Mostafa Ali Ibrahim Salama
Kinematic Design of Omnidirectional Mecanum Wheeled Mobile Robot
One of the main concerns about wheeled mobile robots is the presence of singular
points within their workspaces. In singular positions the robot loses one or several
degrees of freedom. This means that the robot cannot move along (or around) some
directions. It is difficult to control the robot mechanism in singular position. The
avoidance of these singular positions has to be taken into consideration when
selecting the design parameters. A prerequisite to this is through knowledge about the
effect of design parameters and constraints on singularity. In this study, quality
condition index was introduced as a criterion for evaluating singularities of different
configurations of a mecanum wheeled mobile robot obtainable by different design
parameters. It was illustrated that this method can effectively be employed to obtain
the optimum configuration of mecanum wheeled mobile robot with the aim of
avoiding singularity within the workspace. This method was then employed to design
the wheeled mobile robot with different arrangements of mecanum wheels.
Chapter one includes an introduction which shows what is robotics and the
disadvantages that robotics faced like lack of mobility. In addition, an introduction to
what is omni-directional mobile robot, types of omni-directional wheeled platforms,
some special a wheel design, specially the mecanum wheel, and shows the basic
motions for an omni-directional mobile robot with four mecanum wheels.
In chapter two, includes a background about some of the different design ideas
currently being investigated around the world, and literature review which includes
some previous works.
Chapter three shows the kinematic design of wheeled mobile robot with mecanum
wheels, kinematic modeling for wheeled platform, and introduces the index of
Chapter four presents the results and discussions for different cases with different
configurations, different arrangements, and different design parameters.
Chapter five shows the conclusions for the present work as follows,
1. It is apparent that the condition number based on Frobenius norm is smooth everywhere.
2. The value of the roller angle affects the value of the condition number (Index of performance).
3. At condition number = 1: the value of the basic dimension and the corresponding aspect ratio depends on the maximum translational and rotational velocities of the platform (Characteristic Length).
4. (Car like robot) is preferred than any four wheel arrangement.
5. The choice of three wheel configuration is always for small basic dimension (small applications).
At the end of the present work some recommendations which may be added to the present work are presented.|