Velocity control of a unicycle type of mobile robot using optimal pid controller

A unicycle model of control a mobile robot is a simplified modeling approach modified from the differential drive mobile robots. Instead of controlling the right speed, VR and the left speed, VL of the drive systems, the unicycle model is using u and ω as the controller parameters. Tracking is much easier in this model. In this paper, the dynamic of the robot parameter is controlled using two blocks of Proportional-Integral-Derivative(PID) controllers. The gains of the PID are firstly determined using particle swarm optimization(PSO) in offline mode. After the optimal gain is determined, the tracking of the robot’s trajectory is performed online with optimal PID controller. The achieved results of the proposed scheme are compared with those of dynamic model optimized with genetic algorithm(GA) and manually tuned PID controller gains. In the algorithm, the control parameters are computed by minimizing the fitness function defined by using the integral absolute error(IAE) performance index. The simulation results obtained reveal advantages of the proposed PSO-PID dynamic controller for trajectory tracking of a unicycle type of mobile robot. A MATLAB-Simulink program is used to simulate the designed system and the results are graphically plotted. In addition, numerical simulations using 8-shape as a reference trajectory with several numbers of iterations are reported to show the validity of the proposed scheme

Synthesis of medium-chain glycerides using lipase from Candida rugosa

Enzymatic synthesis of medium-chain glycerides (MCG) from capric acid and glycerol was studied using lipase from Candida rugosa. The effects of various reaction parameters such as time, molar ratio of substrates (mmol capric acid/mmol glycerol), amount of lipase, type of organic solvents, and initial water activity (a w ) were studied. The best conditions tested for MCG synthesis at 37°C were, respectively, time, 24 h; molar ratio of substrates, 2.5; and amount of lipase, 100.0 mg. The use of organic solvents greatly influenced the activity of lipase in the synthesis of MCG. Generally, activity of lipase was high in nonpolar solvents with log P values from 3.50 to 4.50, where P is the partition coefficient between water and 1-octanol. The enzymatic synthesis of MCG was preferably carried out at an initial a w of 0.328, which resulted in maximal yield. Analysis of the products of reaction using gas chromatography showed that lipase from Candida rugosa seemed to produce more dicaprin and tricaprin than monocaprin

Pengaruh Sistem Pengendalian Intern Pemerintah, Kinerja Pegawai, Pengawasan Melekat Dan Pengawasan Fungsional Terhadap Efektivitas Pengelolaan Keuangan Daerah (Studi Pada Skpd Kabupaten Lima Puluh Kota Payakumbuh Sumatra Barat)

This study aimed to examine the effect of Government Internal Control System, Employee Performance, Monitoring Fitted and functional supervision on the Effectiveness of Financial Management (Studies in SKPD Lima Puluh Kota West Sumatra). This study used convenience sampling method. The sample in this study is the SKPD Lima Puluh Kota West Sumatra. Respondents were instrumental in this research is 75 respondents consisting of a chief financial officer, financial records staff / accounting and regional inspectorate. The statistical method used to test the hypothesis is multiple regression with the help of SPSS version 18.0. The results provide evidence that the Government Internal Control System, Employee Performance, Monitoring and Control Functional Fitted have significant effect on the Effectiveness of Financial Management through multiple correlation coefficient (R) of 0789 and the relationship is very strong

The Effects of Nano Fillers on Space Charge Distribution in Cross-Linked Polyethylene

The performance of polymeric insulation will be distorted by the accumulation of space charge. This will lead to local electric field enhancement within the insulation material that can cause degradation and electrical breakdown. The introduction of nanofillers in the insulation material is expected to reduce the space charge effect. However, there is a need to analyze potential nanofillers to determine the best option. Therefore, the objective of this research work is to examine two types of nanofillers for Cross-Linked Polyethylene (XLPE); Zinc Oxide (ZnO) and Acrylic (PA40). The effects of these nanofillers were measured using the Pulsed-Electro Acoustic (PEA) method. The development of space charge is observed at three different DC voltage levels in room temperature. The results show that hetero charge distribution is dominant in pure XLPE materials. The use of both nanofiller types have significant effect in decreasing the space charge accumulation. With nanofillers, the charge profile changed to homo-charge distribution, suppressing the space charge formation. Comparisonbetween both the nanofillers show that PA40 has better suppression performance than ZnO

Assessment ranking for green pavement material elements

The development of green roadway in Malaysia is one of the contributions to accomplish Malaysia Go Green Campaign. Hence, sustainable materials are widely used in road construction recently because people are more aware about its implications towards environments. However, people keep trying to find the most suitable sustainable materials to be used in designing road pavement. Hence, a new method is introduced which assessment ranking for green pavement material element and research is developed by finding and adding more green material used in designing pavements in Malaysia. They are then been categorized and analysed in order to identify which will become the most preferred material. Development of questionnaire survey is one of the steps involved as well as analysis of factor and ranking method for all the green material elements used in roads. About 25 respondents including teams from Public Work Department (JKR) and consultant company are chosen to answer the questionnaire survey according to their specialisation in road construction area. The agreement level which is the output from survey will be transferred into Minitab Software and measured using factor analysis. The factor score which is product from factor loading and mean values being restructure and becomes the weightage factor. Thus, all the material elements are ranked based on their weighted factor value. From the analysis of questionnaire survey, alternative binder become the most preferable material to be used for green pavement for it has the largest weighted factor

A review of gelatin: properties, sources, process, applications, and commercialisation

This review begins with a discussion of the general properties of gelatin and its sources, particularly in the food and health industries, and then briefly address the status quo of gelatin in today’s market. Apart from the basic chemical compounds and gelatin types, this paper also discussed the commercialisation of gelatin. This study also highlights the production of conventional gelatin and its current method of processing, i.e. enzymatic hydrolysis. In addition, the variety of raw materials of collagen is outlined and briefly broached the plant hydrocolloids which have been labeled as ’veggie-gelatin’. With regard to the potential and market stability of gelatin, its recent studies are summarised in this paper. Accordingly, this paper focuses on assessing the general utilities of the various sources of collagen as gelatin derivatives. At that basis, the aim of this review is to provide an insight into gelatin in current applications, market value and progress in gelatin extraction

Possible detection of a magnetic field in T Tauri

Medium-resolution $(R\simeq 15000)$ circular spectropolarimetry of T Tauri is presented. The star was observed twice: on November 11, 1996 and January 22, 2002. Weak circular polarization has been found in photospheric absorption lines, indicating a mean surface longitudinal magnetic field $B_{\|}$ of $160\pm 40$ G and $140\pm 50$ G at the epoch of the first and second observations respectively. While these values are near the detection limit of our apparatus, we belive that they are real. In any case one can conclude from our data that $B_{\|}$ of T Tau does not significantly exceed 200 G, which is much less than surface magnetic field strength of the star ($>2.3$ kG) found by Guenther et al. (1999) and Johns-Krull et al. (2000). We discuss possible reasons of this difference.Comment: 5 pages, 3 figure

Multiplicity of Nearby Free-floating Ultra-cool Dwarfs: a HST-WFPC2 search for companions

We present HST/WFPC2 observations of a sample of 134 ultra-cool objects (spectral types later than M7) coming from the DENIS, 2MASS and SDSS surveys, with distances estimated to range from 7 pc to 105 pc. Fifteen new ultra-cool binary candidates are reported here. Eleven known binaries are confirmed and orbital motion is detected in some of them. We estimate that the closest binary systems in this sample have periods between 5 and 20 years, and thus dynamical masses will be derived in the near future. For the calculation of binary frequency we restrict ourselves to systems with distances less than 20 pc. After correction of the binaries bias, we find a ratio of visual binaries (at the HST limit of detection) of around 10%, and that ~15% of the 26 objects within 20 parsecs are binary systems with separations between 1 and 8 A.U. The observed frequency of ultra-cool binaries is similar than that of binaries with G-type primaries in the separation range from 2.1 A.U. to 140 A.U. There is also a clear deficit of ultra-cool binaries with separations greater than 15 A.U., and a possible tendency for the binaries to have mass ratios near unity. Most systems have indeed visual and near-infrared brightness ratios between 1 and 0.3. We discuss our results in the framework of current scenarios for the formation and evolution of free-floating brown dwarfs.Comment: 67 pages, 14 figures, Accepted for publication in AJ, September 2003. First submission to AJ: august 2002, 5 submission

Simultaneous Multi-Wavelength Observations of Magnetic Activity in Ultracool Dwarfs. I. The Complex Behavior of the M8.5 Dwarf TVLM513-46546

[Abridged] We present the first simultaneous radio, X-ray, ultraviolet, and optical spectroscopic observations of the M8.5 dwarf TVLM513-46546, with a duration of 9 hours. These observations are part of a program to study the origin of magnetic activity in ultracool dwarfs, and its impact on chromospheric and coronal emission. Here we detect steady quiescent radio emission superposed with multiple short-duration, highly polarized flares; there is no evidence for periodic bursts previously reported for this object, indicating their transient nature. We also detect soft X-ray emission, with L_X/L_bol~10^-4.9, the faintest to date for any object later than M5, and a possible weak X-ray flare. TVLM513-46546 continues the trend of severe violation of the radio/X-ray correlation in ultracool dwarfs, by nearly 4 orders of magnitude. From the optical spectroscopy we find that the Balmer line luminosity exceeds the X-ray luminosity by a factor of a few, suggesting that, unlike in early M dwarfs, chromospheric heating may not be due to coronal X-ray emission. More importantly, we detect a sinusoidal H-alpha light curve with a period of 2 hr, matching the rotation period of TVLM513-46546. This is the first known example of such Balmer line behavior, which points to a co-rotating chromospheric hot spot or an extended magnetic structure, with a covering fraction of about 50%. This feature may be transitory based on the apparent decline in light curve peak during the four observed maxima. From the radio data we infer a large scale steady magnetic field of ~100 G, in good agreement with the value required for confinement of the X-ray emitting plasma. The radio flares, on the other hand, are produced in a component of the field with a strength of ~3 kG and a likely multi-polar configuration.Comment: 13 pages, 4 figure