Experiences for a User-Friendly Operation of Cassino Hexapod III

A hybrid legged-wheeled obstacle avoidance strategy for service operations

“…Furthermore, with legged locomotion, it can face rough terrains, or to avoid and overcome obstacles by rising one or more legs during a wheeled displacement. This feature of the robot is well presented in [14,17], where the feasibility of a wheeled, legged, and wheeled-legged locomotion is discussed. Since the robot has mecanum wheels, it is also able to carry out complex displacements, where the robot can follow a circular gait without changing its local x or y local axis.…”

“…The control hardware of Cassino Hexapod III is fully onboard. It consists in an Arduino MEGA as the servo-controller, a servo-shield to connect the eighteen servomotors, and a Li-Po battery (Full Power 4S) with a regulator to decrease the voltage to 5 V [14], Fig. 4.…”

Static Balancing of Wheeled-legged Hexapod Robots

“…Every hybrid leg consists of three servomotors, two (180 • servomotor) to enable the pure movement of the leg, and the third (continuous rotation servomotor) to activate the movement of the Mecanum wheel ( Figure 2b). This kind of leg allows the robot to move in any direction over flat surfaces and to easily avoid large obstacles by simply rolling to any position along a straight line or overcoming small obstacles by performing complex movement with a combination of legs and wheels [19]. Its control hardware is fully onboard.…”

“…Wheeled-legged robots combine the best features of two locomotion types: wheel efficiency and velocity alongside legged robots' capability to deal with difficult terrains. Service activities where time can be a matter of life and death, such as search and rescue missions or hospital assistance, are examples of tasks that might benefit significantly from such systems [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. These hybrid systems, robots with legs ending in wheels, can move by driving on the wheels while adjusting with legs to slow changes in terrain height.…”

“…The equations of motion, including the non-holonomic constraints are incorporated into the control structure of a two-wheeled mobile robot [17]. Other studies, such as those of Carbone et al [18,19], address the kinematics/statics/dynamics of a leg for design and control purposes. Wheeled-legged robots have motion and balance issues because of their conceptual design of implementing two locomotion types in each extremity; this causes the robot to swipe during a legged locomotion or vibrate during a wheeled locomotion (having straight legs).…”