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meccanico1-Visitor
1-Visitor
October 21, 2018
Solved

sequence of movements with rotation (pin) + translation(slider)

  • October 21, 2018
  • 2 replies
  • 5597 views

Hello, I should create in my assembly the movement illustrated in the image that I have attached. Each phase is sequential, there are no combined rotation and translation at the same time,

in each passage it occurs, or only rotation of the pin, or only the translation of the slider

 I would like to ask you a tip on how to get started. I've set up a Pin  and a slider constraint, now I suppose I'll be applying some motor  and setting the correct sequence of each movement in Creo Mechanism, but I have no idea how to do it. Use I create parametric 5, I also attached the assembly files . thanksanimation.jpg

Best answer by SweetPeasHub

First you need to solve the circular references warning. (reference to ground part problem with pin.prt for the sketch plane datums and the sketched circle center reference.  see .crc text file generated.)

Then it would be best to have these highlighted parts as a subassembly.

 

SubassemblySubassembly

Next, depending on the type of mechanism analysis wanted, you would need materials assigned so the model has proper masses, as well as continuous velocities in your motor definitions.

 

Finally use tabulated position for the motors.example motor def.example motor def.

 

Timing both motorsTiming both motors

 Of course for smoother accelerations then some intermediate steps would be good to add.

 

 

2 replies

P
19-Tanzanite
pausob19-Tanzanite
19-Tanzanite
October 22, 2018

One way to do it is by is by sequencing the motors.  See this thread, for example.

    S
    SweetPeasHub17-PeridotAnswer
    17-Peridot
    October 22, 2018

    First you need to solve the circular references warning. (reference to ground part problem with pin.prt for the sketch plane datums and the sketched circle center reference.  see .crc text file generated.)

    Then it would be best to have these highlighted parts as a subassembly.

     

    SubassemblySubassembly

    Next, depending on the type of mechanism analysis wanted, you would need materials assigned so the model has proper masses, as well as continuous velocities in your motor definitions.

     

    Finally use tabulated position for the motors.example motor def.example motor def.

     

    Timing both motorsTiming both motors

     Of course for smoother accelerations then some intermediate steps would be good to add.

     

     

      M
      meccanico1-VisitorAuthor
      1-Visitor
      October 23, 2018

      thanks to both for the answer.

      sweetpeahub, I solved the circular reference and set the sequence, thanks for the detailed instructions! what a great satisfaction to see it finally move
      For smoother accelerations / deceleration indicatively how many intermediate steps are necessary?

      S
      SweetPeasHub17-Peridot
      17-Peridot
      October 23, 2018

      I can't give you a number of points to add but I can tell you how I would go about smoothing the accelerations.

      I would create NET LOAD measures on the motors to see what I am asking the motor to provide vs. the motor specs.

       

      NET loads on motorsNET loads on motors

       

      I would look at each motors graphs of Pos / Vel / Acc.

      For example switch Monotonic to Spline and see the effects, such as reducing the acceleration from 600 deg/s^2 to 200 deg/s^2. (not shown)  The problem is the position is less accurate than wanted with the spline.  So I could work on the spline version to add points to get the position more as desired, or I could work on the monotonic to get the accelerations lower.   Lets work with the monotonic.

      Here is before and after my simple revisions.

       

      Motor ChartsMotor Charts

       

      Revised Motor ChartsRevised Motor Charts

       Notice how I removed the point at 5 seconds and now the move is smoother.

      I also added 0.5 seconds between the move at 1 second to 2 seconds.  Of course the other motors timing would have to be stretched as well.  So I guess I did not add points but there will be times this helps the motion, and more required if doing a spline fit.  It really depends among other things what your motor is capable of and what tolerances for position you need, how much you can tolerate for position error or max accelerations/forces.

       

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