Implementation control algorithm for mobile robot based on omnidirectional wheel

This thesis aims to design and develop an implementation the control algorithm in mobile robot based on omni directional mecanum wheel and to be used in further researches. In an attempt to increase orientation capability of conventional wheelchair the system was equipped with four omni-directional wheels. In this study a control algorithm is developed to eliminate heading errors between demanded and real motor speeds taken from directly from system. In order to examine designed controller on real large-scale system, an experimental setup is installed. The experimental setup consists of microcontroller, dc motor drivers, four dc motors coupled with mecanum wheels and quadratic encoder. Mathematical model of this system is also created through forward and backward kinematic with weighted matrix equations,which provides with the decreasing heading error while any of DC Motors operate in unexpected behaviors such as stop or undesired velocity by improved mathematical model unlike relevant works in this area, Transfer function of Dc motor is estimated by the help of measured voltage and speed values. The dc motor model is added into system model to determine needed speed according to user inputs. Created mathematical model is designed and simulated in MATLAB/Simulink environment. In order to validate designed model, different orientation scenarios are given to system independently. Cross-validation is done by independent input-output data sets and it is determined that the model has the residual autocorrelation function inside the confidence interval.Based on the validated model, unlike motor speed responses are without overshoot and oscillation, a sub-control algorithm PD is designed and simulated to reduce settling time and minimize heading errors. Obtained simulation and real system results are compared. Owing to designed controller performance and adaptation of weight unit matrix values, heading error caused by structural, assembly and manufacturing failures is decreased dramatically.