How Custom Vehicle Modeling Works in MATLAB Using Simscape Language
Vehicle dynamics and modeling are among the most important topics in mechanical and automotive engineering. University students often face the challenge of building accurate simulation models of vehicles, whether for coursework, research, or thesis projects. MATLAB and its companion toolboxes, especially Simulink and Simscape, have become the go-to platforms for these tasks.
Simscape, in particular, simplifies the process of modeling physical systems. Instead of manually creating models with basic equations inside Simulink, students can use pre-built blocks that encapsulate entire systems. This not only saves time but also provides a structured way to represent real-world engineering behavior.
But here’s the thing: default Simscape libraries often have limitations. For example, the standard Simscape Driveline library focuses mainly on longitudinal behavior of vehicles. That means if you want to capture both lateral and longitudinal dynamics—essential for realistic tire and vehicle modeling—you need to go beyond the standard blocks. This is where the Simscape language becomes important.
If you need expert-level MATLAB assignment help, in this blog, our team explains how custom vehicle modeling can be carried out using the Simscape language. We will walk you through the theory of customized tire modeling, 3-DOF and 6-DOF vehicle dynamics models, and the differences between Simscape and Simscape Multibody.
Why Use Simscape for Vehicle Modeling?
Before diving into custom modeling, let’s first understand why Simscape is valuable in the first place:
When modeling vehicles in Simulink, you often start with fundamental equations that describe motion, forces, and dynamics. While this approach gives complete control, it quickly becomes overwhelming. The more detailed the system, the more time you spend writing and debugging equations instead of analyzing the vehicle’s performance.
Simscape solves this by providing physical modeling blocks. Instead of connecting abstract mathematical functions, you connect physical components like tires, drivetrains, or vehicle bodies. Each block represents the behavior of an entire system, with defined inputs, outputs, and conserving ports (which exchange physical quantities like force, velocity, or rotation).
This modular approach means you can build, test, and expand complex vehicle systems more easily. And when Simscape’s built-in blocks are not enough, the Simscape language lets you define your own.
The Need for Custom Tire Models
Vehicle dynamics fundamentally depend on how tires interact with the road. Default Simscape tire blocks capture only longitudinal forces (braking and acceleration). But in real driving, lateral forces (cornering) are equally important. For example, when a car turns, the balance between lateral and longitudinal forces determines whether the vehicle understeers, oversteers, or maintains control.
To model this realistically, more advanced mathematical models like Pacejka ’89 and Pacejka ’96 are used. These models describe how lateral and longitudinal forces interact with slip angles, slip ratios, and vertical loads.
Using Simscape language, students can create custom tire blocks that capture these dynamics.
The process involves:
- Defining conserving ports to transfer speed, torque, and force data.
- Declaring domains, variables, and parameters that describe slip, load, and tire behavior.
- Writing equations that represent how forces vary with different inputs.
The result is a tire block that responds realistically under both braking/acceleration and cornering conditions.
Understanding Vehicle Body Dynamics: 3-DOF Model
Once you have realistic tire models, the next step is to connect them to the vehicle body. A common starting point is a 3-degree-of-freedom (3-DOF) vehicle model.
The 3-DOF model describes the vehicle’s movement in three main aspects:
- Longitudinal motion (forward/backward movement).
- Lateral motion (side-to-side movement).
- Yaw motion (rotation around the vertical axis through the center of gravity).
In Simscape language, this requires defining conserving ports for each wheel. These ports connect to the tire blocks and allow force transmission in both longitudinal and lateral directions.
Additional outputs like vertical load distribution and yaw angle are also defined. Vertical loads are crucial for tire modeling because the grip force changes depending on how much weight is pressing down on each wheel.
By applying steering inputs and monitoring outputs like vehicle trajectory and yaw angle, students can simulate realistic vehicle responses. For example, they can study how a car behaves when differentials are locked or unlocked, or how weight distribution affects understeer and oversteer.
Comparing Vehicle Configurations
One of the advantages of custom modeling in MATLAB is the ability to test different vehicle configurations easily.
In the 3-DOF framework, students can simulate a 4-wheel-drive vehicle under various differential conditions:
- All differentials open.
- Central differential locked.
- Central and rear differential locked.
- All differentials locked.
By saving the center of mass trajectory during simulations, it becomes possible to analyze how the car responds under each setup. As expected, locking differentials increases understeer, because the wheels cannot rotate independently, reducing maneuverability.
This type of analysis is not just academic—it mirrors real engineering decisions in automotive design.
Extending to 6-DOF Vehicle Models
While the 3-DOF model is a good starting point, it simplifies vertical dynamics. In reality, suspension systems, load transfers during cornering, and variations in wheel angles significantly affect vehicle stability.
This is where 6-DOF models come in. A 6-DOF vehicle model includes:
- Longitudinal, lateral, and vertical motions.
- Roll, pitch, and yaw rotations.
Simscape Multibody makes it possible to build such models with a graphical interface. Unlike pure Simscape language models, Simscape Multibody provides visual representations of the vehicle, complete with linkages, joints, and suspension systems.
For students, this has two main benefits:
- Easier to visualize how forces act on the vehicle.
- Ability to include suspension kinematics and load transfer effects.
However, this comes at the cost of higher computational requirements. Solving the system equations for a 6-DOF model with suspension details demands more processing power and simulation time.
Simscape vs. Simscape Multibody
A common question students ask is: Should I use Simscape or Simscape Multibody?
The answer depends on your goals:
- Use Simscape when you want faster simulations, simpler block-based modeling, and when visual representation is not a priority. It’s great for testing driveline configurations, tire dynamics, and control strategies.
- Use Simscape Multibody when visual accuracy and suspension modeling are important. For example, if you want to analyze how suspension geometry affects wheel alignment during travel, Multibody is the better choice.
In many cases, combining both approaches gives the best results. For example, you can use custom tire blocks in Simscape and then integrate them into a Multibody vehicle system for visualization.
Educational Value of Custom Vehicle Modeling
From a student’s perspective, custom modeling provides multiple benefits:
- Deeper understanding of theory – Building blocks in Simscape language forces you to translate vehicle dynamics concepts into equations and parameters. This bridges the gap between classroom theory and practical application.
- Problem-solving practice – Students learn how to deal with incomplete or simplified models and then extend them to more realistic ones. For instance, adding load transfer effects to a basic tire block.
- Preparation for industry – Automotive companies use similar modeling approaches for prototyping and control system design. Experience with MATLAB and Simscape is directly transferable to engineering roles.
- Flexibility for research – Custom models allow researchers to test advanced control algorithms, experiment with new drivetrain layouts, or analyze suspension modifications without needing physical prototypes.
Challenges in Custom Modeling
Of course, custom modeling is not without challenges. Students often face difficulties such as:
- Defining conserving ports correctly so that energy balances are respected across components.
- Managing computational load when extending from 3-DOF to 6-DOF models.
- Choosing the right level of abstraction – A very detailed model may not always be better, especially if the focus is on high-level vehicle control.
- Debugging errors in custom Simscape language code, which requires both mechanical understanding and programming skill.
These challenges are precisely why many students seek MATLAB assignment help. A guided approach saves time and ensures the model is both accurate and efficient.
Future Directions in Vehicle Modeling
The work described here opens several paths for future development:
- Including suspension travel effects and load transfer in tire models.
- Modeling tire wear, temperature effects, or road friction variability.
- Integrating electric powertrains and hybrid driveline systems.
- Expanding from on-road vehicle dynamics to off-road or racing applications.
As MATLAB and Simscape continue to evolve, students will gain even more tools to create realistic, industry-level models without needing physical test setups.
Conclusion
Custom vehicle modeling using Simscape language is a powerful way for students to learn, experiment, and innovate in automotive engineering. By creating custom tire models, building 3-DOF and 6-DOF vehicle systems, and comparing results across different configurations, students gain both theoretical insights and practical skills.
Whether you use Simscape for quick block-based modeling or Simscape Multibody for detailed visualization, MATLAB provides a complete environment for exploring vehicle dynamics.
If you’re working on assignments, thesis projects, or research related to vehicle modeling, mastering these tools will not only help you academically but also prepare you for industry challenges.
At our MATLAB assignment help service, we specialize in guiding students through projects like these. From building custom Simscape blocks to optimizing simulation results, our team ensures that you not only complete your assignments on time but also understand the underlying concepts thoroughly.