No abstract

The deÞning characteristic of a networked control system (NCS) is having a feedback loop that passes through a local area computer network. Our two-step design approach includes using standard control methodologies and choosing the network protocol and bandwidth in order to ensure important closed-loop properties are preserved when a computer network is inserted into the feedback loop. For sufficiently high data rates, global exponential stability is preserved. Simulations are included to demonstrate the theoretical result.

Models of sexual selection generally assume that behavioural courtship displays reflect intrinsic male qualities such as condition, and that males display with maximum intensity to attract females to mate. Here we use robotic females in a field experiment to demonstrate that male satin bowerbirds (Ptilonorhynchus violaceus) do not always display at maximum intensity - rather, successful males modulate their displays in response to signals from females. Our results indicate that sexual selection may favour those males that can produce intense displays but which know how to modify these according to the female response.

In this paper we present a control law for globally asymptotically stabilizing a class of controllable nonlinear systems without drift. The control law combines earlier work in steering nonholonomic systems using sinusoids a t integrally related frequencies, with the ideas in recent results on globally stabilizing linear and nonlinear systems through the use of saturation functions. Simulation results for stabilizing a simple kinematic model of an automobile are included. 'Research supported in part by the Army under grant ARO DAAL-91-G-0191, and NASA under grant NAGZ-243 been presented by Samson [15] and Pomet [14]. In this paper we present some new control laws for a specific class of systems, namely those in so-called chained form [13]. These control laws are based on earlier work using sinusoids for open-loop planning and have connections with the recent work in [17]. Chained systems. We restrict attention to a special class of nonholonomic systems, called chained systems [13]. A two-input system with a single chain has the form: F5 = G-I U I .

A new technique for stabilizing nonholonomic systems to trajectories is presented. It is well known (see [2]) that such systems cannot be stabilized to a point using smooth static-state feedback. In this note, we suggest the use of control laws for stabilizing a system about a trajectory, instead of a point. Given a nonlinear system and a desired (nominal) feasible trajectory, the note gives an explicit control law which will locally exponentially stabilize the system to the desired trajectory. The theory is applied to several examples, including a car-like robot.