UAV Dynamics library now available from Claytex

Overview

Claytex have released the UAV Dynamics library that allows the user to build and analyse the flight dynamics of a UAV in a quick and intuitive modular approach.

Figure 1. Mission experiment diagram layer including UAV, controller, variable payload, mission description, atmosphere and surface models.
Figure 1. Mission experiment diagram layer including UAV, controller, variable payload, mission description, atmosphere and surface models.

Contents

Architecture examples have been included as well as controllers and propulsion devices. The example included is that of a quadcopter that has a designated mission/path to follow and variable payload. Additional architectures are currently being implemented.

Propulsion

Both electrical drives and internal combustion engine propulsion are available within the UAV Dynamics library. We use Modelica library physical connectors to maximise compatibility with third-party models too should you wish to integrate these.

A propeller model is included that can be coupled to either of propulsion devices and geared appropriately where required. The propeller model also takes into account aerodynamic drag to be able to induce yaw via the controller.

Energy storage

Dynamic SOC batteries which are also included allow the study of capacity sizing but also thermal management, particularly under heavier load conditions including payload and external forces such as wind.

The fuel tanks that can be used for ICE based propulsion fuel storage also vary in terms of mass as the fuel gets consumed or replenished.

Flexibility

The library is scalable in terms of detail so we can start with simple propellers and speed based actuation in the preliminary stages where the required motor specs are still unknown. The truly acausal nature of the Modelica language allows us then to quantify the required power and torque from the results to be able to spec an electric motor or ICE to power the UAV.

Figure 2. Snapshot of the simulation window of a mission experiment with variable payload.
Figure 2. Snapshot of the simulation window of a mission experiment with variable payload. Plots are showing the controller inputs for target and actual values for position and yaw (centre plots), together with battery current & SOC and payload mass & inertia.

The user can then literally swap out the speed actuators with physical representations of the electric motors or ICE and rerun the analysis.

Figure 3. Chassis architecture with replaceable propellers and actuators, power electronics and battery.
Figure 3. Chassis architecture with replaceable propellers and actuators, power electronics and battery.

Scaling the detail

The shaft models can be configured via the parameter dialog to have linear, non-linear and even plastic deformation.

The bearing models have optional constraints and play to be able to model lash and therefore rattle within the system. All force and torque reactions to the chassis are taken into account through multi-body connectors.

Figure 4. Diagram of the electrical propulsion system for the UAV using rotational 3d effects for the shafts with optional, play, friction and compliance of the bearings and shafts.
Figure 4. Diagram of the electrical propulsion system for the UAV using rotational 3d effects for the shafts with optional, play, friction and compliance of the bearings and shafts.

Parameter optimization

The models are much faster than real time, lending themselves to controller parameter optimisation and HiL (Hardware in the Loop) testing.

Thermal Management

The UAV Dynamics library includes a module for thermofluids that allows the thermal management of air and liquid cooled systems using an intuitive component based approach with dynamic architecture diagrams that display the states of the fluid around the circuits. The module also includes liquid-to-air and air-to-air heat exchangers.

Model export

We can export the models to be Dymola licence independent so the end user can just run them as s-functions or executables on single or multiple machines.

As a UAV designer, here are the main reasons why you should be interested in the UAV Dynamics library:

  • Fully compliant and supported by Modelica library.
  • Built and maintained by experts in multi-physical systems modelling.
  • Fully capable of representing the multi-physical nature of the UAV without the need for co-simulation:
    • Multibody inc. FEA based compliances
    • Rotational
    • Transnational
    • Hydraulic
    • Thermofluid
    • Electrical
    • Electronic and more.
  • Open models
  • Exportable models
  • Built-in visualisation

Please get in touch for more information or to discuss your specific modelling and simulation requirements.

Written by: Alessandro Picarelli, Engineering Director

Please get in touch if you have any questions or have got a topic in mind that you would like us to write about. You can submit your questions / topics via: Tech Blog Questions / Topic Suggestion.

CONTACT US

Got a question? Just fill in this form and send it to us and we'll get back to you shortly.

Sending

© Copyright 2010-2020 Claytex Services Ltd All Rights Reserved

Log in with your credentials

Forgot your details?