Python script for 'Training microrobots to swim by a large language model'

This repository includes the python script of the following paper:

Z. Xu, L. Zhu*. Training microrobots to swim by a large language model. Phys. Rev. Appl., 23, 044058, 2025. Publisher

If you find our script useful for your research, please acknowledge our work by citing it!

@article{xu2025training,
title={Training microrobots to swim by a large language model},
author={Xu, Zhuoqun and Zhu, Lailai},
journal={Phys. Rev. Appl.},
year={2025}
}

Project dependencies

Ensure your Python version is at least 3.11.4. Install the required libraries for this project:

pip install openai==0.28
pip install numpy
pip install retrying

How to decide which script to run

LLM_control_microswimmers.py is used to control three-link and three-sphere swimmers, and LLM_control_microswimmers_four_DOF.py is used to control four-link and four-sphere swimmers.

How to run this script

python3 LLM_control_microswimmers.py / LLM_control_microswimmers_four_DOF.py

Before running this script, you need to enter your API KEY on line 10 / 12. You can obtain your API KEY by registering on the Open API website. Please note that you must make a deposit before you can use the API KEY.

Select the swimmer to control

In the file LLM_control_microswimmers.py, line 803:
swimmer = ThreeLink() # for the Purcell's (three-link) swimmer
swimmer = ThreeSphere() # for Najafi-Golestanian's (three-sphere) swimmer

In the file LLM_control_microswimmers_four_DOF.py, line 616:
swimmer = FourLink() # for the four-link swimmer
swimmer = FourSphere() # for the four-sphere swimmer

Change swimmer's moving direction (positive or negative)

In the file LLM_control_microswimmers.py, when you want to change the moving direction (positive or negative) for the three-link and three-sphere swimmers:
1. Change the first sentence of the prompt (see line 766).
2. Modify the history-clear section (see lines 783-790).
（If the swimmer is moving in the positive direction, use lines 788-790; if the swimmer is moving in the negative direction, use lines 784-786.）

In the file LLM_control_microswimmers_four_DOF.py, when you want to change the moving direction (positive or negative) for the four-link and four-sphere swimmers:
1. Change the first sentence of the prompt (see line 578).
2. Modify the history-clear section (see lines 594-601).
（If the swimmer is moving in the positive direction, use lines 598-601; if the swimmer is moving in the negative direction, use lines 594-597.）

Change the number of historical demonstrations

In the file LLM_control_microswimmers.py, line 684:
self.history_length = xxx # 

In the file LLM_control_microswimmers_four_DOF.py, line 496:
self.history_length = xxx # 

（'self.history_length' in the script corresponds to the 'n_ht' variable shown in Figure 3 of the manuscript. For the four-link and four-sphere swimmers, 'self.history_length' is consistently set to 20.）