The paper discusses the experimental campaign on the prototype of the small scale ground mobile robot Mantis 2.0. It is a hybrid leg-wheel mobile robot, designed for surveillance and inspection tasks, with a maximum payload (camera, sensors) of 1 kg. Its locomotion system has been conceived to operate both in outdoor environments, on irregular and yielding terrains, and in indoor locations characterized by steps and stairs. Other operative requirements are good speed, energetic efficiency and stable camera vision without oscillations on flat terrains. The Mantis architecture is based on a main body with two front actuated wheels, a passive rear axle with two idle wheels and two rotating legs. While motion on flat and even ground is purely wheeled, with differential steering, when additional traction is required, for example in case of ground irregularities or obstacles, the front legs can rotate, performing a mixed leg-wheel locomotion. The profile of the legs is inspired by the praying mantis, and is specially designed to climb square steps and stairs, grasping the top of the step and lifting up the robot body. For stair/step descent, the legs are equipped with passive degrees of freedom for shock absorption. The multibody simulations and the experimental tests on the Mantis 1.0 prototype have shown the effectiveness of the proposed leg profile both for step climbing and for locomotion on uneven terrains and obstacles. The Mantis 2.0 prototype is equipped with auxiliary passive wheels, which reduce friction between legs and step upper surface in the last phase of step climbing, which is the most critical, in order to improve the reliability of the whole manoeuvre for all friction conditions. The auxiliary wheels are connected to the legs by one-way bearings, in order to avoid loss of traction during the mixed leg-wheel locomotion. The results of the experimental campaign confirm the goodness of the Mantis design, which represents potentially a versatile multipurpose platform for a wide range of unmanned applications. The next step of the research will be the development of an autonomous or semi-autonomous guidance system, capable of coordinating legs and wheels for obstacle climbing without human intervention.
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|Titolo:||Experimental assessment of the climbing performance of Mantis 2.0, a hybrid leg-wheel mobile robot for surveillance|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||04.02 - Abstract in atti di convegno|