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Four omnidirectional-wheeled holonomic mobile robot (left: Perspective view, right: top view ; in the top view yellow box is the UEISIM DAQ, blue box is the wireless router, red boxes are the motor drivers, orange boxes are the batteries, orange ellipses are the infrared sensors, green box is the power inverter and dashed yellow box is the I/O cards.)
Source publication
Indoor locomotion with mobile robots has found applications in industrial part moving, factory floor investigation and cleaning tasks. Holonomic mobile robots have the advantage of moving in tight and winding passages without the need of steering. In this study, a four omni-directional wheeled mobile robot is considered. The mobile robot is kinemat...
Context in source publication
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Citations
... On the other hand, it has yet to be shown that the control is effective in different wheel arrangements. Sahin et al. show that fault tolerance can be achieved using a weighted pseudo-inverse of the Jacobian matrix derived for kinematics in a symmetric four-wheeled mecanum wheel robot [20]. This study shows that it can cope with actuator output anomalies. ...
Wheeled omnidirectional mobile robots have been developed for industrial and service applications. Conventional research on Omni wheel robots has mainly been directed toward point-symmetric wheel arrangements. However, more flexible asymmetric arrangements may be beneficial to prevent tipping over or to make the robot more compact. Asymmetry can also be the result of a motor/wheel failure in a robot with a redundant configuration; in this case, it may be possible to continue operations, but with an asymmetrical arrangement. For controlling such asymmetric arrangements, it is necessary to consider the moment of propulsive force generated by the wheels. Since it is difficult to measure the propulsive force accurately, in this work we model propulsive forces as being proportional to the ground speed of the wheels. Under this assumption, we estimated the robot’s behavior in an asymmetric wheel configuration by considering the balance of the velocity moment, which is the moment of the wheel’s ground speed. By verifying the robot’s behavior with various wheel configurations, we confirmed experimentally that the sum of the velocity moments affects the straightness of the robot and allows us to improve the design of asymmetric wheel arrangements and control during wheel failures.
