Experiments with Cooperative Aerial-Ground Robots

Heterogeneous robot groups are a promising research direction for automating diverse tasks. A functional diierence between individual robot capabilities is likely to allow task-based specialization within the group. We report on experiments with a mechanically heterogeneous robot group consisting of a robotic helicopter and multiple wheeled ground robots. We present a behavior-based control system architecture for each robot. The overall system architecture for the group is discussed. Three case studies are presented in increasing order of group autonomy. We conclude with a discussion of our approach, a survey of related literature, and directions for ongoing and future work. A Introduction This chapter describes experiments in the design and construction of a cooperative, heterogeneous robot group comprised of one semi-autonomous aerial robot and two autonomous ground robots. While several applications for such a group exist, we are motivated in particular by the automated surveillance and reconnaissance of an urban outdoor area using onboard sensing. in robot groups largely focussed on architectural issues for robot control and coordination. However, heterogeneous robot groups have not been studied in much detail. Notable exceptions include the work reported in 25]. We consider a robot group to be heterogeneous if at least one member of the group is diierent from the others in one or more of the following attributes: 1. mechanics, 2. sensing, 3. computing hardware or 4. nature of onboard computation. This relatively loose condition is easily met by the system we describe in this paper. For a systematic analysis and metrics of robot group diversity the reader is referred to 5]. Our experimental testbed (shown in Figure 1) is composed of a robot helicopter and two mobile ground robots, thus making it a morphologically heterogeneous group. The advantages of using a group of robots to perform coordinated activity have been discussed extensively in the literature 13, 3, 6, 25]. These include speedup of task completion time, fault tolerance , and exibility, to name a few. Heterogeneous groups, in particular, allow for the possibility