus enabling an effective application of backpropagation to optimize the parameters of the underlying deep neural network. While the developed approach is applicable to any neural network architecture, it was evaluated on two different architectures based on encoder-decoder networks and convolutional neural networks. Our results show that the minimization of the proposed loss function leads to better results than when more conventional loss functions are used.

Authors

  • Rok Pahič
    Humanoid and Cognitive Robotics Laboratory, Department of Automatics, Biocybernetics, and Robotics, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Jozef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia. Electronic address: rok.pahic@ijs.si.
  • Barry Ridge
    Humanoid and Cognitive Robotics Laboratory, Department of Automatics, Biocybernetics, and Robotics, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; ATR Computational Neuroscience Laboratories, 2-2-2 Hikaridai Seika-cho, Sorakugun, Kyoto 619-0288, Japan. Electronic address: barry.ridge@ijs.si.
  • Andrej Gams
    Humanoid and Cognitive Robotics Laboratory, Department of Automatics, Biocybernetics, and Robotics, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia. Electronic address: andrej.gams@ijs.si.
  • Jun Morimoto
    Dept. of Brain Robot Interface, ATR Computational Neuroscience Labs, Kyoto, Japan.
  • Aleš Ude
    Dept. of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.