Iria the biped

Embedded Computers in Iria

HC11

Iria has a Motorola 68HC11A based Botboard 2 for her main onboard computing. It runs at 2 Mhz and has 33024 bytes of RAM.
The HC11 recieves commands from the host over a serial line and carries out their execution in Iria. The HC11 is also responsible for collecting sensor data and returning it to the host upon demand. Although primarily a slave to the host, it can execute moving servos at various speeds to various positions with only an inital command from the host.

Mini SSC 2

The Mini Serial Servo Controller is a small module that uses a PIC Microcontroller to generate PWM signals for model aircraft servos. Iria has two of these which are slaves under the HC11.

Sensors in or on Iria

Accelerometers

Iria has three ADXL05 accelerometers sensing on X, Y and Z axes. Using these sensors Iria allways knows which way is down or which way it is falling.

Foot Pressure (incomplete)

Iria's feet can feel the pressure applied to standing on different parts of them using a set of eight pressure sensors, one on each corner of each foot. The sensors are made from putting a piece of conductive antistatic foam between two peices of copper-clad board. The resistance between the two boards decreases as pressure is increased. This effect is similar to the operation principle behind a carbon mike.

Joint Position (future)

The servos have potentiometers that could be tapped to return joint position. Currently Iria only has 8 AD inputs and more would have to be added to allow this feature.

Mechanics of Iria

Iria was built by John Hurst. It uses 6 130 oz-in 1/4 scale RC servos and 4 40 oz-in standard size servos. The skeleton is machined aluminum and plastic.

Higher Level Control

The high level control software is being written by Rich Labarca. It runs on a Linux laptop and talks to Iria's HC11 over a serial line.