Linear actuator using ClearPath Integrated Servo System @ 72V DC

MCPV (Motion Control through Position and Velocity) Sounds interesting!

I use MCVC models (Motion Control through VeloCity and some other positioning modes for simpler use cases). They do have a "follow digital position command" mode too, but @Thanos said they were not well suited for motion simulation. They need to finish every move before starting the next. That can become a problem! I think Thanos tested them and I am grateful for him pointing that out to me.


Now, MCPVs might be a different ballgame. It might be that you can give them a "moving" target position and the motor updates its target in real time. You'd have to check.

Yes, they have a very generous return policy and friendly support. Somewhere in their manual it says something to the likes of...
- we ship them to you,
- you try them out,
- we know you will have to mount them to do that,
- we know that they will not be brand new after that,
- please make an effort to be gentle with them, we cared well for them,
- oh, what the hell... "Just don't run them over with a forklift!!!!! PLEAASE!!!!"

So, I'd definitely give them a shot if I were you!


Then again,... there are also SCHP (Software Controled High Power) models. That give you direct access to the motors internal data (position, velocity, torque, current, acceleration, jerk) I shyed away from them last year, because I thought I couldn't handle the coding part. In hindsight I think I better should've gone with them. And you as a software developer should be able to bring them to good use I think those are the only ones where you can actually leave out every position sensing and rely solely on the motors internal sensors.

Let me know,... I am excited someone else tries ClearPath motors.

Dirty

Follow position command” is a feature Teknic implemented very recently.
Although I also have the mcpv (old ones) I can’t use their new feature because Teknic do not alow firmware upgrades arguing they did some changes on the hardware side.

Drop them a message with a SN of your motor. Maybe you will have more luck than me.

@Thanos said he can 1000 percent interface it

Ahh, interesting! Thanks!

I guess I have mixed up "Move to Absolute Position" with "Follow Digital Position Command".


I have found a video of it here. That mode sounds like you can completely ditch belt, and pot and rely on the motors sensors alone That's what I find incredibly attractive about them. And even in the standard version it would give you position control to within ~2.7 micrometers. Thats about a 1/10000th of an inch! (Assuming a ballscrew with a 5mm lead)

I think for now I will stay with the conventional position sensing via belt & pot and control through "Follow Digital Velocity Command". But if someone here on the forums were to try them out, and found that indeed they performed as precise as one would expect. I'd try to sell my MCVCs on eBay.

Well I ordered one of the MCPV servos, power supply, and some various components to build at least one linear actuator. I'll get something thrown together to test out the follow digital position setting.

Oh, that's goooood! Keep me posted how they perform. Especially how they find their position on power up. Do they still need a calibration routine? If you say "no" and you can confirm with the actual hardware, there's a high chance I will follow you.

...as soon as I get my tax return

I think they have a homing function on power up against a hard stop (torque limit ). At least that's what we did before with the older models with pulse-burst mode control.

Thank you!

I couldn't click "Like" and "Informative" at the same time.

Hi,

I'm an engineer at Teknic and came across this forum. @Dirty - Thanks for using Teknic motors and for sharing information about your build! I love your enthusiasm and the encouragement you offer to others.

I noticed some users (including @pmvcda and @Dirty) had some questions about different ClearPath families and control modes, so I wanted to help clarify the difference between ClearPath MC, SD, and SC series motors.

1a - MCVC (Motion Control with Velocity Control).

• This series was designed primarily for torque and velocity applications, (but includes two positioning modes as well).
• For most positioning applications, the MCPV or SDxx families are typically a better fit, but it really depends on the application.

1b - MCPV (Motion Control with Position and Velocity).

• This series has several positioning modes. A couple of MCPV modes I saw mentioned in this thread include:
  • Follow Digital Position - Real time position control through a PWM or variable frequency signal.
  • Pulse Burst Positioning - Lets you command moves by sending a high frequency burst of pulses where each pulse represents a small incremental distance.
• Pros: Unlimited positioning without expensive controller requirements (users don't need to time the step pulses as they would with Step & Dir models).
• Cons: Limited number of speed and acceleration settings and, as @Thanos mentioned, once a stream of pulses is sent to ClearPath, the servo will (necessarily) "play out" all steps before another move can begin.

2 - SD (Step & Direction) -

• This series is controlled via user-supplied Step and Direction or Quad A/B control signals, and offers the greatest flexibility in speed and acceleration control.
• If users are contouring/path following (like in a CNC machine), or they require the ability to change commands on the fly, this type of motor is a good option.

3 - SC (Software Control) -

• This series was designed primarily for point-to-point positioning moves and velocity moves.
• SC systems require the user to write software code, so that's one consideration to keep in mind.
• If you're not familiar with building software projects and/or coding C++ or C#, MC or SD motors may be a better choice.

Homing

@Thanos had a question about Teknic's Hard Stop Homing.

• Most of the ClearPath positioning modes (and all modes mentioned in this post) include Teknic's Hard Stop Homing feature.
• There's a relevant reference in the ClearPath User Manual that describes which modes support which homing features. It's Appendix G: "Homing Methods Listed By Operational Mode".

If you have any questions or want help with servo selection, please feel welcome to email us at Support@Teknic.com.

Aaron B. – Teknic Servo Systems Engineer

@Teknic_Servo ,

I was the one talking to Jon and referred him to this thread. I was under the impression that with the new "Follow Digital Position" mode, it would not complete it's previous command unless "Command Lock" was enabled. I'm hooking up my 56c size ClearPath tonight to the controller to do testing, but saw this and thought I could ask the question again. I was doing the testing through the MSP software and put the RPM's low and the end position count high (to make the 0-100% swing take a while) and then changed the slider, mid-operation, back down to ~20% pwm, and the motor did not complete the original motion. Is that "playing out" scenario not applicable to the Follow Digital Position command?

Dan

Thank you very much for joining this thread.

Having here a direct access to the manufacturer will for sure improve a lot the communication and will help finding the best choice for our application.

Being a lond time user of MCPV series, back than, we couldn’t sorte out the issues with the internal positioning mode.

Now it seems that the firmware update of the MCPV series and its new “follow position command” feature, will allow a much simpler interface, at least to the @Thanos controller.

Best

Ok, so I did confirm that the new MCPV firmware, using the Follow Digital Position Command does NOT have to "play out" any sequences. I did this by setting the RPM on the servo low (100rpm) and testing the limit buttons on the AMC1280USB. The AMC is set to 12bit PWM, absolute position. I set the start and end points to be a single revolution in each direction. I did the button presses to simulate "mid-movement" interrupts with new positions.

Excuse the basic video, but it should illustrate the point.



Hopefully this clears up how they can work with the AMC. Based on this, I'm going to be ordering 5 more motors

Dan

Simply amazing!!!

This is it man!

@hexpod

Here is running your software through a test sequence. @Thanos controller set to 12-bit PWM, absolute positioning. I'm limited to 1000rpm because of being hooked up to 110V (have to get 220V run still). 80:1 worm gear reduction, max position @240,000 counts.

I ran the servo through auto-tuning after hooked up to the gearbox.

This looks like it's going to work!



Dan

How many wires form the controller into the servo are needed?

It’s a custom AMC firmware or it’s running on the regular one?

What’s the exact model name of the motor?

Best.

Stock latest firmware, 2017 board.

Motor: CPM-MCPV-N0561P-RLN

MOTOR > AMC
---------------------------------------------------
Input B+ > 12-bit PWM pin 1
Enable+ > +5v (will eventually go through estop)
Enable-/Input B- > Ground

No homing setup yet, but likely going to set up homing switch that homes on startup.

So 4-wire hookup, technically 3 with grounds tied together.

I haven't been able to test the 34-size motor in the linear actuator application yet because I need to RMA my motor. I'm confident it will work.

Dan

Just be careful concerning the acceleration and torque of this motor. Especially in auto tune once loaded. It can be that you will have to limit it a bit or a lot ;-)

Those motors can accelerate like crazy. Just put a reasonable value in the settings.

Don’t go beyond the ultimate torque limit of your gearbox. No Idea what kind of payload and lever you plan to deal with. 14Nm is a huge force.

I don’t think the accel above 8000 rpmss will be needed.

Amazing

Do the big motors also have an extremely fragile usb connector like the 34 ??

Great job! I was wondering if anyone was going to try these new large clearpath servos!

Funny thing is just yesterday I got a plain step/dir AC servo to work using the same burst pulse code that exists in the AMC1280USB firmware since 2015 for clearpath servos...

Are you kidding me ?

What a great news - Congrats! To bad For my old DC servos. Obviously a simple software limitation in pulse burst mode. It could be so simple to skip the pulses on the direction change to drive the old MCPV ClearPaths.

@Teknic_Servo
Maybe a firmware update could allow it in the future ?