Control a custom robot

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Thread Starter

Penko Mitev

Hello everybody!

We constructed our own SCARA robot for internal company purposes. As for mechanics, everything is ready. However, we still have not decided how are we going to control the unit.

The specifications are:
axis X - 200 W, 0.64 Nm servo with brake, absolute encoder
axis Y - 100 W, 0.32 Nm servo with brake, absolute encoder
Servo drives(it can be 2-axis one or two separate ones)
- Because it's a robot, there must be interpolation between the two axes. PLC or PC-based control over the two servo drives + some additional I/O.

I asked for quotes from different well-known brands such as Beckhoff and Mitsubishi, but the price for control compared to the expenses for building the mechanics is several times higher. The problem derives from the amount of redundant features of the equipment. For example, we were offered a Motion Controller capable of controlling up to 16 axes and at the same time we need just two and so on.

What we are looking for is a low-cost solution for controlling the unit. Because I do not have experience with some brands, that's why I am asking if anyone could suggest a brand manufacturer. It can be a manufacturer from anywhere in the world, well-known or not so popular.

Thank you in advance!
 
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bob peterson

A lot depends on the performance you need.

How much money do you have to spend and what are your requirements, performance wise.

--
Bob
 
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William Sturm

I would suggest a PC based system with a motion card such as a Delta Tau PMAC1 or a Galil DMC. It is hard to find a decent PLC based motion system for a reasonable price. Baldor or Trio controllers would be decent choices also, they may a little easier to program than the first two options. PMAC would be MY first choice, but I am familiar with them.

Bill Sturm
 
Better way vs. PLC is motion controller. Than Dual axes DMC controller with build-in servo amps from Galil maybe good choice for you. Simply programming, 2D interpolation and build-in I/Os with extension option - this is exactly you need.
 
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Ken Emmons Jr.

The axes should probably not be called X and Y on a scara, although it is arbitrary it is confusing with regard to cartesian coordinate systems.

I would recommend getting a contoller that can handle the coordinate system transformations from the scara to cartesian unless you are simply going from a handfull of taught points and don't care what the motion looks like in between (i.e. simple pick and place).

Delta Tau is one of the premier motion control vendors. I believe they have a 4 axis PC104 card that can be used standalone and won't break the bank. They also have other packages options. You can use anyone that can digest analog servo interface, which includes Yaskawa, Mitsubishi, Sanyo Denki, Panasonic... Just about anyone. As Bill suggested you can also buy a PCI version of the card if you want to use a PC along with it for HMI or otherwise. I'd probably use a standalone embedded HMI with Modbus (Red Lion, Maple systems, etc) unless your data input and reporting needs a PC.

KEJR
 
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