How can I solve this problem?

I am applying three different motion input to three different joints. and simulink is giving this error.

Answer 1

[Birdman]

I am not sure, but please make sure that number of AUTOMATICALLY COMPUTED and PROVIDED BY INPUT motions are equal provided by all joints in your model.

[bayram özmen]

All input values must be equal?

[Birdman]

No, you said that you apply motion and torque to some joints. But also, torques have to be automatically computed for the ones you apply motion and vice versa.

[bayram özmen]

I got it. Thank you so much

[Birdman]

If the answer is helpful, can you please accept it?

[bayram özmen]

Yes I can. But I want to ask one more question. I am applying a motion to one joint. but the other ones behave like this joint. why happened like this? I want to apply different motion for each joint. how can ı do this?

[Birdman]

Then, you need to set actuation as Motion and you need to automatically compute torques.

[bayram özmen]

yes I did like that. please can you investigate my simulink model? ı will achieve a constant angle but ı need a motion that have angular displacement angular velocity and angular acceleration. then they will be entered to one simulink to converter. Which units I should choose? Do you think my algoritma is correct?

[Birdman]

As units, I think rad,rad/s,rad/s^2 are allowed. Your algorithm looks okay but maybe the differential equations can not be solved for the inputs you provide. Therefore make sure to give reasonable inputs to your model. That's all I can say without looking at your model on Simulink.

[bayram özmen]

You are so helpful. thank you so so much for your interest. I adjusted the unit as rad. But the results of my kinematic equations are constand value as rad. I applied this to achieve a motion in figure below. But ı applied to joint this. joint did not motion. just stay that position angle. ı want to stay that position by acting. Thats why what should I apply as input?

[Birdman]

But if you apply position command, then it will automatically go to that position and stay.

[bayram özmen]

right I want to stay in that position. But I want to rotate that piece that connect to motor.(circle in figure)

[Birdman]

Oh, you are trying to implement a ball-plate system. That's nice :)

Well, I suggest you to use spherical joint for that connection point to the motor. Spherical joints can rotate in three axis but do not change their positions.

[bayram özmen]

But spherical joint only one torque input. How can I set angle that I want? Also you mean these spherical joints that connect to motorkol in figure.

[Birdman]

The motions will be automatically computed once you apply the reasonable torque values.

[bayram özmen]

you try to tell me, you apply to torque for desired angle. Final position will be desired angle. ı understand true? But ı should apply torque input to revolute joint or spherical joint?

[Birdman]

Apply torque input to spherical joint. If you constructed the model reasonable, then correct values for motions will be automatically computed.

[bayram özmen]

ıt ıs perfect. But ı dont know the necessary torque value for desired position. What should I do?

[Birdman]

Well, you need to find it empirically, I mean by trying.

[bayram özmen]

well, ı will do like that. but ı do not want to one motor. and ı am applying torque to one motor's spherical joint. But other pieces motion. How can I fix one motor when the others are acting?

[Birdman]

What do you mean by fix?

[bayram özmen]

I mean ı have three motor but ı do not want to move of one motor but ı want to move the other two motor. However ı am appling input one motor and all motors are moving?

[Birdman]

If their constraint is satisfied, they may move according to kinematic calculations.

[bayram özmen]

Absolutely you are right. Well Can I apply this method that into figure? Firstly ı find the actuation torque for desired angle and the ı can apply may be. I am not sure?

[Birdman]

Yes, this might work.

[bayram özmen]

I think ıt will work. Also I have a last question. If actuation torque is not a constant, for example ıf ıt is like sinus. How can I apply that torque? I am really very grateful. :)

[Birdman]

There is Sine Wave block in Sources library in Simulink. You may use it.

[bayram özmen]

Thank you so much.If I have a question can I ask to you directly? :)

[Birdman]

Yes but also open a question as well since other people might answer.

[bayram özmen]

sure. thank you so much again. have a nice day

Answer 2

[bayram özmen]

Hi. I am just dealing with this platform. I know how many angle ıt will move so ı solved the necessity angle for that motion in desired angle by inverse kinematic equation. How can I do this? Which block I apply for desired angle? revolute joint block are there between motor and piece that need to move.