How big of a hurdle is inverse kinematics for a delta bot? This McWire successor costs $70 and can be made with several servo's, several hours, and virtually zero tooling: or the Festo iFab if you are looking for a bigger work envolope and prefer steppers:by JohnnyCooper - General
galaxyman7 Wrote: ------------------------------------------------------- > Unfortunately this is only for 2d lines, but since > it is a 3d printer that only prints 2d layers, it > is enough. > Now we combine this equation with the previous > equation for r > r= L1*cos(a) + L2*cos(a+b) > > to get a combined equation with theta, a, and B in > terms of x1, x2, y1, and y2by JohnnyCooper - Polar Machines, SCARA, Robot Arms
So I don't really know much about math or programming and the idea of "spline curves" is a little bit over my head. 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.(I once wrote a couple linesby JohnnyCooper - Polar Machines, SCARA, Robot Arms
Funny enough: is it possible the easiest way to program a robotic arm is to strap a clone of it with sensors in place of the actuators/motors to a CNC mill and use the output to drive the arm's tool path? In industry: I understand that they normally program the robotic arms using a "training" process where either the arm goes limp or each joint is remote controlled, and then the computer just coby JohnnyCooper - Polar Machines, SCARA, Robot Arms
This image came from the the "Personal Subs" mailing list. The folded steel design mirrors my throughts on the way to approach the situation drawing from backhoes for inspiration. In fact: toy excavators may be a good candidate for sourcing a ready built arm waiting for the attatchment of pnuematic cylinders. The arm pictured uses pnuematic cylinders filled with vegetable oil is my understandby JohnnyCooper - Polar Machines, SCARA, Robot Arms
This is the best DIY 3d scanner I've seen yet!by JohnnyCooper - 3D Scanners, Book Scanners, and Optics
The multiple tool head thing has been explored quite a bit in the world of CNC in terms of ATC(automatic tool changers) and CNC lathe turrets. Some of the quick change tailstocks they make for lathe's might interest you. Anyway, I agree that an enclosure filled with inert gas would be the way to go with any sort of metal welding. Strapping a MIG welder to a reprap might be a good way to get theby JohnnyCooper - General
There's a couple of options being explored. The most recent being the use of reprapped servo valves to distribute hydraulic pressure. For simplicity sake, it still may be advantageous to use a piston pump(paste extruder stylie) to directly drive individual syringes. One pump/linear actuator combo per syringe. The advantage of all them them over a mechanical linear drive is weight vs. grunt. Wiby JohnnyCooper - Polar Machines, SCARA, Robot Arms
I've been thinking about the Cyberdyne Hydraulic Control System. . The simplest solution is to use small diameter cylinders to directly drive large diameter cylinders. This reduction in diameter should result in an increase in control. Alternatively: the linear actuators which are used to drive the robot could be composed of two cylinders: -one large diameter for precision control -one small dby JohnnyCooper - Polar Machines, SCARA, Robot Arms
SebastienBailard Wrote: ------------------------------------------------------- > > I don't mind creating a new polar-bot forum. > Does 'Polar-bots and robot arms?' sound good? That sounds great, and thank you for the links as well. Reading through them now.by JohnnyCooper - Polar Machines, SCARA, Robot Arms
SebastienBailard Wrote: ------------------------------------------------------- > 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? > > We've got > > and it will take once people need to start > uploading pictures and parts files to iby JohnnyCooper - Polar Machines, SCARA, Robot Arms
BeagleFury Wrote: ------------------------------------------------------- > > 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 strateby JohnnyCooper - Polar Machines, SCARA, Robot Arms
Sent this to a Delta bot creator, thought it was worth mentioning in this thread as well. Quote Something you may be interested in is the blog post today on the "bowden paste extruder" which uses what seems to be two syringes as a hydraulic linkage to drive the paste. Incredibly light weight. Should be easy to affix to your delta bot as a competitor in the "Gada Prize Competition" If you could prby JohnnyCooper - Polar Machines, SCARA, Robot Arms
QuoteDelta robot By mjcbruin Copy mouse movement (for now) Cost to build: $70 Time to build: 10 hours * Actuators / output devices: 3 servo's * Control method: mouse * CPU: Arduino Decimila * Operating system: windows XP * Power source: USB, servo's by arduino * Programming language: Processing (java), Arduino Quote Arduino code #include SoftwareServo servo1;by JohnnyCooper - Delta Machines
The Bowden Paste extruder might be the way to go for the prototype. Speaking of light weight extruders: These delta bots are stupid easy to fabricate. You can make the structure from carbon fiber rod, and their universal joints can be made on a lathe with a radiusing tool and a ball end mill. Or: 2 hinges to get even simpler. They don't even have to be press fit. You can hold opposing joby JohnnyCooper - Polar Machines, SCARA, Robot Arms
Another option to consider for position feedback is a potentiometer, or magnetic rotary encoder. An infared camera at the end of the arm could maybe be used in combination with computer vision software and IR LEDS around the print bed to find position, although this may have lag issues. One nice thing about a polar bot like this is I can see it being used as a Coordinate Measuring MAchine. A 3Dby JohnnyCooper - Polar Machines, SCARA, Robot Arms
I tried to contribute as best I could but I'm not at the top of my game right now. I thing there should be overview/roadmap of the various blog trackers, vs. forums, vs. wikis. Don't have time to put it in right now.by JohnnyCooper - General
Convert? Aren't the .stl files already compatible? I ask because I don't know much about the various formats so I'm curious about the difference. I say: by all means they should be uploaded, and thank you for making the conversion. I guess it's ultimately the librarian's call? I've been slowly putting dimensions to the parts in solidworks so that machinists can make them from prints. If youby JohnnyCooper - General Mendel Topics
galaxyman7 Wrote: ------------------------------------------------------- > Ok, it looks like Johnny Cooper's team has already > thought of a dual rotating platform, which is > interesting, but I do not see any z axis movement > being very easy on that machine. The robotic arm > will have no linear slides, only rotation. Plus it > can rotate in a full circle, making parts anywheby JohnnyCooper - Polar Machines, SCARA, Robot Arms
I agree completely. My preference is hydraulics for such a project because they are low weight, although gear motors, and worm gears both have their merits. This was my first exposure to the idea. This is what I'm working on. Beagle fury is attacking the mathematics issue, as he's already got a set of hardware. EMC2 claims it supports robotic arms(as well as stewart platforms), howeverby JohnnyCooper - Polar Machines, SCARA, Robot Arms
This draywer slider design is great. Anyone with old cabinets to rip apart can build one.by JohnnyCooper - General
Great idea! I agree with your sentiment. Understanding the concepts in this article is 2/3 of the battle with robotics. I went ahead and added some stuff about stepper drivers vs. controllers because that distinction took me a long time to understand/understand that it exists so that I need to learn about it.by JohnnyCooper - General
Tim, I'm working on a set of injection molds as well. I've already written toolpaths for the following parts; FRAME-VERTEX_6OFF_3 X-180-BEARING-SET Y-MOTOR-BRACKET_1OFF_1 XLR-BRACKET_1OFF I'll keep you advised on my activities in this regard in the future as I tackle them. No sense in us flooding the markets with FRAME-VERTEX's losing money on our molds when nobody is making Y-IDLER-BRACKETS.by JohnnyCooper - For Sale
Is there any reason that a product such as the "T@2" from yamaha or other CD burners couldn't be used for this technology? I've done research on the subject in the past due to an interest in holograms, however it seems particularly relevant to the 3d printer community. Since normally the substrate spins, a spinning mirror or prism system would be necessary, however that's convenient as it meanby JohnnyCooper - Powder Printing and Selective Laser Sintering
How much attention has the micromark XY table gotten from the McWire community? You're looking at around $110 after shipping for a turn key positioning system requiring only a gantry, electronics, and an extruder to get up an running. Add a dremel and it doubles as CNC router which has potential for replacing some of the dependance on commercial lasercutting outfits.by JohnnyCooper - General
Opinions need a name next to them or they don't belong IMHO. If a conflict of interest exists between the person making the referral and the the benifitting party: it should be disclosed. If they chose not to do so: they expose themselves to the risk of being outted and shamed for astroturfing.by JohnnyCooper - Administration, Announcements, Policy
Good reason! Didn't think of that.by JohnnyCooper - General
I suspect the reasoning behind screw drive is familiarity with CNC equipment? Obviously there is more to it than that, however I would think that people would tend to stick with what they know if they aren't familiar with both.by JohnnyCooper - General
I've seen the airsoft bb idea recommended here multiple times, and although I think it's inspired, my contribution to it would be to switch to the steel BB's used for BB guns vs. airsoft. These bearings are at least as accurate, are of smaller size, are virtually the same price, and are capable of much higher loads. Since the surface finish necessary to print bearing quality plastic balls is aby JohnnyCooper - General
Ultimately: you could make a full time job out of it given a sufficient number of machines. Computer vision may have an application here. A part should fit within a boundry which can be superimposed over the video feed, and the print head should move in a predictable manner: EG IR LED.by JohnnyCooper - General