Control Synthesis for an Underactuated Cable Suspended System Using Dynamic Decoupling

This article studies the dynamics and control of a novel underactuated system, wherein a plate suspended by cables and with a freely moving mass on top, whose other ends are attached to three quadrotors, is sought to be horizontally stabilized at a certain height, with the ball positioned at the center of mass of the plate. The freely moving mass introduces a 2-degree of underactuation into the system. The design proceeds through a decoupling of the quadrotors and the plate dynamics. Through a partial feedback linearization approach, the attitude of the plate and the translational height of the plate is initially controlled, while maintaining a bounded velocity along the $y$ and $x$ directions. These inputs are then synthesized through the quadrotors with a backstepping and timescale separation argument based on Tikhonov's theorem

A Decentralized Communication Policy for Multi Agent Multi Armed Bandit Problems

This paper proposes a novel policy for a group of agents to, individually as well as collectively, solve a multi armed bandit (MAB) problem. The policy relies solely on the information that an agent has obtained through sampling of the options on its own and through communication with neighbors. The option selection policy is based on an Upper Confidence Based (UCB) strategy while the communication strategy that is proposed forces agents to communicate with other agents who they believe are most likely to be exploring than exploiting. The overall strategy is shown to significantly outperform an independent Erd\H{o}s-R\'{e}nyi (ER) graph based random communication policy. The policy is shown to be cost effective in terms of communication and thus to be easily scalable to a large network of agents.Comment: This is the full version of a preprint that will appear in the proceedings of the 2020 European Control Conference (ECC

DISTRIBUTION OF Zanthium indicum AROUND GIRITALE TANK

The area around Giritale tank is the main grazing ground of wild and domestic animalswithin the naturc reserve and thcre has been an increase in the population of Xanthiuntitulicurn (Agada) in this area. In the Flora of Ceylon Trimen recorded this as a rare plantprohably introduced from India. Today, it is reported to be present in more than 7 districtsof the country, mostly in moist areas periodically inundated. It reduces the grazingcapacity and the hooked involucres are reported to cause damage to the internal organs ofthe grazers. Studies are heing carried out to find the distribution and suitable controlmeasures.Area around the tank was sampled at 100m intervals. The plant is capable of producingflowers and fruits irrespective of the time of the year and the size of the plant. When lessthan .'i()(Yr; of the area was covered hy the plant the abundance was taken, as low and whcnit was more than .'i0%, as high. .'i3% of the total area has been identified as highabundance and only 9% as freeThe species has already spread from the edge of water towards the forest. Although thefruits are found, the plant has not established in the forest. Soil moisture, texture and thelight intensity determine the growth of this plant. Fruits get embedded in the mud andalter decomposition two achenes arc released which germinate later. There are reports ofXcmtliitun sp. producing two types of achencs, germinating in consecutive years. Studiesarc heing carried out to investigate this.To improve the grazing capacity of the area it is necessary to control the growth of thisplant. Controlled hurning seems to he the best. Ten other species have heen recordedgrowing with Agada. Crotalaria pallida competes with X. lndicum. reducing itspopulation. The possibility of use of Cuscuta chinensis in the control of Xanthiumindicum is being tested.