Ground mobile robots have used traditional Mecanum wheels in the last decade because they provide them with effective omnidirectional mobility. However, these wheels provide such characteristics only on hard flat surfaces or engineering environments, restricting the applications of Mecanum wheels on outdoor environments. To enable robots to have omnidirectional capabilities, this thesis proposes a novel Mecanum wheel design and prototype capable to overcome obstacles on rough terrains. The goal is to enable robots to move sideways or in any other directions and enable them to overcome obstacles of the size of at least 25% of the wheel's diameter. Thus, allowing ground mobile robots to have omnidirectional mobility when moving on complex rough outdoor environments. The proposed wheel designs, referred to as semicircular and elliptical Mecanum wheels, were prototyped and tested. The results show the effectiveness of such novel wheels to enhance the omnidirectional mobility of ground mobile robots when compared with robots using traditional Mecanum wheels on outdoor applications.