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TeamUR Robo-Project Illustrated

TeamUR the Third utilizes two hacked servo motors as a main source of movement. The servos require a square wave of pulses to rotate. In normal case the pulses should be in range from 0.9ms to 2.1ms with 1.5ms as center position. The refresh rate is 50Hz (20ms). For our hacked servos 0.9ms pulse causes rotation with maximum speed in one direction, 2.1ms causes rotation with maximum speed in other direction. To stop the servo no pulses are supplied. There is a possibility to control servo rotation speed by changing the pulse width.

	The energy is supplied by two NiMH batteries 3.6V each. The nominal voltage of the servos is 4.8-6V however we decided to use lover voltage. It looks that the servos have rather wide tolerance for power supply voltage. Each battery powers one servo motor with its 3.6V. The combined voltage of 7.2V is used to make stabilized 5V for the microcontroller.
	Two transistors (on the left among the resistors) are used to adopt TTL voltage levels from the microcontroller to pulse servos (see simple circuit diagram above). On the left side of the picture you can see two white sockets with servos plugged in.
	Microcontroller generates two square waves: one for each servo. They are shifted by 10ms to allow employ 10ms interrupt scheme.

TeamUR Robo-Project Illustrated

All rights reserved. For problems or questions regarding this web contact [Project Email]. Last updated: May 27, 2004.

All rights reserved.
For problems or questions regarding this web contact [Project Email].
Last updated: May 27, 2004.