COMPLETE LOCOMOTION ANALYSIS OF A SMALL DIFFERENTIALDRIVE MOBILE ROBOTIC PLATFORM

Mobile robots are becoming a part of more and more research areas due to their structural advantages and the increase in usage areas. Differential drive mobile robots are among the most preferred of this type of robots due to the convenience that they provide in engineering studies. It is quite important to test and structurally investigate primary parts such as motors and its sensors before being used in research applications. Before proceeding to further studies, it is very useful to do such tests as they may provide critical information about the robot which can be quite beneficial in terms of time, effort, and cost. To achieve this task, variety of methods are available in the literature such as structural locomotion tests and system identifiaction. In the first part of this study, locomotion tests of a small mobile robot driven by servo motors and operating with a single microcontroller was performed using the velocity propulsion mode. Three different predefined routes were determined for the robot and the accuracy of the robot moving along these routes was investigated. Through these tests, it is aimed to examine how the robot interprets the basic movements such as rectilinear forward motion, curvilinear motion, and rotation around its own axis. The next part focuses on the system identification of the robot. A data-driven model for the robotic platform was developed to make a mobile robot perform the desired movements and system identification. Various step input commands were sent to the robot under consideration and the responses of the robot wheels to these inputs were examined. Circular movements were made to the robot with a range of velocity input values and the relationship between input and output was examined for both wheels of the robot. In the locomotion tests, it was observed that the robot completed the predetermined routes with minor errors. As a result of these tests, theoretical calculations and experimental results were compared and the reasons for the error parameters were discussed. Through system identification tests, it was observed that the right wheel of the robot was more consistent and produced closer to the expected value for each test performed.