Error in yaw rate while using the 3DOF dual track model in SImulink

Hello,

I am current using the 3 DOF Dual track model in simulink from the vehicle dynamics toolbox. In there, i am using the option of external longitudinal forces to replicate the torque generated by the motors on wheel. When i do that, even though i applying the correct torques while steering the yaw rate being generated is very less, which would not be the case in a real life scenarios.

Can someone help me what to do, I want to basically create a yaw rate controller for cornering stability by manipulating the on wheel torque, before I apply this logic in real life i want to test it in Simulink, but somehow this is not working properly and the yaw rates that comes as an output from the block is inaccurate.

Thank you,

Rahul

[Mike Sasena]

Rahul, could you clarify your comments above? You said you're "applying the correct torques while steering". Which specific signals in the block are you using and how are you determining the correct values for them? The yaw rate calculation is shown in the Vehicle Body 3DOF help page:

[Rahul]

Hi Mike,

Thank you for your response. So what I am talking about is that when even i apply constant forces for the two motors on the front axle, still i am receiving incorrect yaw values. Also, I prepared a controller to manipulate the forces such that the output yaw matches the reference yaw, but still I am not able to match the reference yaw, I tried a step response and even a reference yaw via a LUT. I am not sure if it is something that I am not doing correctly or what is happening. Also i had one more question, the output of yaw that we are getting from the dual track model is rad/sec and not rad/sec2? Becuase the unit of the yaw rate is not mentioned in the help document.

Thanks,

Rahul

[Mike Sasena]

Hi Rahul,

Leepakshi has a good explanation in the Answers below. As she mentioned, yaw rate is in rad/s. It's described in the Outputs section of the documentation page here. And yes, an idealized moment on a body by applying forces at the wheel hubs is very different than applying torque at the wheels which is transmitted through tires which react with the ground and have to fight against lateral forces due to friction.

Answer 1

[Leepakshi]

Hello Rahul,

The yaw rate output from the 3-DOF Dual Track Model is in rad/s (yaw rate), not rad/s². If you see low yaw response when applying external longitudinal forces, it’s usually because:

• The model assumes tire forces are generated from slip, not just torque. Applying constant forces without accounting for lateral tire dynamics can lead to unrealistic yaw behavior.
• Ensure correct vehicle parameters (mass, inertia, tire cornering stiffness) and verify that external forces are applied at the correct wheel locations.
• For yaw rate control, use torque vectoring logic with realistic tire models (e.g., Pacejka or MF-Tyre) rather than constant forces.

Hope it helps!