Overview

This project gives a laptop fast, direct control of an Elephant Robotics myCobot 280 for Arduino. It replaces the stock control path, which reads the joint angles at about 50 Hz, with two faster paths:

• Laptop path. The laptop talks to the servo bus directly through an FT232R USB-serial adapter. The loop runs at about 300 Hz on the laptop.
• ATOM path. Custom firmware on the ATOM (the ESP32 board at the end of the arm) runs the loop at 500 Hz. The laptop sends plans and receives telemetry over WiFi.

Both paths use the same plans, the same safety checks and the same recording format. Trajectory planning and analysis stay on the laptop, in Julia.

Status

Area	Status
Direct servo-bus access from the laptop	Works. ~300 Hz write + read loop.
Onboard 500 Hz player on the ATOM	Works. 0 late cycles in all runs so far.
WiFi plan upload, telemetry, OTA updates	Works.
End-effector IMU telemetry	Works. Shows vibration bursts at joint reversals.
Kinematics (RigidBodyDynamics.jl)	Works. Matches the stock firmware’s get_coords to ~1 cm.
Lag compensation and iterative learning control	Works. Circle error 12.5 mm → 0.8 mm RMS.
PWM (torque-like) servo mode	Not tried.
Trajectory optimisation (TORA.jl)	Not connected yet. See TORA.
Emergency stop	None. Disconnect the 12 V supply. See Safety.

The main findings

1. The 20 ms latency of get_angles came mostly from the FT232R’s 16 ms latency timer, not from the ATOM. Set it to 1 ms. See Laptop link.
2. The servo bus is reachable directly from the laptop’s serial port. The base passes the bytes through. See Architecture.
3. The servos are Feetech STS servos with the standard register map. See Servos.
4. In position mode, the servos follow commands with a repeatable lag of 30–120 ms and stick briefly after each reversal. A faster loop does not change this. Lag compensation and learning control do. See Results.

How to read this site

• System describes the hardware: the robot, the wiring, the servos and the ATOM.
• Communication describes the protocols on each link.
• Firmware describes the ATOM firmware and how to build and flash it.
• Software describes the Julia package, the scripts and the Python tools.
• Results records each experiment with its numbers and plots.
• Reference collects the rules and known problems, the register map, the roadmap and the history.