NXT-WheelChair-Control

A library for controlling wheelchairs with R-Net technology used in the NXT Wheelchair project. Library code is based on the code written by redragonx in https://github.com/redragonx/can2RNET and refactored into an object-oriented format.

Usage Instructions

1. Connect a PiCan v2 Hat to a motorized wheelchair's can interface
2. Follow Raspberry Pi socket setup here
3. Using raspi_config disable login over serial and enable hardward serial support
4. Run the main file on a Jetson Nano in client mode
   • python3 main.py client
5. Run the main file on the Raspberry Pi in server mode
   • python3 main.py server
6. Use the provided example socket command to direct the wheelchair on the Jetson Nano
   • Example function in src/wheelchair_interface/clientserver/socket_client.py

Package breakdown

An explanation of each package within the wheelchair_interface main package.

clientserver

The clientserver package handles the implementation of the protocol on the Raspberry Pi and Jetson Nano side.

• nano_client.py
  • Client which receives commands from a socket and passes them over UART to the Pi
• pi_server.py
  • Server which accepts commands over UART and passes them to the wheelchair
• socket_client.py
  • Contains functions to be called within the user's program to send socket commands on the Jetson Nano

protocol

The protocol class contains implementation functions of the protocol discussed in doc/piNanoProtocol.md.

• processor.py
  • Implementation of encode and decode functions for sending instructions over UART
• resources.py
  • Common constants used in different files

input_receivers

The input_receivers package contains example implementations of RNetController or receivers to be run independent and speak to the client in clientserver.

• headtilt.py
  • Interfaces with a head accelerometer and leverages the functionality of clientserver
• WASD.py
  • Runs independently of clientserver and speaks directly to the RNetController.

rnet_controller

The rnet_controller package handles direct communication with the wheelchair through the can protocol. It includes a class to abstract away specific bitstrings used to control the chair and instead gives it an object-oriented interface.

• RNetController.py
  • Class to abstract low-level communication into object-oriented class

Usage

The RNetController class implements the code in an object-oriented format. Once instantiated with the bus number the following functions are available for use:

• drive_forward_seconds
• drive_back_seconds
• turn_left_seconds
• turn_right_seconds

Each have the calling convention of function(seconds: int), where seconds is the amount of time you want the action to repeat.

Other less explanatory functions are as follows:

• set_speed_range
  • Takes an integer 0 through 100 which sets the wheelchair speed to that number.
• stop_chair
  • Takes no arguments.
  • Sends a stop command to the wheelchair, though it should stop on its own after a move timer expires.
• close
  • Takes no arguments
  • Closes the open socket with the can system. Always good practice to close connections.