Fixed-Point Blockset

Simulation Setup

To set up this kind of fixed-point feedback controller simulation, you perform the following steps:

1. Identify all design components.

1. In the real world, there are design components with fixed characteristics (the hardware) and design components with characteristics that you can change (the software). In this feedback design, the main hardware components are the A/D hardware, the D/A hardware, and the analog plant. The main software component is the digital controller.

2. Develop a theoretical model of the plant and controller.

1. For the feedback design used in this tutorial, the plant is characterized by a transfer function. The characteristics of the plant are unimportant for this tutorial, and are not discussed.

   The digital controller model used in this tutorial is described by a z-domain transfer function and is implemented using a direct-form realization.

3. Evaluate the behavior of the plant and controller.

1. You evaluate the behavior of the plant and the controller with a Bode plot. This evaluation is idealized since all numbers, operations, and states are double-precision.

4. Simulate the system.

1. You simulate the feedback controller design using Simulink and the Fixed-Point Blockset. Of course, in a simulation environment, you can treat all components (software and hardware) as though their characteristics are not fixed.

Simulink Model of a Feedback Design

Idealized Feedback Design