Newsletters - MATLAB News & Notes

What's New for Control System Design

New capabilities enable engineers to speed complex product design and increase reliability with model-based design

by Mike Dickens

Release 12 of the MathWorks product family provides an integrated model-based design environment that enables users to develop complex embedded control systems from initial concept through implementation. This environment is based on the new releases of Simulink 4, Stateflow 4, and Real-Time Workshop 4. Using Release 12, control engineers and embedded system designers in the aerospace, automotive, communications, and industrial control industries can eliminate the tedious and error-prone process of manually writing software code. As a result, the overall design process is reduced by eliminating weeks to months of coding time, while the efficiency and reliability of systems are significantly increased.

Simulink, Stateflow, and Real-Time Workshop 4 enable engineers and designers to adopt a unique, model-based design paradigm that supplements or replaces traditional written design specifications and manual software coding. In this paradigm, the interactive, graphical modeling and simulation environment of Simulink, Stateflow, and Real-Time Workshop allows users to model, analyze, and accurately simulate complex, large-scale systems; convert them to instrumented code for rapid prototyping; and then directly generate efficient code for use in target embedded processor applications.

The quality of the code generated by Real-Time Workshop and now Real-Time Workshop Embedded Coder has been improved with each release of software. The goal is to deliver high-quality code for embedded systems that matches the efficiency of optimized hand-written code.

Faster simulation

One of the major enhancements to the new control design solution is faster simulation of dynamic systems, provided by the new Simulink Performance Tools. Control design engineers will also have an improved simulation experience with Stateflow's new model caching technology during the simulation of larger models.

Model-based design enhancements

Customers have asked us to provide tools that aid in their development when using a model-based design paradigm. Another significant improvement in Release 12 is a new integrated Simulink graphical debugger, requested by customers for the design of large-scale models. Improved model navigation tools quickly traverse complex systems to aid in the understanding of large models having hundreds of subsystems. The design capacity of Stateflow has been enhanced to support larger models that include hierarchical subcharts. Model differencing in Simulink Performance Tools provides a color graphical view of the changes made between different versions of the system model. The enhanced library model browser and linking capability facilitates modularity and sharing of Simulink and Stateflow designs. Secure model encryption provides protection for intellectual property when designs are shared with clients or vendors. Additional tools are provided for reporting test coverage of models during simulation, and profiling the performance of each of the model's component subsystems. These new capabilities enable you to build extensive real-world control designs using a model-based design environment.

Easy event scheduling and graphical functions in Stateflow

Stateflow 4 allows users to incorporate temporal logic operators, such as "after" and "every" into complex, event-driven embedded systems. As a result, Stateflow is the only graphical modeling and simulation environment to employ a convenient event-scheduling mechanism specifically designed for accurate and efficient code generation of event-driven systems. The unique solution frees users from the tedious and error-prone tasks of handling the timers and counters usually associated with event scheduling. Graphical functions, an additional capability in Stateflow 4, introduces the ability for users to define functions using flow graphs. Further advancing Stateflow's visual programming paradigm, graphical functions provide users with a powerful way to express logic flow in a Stateflow chart.

Enhanced code generation

The significant highlight of this newest control design version is greatly enhanced code generation provided by Real-Time Workshop 4, the code generation engine for Simulink 4. You can first generate and easily modify code for rapid prototyping and hardware-in-the-loop testing of Simulink models with Real-Time Workshop. You can then generate code with Real-Time Workshop Embedded Coder as optimized, embeddable ANSI C for use on multiple target operating systems and hardware platforms with stringent RAM/ROM constraints. As the automatic code generation engine for the Stateflow environment, Stateflow Coder works with Real-Time Workshop Embedded Coder to produce highly structured C code for the Stateflow portion of a Simulink model. With version 4, the generated code's ROM size and static RAM requirements are significantly reduced-in some cases by more than 80 percent with respect to code generated by earlier versions of Stateflow Coder. As a result, the generated code runs faster, is more readable, and rivals hand-written code. The code generated by Real-Time Workshop and Stateflow Coder has continued to improve in quality in terms of RAM size, ROM size, and execution speed over the last several product releases. With Release 12, great improvements in code efficiency have been made, so that many customers will consider the code ready to be used in pilot projects and inserted into their code validation processes. Code generated from Simulink models has already been used in production automotive powertrain control designs and has received FAA certification in aerospace applications.

Significant toolbox and blockset improvements

The Control System Toolbox has been enhanced with a new SISO (single-input/single-output) Design Tool for compensator design. The LTI Viewer has also been improved so you can set preferences and customize plots.

With the new SISO Design Tool, an interactive GUI for analyzing and tuning single-inupt/single-output feedback control systems, you can drag poles and zeros and immediately see how the system reacts. A linked LTI Viewer displays open- and closed-loop response plots.

The Fixed-Point Blockset has 12 new blocks with Release 12, for a total of 31. It also features faster simulation speed, explicit overflow saturation logging, and advances for modeling filters of any order. The Power System Blockset 2 can now handle larger, more complex models with improved simulation speed. In addition to the continuous simulation of power systems previously available, you can now also discretize your Power System Blockset model for even faster simulation of your electrical systems.

MATLAB is fully integrated for control design

Finally, MathWorks Release 12 includes the latest version of MATLAB, version 6, which features advanced user interface access to all MATLAB functions. The advanced capabilities of MATLAB 6 are fully available to control engineering applications that require data modeling, analysis, and visualization tools.

Two new products in Release 12 for Simulink

Two new products have been developed for Release 12, Real-Time Workshop Embedded Coder and Simulink Performance Tools. Real-Time Workshop Embedded Coder can generate code from Simulink models as optimized, embeddable ANSI C for use on multiple target operating systems and hardware platforms. Simulink Performance Tools provides faster simulations of large dynamic systems, together with advanced capabilities to enhance model-based design

.  Learn more about control design or view product literature. /applications/controldesign/