Overview – Pololu TReX User Manual

Page 2

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1. Overview

The

TReX Dual-Motor Controller

[http://www.pololu.com/catalog/product/777]

is a versatile DC motor controller

designed to seamlessly blend autonomous and human control of small- and medium-sized robots. The TReX can
control two bidirectional and one unidirectional motor via three independent control interfaces: radio control (RC)
servo pulses, analog voltage, and asynchronous serial (RS-232 or TTL). It uses five input channels to receive the RC
or analog control signals. When operating in RC or analog mode, the five channels function as follows:

Channel 1: motor 1 speed and direction or, if in mix mode, turn left/right

Channel 2: motor 2 speed and direction or, if in mix mode, go forward/reverse

Channel 3: auxiliary (unidirectional) motor speed

Channel 4: can be used to enable “flipped mode”, which allows invertible robots to be controlled as normal
when they are inverted

Channel 5: determines whether the motors are controlled by the channel inputs or the serial interface; this
channel allows you to switch between autonomous and human control at will

The serial interface can switch instantly with one of the other two interfaces, allowing mixed autonomous and remote
control. For example, a robot could be configured to run autonomously most of the time, but a human operator could
override the autonomous function if the robot gets stuck or into a dangerous situation. If the serial mode is selected
as the primary interface, high-resolution measurements of all five channel input signals (be they RC pulses or analog
voltages) are made available to the autonomous robot controller, allowing for complex and unlimited mixing of
operator control and sensor input. For example, the TReX would be a great motor controller for a line-following robot
whose overall speed is controlled by an RC throttle, or an RC car with sensors that autonomously dodges obstacles in
its path as you drive it around.

Pololu TReX User's Guide

© 2001–2013 Pololu Corporation

1. Overview

Page 2 of 24

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