Hardware and Firmware of the Solo Quadruped Master Board.

This board centralises all the sensor and actuator data and provides wired and wireless connection to a realtime computer.

Connectivity:

• SPI: Address up to 8 SPI Slave: (max 80Mhz, DMA capable) compatible with BLMC µDriver SPI interface
• Wifi: Wireless communication with a computer via raw ESP-NOW: round trip time of 1.2ms (including driver and OS latency) for a 127bytes message.
• Ethernet: Wired communication with a computer via raw frames: round trip time of 0.2ms (including driver and OS latency) for a 127bytes message.
• GPIO: 4GPIO free. Can be mapped to I2C, UART etc.. Two of them are curently used for IMU communication via UART
• UART: Used to upgrade the ESP32 firmware, free on normal operation.

The board is programed via the ESP-IDF tool chain https://github.com/espressif/esp-idf

Wireless closed loop control at 1kHz demo (click to see video):

IMU, ethernet closed loop cntrol at 1kHz demo (click to see video):

Red fade: Waiting for init
Magenta fade: SPI Autodetect
Blue fade: waiting for first commmand
Green fade: Active control
Yellow blink: ethernet link down state awaiting for link up
Red blink: error state (communication with PC), awaiting for new init msg
White blink: state machine error (should never happen)

Here are some helpful links to the documentation :

How to flash the Master Board (install esp-idf and flash the firmware)

SDK : How to prepare your interface and run the example

Master Board State Machine Description

Description of the communication between the Master Board and the computer

Description of the BLMC µDriver SPI interface

Wiring the MasterBoard

Master Board Ordering and Preparation

Thomas Flayols
Etienne Arlaud

BSD 3-Clause License

Copyright (c) 2019, LAAS-CNRS, Max Planck Gesellschaft, New York University

Open Dynamic Robot Initiative