Pneumatics Library

Pneumatic Multi Position Cylinder Drive

Overview

The Pneumatics Library is intended for the modelling and simulation of pneumatic circuits and systems for design, component sizing and control design. It allows the user to verify and optimize the design of a complete pneumatic system from early design phases to production. Unlike other special-purpose tools for the same type of simulations, the Pneumatics Library has an open, object-oriented architecture to allow the inspection of all the models at the Modelica source code level and the customization of these to fit the user’s requirements.

There are more than 80 components in this library to cover standard applications like cylinders and motors, valves and nozzles, lumped volumes, lines and sensors. Specially designed components can be easily modelled as well by modifying the existing classes. The library includes examples to demonstrate the usage of the components and all relevant effects are available as sub-models.

Key Features
Library Contents
Applications
Resources
    • Simple, efficient and accurate modelling and optimization of complex pneumatic systems, such as brakes, suspensions and machine tools.
    • Full product virtual testing: system and component design in the same tool. Well suited for control design.
    • Customizable and extendable by means of sub-components. Users can connect components freely as the desire (e.g., in series or in parallel), which eases the implementation of non-standard configurations. No special components for splits or mergers are required.
    • Wide range of standard components: models for cylinders, motors, valves, nozzles, lines and volumes.
    • Seamless integration with other Modelica libraries.
    • Real-time multi-engineering capability.
    • Hardware-in-the-loop applications availability.
    Animated Pneumatics Diagram
  • The Pneumatics Library consists of the following packages:

    • Examples: includes basic application examples of the library, such as cylinder driven models (single and multiple) control cases using pneumatic components or visualization examples.
    • Interfaces: basic functions, connectors and partial models that the components require.
    • Environment: model that defines the gas used by the pneumatic system. It also contains data of the environment.
    • Supply: models of components used for supply of compressed air.
    • Cylinders: several models for cylinders and some motors.
    • Directional valves: valves that control the direction of the flow.
    • FlowControlValves: package for the valves that control (or restrict) flow or pressure.
    • Visualizers: classes for result visualization.
    Pneumatics Library
  • Some of the most relevant applications of the Pneumatics Library include automotive suspensions and brakes, machine tools and jackhammers. The library can be used in the fields of construction equipment and suppliers, commercial vehicle design and manufacturing companies and the aerospace industry. The models can also be used for real-time and hardware-in-the-loop applications.

    Example application – Air spring tuning for a military vehicle

    Suspension system design for heavy vehicle applications with multiple axles poses special problems as standard spring and damper configurations generally are too weak to carry the excessive load of armoured vehicles. Additionally, with more than two axles, the stiffness and pre-load distribution between the axles greatly affects the vehicle stability and performance. As a result, seemingly small changes on tolerances and operating conditions may change the over-all behaviour dramatically. Due to the size and weight, prototype testing in real-life tests is both costly and related to a significant risk.

    The air spring element was modelled, using the Hydraulics and Pneumatics libraries. The initial tuning was carried out in a test rig for the spring. As a second step, using the Vehicle Dynamics library, the spring element performance was evaluated in both a simplified quarter car model, as well as in a full vehicle for different scenarios.

    With simulation of the generated multi-domain, model, realistic operating conditions could be established both for the spring components and the vehicle as a whole. At system integration level, inherent nonlinear properties with significant impact on the overall safety and performance of the vehicle were discovered in the safe simulation environment.

    Air Spring Tuning Vehicle Animation

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