Simulazione Integrata di Meccanica Elettronica e Controllo per sistemi Spaziali
Integrated mechatronic simulation for space systems

Project Scientific Rationale

The present proposal is conceived within the framework of a national forum aimed at defining a strategic program to pursue research in robotics with a clear space connotation. Fully inspired by the document produced by the ASI Working Group on "Space Robotic Technologies", seven projects are being submitted to match each of the key actions identified; namely: Robotic Manipulation, Robotic Exploration, Hw/Sw Architectures, Artificial Intelligence, Modelling and Simulation, Tele-operation, Artificial Vision. The leading academic/research-council groups are involved with contributions from the main scientific areas in robotics including: automatic control, mechanics and computer science. All of them have a reputed international visibility and have already been engaged into contracts with ASI in the last years. The research efforts are expected to produce visible fallout on the space projects of interest for the Agency, such as EUROPA, PAT, SPIDER, as well as the Cooperative Dual-Robot System, which has been recently installed at the Research Centre in Matera. Noticeably, two major companies in the field (Tecnomare and Tecnospazio) have shown their interest into the program and are committed to offer facilities and support to the development of the activities of some projects. A tight coordination among the various projects will be accomplished during the three years of duration and an annual program workshop will be organized to trace the current state-of-the-art and foresee challenging research perspectives. In sum, the proposed program is believed to constitute the nutshell for the establishment of a national network of excellence on space robotics technology in the near future.

Methods and Technical Description

The purpose of the research we are proposing is to develop SIMECS (provisional acronym from Space Integrated Mechanics Electronics and Control Simulation), a multi-domain modeling and simulation environment for robotic and mechatronic space systems. SIMECS offers acausal hierarchical modular modeling capabilities, to ensure models reuse, and a  “natural” (not requiring modeling specific knowledge) approach to complex model definition. The hierarchical model building allows one to build a complex model by connecting simpler (lower level) models over and over again. A library of basic acausal (i.e., whose equations are stated without consideration of the computational order) models of the physical components of a space robotic system shall be developed.

Existing in-house model libraries and commercial tools shall be used as far as possible and the development of new service (e.g., 3D graphic animations) software minimized. Most of effort shall be related to modeling, and the wide past experience on modeling of the units taken advantage of as far as possible. A minimum set of essential interface functions shall be developed, for the effective and efficient use of the modeling and simulation software. Among them the 3D graphic animation of simulation results and masks to input model parameters.

The mechanical structure is the most complex and critical component. The model of a mechanical structure shall be built in a modular way, being basic bricks the model of robot links (either rigid or elastic bodies) and that of joints, with proper motion degrees of freedom and rigid or elastic constraints. The model of few common mechanical structures (e.g., a spherical wrist) shall be built in the development phase, also for the purpose of testing the modeling and simulation environment. The model library shall contain also basic robot control and motion planning algorithms.

The overall simulation environment and model library are tested with respect to an existing robot. Data gathered on space qualified hardware are compared to simulation results for the purpose of refining and validating models. The simulation model of one of the ASI robotic arms is developed for demonstration purposes. The EUROPA arm (SPIDER like arm) is the candidate at the moment. In the third year of the research a model of the humanoid envisaged by the ASI Working Group on “Space Robotic Technologies” could be built, too.

SIMECS is first of all conceived as a tool to support the conceptual and detailed design phases of a spacecraft, but arrangements are introduced to obtain also real time versions of the modeling software suitable for implementation in testing, check-out, training, and teleoperation facilities. SIMECS software is conceived as an open tool, suitable to be integrated with other environments and facilities, and in particular with those available in CSR. During the development activities, specifications can be prepared to permit the integration with CSR facilities and at the end of the project the software made available to be used by the CSR. Also geographically distributed simulations can be designed and developed. For instance, in the third year of the project the decision can be taken to build a prototypical real time simulation facility at Politecnico di Milano supporting teleoperation from a remote operator at CSR or elsewhere, or to test and check-out a real control system.

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