Two Motors in Series on one Shaft - Simscape

I have two simple motor components, each with two ports for the mechanical rotational domian in Simscape. One port for the housing and one for the shaft itself. I try to combine both on one shaft, such that the torque will be added and the rotational speed is equal. Each motor should generate torque between groung and the shaft.

To make it clear, I attached a very simple model with two ideal toeque sources (like the motors are) and connected them in a way, such that I think it should be approbiate. But it isn't. The attached example doesn't run. What is the problem and how can I make this simple example run?

One sidenote: each motor should be connected to ground. So it should also be possible to run the system by only one of both motors. Think about a kind of redundant system structure. I know there are example where a motor drives a generator etc., but that doesn't help, since I like to drive a system attached to the shaft with both of the motors.

Answer 1

[Adarsh]

Hi @Marcel Thevagt,

I understand that you are trying to simulate a model where you are generating higher torque by using two simple “Ideal Torque Source” in series and encountering an error in doing so.

The reason for the error is the missing of the “Inertia” block between the “Ideal Torque Source” and “Ideal Rotational Motion Sensor”. Because when torque is generated by the “Ideal Torque Source” there is no mechanical body to store the generated torque.

The “Inertia” block acts as a rotating mass that resists changes in its angular velocity and stores the generated angular velocity and energy.

Hence, by placing the “Inertia” block between the “Ideal Torque Source” and the “Ideal Rotational Motion Sensor” the error will be resolved and the simulation of the model can be performed.

Below is an image of the final Simulink model after adding the “Inertia” block:

For more information the following documentation link can be referred:

https://www.mathworks.com/help/simscape/ref/inertia.html

Hope this helps!