Sensor fusion and actuator system of a quadrotor helicopter

This article focuses on the sensor and actuator system of an autonomous indoor quadrotor helicopter. The sensor system has two parts: an inertial measurement unit (IMU) and a vision system. The fusion between the two systems is solved by extended Kalman filters. The calibration of the inertial measurement unit is described for various types of errors. The variance analysis is performed for the noise sources of sensors. The actuators of the helicopter are the four rotors. The identification and low level control of the brushless DC motor based rotor system is also presented. The embedded control system integrates a lot of processors and communication lines. The verification of the system´s parts were performed under real-time conditions. The main results of the paper are the new calibration algorithm for the different sensors and the real-time realization of the complex sensory system that may be part of a formation control system of UAVs

High precision GPS positioning with multiple receivers using carrier phase technique and sensor fusion

This paper presents a carrier phase differential GPS technique for vehicle navigation. The orientation and position of the vehicle can reliably be calculated by the proposed solutions. The developed methods are aided by inertial and magnetic sensors. They are designed for dead reckoning and to handle phase slip. Therefore these solutions can be applied when the set of the available satellites changes frequently. Extended Kalman filters perform state estimation. The paper also presents the low-cost hardware/software architecture of the navigation system. The effectiveness of the methods have been proven in real car and flight tests

Mathematical models fof simulation of continuous grinding process with recirculation

New mathematical and computer models and simulation programs were elaborated for studying processes of continuous grinding mills working with classification and partial recirculation of the product. The computer models were developed on the basis of the axial dispersion model taking into consideration also the effects of the mixing of the material to be ground. The effects of changes of parameters of both the mill and the material were studied. The stationary states of the continuous grinding mills working with and without classification and recirculation were compared to each other. The mathematical models and the computer programs developed are suitable for computing the processes of the grinding mills either with or without recirculation. They are usable for simulation based analysis and design of both continuous and batch grinding devices

Chlamydia pneumoniae in atherosclerotic middle cerebral artery

Background and Purpose—Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke. Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. Methods—Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. Results—Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. Conclusions—The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases

A felső-paleozoikumi Turonyi Formáció (Szlavóniai–Drávai-terrénum) pelites kőzeteinek ásványtani és kőzettani jellemzői | Mineralogical and petrological characteristics of mudrocks from the Upper Palaeozoic Turony Formation (Slavonia–Drava unit)

Munkánkban a felső-paleozoikumi Turonyi Formáció (Villányi-hegység nyugati szárnya) nagyon kisfokú metamorf pelites kőzettípusainak (agyagpala és metaaleurolit) ásványtani és kőzettani jellemzését végeztük el. Eredményeink alapján a Turonyi Formáció kőzeteit elsősorban albit, kvarc, illit±muszkovit, klorit (klorit/szmektit kevert szerkezet), hematit; kis mennyiségben kalcit és dolomit, illetve alárendelten albitosodott káliföldpát és szmektit alkotja. Akcesszóriaként opak ásványok (pl. pirit), turmalin, cirkon, monacit, rutil és apatit fordul elő. Az ásványos összetétel alapján a Turonyi Formáció üledékképződésekor — száraz és meleg éghajlati viszonyok mellett — a sóstavi (playa) környezetbe uralkodóan felzikus törmelékanyag szállítódott. A vizsgált kőzetek jelenlegi ásványos összetétele a korai diagenetikus, illetve betemetődési diagenetikus folyamatok (nyílt rendszerben végbement albitosodás, illitesedés, kloritosodás) hatását tükrözi. | In this paper, the results of mineralogical and petrological studies of very low-grade metapelitic sedimentary rock types (i.e. slate and metasiltstone) of the Upper Palaeozoic Turony Formation from southern Transdanubia (western flank of the Villány Mountains, SW Hungary) are presented. The studied Turony samples are predominantly composed of albite, quartz, illite±muscovite, chlorite (mixed chlorite–smectite) and haematite. Additionally, calcite, dolomite and rare albitized Kfeldspar and smectite also occur. Moreover, there are some accessory minerals such as opaque grains (e.g. pyrite), tourmaline, zircon, monazite, rutile and apatite. The mineralogical composition of these rocks suggests a relatively felsic provenance area and reflects the cumulative effects of the early and subsequent burial diagenetic processes (such as albitization) in an open system, illitization and chloritization during warm and arid climatic conditions in a playa lake