By continuing my first posting about introduction Vn4D in Indonesian language, now I'll make some simple application for this software to perform dynamic simulation, this is an example for multi-body simulation and I made in a bit complex system but with simplealgorithm. I'm only explaining the algorithm not the syntax so you can apply with other software.
Let's get straight to the point, first of all before starting simulation we need a model, see picture below:
I divide in to three part mechanism:
1. Dropper : This mechanism transferring box from top to bottom conveyor, consist of spade and sphere as weighter
2. Convey : Moving object in horizontal direction or transferring box from dropper to lifter and contrary
3. Lifter : More complex mechanism that transferring box from bottom to top conveyor, divide again in two component (mover and riser) with detailed each in the picture above.
Next step are planning how our mechanism work, see diagram below for overview.
How to make our simulation run with following diagram above, I'll make it simple by using question-answer method for better understanding.
Q: How to make the box move via bottom conveyor to the lifter?
A: Set conveyor surface velocity to "n" mm/s and don't forget to set collide behavior between box and conveyor, remember to set collide on a pair of body that really means to be touching each other in simulation
Q: What triggering lifter starts to work?
A: lifter work when the box fully leaving conveyor, first we have to know weight of conveyor and box independently then read constraint force if only measure weight of conveyor its mean box already leaving the conveyor surface and combine with other parameter to indicate when lifter work for lifting or reset to its original position, such as readable constraint force at the top conveyor.
Q: I see the mini lifter and the raiser move at the same time with different slot distance, how to make this happen?
A: it’s just simple, we know the distance now the speed for each found by comparing V1/d1=V2/d2, since they travel at the same time, you'll find V1 and V2 value.
Q: How does the actuator works?
A: Of course readable parameter of distance become indicator, no matter mini lifter or raiser as the reading object they reach the top at the same time, then actuator will pushing pad until fully stroke
Q: How does the motor works?
A: Motor work when actuator are fully stretched, then rotate with certain angular velocity until desired angle position achieve and back to reset position when constraint force of top conveyor read sum of weight box and conveyor itself.
Q: Are setting parameter for top conveyor same with bottom conveyor?
A: Yes it does, just velocity direction need to set an opposite.
Q: How to make Dropper work by using its natural movement?
A: Now this is need a calculation out side from software since there aren't control except limiting hinge movement by degree, first we have to now length of arm between hinge with sphere (l1), weight of sphere (F1) then length of arm from hinge to spade center gravity (l2) and spade weight (F2), of course weight of box (Wb) as known variable, then make sure current condition are meet with this equation F1*L1<(F2+Wb)*L2, if doesn't you can edit sphere weight without changing dimension shape.
Clips below are generated output from Vn4D, I also give a graph to monitor what torque motor that needed to lift the raiser component with constant velocity
That's the algorithm for our mechanism, simple isn't it??? Now try it with your own imagination, what else this model can do....you decide it.
In this dynamic simulation you can do half of your work and cut much of time before advance to prototyping stage, with wide range of application in laboratories for an experiment or in industry by designing some manufacture assembly process even robotic movement which is applying automatic controller, of course with considering mechanical principles
Post a Comment