Simulink Real-Time

The core function is the automatic translation of Simulink block diagrams and Stateflow charts into optimized, standalone C code. This code is compiled with a real-time kernel for execution on a dedicated target machine. The process ensures deterministic execution, where the model's step time is guaranteed to be met on every cycle, which is critical for closed-loop control validation.

• Rapid Prototyping: Enables quick iteration by deploying controller designs directly to hardware.
• Production Code Foundation: The generated code often serves as a reference for final embedded software.

The generated real-time application runs on a dedicated target computer, physically separate from the host PC used for development. This target is typically a real-time operating system (RTOS) like the MathWorks real-time kernel or a commercial RTOS (e.g., VxWorks).

• Deterministic Scheduling: The RTOS guarantees task timing, isolating the real-time model from non-deterministic processes on a general-purpose OS.
• Hardware-in-the-Loop Core: The target computer hosts the plant model and interfaces with physical I/O, forming the heart of the HIL test system.

Provides extensive support for interfacing with physical hardware through I/O boards installed in the target computer. These boards handle the critical signal conversion between the digital simulation and the analog/digital world of the Device Under Test (DUT).

• Analog & Digital I/O: For reading sensor voltages and driving actuator commands.
• Communication Protocols: Direct support for CAN, EtherCAT, ARINC 429, and serial interfaces.
• Signal Conditioning: Built-in scaling and calibration for matching sensor/actuator ranges.

Engineers can interact with and monitor the running real-time application from the host Simulink environment without stopping execution. This enables dynamic parameter tuning, signal monitoring, and data logging.

• Tunable Parameters: Adjust gains, setpoints, or model coefficients on-the-fly.
• Real-Time Data Visualization: Plot signals as they are generated by the target.
• Triggered Data Capture: Log high-speed data based on specific events or conditions.

Ensures the model executes within a hard real-time deadline on every time step. The system provides tools for timing analysis to verify that the worst-case execution time (WCET) is less than the sample period.

• Sample Time Enforcement: Guarantees model tasks complete before the next sample period begins.
• Overrun Detection: Flags and logs any instance where the real-time deadline is missed, a critical failure in HIL testing.
• Multirate Execution: Supports models with multiple, synchronized sample rates.

Functions as the core real-time engine within larger automated test systems. It integrates with frameworks like Simulink Test and SystemTest for creating, managing, and executing comprehensive test suites.

• Automated Test Sequences: Run pre-defined test vectors and scenarios.
• Requirements Tracing: Link test cases to high-level requirements (e.g., with Simulink Requirements).
• Continuous Integration (CI): Supports integration into CI/CD pipelines for regression testing.

Real-time simulation is a computational paradigm where a model of a physical system is executed at a speed that matches or exceeds the actual passage of time. This deterministic timing is non-negotiable for HIL testing, as the simulated plant must react to hardware inputs within the strict deadlines of the physical world.

• Hard Requirement: Simulation step time must be less than or equal to real-world sample time.
• Deterministic Execution: Outputs must be produced within a guaranteed, bounded timeframe.
• Simulink Real-Time Role: It compiles Simulink models into real-time C code and runs them on a dedicated target computer with a real-time kernel to achieve this deterministic execution.

Rapid Control Prototyping (RCP) is the complementary workflow to HIL testing. Instead of testing physical hardware against a simulated plant, RCP uses a real-time target computer (like one running Simulink Real-Time) to execute a prototype control algorithm and directly command physical actuators, with feedback from real sensors.

• Primary Goal: Accelerate the design and field-testing of new control algorithms.
• Hardware Role: The real-time computer acts as the controller, interfacing with the actual plant.
• Connection to Simulink Real-Time: The same toolchain is used to deploy and execute controller models in real-time on prototype hardware, allowing engineers to iterate designs quickly before committing to embedded code.

A Real-Time Operating System (RTOS) is a specialized OS kernel that provides deterministic scheduling, interrupt handling, and inter-task communication. It is the foundational software layer that enables a standard processor to guarantee real-time performance.

• Key Feature: Preemptive, priority-based scheduling ensures high-priority tasks (like model execution) always meet their deadlines.
• Simulink Real-Time Basis: The product includes a streamlined, real-time kernel (formerly based on QNX) that runs on the target PC, managing the execution of the compiled model, I/O drivers, and communication tasks.
• Contrast with GPOS: Unlike general-purpose operating systems (Windows, Linux), an RTOS sacrifices flexibility and features for timing predictability.

xPC Target was the predecessor product name for Simulink Real-Time. It refers to the legacy technology for turning a standard PC into a real-time target machine using a bootable real-time kernel.

• Historical Context: The original solution for real-time execution of Simulink models on inexpensive PC hardware.
• Evolution: The technology was rebranded and integrated more deeply into the Simulink environment as Simulink Real-Time.
• Technical Continuity: Many core concepts—like the target boot disk, real-time kernel, and host-target communication—remain central to the current product. Understanding xPC Target provides historical insight into the tool's architecture.