Fuzzy control of direct drive manipulators

Direct drive motors, sometimes referred to a torque motors are speciality servo actuators which posess high torque capacity without the necessity of gears. The author worked on a number of direct drive robots and their control methods since early 1990s when Professor Okyay Kaynak taught him fundamentals of fuzzy control and gave him the opportunity of experimental work on direct drive robotics. This chapter presents samples of the studies of the author on indirect fuzzy control implemented on direct drive robots between 1993 and 2012. The role of on-line controller parameter adaptation for sliding mode trajectory controllers, force controllers and for the integration of visual servoing and force control is discussed with case studies

CHEMICAL STRUCTURES OF PYRIDINE EXTRACTS AND RESIDUES OF COALS AS INDICATED BY SOLID-STATE C-13 NMR

WOS: A1984SJ21400016

Chemical structures of pyridine extracts and residues of coals as indicated by solid state 13C NMR.

The pyridine extracts and the residues of four Turkish coals were investigated in the solid state by CP/MAS C-13 NMR. No systematic correlation was observed between the ranks of the coals and the aromaticities of the pyridine extracts. There were pronounced structural differences between the pyridine extracts and the corresponding parent fuels and these differences were most prominent in the lower rank coals. In general, the C-13 NMR spectra of the residues were quite similar to those of the corresponding parent fuels. © 1984

Direct liquefaction of high-sulfur coals: Effect of the catalyst, the solvent, and the mineral matter

Two low-rank coals with high sulfur contents (Gediz subbituminous coal: 7.6 wt % S:dry basis. Çayirhan lignite: 5.7 wt% S:dry basis.) were subjected to hydroliquefaction. Liquefaction conditions included dry or solvent mediated runs under pressurized hydrogen without added catalyst or with the impregnated catalyst precursor ammonium heptamolybdate (AHM). Gediz coal having higher sulfur content gave 90% conversion in the absence of catalyst and solvent. Maximum conversion (98%) and maximum oil + gas yield (70%) from this coal were obtained by impregnating AHM onto coal and carrying out liquefaction in H2/tetralin system at 450 °C for 30 min. Under the same conditions, Çayirhan lignite gave 85% conversion and 70.5% oil + gas yield. The superior hydrodesulfurization effect of impregnated AHM on the oil fraction when used in the absence of solvent (less than 0.1% S in lignite's oil and less than 1% S in subbituminous coal's oil following one-stage hydrogenation) is a promising finding of this work. AHM was found to be much more effective in liquefaction of Çayirhan lignite and this has been ascribed to the well-dispersion of AHM throughout this lignite's structure via a cation-exchange mechanism through oxygen functionalities. Strong evidence for the catalytic effect of clay minerals in coal structure on char-forming reactions during liquefaction was observed by making use of liquefaction reactions of demineralized coal samples. It was also observed that tetralin had a retarding effect on the condensation and subsequent cross-linking reactions

Investigation of pyridine extracts and residues of coals by solid-state 13C n.m.r. spectroscopy

The 13C n.m.r. technique of cross polarization with magic angle spinning was applied to seven coals in their original states and the components obtained after pyridine extraction. It was observed that for the higher rank coals, short and straight alkyl groups are preferentially transferred to the extracts, while long-chain alkyl groups, branched alkyl groups or alicyclic structures are concentrated in the residues. Aliphatic ether or ester moieties were also observed to be concentrated in the residues. For all coals the computer-generated composite extract-residue spectra differed appreciably from the spectra of the original coals, indicating that some structures may be lost or that some structural conversion may occur during the extraction procedure. It was concluded that caution should be used in trying to determine detailed organic structural information of a coal from data obtained on its pyridine extract. © 1986.The authorsg ratefullya cknowledgep artial support of this work by the NATO researchg rantsp rogramme

ON THE MECHANISM OF REACTIONS OF ETHYL IODIDE WITH AROMATIC ANION SOLUTIONS

WOS: A1983RH05400062

Direct liquefaction of high-sulfur coals: Effects of the catalyst, the solvent, and the mineral matter

WOS: 000178122100005Two low-rank coals with high sulfur contents (Gediz subbituminous coal: 7.6 wt % S:dry basis. Cayirhan lignite: 5.7 wt%, S:dry basis.) were subjected to hydroliquefaction. Liquefaction conditions included dry or solvent mediated runs under pressurized hydrogen without added catalyst or with the impregnated catalyst precursor ammonium heptamolybdate AHM). Gediz coal having higher sulfur content gave 90% conversion in the absence of catalyst and solvent. Maximum conversion (98%) and maximum oil + gas yield (70%) from this coal were obtained by impregnating AHM onto coal and carrying out liquefaction in H-2/tetralin system at 450 degreesC for 30 min. Under the same conditions, Cayirhan lignite gave 85% conversion and 70.5% oil + gas yield. The superior hydrodesulfurization effect of impregnated AHM on the oil fraction when used in the absence of solvent (less than 0.1% S in lignite's oil and less than 1% S in subbituminous coal's oil following one-stage hydrogenation) is a promising finding of this work. AHM was found to be much more effective in liquefaction of Cayirhan lignite and this has been ascribed to the well-dispersion of AHM throughout this lignite's structure via a cation-exchange mechanism through oxygen functionalities. Strong evidence for the catalytic effect of clay minerals in coal structure on char-forming reactions during liquefaction was observed by making use of liquefaction reactions of demineralized coal samples. It was also observed that tetralin had a retarding effect on the condensation and subsequent cross-linking reactions