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Pololu TReX Dual High Power Motor Driver The TReX Dual-Motor Controller 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 invertable 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.

 

General Specifications & Features

* operates at 6 - 16 V
* two primary motor outputs provide bidirectional control with 30 A peak and 13 A continuous
* option to use motor 1 and motor 2 outputs together to control a single, more powerful bidirectional motor with 60 A peak and 25 A continuous
* one unidirectional auxiliary output delivers over 15 A continuous
* motors can be set to any of 128 distinct speeds in each direction, allowing for a great deal of control
* measures approximately 1.9" x 1.9" x 0.8"*
* mode-select jumper determines which interface (asynchronous serial, RC, or analog) is in control
* upgradable firmware

* The unit's height can be substantially reduced if you purchase the kit version and solder it together yourself without the connectors.

RC/Analog Control Features

* high-resolution input channels: 12-bit RC pulse width measurements (1 us accuracy) and 10-bit analog voltages measurements
* five input channels as detailed above: motor 1, motor 2, auxiliary motor, flip mode, and serial override
* Battery Elimination Circuit (BEC) jumper lets the TReX optionally power your RC receiver or analog controller
* mix-mode jumper allows for single-stick motor control of differential-drive robots
* automatic calibration for your particular RC or analog controller (the TReX can learn the channel ranges)
* the serial interface can be used to configure numerous parameters that affect how the TReX behaves:
  - the channel calibrations values (max, min, neutral, and deadband size) can be explicitly set
  - each RC channel can be set as "required"; if a required RC channel becomes too noisy or dies, the motors are   shut down until "safe-start" conditions are met
  - each channel can optionally be set as "ignored" to ensure that noise on an unused channel won't interfere with operation (this can be especially useful when running in analog mode)
  - each channel can be reversed
  - each channel can be parabolically scaled to give less sensitive slow-speed control
  - motors 1 and 2 can independently be set to coast or variable brake while their channels are in the deadband
  - motor PWM maximums can be changed, allowing for control over how a motor speed setting relates to its actual speed; these parameters can be used to correct for asymmetries between motors 1 and 2 or to compensate for motor voltages that are higher than is desirable for your particular application
  - each motor can be given an acceleration value that affects how quickly its speed increases
  - each motor can be given a current limit; motor speed will automatically adjust to try to keep its current from exceeding this limit
* as a safety precaution, RC/analog is not given control of the motors until the "safe-start" condition is met (the controller is not trying to drive any of the motors, serial override is disabled, and all required channels are present and healthy)

Serial Interface Features

* supports both RS-232 and TTL (logic level) bidirectional serial communication
* supports 11 common baud rates ranging from 1200 to 115,200 bps
* accepts two command protocols:
  - expanded protocol allows the TReX to be daisy-chained to additional Pololu servo and motor controllers (including other TReXes) on the same serial line
  - compact protocol is two bytes shorter than the expanded protocol and allows for both motors 1 and 2 to be simultaneously set by sending just three bytes
* all five high-resolution channel input values can be requested using a serial command, and the serial controller can then base its motor-control actions in part on those values
* remapped channel input values can be requested using a serial command; these are single-byte values that reflect what the TReX would tell the motors to do if it were in control
* supports optional 7-bit cyclic redundancy checking (CRC-7), which provides a robust transmission and reception error-detection method
* optional automatic motor shutdown if a serial error occurs
* optional serial timeout feature that automatically stops all motors if there is no serial activity for a specified duration

The TReX does not require use of the serial interface to function; it will work right out of the box as an RC/analog motor controller (or speed control). Note that you will not have access to the full suite of features the TReX provides if you do not make use of the serial interface, however.

Note: The TReX motor driver board is available separately as the dual high-current motor driver, which has additional information about how much current the board can deliver.


Download TReX Configurator file