A Deep Inverse-Mapping Model For A Flapping Robotic Wing (ICLR 2025)

Official PyTorch Implementation for the "A Deep Inverse-Mapping Model for a Flapping Robotic Wing" Paper (ICLR 2025)

Figure 1: The experimental setup of our custom-built robotic flapping wing system, featuring force sensors and synchronized motion tracking cameras for data collection. Figure 2: Overview of the proposed ASL architecture for Inverse-Mapping

Setup

1. Clone the repository:

git clone https://github.com/hadar933/AdaptiveSpectrumLayer.git
cd repo

2. Create a virtual environment and activate it:

python3 -m venv venv
source venv/bin/activate

Optional: Configure the Python interpreter in VS Code

Configure the Python interpreter in VS Code:

• Press Ctrl+Shift+P to open the command palette.
• Type Python: Create Environment and select venv

3. Install the dependencies:

pip install -r requirements.txt

Structure

The project is organized into several directories, each with a specific purpose:

• ML
  Implements core machine learning functionality using PyTorch. This includes:

  • Preprocessed data from our flapping wing system.
  • A Zoo subdirectory with neural network implementations, including the Adaptive Spectrum Layer (ASL) and other architectures.
  • Dataset handling.
  • Normalization and training utilities (e.g., fit, predict, evaluate).

• DataHandler
  Contains utilities for:

  • Data encoding: e.g sin-cos encoding, or calculation of torques from forces.
  • Preprocessing: a basic class that performs resampling, interpolation, etc.
  • Synchronization scrips for matching signals by their start times and consequtive difference value.

• LTSFLinear
  A fork of the primary paper implementation, this directory contains various neural network models, including NLinear, NLinear and FEDformer, for benchmarking.

• Utilities
  Contains miscellaneous scripts for plotting, data splitting, adding explainability to the analysis, etc.

• Camera
  Handles raw image data and camera calibration. It includes scripts for:

  • Extracting 3D coordinates.
  • Tracking trajectories.
  • MATLAB stereo camera setup calibrations

• Forces
  Processes raw data from force sensors and prepares it for downstream analysis.

Note
The Camera and Forces directories are primarily included for clarity and completeness. These directories were used to generate the already ready-to-use data located in the ML/Data directory. Users can directly utilize the data in ML/Data without needing to refer to the aformentioned dirs.

Usage

To run a training job:

cd ML && python main.py

When running main.py, TensorBoard logs are saved under ML/tb_runs, and saved models are available in ML/saved_models.

To start TensorBoard and visualize the logs, use the following command:

tensorboard --logdir=ML/tb_runs

Datasets

Our implementation supports two types of datasets: our proprietary flapping wing system data and open-source datasets from previous works (references to be added). Each dataset consists of two PyTorch tensors:

• Kinematics: Describes wing movements in their respective coordinate systems
• Forces: Contains the generated forces when the wing moves according to the specified kinematics

Proprietary Dataset

Our dataset was collected using a custom-built robotic flapping wing system (shown below). The data includes:

• Kinematics: a list of 153 tensors, with shape [T_i, 3]. Namely - each of the 153 experiments has T_i time points, with $min_i {T_i} = 550$ and $max_i {T_i} = 3787$, and three features that represent wing rotation angles pitch, yaw and roll.
• Forces: a list of 153 tensors, with shape [T_i, 4]. Same as above, aside from the 4 features that represent 4 force sensors measurements

The data is sampled at a rate of $5000 \texttt{Hz}$.

[Image placeholder - will be added]

Open Source Datasets

We also provide support for previously published datasets to enable direct comparison with existing work. These include:

The tensor shapes follow the same convention as our proprietary dataset, with

• Kinematics tensor shape [548, 470, 3]: 548 experiments, 470 time points, 3 angles of wing rotation (pitch, yaw, roll)
• Forces tensor shape [548, 470, 5]: 548 experiments, 470 time points, 3 force measures + 2 torque measures (to a total of 5 features)

The data is sampled at a rate of $25 \texttt{Hz}$.

Note
In the open source datasets, all experiments have the same length.

Download

These datasets are already present in this git repository under the ML/Data directory. You can also access these datasets via this link

Citation

If you find this code useful, consider citing our paper with:

@inproceedings{
  sharvit2025a,
  title={A deep inverse-mapping model for a flapping robotic wing},
  author={Hadar Sharvit and Raz Karl and Tsevi Beatus},
  booktitle={The Thirteenth International Conference on Learning Representations},
  year={2025},
  url={https://openreview.net/forum?id=254NJe9JEw}
}

Acknowledgments

Special thanks to the following repositories and resources:

• The paper "State-space aerodynamic model reveals high force control authority and predictability in flapping flight" (arXiv) by Yagiz E. Bayiz and Bo Cheng, for providing a strong structure to be compared against and a reliable open source dataset.
• The repository LTSF-Linear for their multiple architecture implementations.
• Beatus Lab, for providing the infrastructure and expertise to build such a unique experimental setup.