<title>Development of PetRo: a modular robot for petlike applications</title>

We have designed and are developing a modular robot system called PetRo (Pet Robot) as part of the ReLIVE project. In this paper we briefly introduce the ReLIVE project to give an overall picture of the context within which we are developing PetRo. We compare the design and functions of PetRo to the modular robots we have surveyed, we also give a listing of the Degrees-of-freedoms our configuration deliver. There have been several issues to address during the development of PetRo such as the design of the shape and joints. We present the results we have achieved as well as the simulations we have run to analyse the mobility and self-assembly of the system in a combination of one, two and four modules. More specifically the outcomes from the fabrication of the first module are presented as well as the necessary changes in the design required from the results. Several trade-off had to be made between the complexity of the design and the simplicity of the actuation and control; we present these alongside our reasons to select the current configuration with self-configuration and overall mobility in mind. We also put forwards proposals regarding the inclusion of an array of sensors for an autonomous behaviour, we explain our vision of a herd of PetRos with social behaviours.