Experimental motion control behaviour of a mobile robot with spinning turret

A computer wireless-controlled mobile vehicle is described. The vehicle is designed to optimize the cinematic and dynamic behaviours. It has a circular shape, two fixed axis driven wheels, independent brushless motors coupled with a pair of ball wheels; and a third actuator driving a spinning turret (superior platform) to reduce the inertial couple during the turns. The feedback signals are generated by two optical incremental encoders linked to the motor shafts for velocity signals and by odometric sensors for position signals. Two track-balls, each of them with two encoders, are used to measure and control the mobile robot displacement on the floor. Moreover, a protection bumper surrounds the perimeter of the lower platform and it works like a switch. Several experimental tests have been developed and we show the evaluation of the position error in a closed loop paths, reporting the difference between the starting point and the final one. The motion control strategy is described with comments about the choice of the control parameters.