Engineering Commons^™

Maritime Traffic Management: A Need For Central Coordination?, Fulko Van Westrenen, Gesa Praetorius

Gesa Praetorius

Traffic management is not formally organised in the maritime domain. Ships are autonomous and find their own way. Traffic is organised through rules, regulations, and “good seamanship”; it is a distributed system. In areas of high traffic-density support is proved by vessel traffic service (VTS) to promote traffic safety and fluency. VTS does not take control. This organisational structure has proven itself in situations with sufficient resources. When resources become insufficient (e.g. not enough sailing space), the traffic needs an organising mechanism. In this article, the authors argue that the most promising way to do this is by organising centralised …

Situation Awareness And Maritime Traffic: Having Awareness Or Being In Control?, Fulko Van Westrenen, Gesa Praetorius

Gesa Praetorius

Situation awareness (SA) is generally seen as a mental representation of the system state, an objective measure of the ‘situation out there’. In this article, the authors make an argument that SA can only have a meaning in relation to the task of the user and characteristics of the system. This will be argued with the help of a specific environment: vessel traffic monitoring. The long-time constants and the complex constraints imposed on the ship require that the operator monitoring the traffic has a good SA: the operator must make long-term predictions about possible traffic developments. For this, being in …

Robust Adaptive Control For Industrial Robots - A Decentralized System Method, M Liu, Christopher Cook

Christopher Cook

An adaptive control approach is presented for the tracking control of industrial robots. The approach utilizes the fact that a robot model can be described by equations that are linear in the system's unknown parameters. Taking uncertainties into account, the resulting controller has the property of robustness. The proof of stability and analytical results of the boundness of position tracking errors are given. By introducing filter operations in state measurements, the approach avoids the difficulty of measuring the accelerations of the robots' actuators. Simulation results are also presented

Gait Transitions For Quasi-Static Hexapedal Locomotion On Level Ground, Galen Haynes, Fred Cohen, Daniel Koditschek

Daniel E Koditschek

As robot bodies become more capable, the motivation grows to better coordinate them—whether multiple limbs attached to a body or multiple bodies assigned to a task. This paper introduces a new formalism for coordination of periodic tasks, with specific application to gait transitions for legged platforms. Specifically, we make modest use of classical group theory to replace combinatorial search and optimization with a computationally simpler and conceptually more straightforward appeal to elementary algebra.

We decompose the space of all periodic legged gaits into a cellular complex indexed using “Young Tableaux”, making transparent the proximity to steady state orbits and the …