Ugo II

Click here to download pictures of Ugo II: Top view (18 KB) Side view (24 KB) Front view (16 KB) General view (15 KB)

"Ugo II" is a small robot 25 cm long, 14 cm wide and 20 cm high.
I had build it because I wanted to make experience with ultrasound remote sensing.
The robot task is to look for an object and catch it. The object that I use is for instance a cardboard pipe 10 cm high and 5 cm in diameter, placed by the robot at a distance up to 1.5 meters.
To accomplish its job the robot executes the following actions:

• begins turning on itself for half a circle, from left to right, scanning the space around with its sonar and memorizing a map of the reflections
• selects which was the shortest reflection (= the closest object) and turns back until points towards it
• moves forward until comes 10 cm close to the object
• scans half a circle again and refines its heading towards the object
• lowers its claw, opens it and moves forward until a light sensor detects that the object is between the "finger-tips"
• closes the claw, catches the object and raises it
• turns back and brings the object to the start point
• deposits the object and stops

"Ugo II" is provided with

• a control board with a Z80CPU, a 6522VIA, one 2KB EPROM and one 2KB RAM
• two stepper motors
• a 40kHz sonar sensor
• a claw controlled by two DC motors, which mounts a couple of infrared transmitter and receiver diodes on the "finger-tips"
• a 12V, 2Ah lead battery

The robot stands on three wheels. Two are mounted on the sides, directly on the stepper motors axes. The third one is a caster and acts simply as a third point of balance.
The different movements of the robots are simply accomplished by an appropriate control of the two stepper motors. When the two motors turn simultaneously in the same direction, the robot moves straight (forwards or backwards). When the two motors move in opposite directions, the robot turns.
The pulses needed to control the stepper motors are generated by software.

The Z80CPU was programmed in assembler. This time, after the experience done with "Ugo I", I had prepared an assembler compiler in Basic and I was also able to download the code from the PC to the control board via the RS232.

Email: riccardo.rocca@hotmail.com

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