Modeling, Stability Analysis, and Testing of a Hybrid Docking Simulator

A hybrid docking simulator is a hardware-in-the-loop (HIL) simulator that includes a hardware element within a numerical simulation loop. One of the goals of performing a HIL simulation at the European Proximity Operation Simulator (EPOS) is the verification and validation of the docking phase in an on-orbit servicing mission.....Comment: 30 papge

MOSAR : Modular spacecraft assembly and reconfiguration demonstrator

With rapid development of space systems in recent years and their limited lives, it is imperative that a sustainable space development approach is developed to support more affordable access to space for all stakeholders. The European Commission hence funded the MOSAR project which aims to create a new paradigm technology to address this increasing challenge. This paper provides an overview of this technology’s preliminary development to enable on-orbit servicing. Building on five successful projects which collectively created all required common building blocks for both planetary explorations and in-orbit missions, a novel architecture is proposed to create a walking manipulator to demonstrate its unique capability in both space system assembly and on-orbit servicing. Preliminary design concepts of a walking manipulator and spacecraft modules are shown. A dedicated simulator is also developed to evaluate the proposed novel architecture for these targeted applications

A NOVEL HUMAN-IN-THE-LOOP TESTING FACILITY FOR SPACE APPLICATIONS

To analyse the interaction between the piloting astronaut and lunar lander dynamics while landing on the south pole of the moon, The European Space Agency (ESA) has initiated together with Thales Alenia Space (TAS), GMV Aerospace and Defence SAU (GMV) and The German Aerospace Centre (DLR) a project entitled “Human-In-the-Loop Flight Vehicle Engineering“. For this purpose, the DLR Robotic Motion Simulator (RMS) was transformed into a novel Humanin- the-Loop testing facility for space applications. The RMS represents a new class of motion simulators being currently developed at DLR that allow for extreme tilt angles and manoeuvres. It is based on an industrial 6 Degrees of Freedom (DOF) robot arm that is mounted onto a 10m long linear axis. The system therefore has a redundant 7 DOF architecture to induce motion cues onto an attached simulator cell. A highly modular simulator cell was configured for landing on the moon with three touch screens that were used to interact with the Human Machine Interface (HMI), Throttle and Joystick instruments, a virtual window to the outside, a headset and a surveillance camera for the piloting astronaut. The joystick features 3 DOFs and the throttle features adjustable damping along with many buttons that were used as inputs to the simulation. For the Moon landing scenery, a highresolution lunar crater visualization based on DLR’s Visualization 2 library was developed. Rocks and Boulders were distributed over the surface of the simulated region of the moon according to the Size-Frequency Distribution (SFD) for moon craters. ESA astronaut and test pilot Roberto Vittori tested various lunar landing manoeuvres using flight controls algorithms developed in HITL and motion simulation, provided by GMV, and was able to experience how the spacecraft behaves in critical phases of the lunar landing and intervene to control it. In one scenario the Landing GNC Automatic Mode was set to a landing zone where there were boulders. Vittori then had the option to intervene within a certain time window and, using touchscreens, select an alternative landing site. If needed, he was able to switch to Astronaut Manual Mode and pilot the lunar lander manually as it descended onto the lunar floor. Two Manual Control strategies were tested: Full Force / Torque Control and Rate Control. Two Motion cueing algorithms for low gravity environments were tested. Further experiments are planned

An intelligent, free-flying robot

The ground based demonstration of the extensive extravehicular activity (EVA) Retriever, a voice-supervised, intelligent, free flying robot, is designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The major objective of the EVA Retriever Project is to design, develop, and evaluate an integrated robotic hardware and on-board software system which autonomously: (1) performs system activation and check-out; (2) searches for and acquires the target; (3) plans and executes a rendezvous while continuously tracking the target; (4) avoids stationary and moving obstacles; (5) reaches for and grapples the target; (6) returns to transfer the object; and (7) returns to base

Astrobee Robot Software: A Modern Software System for Space

Astrobee is a new free-flyer robot designed to operate inside the International Space Station (ISS). Astrobee capabilities include markerless navigation, autonomous docking for recharge, perching on handrails to minimize power and modular payloads. Astrobee will operate without crew support, controlled by teleoperation, plan execution, or on-board third parties software. This paper presents the Astrobee Robot Software, a NASA Open-Source project, powering the Astrobee robot. The Astrobee Robot Software relies on a distributed architecture based on the Robot Operating System (ROS). The software runs on three interconnected smart phone class processors. We present the software approach, infrastructure required, and main software components. The Astrobee Robot Software embrace modern software practices while respecting flight constraints. The paper concludes with the lessons learned, including examples usage of the software. Several research teams are already using the Astrobee Robot Software to develop novel projects that will fly on Astrobee

The DLR Robots library - Using replaceable packages to simulate various serial robots

In order to simulate different kinds of serial robots, the implementation of functionalities such as the calculation of their direct and inverse kinematics, visualization, collision behavior, etc. is necessary. However, providing these functionalities in robot specific models leads to additional modeling overhead in cases where one would like to switch between several different robot models. The DLR Robots library demonstrates an implementation of all robot specific components as replaceable Modelica packages, allowing for an user-friendly way to exchange robot models without modifying the general structure of the overlying model. The simulation of robotic systems is a great example for the multi-domain versatility of Modelica, combining multi-body mechanics with controllers, electric drives and algorithms, e.g. path-planning. A multitude of scientific works use Modelica to simulate a specific robot, providing models for the mechanics and all other components exclusively for the simulated robot. Other approaches use parameter sets to simulate more than one robot model within a given structure. However, both approaches lack flexibility regarding switching between different robot types in a Modelica model, e.g. if the number of axes is changing. In this case, instead of changing a parameter value, the complete model structure has to be altered and adapted for the new robot model. In this paper, a new approach to model robots in Modelica is presented. By separating the robot functionalities (e.g. visualization, dynamics, path-planning, etc.) from the model-based description of the robot itself, and wrapping the latter in a replaceable package, it becomes possible to switch between entirely different robot models without the need for changing the structure of the main model. This approach is inspired by the Modelica Media library, where different media provide their own functions and models, also wrapped in a replaceable package, enabling the user to switch easily between different media in a model. Utilizing the scripting language LUA, it becomes possible to control the simulated robots with a virtual robot controller. This enables the user to design complex robot programs and execute them in a Modelica simulation. Several applications of the library are shown, from feasibility studies of robotic systems to real-time path-planning algorithms for real robot arms

Aerospace medicine and biology: A cumulative index to a continuing bibliography (supplement 345)

This publication is a cumulative index to the abstracts contained in Supplements 333 through 344 of Aerospace Medicine and Biology: A Continuing Bibliography. Seven indexes are included -- subject, personal author, corporate source, foreign technology, contract number, report number, and accession number

MMX Rover Simulation - Robotic Simulations for Phobos Operations

The MMX Rover, developed by CNES and DLR, will fly to and explore the surface of the Martian Moon Phobos within the JAXA Martian Moon Exploration Mission. It will be the first wheeled locomotion system in a milli-g environment. In the development of the rover, simulations have been used to test and develop its robotic activities. This paper presents the multi-physics simulations that are being used. The overall simulator setup and its main components are discussed. To provide appropriate simulations for the var-ious topics while maintaining a unified simulator, a modular approach was required. The different modules and their role will be outlined. For this, Dymola's implementation of the Mod-elica modeling language provides the basis, especially regarding multi-body dynamics, and the possibility to include external libraries, e. g. for environment interaction, control logic and visualization. Finally, examples for the simulator used in driving, uprighting, alignment and separation will be presented. These examples illustrate the approach on experiment design, setup and result evaluation. To date the MMX Rover simulator is regarded as an indispensable development and analysis tools, especially since representative lab experiments are much limited when designing a robotic system for milli-g operations. It is also planned to be used during operations phase for planning and analysis

ESROCOS: a robotic operating system for space and terrestrial applications

ESROCOS (http://www.h2020-esrocos.eu) is a European Project in the frame of the PERASPERA SRC, (http://www.h2020-peraspera.eu/), targeting the design of a Robot Control Operating Software (RCOS) for space robotics applications. The goal of the ESROCOS project is to provide an open-source framework to assist in the development of flight software for space robots, providing adequate features and performance with space-grade Reliability, Availability, Maintainability and Safety (RAMS) properties. This paper presents the ESROCOS project and summarizes the approach and the current status