LOGIKA & PEMROGRAMAN KOMPUTERMATLAB & Simulink PEMBENTUKAN SISTEM KONTROL (Wayan Nata Septiadi,ST) TEKNIK MESIN FAKULTAS TEKNIK UNUD 2009
Some Advanced Features • Creating hierarchical models using subsystems. • Writing S-functions for Customization & Creating new blocks. • Implementation of Conditions & Logics. • Importing CAD models to SimMechanics. • Creating Virtual Worlds & Animations. • Soft Computing in Control. • Real-Time Technology & Hardware in the Loop Simulations.
Example: A Control System This example illustrates the modeling of a more complex system, which is the thermodynamics of a house and its temperature control system. This demo also illustrate the usage of subsystems to create hierarchical models.
S-Functions • You can use S-Functions to customize and createyour own blocks. • An interesting example is providing custom animations for Simulink block-diagram models.A simple example of a mass-spring sys with an animation S-Function is provided as a demo named dblcart1 in the software documentation. • A general M-file S-function template is also provided in: C:\MATLAB\toolbox\simulink\blocks\sfuntmpl.m which can be used as a guide to write M-file S-functions. For more information see the separate Writing S-Functions PDF guide.
Implementation ofConditions &Logics • Simulink: Conditionally Executed Subsystems: enabled/triggered/triggered-enabled subsystems Control Flow Statements & Blocks • StateFlow: For implementation of more complex Flow Control Logics (Event-controlled models)
SimMechanics What Is SimMechanics? • SimMechanics is a block diagram modeling environment for the engineering design and simulation of rigid body machines and their motions, using the standard Newtonian dynamics of forces and torques.
Physical vs. Mathematical Modeling • Simulink (normal) blocks:represent mathematical operations or operate on signals, • Physical Modeling blocks:represent physical components or relationships directly, Note:Sensors & Actuators are used to connect these two kinds of blocks.
SimMechanics Analysis Modes: • Forward Dynamics analysis: integrates applied forces/torques, maintaining imposed constraints, and obtains resulting motions. • Inverse Dynamics analysis: finds the forces/torques necessary to produce user-specified motions in topologically open systems. • Kinematics analysis: finds the forces/torques necessary to produce user-specified motions in topologically closed (loop) systems. • Trimming analysis: searches for steady or equilibrium states of a system.
SimMechanics Block Libraries • Bodies Library • Joints Library • Constraints & Drivers Library • Sensors & Actuators Library • Force Elements Library • Utilities Library
Essential Steps to Build a Model • Select Ground, Body, and Joint blocks. • Position and connect blocks. • Configure Body blocks. • Configure Joint blocks. • Select, connect, and configure Constraint and Driver blocks. • Select, connect, and configure Actuator and Sensor blocks. • Encapsulate subsystems.
Example#2 • One Degree of Freedom Mass-Spring-Damper System • Solution Methods: MATLAB:Solving the DE with an IVP/ODE solver Control Toolbox:Transfer Fcn, State Space Modeling Simulink:DE-solving, Transfer Fcn, State Space SimMechanics:Physical Modeling
Assignment 2-D Bounce & Pitch Vehicle Model • Model the suspension system physically using SimMechanics. • Compare the modeling approach with the mathematical one, done previously using Simulink.