SimMechanics - Documentation

Contents

Index

• Getting Started

• Modeling Mechanical Systems

• Representing Machines with Models

About SimMechanics Models

Creating a SimMechanics Model

Connecting SimMechanics Blocks

Interfacing SimMechanics Blocks to Simulink Blocks

Creating SimMechanics Subsystems

Creating Custom SimMechanics Blocks with Masks

• Modeling Grounds and Bodies

About Bodies and Grounds

Modeling Grounds

Modeling Rigid Bodies

Working with Body Coordinate Systems

• Modeling Degrees of Freedom

Modeling Joints

Creating a Joint

Modeling Massless Connectors

Modeling Disassembled Joints

• Constraining and Driving Degrees of Freedom

About Constraints

Types of Mechanical Constraints

What Constraints and Drivers Do

Directionality of Constraints and Drivers

Solving Constraints

Restrictions on Using Constraint and Driver Blocks

Constraint Example: Gear Constraint

Driver Example: Angle Driver

• Cutting Machine Diagram Loops

Rules for Valid Machine Diagram Loops

Rules for Automatic Loop Cutting

Specifying a Loop Joint for Cutting

Displaying the Cut Joints

For More About Disassembled and Cut Joints

For More About Constraints and Drivers

• Applying Motions and Forces

About Actuators

Actuating a Body

Varying a Body's Mass and Inertia Tensor

Actuating a Joint

Actuating a Driver

Specifying Initial Positions and Velocities

• Sensing Motions and Forces

Sensing Body Motions

Sensing Joint Motions and Forces

Sensing Constraint Reaction Forces

• Adding Internal Forces

About Force Elements

Inserting a Linear Force Between Bodies

Inserting a Linear Force or Torque Through a Joint

Customizing Force Elements with Sensor-Actuator Feedback

• Combining One- and Three-Dimensional Mechanical Elements

About Interface Elements

Working with Interface Elements

Example: Rotational Spring-Damper with Hard Stop

• Validating Mechanical Models

Essential Tests for Model Validity

Verifying Model Topology

Counting Model Degrees of Freedom

• Running Mechanical Models

• Configuring SimMechanics Models in Simulink

SimMechanics and Simulink Options

Distinguishing Models and Machines

Machine Settings via the Machine Environment Block

Model-Wide Settings via Simulink and Simscape Software

• Configuring Methods of Solution

About Mechanical and Mathematical Settings

Defining Gravity

Choosing Your Machine's Dimensionality

Choosing an Analysis Mode

Hierarchy of Solvers and Tolerances

Controlling Machine Assembly

Maintaining Constraints

Configuring a Simulink Solver

Avoiding Simulation Failures

• Starting Visualization and Simulation

About Simscape and Visualization Settings

Using the Simscape Editing Mode

Setting Up Visualization

Starting the Simulation

• How SimMechanics Software Works

About Machine Simulation

Model Validation

Machine Initialization

Force Analysis and Motion Integration

Stiction Mode Iteration

• Troubleshooting Simulation Errors

About Simulation Errors

Data Validation Errors

Ground and Body Geometry Errors

Joint Geometry Errors

Block Connection and Topology Errors

Motion Inconsistency and Singularity Errors

Analysis Mode Errors

• Improving Performance

Optimizing Mechanical and Mathematical Settings

Simplifying the Degrees of Freedom

Adjusting Constraint Tolerances

Smoothing Motion Singularities

Changing the Simulink Solver and Tolerances

Adjusting the Time Step in Real-Time Simulation

• Generating Code

About Code Generation from SimMechanics Models

Using Code-Related Products and Features

How SimMechanics Code Generation Differs from Simulink

Using Run-Time Parameters in Generated Code

• Limitations

About SimMechanics and Simulink Limitations

Continuous Sample Times Required

Restricted Simulink Tools

Unsupported Simulink Tool

Simulink Tools Not Compatible with SimMechanics Blocks

Restrictions on Two-Dimensional Simulation

Restrictions with Generated Code

• Analyzing Motion

• Dynamics of Mechanical Systems

About Machine Dynamics

Forward and Inverse Dynamics

Forces, Torques, and Accelerations

• Finding Forces from Motions

About Inverse Dynamics in SimMechanics Software

Inverse Dynamics Mode with a Double Pendulum

Kinematics Mode with a Four Bar Machine

• Trimming Mechanical Models

About Trimming in SimMechanics Software

Unconstrained Trimming of a Spring-Loaded Double Pendulum

Constrained Trimming of a Four Bar Machine

• Linearizing Mechanical Models

About Linearization and SimMechanics Software

Open-Topology Linearization: Double Pendulum

Closed-Loop Linearization: Four Bar Machine

• Motion, Control, and Real-Time Simulation

• Guide to This Chapter

About the Stewart Platform and How It Is Modeled

About the Case Studies

Products Needed for the Case Studies

• About the Stewart Platform

Origin and Uses of the Stewart Platform

Characteristics of the Stewart Platform

Counting Degrees of Freedom in the Stewart Platform

• Modeling the Stewart Platform

How the Stewart Platform Is Modeled

Modeling the Physical Plant

Modeling Controllers

Initializing the Stewart Platform

Identifying the Simulink and Mechanical States of the Stewart Platform

Visualizing the Stewart Platform Motion

• Trimming and Linearizing Through Inverse Dynamics

About Trimming and Inverse Dynamics

What Is Trimming?

Ways to Find an Operating Point

Trimming in the Kinematics Mode

Linearizing the Stewart Platform at an Operating Point

Further Suggestions for Inverse Dynamics Trimming

• About Controllers and Plants

Modeling Controllers in Simulink and Plants in SimMechanics Software

Nature of the Control Problem

Control Transfer Function Forms and Units

Controller-Plant Case Study Files

For More About Designing Controllers

• Analyzing Controllers

Implementing a Simple Controller for the Stewart Platform

A First Look at the Stewart Platform Control Model

Improper and Biproper PID Controllers

Analyzing the PID Controller Response

• Designing and Improving Controllers

Creating Improved Controllers for the Stewart Platform

Designing a New PID Controller

Trimming and Linearizing the Platform Motion

Improving the New PID Controller

Synthesizing a Robust, Multichannel Controller

• Generating and Simulating with Code

About the Stewart Platform Code Generation Examples

For More Information About Code Generation

Learning About the Model

Generating an S-Function Block for the Plant

Model Referencing the Plant

Generating Stand-Alone Code for the Whole Model

• Simulating with Hardware in the Loop

About Dedicated Hardware Targets for Stewart Platform Simulation

For More Information About xPC Target Software

Files Needed for This Study

Adjusting Hardware for Computational Demands

Downloading a Complete Model to the Target

Configuring for Realistic Hardware

• Introducing Visualization and Animation

• About SimMechanics Visualization

Starting SimMechanics Visualization

Using SimMechanics Visualization

• About Body Color and Geometry: Default, Standard, and Custom

About Body Color: Default and Custom

About Body Geometry: Default, Standard, and Custom

Standard Body Geometry: Equivalent Ellipsoids

Standard Body Geometry: Convex Hulls

Custom Body Geometry and External Graphics Files

• Hierarchy of Body, Machine, and Model Visualization Settings

Visualized Geometries and Colors from Body Block Settings

Body Block Settings Affecting Body Visualization

Visualization Settings in the Machine and Model Hierarchy

• Getting Started with the Visualization Window

• Introducing the SimMechanics Visualization Window

About the Visualization Window

Opening and Updating the Visualization Window

Visualization Toolbar and Its Controls

• Controlling Body and Body Component Display

About Body and Body Component Display

Interpreting the Body Display Symbols and Shapes

Changing Body Display Symbols

Changing Body Display Shapes

• Setting and Manipulating the Camera View

Setting the Background Color

Interpreting the Camera Projection, Field of View, and Viewpoint

Automatically Sizing the Camera Field of View

Automatically Setting a Camera Viewpoint

Actively Controlling the Camera Viewpoint

Camera Viewpoint and Mouse Controls

• Communicating with the Model from the Visualization Window

Highlighting Bodies, Body Components, and Body Blocks

Updating the Model Diagram

Saving Visualization Settings to the Model

• Controlling and Timing Simulation from the Visualization Window

Starting, Pausing, and Stopping the Simulation

Timing the Simulation

• Controlling Animation

About Animation

How Animation Works

Automatically Adapting the Camera View to the Displayed Motion

Changing How the Animation Is Updated

Speeding Up the Animation in Real Time

• Recording Animation

About Recording

How Recording Works

Recording Animations

Compressing Animation Recordings

Controlling the Size of the Recorded Animation

Playing Recordings of Animation

• Visualization Menus and Their Controls

About the SimMechanics Visualization Window Menus

Simulation Menu

• Customizing Visualization and Animation

• About Custom SimMechanics Visualization

Customizing Visualization Settings

Creating an External Virtual Reality Client

• Customizing Visualized Body Colors

Choosing Custom Body Colors

Switching Between Default and Custom Body Colors

• Customizing Visualized Body Geometries

Choosing Custom Body Geometries

Switching Between Standard Body Geometries

About STL Body Graphics Files

Obtaining STL Body Graphics Files for Custom Body Geometries

Switching Between Standard and Custom Body Geometries

• Visualizing with a Virtual Reality Client

About Virtual Worlds for Machines and Models

Creating Virtual Worlds for SimMechanics Models

Interfacing SimMechanics Models with Virtual Worlds

• Importing Mechanical Models

• Introducing Mechanical Import

About Mechanical Import and CAD Translation

Requirements for CAD Export and Mechanical Import

Essential CAD Translation Steps

• Generating New Models from Physical Modeling XML

About Generated SimMechanics Models Based on CAD

Generating a New Model from a Physical Modeling XML File

• Working with Generated Models

About CAD-Based Models

Common Features of CAD-Based Models

Manually Modifying and Extending Generated Models

Troubleshooting CAD-Based Models

• Updating Generated Models Using Physical Modeling XML

About Model Update and Mechanical Import

Updating a Machine in a Generated Model with Revisions

Adding a New Machine to a Generated Model

Replacing Generated Model or Subsystem Contents with a New Machine

• Controlling Model Update

About Associativity and Updating

Working with Associativity in Common Updating Situations

Controlling How Update-Import Changes Individual Blocks and Connections

Associativity in an Updating Sequence Example

• Computer-Aided Design Translation

• About CAD Translation

Introducing the Case Studies

For More About CAD Assembly Export

For More About Mechanical Import and Model Generation

Glossary for Specialized CAD Terms

• Translating a CAD Part into a Body

Locating the Single-Part Assembly Files

Viewing the CAD Assembly

Exporting the CAD Assembly

Generating the SimMechanics Model

• Translating CAD Constraints into Joints

Modeling CAD and SimMechanics Degrees of Freedom

Locating the Constraint Assembly Files

Generating the Two-Part Models: Common Steps

About the Common Block Structure of the Two-Part Models:

Modeling a Six-DoF Joint

Modeling a Prismatic Joint

Modeling a Revolute Joint

Modeling an Inplane Joint

Modeling a Spherical-Spherical Massless Connector

• Updating and Retranslating a CAD Pendulum

About Assembly Re-Export and Model Update

Locating the Assembly Files

Translating the Assembly For the First Time

Updating the Original Imported Model with Changes to Bodies

Adding a New Body to Create a Triple Pendulum

Updating an Existing Generated Model While Retaining Manual Joint Replacements

Selectively Updating an Existing Generated Model

• Translating a CAD Robot Arm

Locating the Robot Arm Assembly Files

Viewing the Robot Arm Assembly

Exporting the Robot Arm Assembly

Generating and Completing the Robot Arm Model

Simulating and Observing the Robot Arm Motion

• Translating a CAD Stewart Platform

Introducing the Stewart Platform

Introducing the Stewart Platform Assembly

Viewing the Stewart Platform Assembly

Exporting the Stewart Platform Assembly

Generating the Stewart Platform Model

Visualizing the Stewart Platform Motion

• Configuration Parameters

• SimMechanics Pane: General

SimMechanics Pane Overview

Warn if machine contains redundant constraints

Warn if number of initial constraints is unstable

Mark automatically cut joints

Display machines after updating diagram

Show animation during simulation

Show only port coordinate systems

Default body color (RGB)

Default body geometries

• Technical Conventions

• Mechanical Conventions and Abbreviations

Right-Hand Rule Is Assumed

Vector Multiplication

Common Abbreviations

Mechanical Units

• Release Notes

SimMechanics roadmap page

	Blocks:
	By Category
	Alphabetical List

	Functions:
	Alphabetical List

	CAD Interfaces:
	SimMechanics Link



	Documentation Set

	Getting Started
	Introduces SimMechanics and gets you started with mechanical modeling

	User's Guide
	Provides tutorials and comprehensive information about SimMechanics

	Visualization and Import Guide
	Provides tutorials and comprehensive information about SimMechanics visualization and model import and generation

	Examples in Documentation
	Lists major examples in the SimMechanics documentation



	Product Demos

	SimMechanics Demos
	Presents a collection of demos that you can run from the Help browser to help you learn the product



	What's New

	Release Notes
	Summarizes new features, bug fixes, upgrade issues, etc.



	Printable (PDF) Documentation on the Web

PDF documents reflect the most recent version of SimMechanics and might describe features not available in earlier versions of the software.
	SimMechanics Getting Started Guide
	SimMechanics User's Guide
	SimMechanics Visualization and Import Guide
	SimMechanics Reference
	SimMechanics Release Notes

The MathWorks Web Site Resources

	Demos
	MATLAB Central
	Product Page
	Platforms & Requirements

	Related Books
	Related Products
	Technical Support

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