Dynamic Modeling and Construction of a New Two-Wheeled Mobile Manipulator: Self-balancing and Climbing

Designing the self-balancing two-wheeled mobile robots and reducing undesired vibrations are of great importance. For this purpose, the majority of researches are focused on application of relatively complex control approaches without improving the robot structure. Therefore, in this paper we introduce a new two-wheeled mobile robot which, despite its relative simple structure, fulfills the required level of self-balancing without applying any certain complex controller. To reach this goal, the robot structure is designed in a way that its center of gravity is located below the wheels' axle level. The attention is more paid to obtaining a self-balancing model in which the robot’s arms and other equipment follow relatively low oscillations when the robot is subjected to a sudden change. After assembling the robot using the Sim-Mechanics toolbox of Matlab, several simulations are arranged to investigate the robot ability in fulfilling the required tasks. Further verifications are carried out by performing various experiments on the real model. Based on the obtained results, an acceptable level of balancing, oscillation reduction, and power supply is observed. To promote the self-balancing two-wheeled mobile manipulator, its platform is modified to climb high obstacles. In order to obtain this aim, some transformations are done in mechanical aspects like wheels, arms and main body without any increase in DOFs. The robot is supposed to follow proposed motion calculated according to stability criteria. The kinematic equations are utilized to find a possible motion. In a dynamic simulation, the robot ability in passing over an obstacle is verified.