Make Life Accessible - Motor Suite Test - blog 8

Hi Doug

I have a favour to ask you. I am roadtesting the FRDM-KV31, LVPMSM motor controller and Linix motor. After reading your design challenge blog, and downloading various documents, it is clear that getting these components to work with the Kinetis Motor Suite will depend on exactly the right combination of obsolete software. I also found that the KV31F boards come with different firmware, depending on their age.

To save me hours of pain (like the 33+ hours you experienced), it would be great if you could firstly check what your KV31F board enumerates as when you plug it into a PC. This assumes a) you still have it, b) you can still find it!

It should either show up as MBED <drive letter> , or FRDM-KV31F <drive letter>.

Next, can you remember or have you a note of, which versions of:

• Kinetis Motor Suite
• Kinetis SDK

worked with Kinetis Design Studio v3.0 and the hardware you were sent? I appreciate that almost three years have elapsed since this project.

Any answers at all would help narrow down what I need! I asked NXP for some help but they said that they "will no longer be licensing" KMS and pointed me towards MCUXpresso (without KMS). I can do this, but I'd rather have a play with KMS first.

Thanks in anticipation.

Steve

Oh that's quite a bit of reduction. I know of some UK suppliers of gears (e.g. worm gear sets or just spur gears) or timing belt, that will get you perhaps 50:1 or 100:1 max reduction, so several stages of it would be needed (i.e. 3 or 4 stages). Would need sub-millimeter accurate 3D printing or some adjustable capability so you can put in the right place and tighten screws.

If you need the details let me know, I'll dig out the names I've ordered from them once or twice. But maybe you know of a supplier closer to you.

But the other method you suggest has a lot of value, i.e. no need to run at the slowest speed, and only power it on and off intermittently, e.g. power it on every minute and just count the revolutions using the hall sensor if the FOC algorithm implementation doesn't have a hook to program how many revolutions you need. I did that with a brushed DC motor, and the error was tiny (and the error won't accumulate since it is possible to compensate in each subsequent minute).

Edit media

Dimensions x Small Medium Large Custom

Subject (required) Brief Description Tags (separated by comma) Video visibility in search results Visible Hidden

Parent content

Getting Started with the Infineon DC Motor Control Board Comment on Make Life Accessible - Motor Suite Test - blog 8

Poster

Upload Preview

Ok

Cancel

I think we're talking about the same thing. Section 4.3 of that document mentions a hall sensor can be used. Presumably it waits for a transition from high to low (or vice-versa) to get a repeatable precise position fix, that repeatable position would occur every  180 degrees or every 360 degrees (depending on what that algorithm needs).

I am tracking the sun - which is obviously pretty slow at one revolution per day, but I can use short, higher speed, motions periodically to emulate continuous tracking. I still will need to gear the motor down significantly. Its minimum speed right now is 288000 revs per day and I need 1 rev per day.

Right. Hall effect sensor changes its state every 180 degrees of electrical revolution. Place three hall effect sensors 120 degrees (or 60 degress) apart and bam, you know absolute position with 60 degrees resolution. Check Figure 67 in this document:

http://www.st.com/content/ccc/resource/technical/document/user_manual/5e/5e/d2/cb/07/35/45/a6/CD00298474.pdf/files/CD002…

(This document also describes in Section 8.2 High Frequency Injection technique i mentioned earlier.)