Design of an Automatic Load Positioning System for Hoist Operations

The operation of a helicopter with an externally slung load is highly demanding for the flight crew. Without having a direct view on the load, the pilot needs assistance by a crew member for load handling, e.g. load positioning. During Helicopter Hoist Operations (HHO), the hoist operator gives instructions to the pilot and stabilizes the load motion. An automatic load positioning system for HHO is designed with the aim to reduce the workload of the flight crew and to improve the load handling performance. The control system consists of a multi-loop architecture that is designed using multi-objective optimization. The system was designed to achieve best performance in load positioning for the entire cable length range of the rescue hoist. Load positioning performance is a function of the cable length; faster automatic load positioning can be achieved with shorter cable lengths. This paper describes the overall design process covering the tools, control law architecture, optimization, and the validation using DLR’s simulator

Topographic Features of Neisseria Catarrhalis Strains

The surface features of several bacterial species belonging to the Neisseriaceae including Neisseria gonorrhoeae, N. meningitidis and Veillonella parvula have been reported. During fimbriation studies with N. catarrhalis negative staining revealed a surface pattern differing from those found with other species of this genus. This report presents a comparative study with three N. catarrhalis strains. Consideration is given only to the physical aspects of intact cell wall structures.Of the three Neisseria catarrhalis strains used, one came from the stock culture collection of the Bacteriology Section, Division of Biological Sciences, University of Southern California, Los Angeles, while the remaining strains (ATCC 8176, ATCC 8193), were from the American Type Culture Collection, Rockville, Maryland.</jats:p