force) remains inadequate. Similar remarks apply to actuator and transmission technology.
Other current activities in the telerobotic area concern the development and use of new materials and the exploitation of advances in microelectromechanical systems. The availability of extremely small structures (including sensors and actuators) is stimulating exciting new work on microtelerobotic hardware and the interface and control problems associated with scaling down movements and forces from human scale to micro scales.
Also, and partly as a consequence of the advances in microelectromechanics, engineers are beginning to think about the possible benefits and feasibility of creating teleoperator systems that make use of distributed telerobotics, that is, a large number of relatively simple, relatively small telerobots with relatively narrow bandwidth communication among these telerobots. The use of multiple patrol telerobots for security purposes is one example of such an application. A major challenge in this area, aside from the development of the telerobots themselves, concerns the nature of the human-machine interface and the design of a display and control system that treats the set of telerobots as an integrated system rather than as a collection of independent entities that require a separate interface for each telerobot (and perhaps a whole set of human operators rather than a single operator).
The general problem of networking telerobotic systems, either in the sense of networking telerobots or networking the human operators, has received relatively little attention.
Communication networks can transform VEs into a shared environment in which individuals, objects, and processes interact without regard to their location. These networks will allow us to use VE for such purposes as distance learning, group entertainment, distributed training, and distributed design.
Currently, the two application domains in which the most networking activity is occurring are entertainment and national defense. In the entertainment industry, VR companies are in the process of forming cooperative arrangements with cable television companies to develop multi-user games and interactive shopping.
Applications for the military have focused on large-scale simulated network training exercises, such as those offered by SIMNET. In SIMNET, as many as 300 soldiers in tank and aircraft simulators located at different military bases can engage in a realistic battle against an intelligent enemy on a common battlefield. Currently, the Defense Department is using