QEDAgreed, I have done it before where we didn't need tight control, in this case +/- 0.1", and didn't have motion controllers.
Those 7 equations for position are correct but you need to compute the times too. t56 should always be positive unless the deceleration rate is so low that the peak decel ( negative accel ) is not reached. In that case t56 is 0 and that segment does not exist. The same can happen with t12.
Yep, we figured that much.I certainly trust what you're saying Peter. You know way more about motion than I do, or probably anyone else here!! I wasn't one that suggested it was easy, only that I believe a PLC is capable, depending on the PLC being used. That doesn't necessarily mean I think its "easy" with a PLC. It's one of the reasons on our next machine build, I'm going with an RMC controller married with a PLC. That, and the RMC software makes it so much easier for a technician to create his/her own programs without me having to write PLC code and/or create special software for them, every time they require a new motion program, which will be rather frequently.
I love the product. If/when it gets full EtherCAT support, it will be perfect. But not until then.
Oh, and by the way, there are only four equations:
Troll complete. Thank you
Peter, you really gotta come to Rochester some time so we can meet.
Although to be fair, those integrals, plus the discrete jerk function, do represent the same system and are the basis for the 17 equations. And OP did say it was great to know the math and physics. That said, I agree the integrals are in a somewhat less than solvable form.
Obviously the OP found a solution but it is not perfect and is not optimal. I started a thread over a year about PLC vs motion controllers over a year ago where I listed many reasons one should use a motion controller. I/we often get asked, "can your motion controller do this"busarider said:
We can meet using Skype. We can share screens. I did this MANY Saturday mornings with forum member Pandiani. We would often talk for an hour or more. Pandiani first came to the forum when he was a college student. He had a control problem that I knew that was contrived. I helped him through getting his masters degree. He now is in charge of the controls for the power plants in Tuzla, Bosnia. Pandiani bought Mathcad and has followed me on my Peter Ponders PID YouTube channel.drbitboy said:
The problem is how do you generate the 17 equations?
Obviously the OP found a solution but it is not perfect and is not optimal. I started a thread over a year about PLC vs motion controllers over a year ago where I listed many reasons one should use a motion controller. I/we often get asked, "can your motion controller do this"busarider said:
We can meet using Skype. We can share screens. I did this MANY Saturday mornings with forum member Pandiani. We would often talk for an hour or more. Pandiani first came to the forum when he was a college student. He had a control problem that I knew that was contrived. I helped him through getting his masters degree. He now is in charge of the controls for the power plants in Tuzla, Bosnia. Pandiani bought Mathcad and has followed me on my Peter Ponders PID YouTube channel.drbitboy said:
The problem is how do you generate the 17 equations?
Short moves require only 3 segments.
I've used a lookup table with 1024 entries for square roots. If the input is > 1024 then you simply scale up the inputs an outputs by factors of 4 and 2 (i.e by bit shifting) It's all integer arithmetic, but the encoder is only integer after all.
