PololuJrkUSB

A command-line tool for driving the Pololu Jrk USB motor controllers. https://www.pololu.com/docs/pdf/0J38/jrk_motor_controller.pdf

Hardware

The jrk provides bidirectional control of a DC brush motor via a USB mini-B 5-pin interface. It can be driven with open loop feedback, or a closed loop using 0V5V analog control or digital control up to 2MHz with a 1ms PID. RC PWM, full-duplex TTL serial, and 0V5V potentiometer control is also available, though this program assumes USB serial. The control model is ACM, supported by the cdc_acm Linux kernel module.

• jrk 21v3
  • Vendor: 0x1ffb
  • Device: 0x0083
  • 5V28V
  • 3A continuous, 5A peak
• jrk 12v12
  • Vendor: 0x1ffb
  • Device: 0x0085
  • 6V16V
  • 12A continous, 30A peak

Building

Run make.

Dependencies

• GNU Make
• C++ compiler
• pkg-config
• libreadline
• libusb-1.0

Usage

In order to run as a normal user, write and read capability is necessary for both the specified /dev/tty* node and the raw usb device, which can be found in /dev/bus/usb/BUS/DEV. BUS and DEV can be found with lsusb -t.

Launch the program with the USB serial device node as its argument for interactive keyboard-driven use. The help text will be printed in response to the 'help' command. Other commands include:

• 'input': Read input (0..4095)
• 'target': Read target (0..4095)
• 'feedback': Read feedback (0..4095)
• 'sfeedback': Read scaled feedback (0..4095)
• 'errorsum': Read error sum (integral) (-32768..32767)
• 'cycletarg': Read duty cycle target (-32768..32767)
• 'cycle': Read duty cycle (-600..600)
• 'eflags': Read error flags
• 'settarget': Set target, takes argument between 0 and 4095, inclusive
• 'off': Turn motor off

Copyright and thanks

Copyright Nick Black 2019. Licensed under Apache-2.0.

Hardware and financial support were provided by Greenzie of Atlanta, makers of autonomous lawnmowers.

All errors are my own.