Create a Multibody Model

Multibody systems consist of multiple interconnected bodies that undergo translational and rotational displacements. Engineers can use Simscape™ Multibody™ to optimize multibody designs and enhance system performance across diverse engineering fields, including automotive, aerospace, robotics, and biomechanics. To model a multibody system and analyze its dynamics behaviors, follow these high-level steps:

  1. Study the System to Model: Identify the bodies, joints, and constraints to include in the model. Consider the forces and torques that act between bodies or directly at the joints.

  2. Model the Bodies: Define the properties of each body and add frames to facilitate the connection of joints and constraints.

  3. Assemble the Multibody System: Connect pairs of bodies through joints. Use gears and other kinematic constraints to control body motion.

  4. Specify and Sense Dynamics Variables: Define the external loads, interactions between bodies, and joint actuation inputs. Measure the forces, torques, and motion variables over time.

You can model a multibody system by using block diagrams or MATLAB® classes.

When to Use Block Diagrams

Use block diagrams to construct your multibody model when your project requires:

  • Graphical Representation: You prefer a visual approach to modeling. Simulink provides a block diagram interface that represents physical systems and their interactions.

  • Complex Systems: Your system involves contacts, flexible bodies, control systems, and signal processing.

  • Continuous-Time Simulation: Your system primarily involves continuous-time dynamics.

  • Real-Time Simulation: You are interested in real-time simulation or hardware-in-the-loop testing.

To learn more about building a multibody model using block diagrams, explore these tutorials:

When to Use MATLAB Classes

Use classes to construct your multibody model when your project requires:

  • Building a Multibody System Programmatically: MATLAB classes offer robust tools for automating model creation, making them ideal for repetitive model structures. They also offer seamless integration with programming-based products and toolboxes, such as Robotics System Toolbox.

  • Instantaneous Kinematics or Dynamics Analyses: MATLAB classes excel in evaluating a system's dynamic state at a specific instant, including velocities, accelerations, and forces. This capability allows for precise data extraction, reducing computational time and cost, especially in complex and time-consuming simulations. They are ideal for projects that require numerous analyses at a single time point, facilitating design optimization, sensitivity analysis, and scenario exploration without the overhead of dynamic processing.

To learn more about building a multibody model using MATLAB classes, explore these tutorials:

See Also

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