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General discussions. For specific printers / electronics / fabrication methods / softwares, please see other sections.
Re: Using GPL for hardware is a bad idea - 15 years ago
jbayless Wrote: ------------------------------------------------------- > Pardon me for the confusion... I definitely don't > want to limit distribution or construction of the > hardware. But, if someone makes an improved > hardware design that is based on ours, will the > GPL require them to release the documentation for > their improvements? As I understand the GPL, they woulby BeagleFury - Administration, Announcements, Policy
Re: Robotic arm printer - 15 years ago
The physical hardware is looking great. Good job. How were you planning on feeding the plastic to the extruder? Bowden extruder? I suspect you'll find, as I did, that software for these kinds of machines become the hardest challenge. In my opinion, this is a very good thing, because: - It is just as easy to give someone a copy of complicated software as it is to give them a copy of simple sby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Using GPL for hardware is a bad idea - 15 years ago
jbayless Wrote: > Anyway, the SpoolHead team was also planning to > release our work under the GPL when we're done our > project. I think it even said so in our project > proposal. But reading over this thread, maybe > that's not the best license for us? What we'd like > is to have an appropriate copyleft license for it. > BeagleFury, you seem to be quite knowledgeable >by BeagleFury - Administration, Announcements, Policy
Re: Velocity, Accelleration, and Jerk - 15 years ago
JohnnyCooper Wrote: ------------------------------------------------------- > - > needs-no-computer/ > > Is there anything that can be learned from these > guys? An ARM based microcontroller probably could produce reasonable speeds for computing polar paths assuming it had enough memory. I'm not sure to which it is you refer, however. I read thru the link, but didn't see anythiby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Using GPL for hardware is a bad idea - 15 years ago
"People often ask about the possibility of using the GNU GPL or some other kind of copyleft for hardware designs. Firmware such as programs for programmable logic devices or microcoded machines are software, and can be copylefted like any other software. For actual circuits, though, the matter is more complex. Circuits cannot be copylefted because they cannot be copyrighted. Definitions of ciby BeagleFury - Administration, Announcements, Policy
Re: Using GPL for hardware is a bad idea - 15 years ago
You can certainly take the GPL, and try to rework it; to do so could get very expensive unless you can find someone in the legal community to volunteer some time. Clinging to GPL because it's your favorite is sort of like clinging to your Pajamas, and wearing them to work, because, heck, they work so good in the bedroom, they must certainly be good enough for board room. As far as I can tell, nby BeagleFury - Administration, Announcements, Policy
Using GPL for hardware is a bad idea - 15 years ago
This is a continuation of a misconception between someone who took some hardware file documents, modified them, and then sold hardware. As noted in the Wikipedia article on open source hardware, there is a clear mismatch between GPL and hardware. First and foremost, the language in GPL and LGPL refer to software components, compiled executables, software artifacts, documentation, etc. Applyingby BeagleFury - Administration, Announcements, Policy
Velocity, Accelleration, and Jerk - 15 years ago
So I've come to terms that I probably will not solve the motion problem using polynomials and analytic techniques -- limiting velocity, acceleration, and jerk to a pre-specified set of limits; it feels I could do it given enough time and concentration, but I've not had the time nor concentration to focus on it outside of my other responsibilities. So, I will try a new tactic. Instead of: 1. sby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Software - 15 years ago
> When you say "splines", what do you mean? Usually, a cubic spline, but more generally, any polynomial spline to approximate the motion. > Are you going to use some kind of polynomial equation for each motor in order to simulate straight line motion? Sort of. Take a look at the curves I generated that trace out a particular 'build' on my builders blog for repola computations Those curby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Software - 15 years ago
JohnnyCooper Wrote: > Would it be possible for you guess on a scale from > 1 to 10 how close are you to having a functional > G&M code converter to control 2 DoF? 3? 4? 6? I'm > not even 100% sure that's the objective? I see > code and math and my eye's just kind of gloss > over. It's hard for me to judge. Not close for what I want, but very close if I didn't compensate foby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Software - 15 years ago
The solution I took was to use the closed form equations for the angles, get 4 positions an a target line for every motor involved in the equation (X, Y, Z, Extruder, possibly even Temperature and fan speed), and generate a parametric spline curve for each axis using the corresponding position from those 4 points. Then, sample the error on a set of points falling between the 4 points.. if errorby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Hydraulics System - 15 years ago
If I'm reading your ideas correctly, you would have a single high power pump to create a pressure reservior, and then direct flow to individual cylinders, correct? This reduces the overal cost/complexity because you replace individual motors with electronicly controlled valves..? One other possible branch would be to adapt something along the lines of the peristaltic pump to drive a larger boreby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Software - 15 years ago
> I do use a laptop to control the cnc. How is this different than using an Arduino to control it? Won't the program you are proposing also take up bandwidth, needing real time priority? I know the microcontroller gives feedback to the computer, but even then, bandwidth will affect how the machine performs by slowing down calculation times. Yes. It still requires real time responses, but thby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Power MOSFETs - 15 years ago
nophead Wrote: > No it isn't current flowing through the gate that > causes heating. When the MOSFET is off the current > is zero and when it is on the voltage is close to > zero, so in both states the power dissipated is > small. During the switching transition the MOSFET > is half on so has significant current and voltage, > hence a lot of power is dissipated for the time oby BeagleFury - Controllers
Re: Polar Software - 15 years ago
galaxyman7 Wrote: ------------------------------------------------------- > Isn't Mach 3 a real time program? I have a cnc > controlled by parallel port and it doesn't have > any problems with bandwidth. Why would this be any > different? I don't recall if Mach 3 has realtime extensions or not. Several multi-tasking operating systems do have real time extensions; however, some usersby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Power MOSFETs - 15 years ago
The other thing with MOSFETs is to try to pull them high as fast as possible; typically, you them driven at lower than threshold voltage, or higher than saturation voltage. The shorter amount of time spent dwelling between these two voltages, the less heat will be generated by current flowing thru the gate during the transations. Also, N Channel MOSFETs typically have about 1/3 resistance thanby BeagleFury - Controllers
Re: Polar Software - 15 years ago
galaxyman7 Wrote: > Do you have a reprap already so you can print one out? I do not. Part of my own goals include a simple and easy to build polar repstrap (I.E, RepOlaRap is primarily a repstrap, and secondarily, a reprap if things look advantageous when compared to Mendel.) In terms of your idea for firmware, you can certainly try something along the lines of an EMC2 RepRap. The biggestby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Software - 15 years ago
My current firmware assumes Arduino, using USB over Serial. I used standard Arduino libraries, which is part of the reason I use windowing and crc checking (Arduino serial comms drops packets under high throughput situations drops data, presumably because TX data does not use a ring buffer.) In terms of data format, I may eventually wrap transmitted packets with CRC and length markers too, to eby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Software - 15 years ago
I use a bytecode interpreter on the firmware side; it consists of the following registers: motionRegister - 32 bit controlID - 8 bit stepCount - 16 bit Bytecode instructions are coded as: 1xxxxxxx - shift motionRegister - motionRegister <<= 7; motionRegister |= xxxxxxx 01xxxxxx - set controlID = xxxxxx 001xxxxx - load motionRegister - motionRegister = xxxxx (sign extended) 0001xxyyby BeagleFury - Polar Machines, SCARA, Robot Arms
Polar topologies - 15 years ago
Wanted to throw out a thread that discusses the different topologies for polar bots. My discussions below assume that the printhead itself includes the same degrees of freedom as a corresponding cartesion bot (I.E, extruder rate and extruder temperature.) There are 5 total degrees of freedom for the physical orientation of a generic print head. One set of variables (cartesion) for describingby BeagleFury - Polar Machines, SCARA, Robot Arms
Polar Software - 15 years ago
I wanted to toss out for ideas for software. What I'm currently working on for software consists of microcontrol and host software. The microcontrol software basis uses cubic polynomial spline curves for each motor and control target position. - this code uses integer addition only. - uses a simplified generic 'controller' bytecode, for example, bytecodes for: * set control #A, parametby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Okay.. wiki is still a bit messy. I'm not quite sure where to start there. Here is the tool path that I see with my current strategy: 1. Model -> STL (leverage existing tool) 2. STL -> RepRap GCode (leverage existing tool) 3. GCode -> SplineCode (under development) 4. SplineCode -> FirmwareDriver (under development) I'll skip describing 1 and 2. For 3, I see two strategies: A nuby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
> Would sourceforge be the way to go? Seems like > you're developing kinematics > libraries/interpretters for EMC2. Is that off > base? Maybe -- I've not used sourceforge much. I'll see if I can compose what I've got into a rational description, and post it to the polar wiki page.by BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
> We've got > > and it will take once people need to start > uploading pictures and parts files to it. Actually, I was looking for something more suited to multi-person development and collaberation, and also, more general than for a specific robot. The strategy I'm employing does not care what the mapping functions are, be they arcos, exp, log, or whatever. It only requires theyby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: The Reprap's impact on the environment - 15 years ago
Nice work, Anton. Interesting read. It might also be interesting to include the aspects of 'cradle to cradle' lifecycle that reprap might encourage, where the only 'waste' is energy consumed. Material degraded beyond the point of being commercially viable may still be viable at a personal/individual level.by BeagleFury - General
Re: Polar Rep Rap - 15 years ago
galaxyman and I have sent a few pm's back and forth for collaberation. I think it would be great to create a blog/wiki/forum specific for discussion and collaberation, relating to the software needs for non-linear mechanics. Anyone want to volunteer? Given this, I will post all the details of what I've done so far in software, with details in terms of math and equations and strategy and approaby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
galaxyman7 Wrote: ------------------------------------------------------- > Wow, I just found a paper explaining the > mathematics of robotic arms! This is exactly what > I was looking for. I have attached it. It is in x, > y coordinates, which for me is r, z coordinates. > So I will still need to do some work on it. Law of cosine is awesome if you want to solve for angles given tby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Oh, and just looked at the linkage systems you propose. Would be interesting, but not sure how you'd get the stiffness needed without good bearings. In terms of model space, take the image I posted, cut a quadrant from it, and then rotate it around in 3D, and that should give you the topology for the rotating base, with a two link planar system for height and radius degree of freedom..by BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
galaxyman7 Wrote: -------------------------------------------------- > but I do not see any z axis > movement > being very easy on that machine. I've considered a polar z axis as well. Until I get everything in X and Y, I decided to table that work, since worst case, I could use a linear bearing and threaded rod drive for that stage -- there is no great need for speed. One problem I rby BeagleFury - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
You might want to check my Re(pOlaR)ap development, or even pitch in if you want. I've got moving XY, and am working on software to accelerate printing. I also have a few posts on the Builders blog, and a video showing simple drive motion on XY. My goals include creating an easy to build repstrap, and create a fully printable design as well to improve some areas (geared motors). The dual diskby BeagleFury - Polar Machines, SCARA, Robot Arms