Recursive convex replanning for the trajectory tracking of wheeled mobile robots

The article consider the Cartesian trajectory tracking of wheeled mobile robots to be performed by a hybrid control scheme with feedforward inverse control and a state feedaback that is only updated periodically and relies on a recursive convex replanning of the reference trajectory. This approach applied to the standard unicycle model is shown to maintain its efficacy also in presence of noise or unmodeled robot dynamics. Explicit, sufficient conditions are provided to ensure global boundedness of the tracking error. Experimental results are presented using Lego Mindstorm mobile robots

The Carbon Sequestration Potential of Soils: Some Data from Northern Italian Regions

It is well known that soil plays, within terrestrial ecosystems, an essential role in many biogeochemical cycles and in the regulation of greenhouse gas fluxes. Less known, and often underestimated, is the importance of carbon sequestration potential of soil, especially trough humified carbon. Even within the agro-forestry practices of the Kyoto Protocol, most of the attention is devoted to the biomass carbon storage, rather than soil carbon sequestration. The highest potentialities for carbon sequestration are related to the arable lands, that accounts for the 11% of earth surface; the increase of 0.1% of organic carbon content in the 0-30 cm layer of cultivated soils, achievable with minor adjustment of agronomic practices, is equivalent to the sequestration of 5,000 millions t of carbon. On the other hand, the conversion of a grasslands into cultivated land determine, during 50-70 years, a release of 80-150 t CO2 ha-1.Within this paper the estimate of soil organic carbon of three Northern Italian regions is presented

Design, development and test of a vibration monitoring embedded system

This paper presents the design, development and test of a Controller"based embedded system designed to monitor vibration profiles during the shipment of products along the supply chain. A digital accelerometer detects the mechanical shocks while sensors, embedded as auxiliary devices, trace, wherever is necessary, other variables like the temperature, pressure, moisture, etc. The developed system is managed by a Cortex M3 Controller characterized by high performances and low consumption. All data, acquired during the transport, are periodically stored on a large capacity SD card and can be diplayed thanks to a user"friendly interface. In addition, the developed system can, also, interface with a shaker to perform, in laboratory, simulations and tests reproducing the stress profiles measured on the field. Evaluations of the quality degradation of products are thus possible. In the last section of this paper, a case study, presenting an analysis of mechanical stresses in the fresh fruit supply chain, is presented and discussed