udaan 1.0.1

Quadrotor dynamics and control for cable-suspended payload systems

A Python mujoco based models and controllers for quadcopter cable-suspended payload systems.

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Developed as part of the thesis: Dynamics and Control for Collaborative Aerial Manipulation (Kotaru, 2022). Original research code: vkotaru/floating_models. This package is the cleaned-up public release, refactored with Claude.

Features

:helicopter: Quadrotor dynamics	Single and multi-vehicle SE(3) rigid-body simulation
:control_knobs: Geometric controllers	PD on SE(3), L1 adaptive on SO(3), force allocation
:chains: Cable-suspended payloads	Tendon and multi-link cable models with S2 pendulum dynamics
:people_holding_hands: Cooperative transport	N-quadrotor point-mass and rigid-body payload systems
:joystick: MuJoCo integration	Physics-backed simulation with GLFW rendering and GIF recording
:straight_ruler: Manifold library	SO(3), S2 exponential maps, geodesic stepping, config errors
:chart_with_upwards_trend: Trajectory generation	Polynomial, circular, Lissajous, and smooth reference trajectories
:desktop_computer: CLI interface	udaan run commands for quick demos and experiments

Installation

pip install -e .

MuJoCo is included as a core dependency. VPython visualization is optional:

pip install -e ".[all]"

Quick Start

CLI

udaan run quadrotor -t 10                             # quadrotor with geometric control
udaan run quad-payload -t 10 -m tendon                # quadrotor + cable-suspended payload
udaan run multi-quad -n 3 -t 10                       # multi-quadrotor cooperative payload
udaan run multi-quad-rigid -t 10                      # multi-quadrotor rigid-body payload
udaan run fleet --demo l1-comparison -t 10            # L1 vs PD controller comparison
udaan run fleet --demo gain-sweep -t 10               # PD gain tuning comparison
udaan run quadrotor -t 5 -r out.gif                   # record to GIF

Python

import udaan as U
import numpy as np

mdl = U.models.mujoco.Quadrotor(render=True)
mdl.simulate(tf=10, position=np.array([1., 1., 0.]))

Documentation

:pushpin: Controller roadmap

Controller	System	Status	Reference
Geometric PD (SE(3))	Quadrotor	:white_check_mark: Implemented	Lee, Leok, McClamroch 2010
Geometric L1 Adaptive (SO(3))	Quadrotor	:white_check_mark: Implemented	Kotaru, Wu, Sreenath 2020
Geometric PD (SE(3) x S2)	Quad + Payload	:white_check_mark: Implemented	Sreenath, Lee, Kumar 2013
Propeller Force Allocation	Quadrotor	:white_check_mark: Implemented	—
Differential Flatness	Quad + Payload	:construction: Partial (flat2state utils)	Sreenath, Lee, Kumar 2013
NLMPC (CasADi)	Quadrotor	:memo: Planned	—
VBLMPC	Quad + Payload	:memo: Planned	Kotaru, Sreenath 2020
Geometric PD	Multi-Quad Payload	:memo: Planned	Lee 2014
RL (Gymnasium)	All	:memo: Planned	—

:package: Package API reference

Base Models (udaan.models.base)

Math-only dynamics, no simulator dependency.

Model	State Space	Description
Quadrotor	SE(3)	Rigid body quadrotor, wrench/accel/prop-force inputs
QuadrotorCSPayload	SE(3) x S2	Quadrotor + cable-suspended point-mass payload
FloatingPointmass	R3	3D point mass with gravity
S2Pendulum	S2	Spherical pendulum on the 2-sphere
PointmassSuspendedPayload	R3 x S2	Single point-mass agent with suspended payload
MultiPointmassSuspendedPayload	R3 x (S2)^n	Multiple point-mass agents, shared payload

MuJoCo Models (udaan.models.mujoco)

MuJoCo-backed physics with GLFW visualization.

Model	Description
Quadrotor	Single quadrotor
QuadrotorCSPayload	Quad + payload (tendon or links cable model)
MultiQuadrotorCSPointmass	N quadrotors, shared point-mass payload
MultiQuadRigidbody	N quadrotors, shared rigid-body payload
QuadrotorFleet	N independent quadrotors for controller comparison

Manifold Library (udaan.manif)

Class/Function	Description
SO3	Rotation matrix with exponential map stepping
S2	Unit sphere with geodesic stepping, config error
hat / vee	Skew-symmetric matrix operators
rodrigues_expm	Rodrigues rotation formula
expm_taylor_expansion	Matrix exponential Taylor approximation

Utilities (udaan.utils)

Module	Description
trajectory	Smooth, polynomial, circular, and Lissajous trajectory generators
flat2state	Differential flatness maps for quadrotor and payload systems
assets	MuJoCo XML model generator
vfx	VPython-based visualization (base models)

License

BSD 3-Clause License. See LICENSE for details.