New 6-axis Double-Closed-Loop Controller?

[brccrb]

I had an old milling machine that wouldn't do what I wanted it to do. I just wanted it to run as fast as possible without making any mistakes the first and every time (isn't that what everyone wants? . Being a nerd with, uh, some interesting history, a solution was built (don't ask why ... because it seemed needed).

Leaving out all the cool nerd stuff, it now does what I want when I want (minus breaking the laws of physics). A friend was impressed with the solution and suggested it would make a great product.

I'm more nerd than CNC guy and don't know everything that is out there. I am looking for opinions if this product might draw interest before dedicating more resources to it.

Specs:
********
Name: CNCBrain
Retail: $499
Axis: 6
Interface: Windows via the USB port. Supports user defined VB script commands.
Software: Windows form application.
SDK: Yes. COM object. Don't like the GUI, build what you like in whatever language suits you.
Device: High-Speed USB to hardware massively parellel processor motion control.
Ports:
1 - 25pin D - sensors, motors, switches, etc..
14 - 9pin D - Linear scales (X1, X2, Y, Z1, Z2 ... some have two that add together), Rotary scales (A, B, C), Motor rotary encoders (X,Y,Z,A,B,C ... for double-closed loop).
Modes: (each axis can be any of the following)
Direct - No sensors, only theoretical control.
Closed - Uses linear or rotary encoder for feedback control. Auto corrects on error.
Double-Closed - Uses rotary encoder on motor along with Closed loop sensors to profile errors before they occur.
Spindle Control: PWM out. Sensor in. Direction Out. Power Out. VB Script optional.
Touch Probes: 1 NC, 1 NO. Save file output. One for touch probe, the other for tool height measurement.

Other Features:
********
Automatic Path Correction: In Closed Loop or Double-Closed Loop errors or pre-errors, paths are automatically recalculated. Basically, if you want, the machine doesn't stop because something didn't go as planned.
Double-Closed-Loop: This mode is a proactive mode. By watching the motors, the entire system can be adjusted for pre-error conditions.
Spindle scale: This lets the table motion to be matched to the spindle speed. If the spindle slows down, the table speed is scaled to match the spindle. Think of it as a "bit saver".
AutoHold: Even if an axis isn't in motion, the system will correct (when possible) for drift.
Watchdog: You can set "normal" behavior. Such as the spindle range, etc. which if invalidated, can trigger a "Panic" state to shut the machine down. This isn't intended for unattended operation, but things tend to go wrong when you are a few steps away.

Photo:


Funny note:
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Once during a 4-axis run, a backlash spring broke. This introduced into the machine a 1/4" slop along the Y-axis. The run completed, but I didn't even notice the spring until I went to unload the machine. I leaned against it and it moved. I got out the calipers and the part was perfect. It was a full 4-axis run with 3-axis machining at 0, 90, 180, and 270 deg.


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So, are there others out there with "less than perfect" machines that could use the double-closed-loop feedback for the price?

If I'm waisting my time, then thanks. If there is interest, I'll take out an ad on this site and we'll see where it goes.

Your thoughts are appreciated.

Regards,
Bruce

[cueshark]

if this would work with mach i imagine there would be a lot of interest. greg

[brccrb]

Mach support would be up to Art. For him, it should be quite easy since the SDK has a COM object he could just drop in (he's done much more complicated stuff for sure).

A decent GUI would come with the controller. So you wouldn't need another piece of software. But Art has done a great job on Mach.

Thanks for the input!

[MrWild]

How are the drives operated? PWM, analog, or step/direction?

[cnc-it]

Hi Bruce
This looks very promising .
The Pc controlled cnc machine is becoming more and more popular especially as a way of bringing a good machine with old equipment back up to date.

Will it work with any type of drive/servo.

What is the maximum encoder resolution that can be handled..

Any reason for choosing USB over firewire..?

Will it do 5 axis symultaneous machining with the right cadcam package.

Cheers
John.

[turmite]

Bruce I would be very interested in one but I would like to see a video and know about warranty etc? There is a new system coming out for the Mach system called smooth stepper that will sell for less money, but I am not sure it is going to have closed loop feedback, or at least with correction.

What about i/o's? Can this be interfaced with plc's and other hardware?

Mike

[cncservices]

As a retrofitter, I'm interested. Add me to update list please.

Jim

[brccrb]

Guys, I really appreciate your input and questions. Your experience and wisdom means alot.

I'll try to get a website up with more specs and some videos soon.

Answers to Questions:
1) Step/Direction at the moment. It can be configured for PWM, but I've not done that yet (except for the spindle control). But there is PLENTY of processing room left on the board.

2) Max Encoder Resolution. Great question. Internally (this is kinda weird), it is variable bit math, so in theory, there is no limit. I need to see what it is set for at the moment.

On the linear, I've tested 5 micron, but it was designed for the 0.5micron (just in case). On the rotary, it currently has been test at 4000 steps/turn for the motors (it can handle more, just not tested it).

3) PLCs and other hardware? I don't see why not. It has plenty of pins available. I wasn't sure what in all it was going to run when finished, so it was designed with OEM in mind.

Actually, there is the main board (with the goodies) and a separate breakout board. So, we could either make separate breakout boards with different plugs or it could be used in an OEM configuration.

4) Yes, 5 and 6 axis simultaneous. Currently, I run mostly 4 axis. Design in Rhino (flowing curves and simple interface). Convert to 3D with MadCam (been with it since 1.0 ... Beta MadCam does 4 axis). Most of the time, I position the part in Rhino at (0,0,0) matching the machine, then run 3axis cuts, then rotate as needed (inserting rotation tags), then 3axis cuts.

For 5 and 6 axis, I've only ran in testing, but the logic is identical to 4 axis.

5) USB over Firewire. Well, I had already designed the USB 2.0 interface with drivers. And I had designed the processing core separately. So, when designing the CNC Brain, I "borrowed" my other designs.

The instructions are carried out on the controller board, so the communication is quite simple. More house keeping. The controller caches hundreds of G-Code commands. Either is overkill.

Generally, between the PC and the controller, it can sustain 30MBytes/sec (actual tested throughput, not theoretical).

6) Warranty. I was planning on 6 months.

7) Wasn't asked, but thought I would throw it in. For the SDK, I'm including the source code for the default GUI (C# .Net ... yeah, I know, but a lot of people like it). That way, if you want your own, you don't have to start from scratch.

I hope this answered the questions. If not, I'll try again.

If you have more, please don't hesitate to ask.

Thanks! bruce

[JerryFlyGuy]

Bruce, can you tell us a bit more about how it's all connected w/ encoders and the drives? Would you route the encoder lines to the 'brain' and then somehow send that in duplicate over to the drive or?

By the look's of it, a guy might get pretty good at soldering DB plugs!

Have you contacted Brian or Art over at Artsoft? I'd like to hear if there is the possibility of them building a plug-in for this.. it sounds like the perfect fit..

Jerry

[ger21]

Since Art has retired, he probably won't do it, and Brian seems to already have too much on his plate. That's if it's even possible to do with mach. I have a feeling it may not be, due to the way Mach works internally.

[maquiza]

I am also interested!!!

[turmite]

Bruce check your pm's!

Mike