The Epi.q-1 is a very interesting small mobile robot. As an adaptable “wheel-legged” hybrid robot, it utilizes a locomotion system that combines the advantages of both wheeled and legged robots, which allows it to move on flat, steep, and uneven ground.

In particular, Epi.q-1 can climb over obstacles and steps of varying sizes. For this purpose, “its operating mode adapts to ground conditions and changes ... from rolling (on wheels) to stepping (on legs). ... Robot locomotion drive-generating units use an original driving mechanism” that can vary or limit the degrees of freedom, according to the operating conditions. “Locomotion units consist of a motor linked to a gear (double epicyclical chain) and an axial device (mini-motor and lead screw system) that is able to lock or unlock some [depths of field (DOF)] of the kinematic chain.” The robot can also change the configuration of the locomotion unit from a closed to an open configuration, in order to reach restricted spaces, climb stairs, and overcome tall obstacles--up to 72 percent of the locomotion unit’s height. This configuration-changing ability is useful for both transportation and operations in a restricted environment.

As presented in the paper, the authors tested the robot experimentally on flat, inclined, and undulating ground; stairs; high obstacles; and even on different surfaces with increasing friction--plexiglass, paper, and plywood. The experimental tests reveal some drawbacks of the adopted configuration-changing mechanism, so the authors foresee the implementation of a new design, with a different positioning of the axial device, for future work. The authors claim that the mechanical design, although implemented on a robot, can be used in many applications, such as stair-climbing wheelchairs.

Overall, this is an interesting research paper on the design and operation of mobile robots. It could be useful to students and researchers who are interested in robotics.