A comprehensive understanding of the control of flexible fins is fundamental to engineering underwater vehicles that perform like fish, since it is the fins that produce forces which control the fish's motion. However, little is known about the fin's sensory system or about how fish use sensory information to modulate the fin and to control propulsive forces. As part of a research program that ...

This paper presents a locomotion control implementation of a robotic system mimicking the undulating fins of fish. To mimic the actual flexible fin of a real fish, we created a ribbon fin type actuation device with a series of connecting linkages and attached it to the robotic fish. By virtue of a specially designed strip with a slider, each link is able to turn and slide with respect to the ad...

1) Peatland Forestry, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland 2) Department of Biological and Environmental Sciences, University of Jyväskylä, P.O. Box 35, FIN-40351 Jyväskylä, Finland 3) Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland 4) Laboratory of Environmental Microbiology, National Public Health Institute...

1 School of Science, Aalto University, PO Box 15500, FIN-00076 Aalto, Finland [email protected], 2 ControlThings Oy, R̊abackavägen 7, FIN-06650 Hammars, Finland [email protected] 3 Posintra Oy, Electrical Building Services Centre, Gnistvägen 1, FIN-06150 Borg̊a, Finland. [email protected] 4 School of Science, Aalto University, PO Box 15500, FIN-00076 Aalto, Finland Jan.Holm...

Juha Helenius Department of Applied Biology, PO Box 27, FIN-00014 University of Helsinki, Finland, e-mail: [email protected] Jarmo K. Holopainen MTT Agrifood Research Finland, Plant Production Research, Plant Protection, FIN-31600 Jokioinen, Finland. Current address: Department of Ecology and Environmental Science, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland Erja Huusel...

This is the first known report on the skeletal and muscular systems, and the skin histology, of the pectoral fin of the rare planktivorous megamouth shark Megachasma pelagios. The pectoral fin is characterized by three features: 1) a large number of segments in the radial cartilages; 2) highly elastic pectoral fin skin; and 3) a vertically-rotated hinge joint at the pectoral fin base. These fea...

The dynamics of pectoral fin rowing in the threespine stickleback are investigated by measuring the instantaneous force balance on freely swimming fish throughout the stroke cycle and comparing the measured forces with fin motions and an unsteady, blade-element model of pectoral fin propulsion. Both measured and modeled forces suggest that attached vortex and circulatory forces and not inertial...

In this study, the thermal performance analysis of porous fin with temperature-dependent thermal conductivity and internal heat generation is carried out using Haar wavelet collocation method. The effects of various parameters on the thermal characteristics of the porous fin are investigated. It is found that as the porosity increases, the rate of heat transfer from the fin increases and the th...

We consider two related one-dimensional steady-state problems of heat conduction/radiation in a cooling fin. In both problems the solution consists of the value of a parameter (length of the fin) and a monotone temperature distribution in the fin. Three boundary conditions are accordingly imposed: temperature at both ends of the fin and heat flux at one end. We show that these problems have sol...

The median fins of fishes consist of the dorsal, anal, and caudal fins and have long been thought to play an important role in generating locomotor force during both steady swimming and maneuvering. But the orientations and magnitudes of these forces, the mechanisms by which they are generated, and how fish modulate median fin forces have remained largely unknown until the recent advent of Digi...