Eka Maulana

Inverse kinematics of a two-wheeled differential drive an autonomous mobile robot

In this research, an inverse kinematic model for automatic mobile robot has been experimental designed by direct controlling of two-wheeled differential drive method. An orientation of the robot toward lined track is observed to evaluate the right position by controlling the speed differences between the rears two-wheeled separately. The angular speed of the rear wheels calculated according to the desired linear speed of the robot and an error occurs to the angle of the robot orientation affected by of radius of the rear wheel, distance between the two driven rear wheels, and the curvature of turn movement the mobile robot. Two font-wheels were designed flexible as a free wheel mechanism to follow the lined track. A system performance was analyzed to obtain the robot characteristic response.

Inverse kinematic implementation of four-wheels mecanum drive mobile robot using stepper motors

An implementation of inverse kinematic model is applied for the mobile robot using four-wheels mecanum drive. The implementation is designed for omni-directional movement without changes the robot position on a facing direction. Four stepper motors are used to drive the mecanum wheels due to these types have a good precision. This speed control feedback is not necessary. The radius of the mobile robot dimension is defined by the same distance of a and b length between wheel axis and body center of 170 mm. The inverse kinematic is conducted to control the mobile robot movement and to convert the robot velocity component of v_x, v_y, and ω toward angular velocity each wheels of ω₁, ω₂, ω₃, ω₄ and wheel turn direction. Kinematic calculation and control mechanism are proceed by a master microcontroller and multi-slave microcontrollers which connected using SPI communication protocol. The theta angle θ is described by v_x and v_y vector velocity direction toward center point of the mobile robot. The movement capabilities are performed by linear direction according to the certain angle of the robot movement θ of 0° to each multiples of 45° thus obtained wheel velocity and angle movement average errors.

PV Smart Grid Monitoring System Based on Hybrid Telepot and Web Server

With the rapid growth of communications via the Internet, the need for an effective firewall system which has not badly affect the overall network performances has been increased. In this paper, a Field Programmable Gate Array (FPGA) -based firewall system with high performance has been implemented using Network FPGA (NetFPGA) with Xilinx Kintex-7 XC7K325T FPGA. Based on NetFPGA reference router project, a NetFPGA-based firewall system was implemented. The hardware module performs rule matching operation using content addressable memory (CAM) for higher speed data processing. To evaluate system performance, throughput, latency, and memory utilization were measured for different cases using different tools, also the number of rules that an incoming packet is subjected to was varied to get more readings using both software and hardware features. The results showed that the designed firewall system provides better performance than traditional firewalls. System throughput was doubled times of the one with Linux-Iptables firewalls.

The effect of photoelectrode TiO 2 layer thickness to the output power of chlorophyll-based Dye-Sensitized Solar Cell (DSSC)

DSSC (Dye-Sensitized Solar Cell) is conducted by doctor blading TiO2 deposition method to the substrate material. Couple of TCOs (Transparent Conductive Oxide) of Indium Thin Oxide are used as substrate of photo electrode and counter electrode. The variation of TiO2 layer thickness is deposited on to photo electrode layer by adjusting level of masker thickness. The variation of masker layers are used of 100, 200, and 300 μm thickness. The DSSC structure is designed by combination of TCO glass, TiO2 nanoparticle, natural chlorophyll dye ectract from jatropha leaves, electrolyte solution and carbon layer. A extracted chlorophyll absorbance spectra is investigated by UV-1601 spectrophotometer at 200-800 nm wavelength. According to the DSSC measurement by 7 watt LED lamp, it was obtained the maximum electrical characteristic of open voltege circuit Voc and sort circuit current Isc are 321 mV and 15.2 μA, respectively. The maximum output power was achieved by 292 μm TiO2 layer thicness of 1008 × 10-9W produced by 292 μm layer thickness applied on 1.7×1.7 cm active area of DSSC.