AgOpenGPS WAS-less Firmware for Teensy 4.1, UM981/UM982, and KeyaMotor

Overview

This firmware integrates the UM981 for roll and pitch-corrected positioning with true orientation using a single antenna. It is designed for use with a Teensy 4.1, UM981 or UM982, and KeyaMotor. The first well-working WAS-less algorithm and UM981 GPS receiver.

Features

• Single-antenna positioning with roll and pitch correction.
• GUI-based configuration using GUI_settings.py.
• Real-time data visualization via GUI_plots.py (UDP-based serial output, sensor data plotting, and configuration updates).
• Kalman filter-based wheel angle estimation, leveraging:
  • Keya Motor encoder.
  • True vehicle heading from UM981 corrected position or UM982 dual-antenna setup.
  • Sensor fusion, where the encoder dominates during rapid changes, while true heading compensates for drift.
• Designed for a custom PCB.

Configuration & Usage

AgOpenGPS Settings Adjustments

• Pressure Sensor Active → Used for debugging via the guide activation button (controls serial output data).
• Invert WAS → If enabled, a green angle sensor is used; otherwise, the wheel angle is estimated.
• isDanfoss Button (Green When Sending Settings from AOG) → Saves settings for Keya; calibration is crucial:
  • Offset Calibration: Represents the "empty run" of the steering wheel before affecting the wheels.
  • Sensor Counts: Must be precise to ensure accurate wheel angle compensation.
  • Ackerman Fix: Implemented but rarely needed (default: 100).
• Cytron/IBT2 Toggle for Multi-Tractor Support:
  • Some tractor-specific measurements (e.g., antenna & UM981 position) are stored in the Teensy’s memory.
  • These settings are sent by GUI_settings.py and differ per tractor.
  • Cytron/IBT2 setting allows switching between tractors:
    • When measurements are sent, they are stored in the active profile.
    • On startup, the active profile configures UM981 accordingly.

Steering Wheel Sensor Improvement

• Enhanced detection of manual steering input by using a running average of the ratio between current and encoder speed.
• Ensures a highly sensitive threshold for detecting manual steering.

Installation & Setup

1. Configure UM981/UM982 as per ArduSimple guidelines.
2. Use GUI_settings.py to send settings to the Teensy.
3. Use GUI_plots.py for real-time data visualization and debugging.
4. Ensure proper calibration of the wheel angle estimation algorithm.
5. Use the Cytron/IBT2 toggle if switching between tractors.

---

This firmware enhances precision and usability for AgOpenGPS users by integrating advanced sensor fusion and real-time configurability. 🚜⚡