Overview of OpenHRP3

OpenHRP3 (Open Architecture Human-centered Robotics Platform version 3) is an integrated software platform for robot simulations and software developments. It allows the users to inspect an original robot model and control program by dynamics simulation. In addition, OpenHRP3 provides various software components and calculation libraries that can be used for robotics related software developments.

OpenHRP3 is developed as a one of the complementary project called "Distributed component type robot simulator", executed by "Cooperation of Next Generation Robots" that belongs to "Government Cooperation of Science and Technology". Dynamics calculation engine is almost developed by "Nakamura Lab, Dept. of Mechano Informatics, University of Tokyo" and graphical interface is done by "General Robotix, Inc". The other parts are developed as a cooperate work of "Humanoid Resarch Group" and "Task-Intelligence Research Group" at "Intelligent Systems Research Institute", "National Institute of Advanced Indrustrial Science and Technology(AIST)".

And even the "Distributed component type robot simulator" project is over, AIST is continuing the developing process as part of under-developing OpenRT Platform that linked with "Intelligent technology development project for Next generation robots".

This Version 3 ( so-called OpenHRP3) is considerably improved development compared to the the previous distribution of OpenHRP version 2. Moreover, OpenHRP3 distributes as an open-source software.

OpenHRP3 Main Interface

Features of OpenHRP3

OpenHRP3 is designed as a distributed object system. It is composed of a client program that manages the servers and a group of server programs that offers various functions. This composition caused to improve the maintainability and the portability in large-scaled simulation system developments.

OpenHRP3 corresponds with the OpenRTM that is a distributed middleware for robots. At present, controller can be developed as a RT component of OpenRTM. Various sensors to be simulated, are scheduled to make accessible as RT components, in future.

The dynamics calculation engine of OpenHRP3 has two editions, the development of the Tokyo University, and the development of AIST. Each has the following features:

  • Tokyo University edition
    • This edition applies an original algorithm for a forward dynamics algorithm. In the algorithm, computational complexity is in proportion to the number of the joints, and simulation of closed link mechanism is possible, too. In algorithm of similar performance, it is one of the fastest one all over the world, so it can execute high-speed simulation as to a complicated model.
    • This edition uses rigid body contact model which is more stable numerically and formulates a condition about reaction force including frictional force as linear complementarily problem (LCP). And we developed original LCP solver which can get a solution in robust and high speed for a numerical value error. It can calculate contact force between arbitrary polygon by using an interference analysis module with.
  • AIST edition
    • This edition applies Featherstone's algorithm and performs a forward dynamics calculation in computational complexity to be proportional to the number of the joints.
    • For a calculation of contact force, this edition applies algorithm that calculates a solution of a restraint condition in convergent calculation. So it can make rigid body contact stable in numerical computation.
    • The design of the dynamics calculation program is conscious of that users use it as a library from the outside. We provide a good library of the convenience that users can apply in a controller and development of a pattern generator.