P6W Six Wheels Prototype of Robovolc
The robot P6W is a 1:4 scale reproduction of the robot Robovolc, realized in order to perform reproducible traction test in laboratory (The real robot is really voluminous: 1.5m long and about 300Kg weight). It is a six independently wheels robot with a four DoF articulated chassis, it measures only 40 cm and weight 3 kg.
The on board microcontroller Motorola MPC555 pilots six power boards, each with current control loop on board. The torque (current) control is a ON/OFF control realized at the frequency of 17KHz by the IC L6506, while the speed feedback is done by the microcontroller at a freuency of 1KHz using digital encoders.
The robot is driven through a host PC, during tests acquired data (torques, ref speeds, actual speeds, inclinometers, other variables) is stored in the microcontroller RAM and can be passed to the host PC via a serial cable for post-eaboration purpose.
This robot has been adopted for various traction research: i)torque optimization for maximum traction and minimum power consumption in rough terrain. ii)torque optimization for redundand actuated robot in sandy environment. iii)torque redistribution for minimum power consumption during rotation for skid-steered robots.
Images and Videos
D. Caltabiano, G. Muscato, "A Comparison between different traction methods for a field robot", IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2002, EPFL, Lausanne Switzerland, Sep.30-Oct.4 2002.
D. Caltabiano, D. Ciancitto, G. Muscato, "Experimental Results on a Traction Control Algorithm for Mobile Robots in Volcano Environment", IEEE International Conference on Robotics and Automation, ICRA 2004, April 26 - May 1, 2004, New Orleans, LA, USA.