PneuDrive: Embedded Pressure Control

Most existing pressure control systems on the markers are either too small in terms of flow rates, or too bulky in terms of size. I designed PneuDrive to fit a few key requirements:

1. Large Scale
   • Regulate pressures of up to 80 psi
   • Provide high-flow rates with proportional flow valves
2. Distributed Control
   • Control at least 12 valve/chamber pairs
   • Minimize wiring and tubing over distances of about one meter
3. Expandable
   • Capability to incorporate additional sensors (e.g., IMUs) for future work
4. Easy to Use
   • Use low-cost, off-the-shelf components that are easy to replace
   • Open-source software that is customizable
5. Communication
   • Easy connection to other devices with low latency
   • Reliable communication for real-time control loops

PneuDrive works by daisy-chaining multiple board together on a robust RS485 communication bus.

Each board has a microcontroller that reads pressure sensors and controls proportional flow valves.

The accompanying C++ library is easy to use via ROS or with Python bindings:

import numpy as np
from pneudrive_py import PressureController

uart_port = '/dev/ttyS1'
num_devices = 4
my_controller = PressureController(uart_port, num_devices)

#check communication with all expected devices
my_controller.ping_devices()

pressure_cmd = np.array([1,2,3,4])
for i in range(num_devices):
    my_controller.set_pressure_commands(i, pressure_cmd)
    data = my_controller.get_pressure_data(i)

For more info, check out my paper here