⚡ electrical engineering

RotorSuite: A MATLAB/Simulink Toolbox for Tilt Multi-Rotor UAV Modeling

This paper introduces RotorSuite, a comprehensive MATLAB/Simulink toolbox that streamlines the accurate modeling and simulation of diverse multi-rotor UAV dynamics, including advanced tilted and tilting platforms, through both analytical and physics-based approaches to support research, education, and industrial development.

Original authors: Nicola Cigarini, Giulia Michieletto, Angelo Cenedese

Published 2026-02-24

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CC BY 4.0

Original authors: Nicola Cigarini, Giulia Michieletto, Angelo Cenedese

Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine you are an architect trying to design a new kind of flying robot. In the past, most flying robots (drones) looked like simple, flat "X" shapes with four propellers spinning on the same level. They were easy to build and easy to understand.

But now, engineers are building "super-drones." These are machines with propellers that are tilted at weird angles, or even propellers that can move and tilt while the drone is flying. These new designs are incredibly agile and can do things regular drones can't, like pushing against a wall or flying sideways with power.

The Problem:
Designing these fancy new drones is a nightmare for engineers. To make them fly, you have to write thousands of lines of complex math to figure out how the tilted motors affect the flight. It's like trying to bake a cake by calculating the exact chemical reaction of every egg and grain of flour by hand. It takes forever, it's easy to make a mistake, and if you want to change the design (like tilting a motor by 5 degrees), you have to rewrite all the math from scratch.

The Solution: RotorSuite
This paper introduces RotorSuite, a new software toolbox (a collection of pre-made tools) for MATLAB and Simulink. Think of RotorSuite as a "Lego set for drone engineers."

Instead of doing the math by hand, you just plug in a few numbers into a digital box:

"How many motors do I have?"
"How long are the arms?"
"Are the motors tilted up, down, or sideways?"

Once you set these parameters, RotorSuite automatically does all the heavy mathematical lifting. It builds the entire flight model for you instantly.

How It Works (The Two "Engines")
RotorSuite is special because it offers two different ways to simulate the drone, like having two different video game engines:

The "Math Engine" (Analytical Approach): This is like a fast, simplified video game. It uses pure math equations to guess how the drone will fly. It's super quick and great for testing control ideas.
The "Physics Engine" (Physics-Based Approach): This is like a high-end, realistic flight simulator (think Microsoft Flight Simulator). It builds a 3D model of the drone with real weight, real motor parts, and even the tiny delays in the motors spinning up. It's slower but much more realistic.

The "Twin Test"
The authors tested their toolbox by building a complex, six-motor drone with tilted propellers. They ran the exact same flight test (flying a figure-eight pattern) in both the "Math Engine" and the "Physics Engine."

The Result:
The two engines produced almost identical results. The drone flew the same path, and the errors were tiny. This proves that RotorSuite is reliable. You can use the fast "Math Engine" to design your drone, and then switch to the "Physics Engine" to double-check that it will actually work in the real world without building a physical prototype first.

Why This Matters

For Students: It makes learning about complex drones easy. You don't need to be a math genius to understand how a tilted rotor works; you just turn a dial and watch the simulation.
For Researchers: It saves months of work. Instead of spending weeks deriving equations for a new drone shape, they can spend that time inventing new ways to fly.
For Industry: It allows companies to prototype new drone designs digitally, saving money on failed physical builds.

In a Nutshell:
RotorSuite is a user-friendly toolkit that turns the difficult, error-prone job of designing complex, tilted drones into a simple "plug-and-play" experience, letting engineers focus on innovation rather than tedious math.

1. Problem Statement

The field of aerial robotics has evolved from standard coplanar quadrotors to advanced tilted and tilting multi-rotor platforms. These designs offer superior maneuverability and full actuation capabilities by allowing propeller axes to be arbitrarily oriented (fixed tilt) or dynamically adjusted (tilting). However, modeling and simulating these complex systems present significant challenges:

Complexity: Deriving dynamic equations for arbitrary rotor layouts (varying cant, dihedral, and azimuth angles) is mathematically intensive.
Time-Consuming & Error-Prone: Manual derivation and implementation are prone to human error and are highly dependent on the user's expertise.
Lack of Flexibility in Existing Tools: Current MATLAB/Simulink solutions (e.g., UAV Toolbox, Aerospace Blockset) often rely on predefined templates (e.g., star-shaped, collinear layouts). Modifying the underlying structure for custom or tilted designs typically requires manual restructuring of the model, limiting design exploration and rapid prototyping.

2. Methodology

The authors propose RotorSuite, a comprehensive MATLAB/Simulink toolbox designed to model and simulate a broad class of multi-rotor platforms through a unified framework. The methodology is built on two distinct but complementary approaches:

A. Theoretical Foundation

The toolbox models an $n$ -rotor platform as a rigid body in 3D space. It defines:

Kinematics: Governed by position ( $p$ ) and orientation ( $R \in SO(3)$ ) dynamics.
Actuation: Propeller positions are defined by arm length ( $\ell$ ), azimuth ( $\gamma$ ), and elevation ( $\delta$ ) angles. Propeller orientation is defined by cant ( $\alpha$ ) and dihedral ( $\beta$ ) angles.
Dynamics: The total control force ( $f_c$ ) and moment ( $\tau_c$ ) are derived as linear functions of the squared propeller speeds ( $u = \omega^2$ ) via input matrices $F$ and $M$ . These matrices depend on the geometric configuration and are time-varying for tilting platforms.
Equations of Motion: The system follows Newton-Euler equations, accounting for gravity, mass, and inertia.

B. Dual-Layer Simulation Architecture

RotorSuite implements a dual-layer approach to cater to different fidelity needs:

Analytical Approach (Numerical):
- Utilizes a single configurable Simulink block (TMR - Tilt MultiRotor).
- Users define parameters (mass, inertia, propeller geometry, coefficients) to generate the dynamic model directly via MATLAB functions.
- Ideal for control design, state estimation, and rapid algorithm testing.
Physics-Based Approach (Simscape):
- Uses a library of modular Simscape Multibody components.
- Explicitly models the physical structure, including the main body, arms, motor-propeller assemblies, and tilting mechanisms.
- Captures higher-fidelity effects such as detailed mass distribution, inertia tensors, and actuator dynamics (e.g., finite rise times).

3. Key Contributions

Unified Framework: RotorSuite is the first toolbox to provide a cohesive framework for defining and simulating arbitrary tilted or tilting multi-rotor platforms solely through parameter settings, without manual model restructuring.
Versatility: It supports a wide range of configurations, including coplanar/non-coplanar, zero-tilt/tilted/tilting, star-shaped/non-star-shaped, and independent/interdependent angle parameters.
Accessibility & Documentation: The toolbox is cross-platform (Windows, Linux, macOS), requires minimal add-ons, and includes extensive documentation and examples (e.g., standard quadrotors and fully actuated hexarotors) suitable for both research and education.
Dual-Mode Capability: It uniquely bridges the gap between fast, analytical numerical simulation and high-fidelity, physics-consistent simulation within the same environment.

4. Results

The authors validated the toolbox using a fully actuated coplanar star-shaped interdependent-cant & dihedral-tilted hexarotor (6 rotors).

Experimental Setup: A geometric controller based on $SE(3)$ trajectory regulation was implemented for both the analytical and physics-based models. The platform was tasked with tracking a figure-eight trajectory.
Performance Comparison:
- Tracking Accuracy: Both simulation approaches yielded nearly identical results. The mean absolute position tracking error was negligible (approx. $1.7 \times 10^{-3}$ m for analytical vs. $1.7 \times 10^{-3}$ m for physics-based).
- Orientation Errors: Minor discrepancies were observed in orientation errors during transient phases (takeoff/landing), attributed to differences in how inertia matrices were calculated (lumped vs. distributed mass).
- Actuator Dynamics: The physics-based model introduced finite rise times in propeller speeds due to actuator dynamics, whereas the analytical model applied inputs instantaneously. Despite this, the difference in spinning rates ( $\Delta\omega$ ) remained bounded within $[-2, 2]$ rad/s.
Conclusion on Consistency: The results confirm that the physics-based setup captures additional physical nuances without compromising the steady-state tracking performance predicted by the analytical model.

5. Significance

RotorSuite addresses a critical gap in the aerial robotics community by democratizing the modeling of complex, non-standard UAVs.

For Researchers: It accelerates the design cycle, allowing for the rapid prototyping and validation of novel tilted/tilting architectures without the burden of manual mathematical derivation.
For Industry: It provides a robust tool for validating platform capabilities and control strategies before hardware deployment, reducing development costs and risks.
For Education: Its intuitive, parameter-driven interface makes it an excellent tool for teaching advanced UAV dynamics and control concepts.

In summary, RotorSuite offers a scalable, high-fidelity, and user-friendly solution for the next generation of multi-rotor UAV design and analysis.