How to simulate the load on an induction motor that is responsible for moving a vibrating conveyor belt?

I are trying to simulate a motor circuit that is being using in a manufacturing line. The model of the induction motor is nearly done thanks to MATLAB staff. But, now am stuck at the load problem where I don't know how to simulate the load. In this case, the load on the motor is that its responsibe for the spinning of conveyor, as per an employee of the factory. The Conveyor carries caps in/out of the capping section.

Due to lack of expertise in this domain I am unable to figure out how to simulate the load.

I have attached the 3 phase induction model with the post.

Any suggestions are welcome. Thank you !.