Servo Motor Controller

efly

Recently I would like to design a robot arm (~human size), however, the hobby servo is not enough to support the total weight, is that possible I can buy some “high torque industry servo” then connect to PSC? (Refer to below photo)
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On the other hand, I am curious to know what kind of motor (Servo, DC, air/hydraulic piston etc&#8230[noparse];)[/noparse] for Japanese robot (such as ASIMO) in order to control its arm/joints moment, for my opinion, it is quite similar to industry robot arm, did any robot builder have any idea?
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Appreciate if someone can reply. Many Thanks!

Mike Green

The PSC will only work with hobby servo motors that respond to 1-2ms logic level pulses that repeat about 50/second and are used to set the servo position or speed and direction. The pictures you have shown appear to be of DC motors with/without gearboxes. These require a high power driver (like the Parallax HB-25) and a position encoder along with a controller that handles the encoder and keeps track of the position and/or speed of the motor. Alternatively, you can use a stepper motor, probably with a gearbox, and a driver for the stepper motor (like: http://www.parallax.com/detail.asp?product_id=27938). You'll still need some kind of position sensor for recalibrating the stepper motor's position periodically.

There are some higher torque servos sold by CrustCrawler, but these use a non-standard communication protocol that would not work with the Stamps. It could work with the SX or Propeller processors. They sell their own controller, but I believe it's designed to connect to a PC rather than a controller like the Stamp.

efly

Dear all,
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I just found some powerful “12~24V Gear DC motor” (torque definitely higher than hobby servo), so that I may use this to instead the servo in order to control my robot arm. However, as I look through parallax product such as motor mind, HB-25, PWMPAL etc, there are only able to control max two DC motors in the same time, but my project need at least 16-axis (mean 16 motors), so is that possible I can buy 16 motor mind and link all together to one basic stamp BOE?
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Or else do some of you have better suggestion? ·Servo amplifier etc, I really lack of knowledge in motion control field….
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My problem:· Looking for DC/Servo motor controller that able to control my robot arm (min 16 channels).
···················· Weight of·robotic arm: 1kg
···················· Length of robotic arm : 60cm (As fully extend)
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Appreciate if you have any good advice.····

kelvin james

I think for ease of use, assembly and price, you would be better off with the PSC which can run 16 servos > up to 32 with 2 boards, and some geared servos. Geared servos can push a lot of weight, more than what your arm requires. Plus you have built in position sensing with a servo, going the dc route is going to be complicated and expensive to achieve the same thing. Geared servos are not cheap, but you may only need them for load bearing joints, regular servos may work fine for a gripper, it depends on the weight you want the arm to handle. I would try and keep your number of joint axis to a minimum, as a servo has pretty good position accuracy, it is not perfect. So a small error in positioning gets multiplied by every axis.

kelvin

www.servocity.com/html/servo_power_gearboxes.html

willy1067

What ever happen to this project?

I am still working on my's

·http://forums.parallax.com/showthread.php?p=641010

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Fernando Gomez

revinc.us
gomez-rivera.com

Never compare yourself with anyone else, there will always be someone bigger·or·smaller·than you.