Engineering and Computer Science at M.I.T. and a member of the Artificial Intelligence Laboratory where he leads the mobile robot group. He has authored two books, numerous scientific papers, and is the editor of the International Journal of Computer Vision. There is an alternative route to Artificial Intelligence that diverges from the directions pursued under that banner for the last thirty some years. The traditional approach has emphasized the abstract manipulation of symbols, whose grounding, in physical reality has. rarely been achieved. We explore a research methodology which emphasizes ongoing physical interaction with the environment as the primary source of constraint on the design of intelligent systems. We show how this methodology has recently had significant successes on a par with the most successful classical efforts. We outline plausible future work along these lines which can lead to vastly more ambitious systems. 1.

We describe an algorithm which allows a behavior-based robot to learn on the basis of positive and negative feedback when to activate its behaviors. In accordance with the philosophy of behavior-based robots, the algorithm is completely distributed: each of the behaviors independently tries to find out (i) whether it is relevant (ie. whether it is at all correlated to positive feedback) and (ii) what the conditions are under which it becomes reliable (i.e. the conditions under which it maximizes the probability of receiving positive feedback and minimizes the probability of receiving negative feedback). The algorithm has been tested successfully on an autonomous 6-legged robot which had to learn how to coordinate its legs so as to walk forward. Situation of the Problem Since 1985, the MIT Mobile Robot group has advocated a radically different architecture for autonomous intelligent agents (Brooks, 1986). Instead of decomposing the architecture into functional modules, such as percept...

Complex systems and complex missions take years of planning and force launches to become incredibly expensive. The longer the planning and the more expensive the mission, the more catastrophic if it fails. The solution has always been to plan better, add redundancy, test thoroughly and use high quality components. Based on our experience in building ground based mobile robots (legged and wheeled) we argue here for cheap, fast missions using large numbers of mass produced simple autonomous robots that are small by today's standards (1 to 2 Kg). We argue that the time between mission conception and implementation can be radically reduced, that launch mass can be slashed, that totally autonomous robots can be more reliable than ground controlled robots, and that large numbers of robots can change the tradeoff between reliability of individual components and overall mission success. Lastly, we suggest that within a few years it will be possible at modest cost to invade a planet with millions of tiny robots. 1.

The paper focuses on one of the problems of design of an autonomous reactive system, namely, specification of its behavior with respect to (often unpredictable) changes occurring in the real world. Several "behavior-oriented" languages are briefly presented, and some formal relationships between two of them --- Process Transition Networks and Statecharts --- are given. The goal of this presentation is to address the need for augmenting the "behaviorbased design" paradigm with theoretical tools both adequate for expressing complex behaviors of autonomous reactive systems pursuing high-level goals, and applicable to both analysis and synthesis tasks for such systems. 1 Introduction The problem of designing an autonomous system capable of acting in the real world has been the subject of much attention in recent years. The research has focused on designing systems with the following attributes: ffl reactivity, in order to allow the system to cope with unpredictable changes in the dynamic...

Brooks postulates in his papers [6, 7] the possibility that intelligence can emerge out of a set of simple, loosely coupled behaviours. This possibility is conjectured on the basis of experiments with a set of robots equipped with subsumption-based control systems. In this paper we briefly present The Behavior Language (BL) used for programming subsumption systems and we show that any BL program is equivalent to a statechart. Then we analyze a simple emergent behaviour and argue that it actually is obtained through appropriate tuning of delays defined in the controlling BL program. The conclusion is that emergent properties arise (if at all) due to the complex dynamics of interactions among the simple behaviours and that this emergence is to a large extent accidental. 1 Introduction The problem of designing an autonomous system capable of acting in the real world has been the subject of much attention in recent years. The research has focused on designing systems with the following at...

Legged Locomotion over Irregular Terrain using the Control Basis Approach May 1996 Willard Schroeder MacDonald, BS EE, University of Massachusetts at Amherst M.S., University of Massachusetts Amherst Directed by: Professor Roderic A. Grupen Robust legged locomotion over natural irregular terrain has yet to be achieved by an autonomous robot. This thesis will present the control basis approach as a viable solution to generating walking gaits on-line for irregular terrain. A control basis is a set of reusable feedback control laws that are task and platform independent. Different walking tasks are achieved by varying the composition functions over the same basis controllers, rather than by geometric planning of leg placements or the design of new task-specific behaviors. Hardware modifications to Thing, a four legged walking robot, are described which allow it to map local terrain features. A control basis and a control composition for walking on irregular terrain is proposed and...