Developing Virtual Testbeds for Mobile Robotic Applications in the Woods and on the Moon

Simulation in the context of engineering often focuses on very special details of global systems. Robot designers usually begin with the analysis of new actuators and joint designs. This corresponds to a "bottom-up"-strategy in the development of simulation models. For classical fields of application of robotics, e.g. in production plants with a well defined environment this is the approved method, because it allows very detailed insights into the analyzed subsystems. On the other hand, unpredictable effects of the interaction of multiple subsystems may easily be overseen. In particular, nontechnical environments like in moon exploration tasks or in a biological environment like in forestry applications are hard to describe in an analytical way to integrate them into an analytical simulation model. This is why this paper presents the idea and some practical aspects of the development of "Virtual Testbeds". In a Virtual Testbed, the entire system is simulated as a whole in Virtual Reality - not only small subsystems of a global system. According to the requirements different subsystems are simulated with different levels of detail. In contrast to the classical "bottom-up"-strategy this can be seen as a "top-down"-approach. Therefore the employment of a multi-body dynamics system as a platform for the development of versatile simulation and testing environments is proposed. Using the examples of the evaluation and testing of an extraterrestrial walking exploration robot design and the development of a method for self-localization in forestry, the idea is further deepened. As a special field of attention the integration of a method of soil simulation as a particular requirement of a Virtual Testbed for walking exploration robots is presented.