This research presents the development of an android-based, voice-controlled autonomous robotic vehicle. This article was developed in a way that the robotic vehicle was controlled using voice commands. An android application combined with an android microcontroller was used to achieve this task. The connection between the android app and the autonomous vehicle was facilitated using Bluetooth technology. The vehicle was controlled with either the aid of the buttons on the app, or by spoken commands from the user. The movement of the vehicle was achieved by using four DC motors connected with the microcontroller at the receiver side. The commands from the app were converted into digital signals using the Bluetooth RF transmitter within a specific range (of around 100 m) of the autonomous vehicle. At the receiver end, the data gets decoded by the receiver and is fed to the microcontroller which moves the DC motors of the vehicle for navigation. The voice-controlled autonomous robotic vehicle performed navigational tasks by listening to the commands of the user. This was achieved by converting voice commands into text strings which are readable by the Arduino microcontroller on the android app in order to control the navigation of the robot. The vehicle was tested under different conditions and was observed to perform better using this technique and also the results were satisfactory when compared with other previous research that has been conducted in this area.

Multilevel inverters (MIs) are designed in such a way that different DC sources could be used to achieve the desired output voltage. This includes high quality output voltage, reduction of voltage stress on the switches, low common mode voltages, better harmonic content and reduction in total harmonic distortion compared to the conventional voltage source inverter. As there will be reduction in THD the size of the filter will also get minimized which decreases complexity of the system. Sinusoidal pulse width modulation technique is commonly employed in MIs in order to obtain undistorted output voltage by eliminating lower order harmonics. Cascaded H-bridge MIs are the most preferable for this purpose due to their modularity, reliability, less usage of clamping diodes and ease of control of circuitry and it also reduces the switching and conduction losses of the system. In this study, 5-level cascaded H-bridge inverter was simulated in MATLAB/Simulink software environment. A prototype of the simulated 5-level inverter was also constructed and the result was compared with that obtained from simulation. The results of both the simulation and experimental measurement have the similar output voltage waveform and the THD value of 33.12% and 33% for the simulation and experiment respectively.