DescriptionWarugadar is a small quadruped robot, built from plexiglas and aluminum. Each leg has three rotation joints, where the rotation axis of the first joint, the hip, is perpendicular to the rotation axes of the other two joints, the knee and the ankle, which have parallel rotation axes.
Actuation is provided by 12 Hitec HS-475HB analog RC-Servos, each containing a DC motor mechanically linked to a potentiometer, gearing, and feedback control loop circuitry. A motor control board provides the servos with the PWM signals.
Warugadar features two piezoelectric film elements placed on the sole of each foot, for a total of eight piezoelectric elements, acting as pressure sensors for foot-terrain contact detection. The piezoelectric sensors are DT1-028K/L and LDT1-028K/L; the difference is that the LDT1 includes a polyester layer laminated to the piezo film, to boost the element voltage output. In this way it is possible to have two sensor in the same area with two different scale. Moreover Warugadar is equipped with a CMUCam3, an embedded vision system.
Data-acquisition and motor-control board are decoupled, one board for actuators, one board for data acquisition from piezoelectric sensors. They are based on PIC 18F452 microcontrollers and communicate wireless using the Xbee devices using the communication protocol ZigBee.