Sunday, 26 February 2012

To Arms

No not a battle cry but what good is a robot with out arms if you noticed Robbie has a arm but with the AX12 servos and springs it can barely move and the shoulder lift servo will over heat quickly even with out the extensions. The price of larger servos is not an option. The torque required for a arm 90cm long to lift a 2 kilo object is over 1000 Kg/cm for the shoulder lift joint. After a bit of research i think i will use stepper motors at least i can start out using some of the old stepper motors and gears i have lying around. I plan to use the steppers for the first 4 joints in the arm at the moment just using motors from a old printer and a arduino to interface with ROS

Saturday, 25 February 2012

Navigation Testing

A video of Robbie driving around under joystick control to test localisation
it works fine but after a while he gets lost


Over the last couple of weeks I have been hard at work refining the control, localisation and general drive functions. While we are not at the stage of autonomous navigation short runs will work. The big fix is still odometery and how the base responds to navigation commands from ROS, The steering is always "fishing" for direction causing the robot to dart from side to side