8 votes
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Can I control more than 18 servo motor with a Raspberry Pi

Raspberry Pi has only one hardware PWM channel and Linux distribution it runs is not a real time system, so software PWM may be very unstable. You are not guaranteed, that your program will be ...
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  • 953
7 votes
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For robot wheel control : Brushless DC motor or Servo Motor?

Let's try and clear things up a little bit... "RC Servo" motors These can be found in radio controlled cars and airplanes to e.g. turn the wheel or actuate various controls in the airplane. They ...
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  • 1,080
7 votes
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Servo horn dimensions - What is 25T?

The T indicates the number of teeth or ridges in the servo spline. You need to match the servo spline to any device splines or they won't mate. :EDIT: Because it's ...
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6 votes

What are the calculations for a badminton robot and mechanisms?

In short, what you are trying to do is well beyond the capabilities of top robotics research labs. That said, here is a short list of general areas you need to look into: Robotic arm dynamics (to ...
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  • 2,679
5 votes
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Measure weight of an object using a servo

This is going to depend on the style of motor in the servo and the style of gearbox. If the servo can't be back-driven when unpowered, then it's likely some form of a worm gear assembly that will ...
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5 votes

What kind of motors do industrial robot have?

Most industrial robot have servo motors. This allows you to control velocity, torque and position of motors - the latter usually in some form of closed-loop control system. I work for Stäubli. Our ...
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  • 249
4 votes

Can I control more than 18 servo motor with a Raspberry Pi

You need a controller like this that can address them individually over I2C. These can be chained together to control more than you'll likely ever need: Adafruit 16-Channel 12-bit PWM/Servo Driver - ...
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4 votes

What servos are suitable for a robot like Boston Dynamics’ Atlas?

The Boston Dynamics’ Atlas robot doesn't actually use servo motors. It uses electrically-powered hydraulic actuation. I saw a presentation by Boston Dynamics' Marc Raibert where (if I remember ...
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  • 1,009
3 votes

Should the therotical parameters match the physical setup constraints when modeling a robot?

If your computed torques are out of the range for your robot, then you are no longer modelling your robot but a different one. You can ignore the torque limits as good as the joint angle limits of ...
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  • 1,335
3 votes
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Controlling digital servos

Digital servos accept the same pulse width and pulse repetition rate as regular analog servos. a b With many RC servos -- both digital and analog -- as long as the "frame rate" (how many times per ...
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  • 4,385
3 votes

Powering 6 servomotors requiring 6V and 2A each

Search aliexpress for '6V switching power supply'. You should find 5Amp or 10Amp ones for $10-$20. Silver boxes with holes in them. You can find them on ebay as well (usually the same chinese vendors ...
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  • 4,235
3 votes

Lifting robotic leg with only one servo

Going forward, a Klann linkage has a near-vertical leg drop action. (See the legs at left in the wikipedia animated GIF.) It has a near-vertical leg lift action if running in reverse. (See the legs ...
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3 votes

Can we simulate a actuator with a very strong torque with a PID controller

What you're asking for cannot be accomplished with a PID controller. As I understand your question, you want to be able to choose PID gains that would always produce a "good" trajectory, ...
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3 votes
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Steering using different speeds in DC motors or using a servo?

I have been working on upgrading an autonomous robot as part of a university project for the past year. As part of my work I have been switching the old skid steering system to a new active steering ...
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  • 121
3 votes

Which kind of motors and how powerfull should they be for a robotic arm

This type of question "how much torque does my robot arm need" has been answered many times on this site: Simple equation to calculate needed motor torque Design and construction of universal robotic ...
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3 votes
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2DOF arm with quick movement: Stepper, servo, or DC motor?

Servo mechanisms are not the "popular" RC-Servos (not-only). Servo is a closed-loop control, not only for motors. Even Steppers could or not be servo-motors. RC-servos are in major cases a DC brushed ...
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3 votes
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How to calculate the right needed Power?

The maximum (or required) torque alone is not enough for sizing a motor, it is one of the factors. Motor maximum (sometimes refereed to as peak) torque differs from nominal torque. The maximum ...
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3 votes
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Servo Starts Oscillating Under Disturbance

I can add one more point to RowanP's excellent list: the servo's PID is unreliable, not because of a defect, but because it is mistuned for your application. Recall that tuning a PID control is arcane,...
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  • 1,136
2 votes

Electronic Speed Control Concepts

First a little warning: This answer is one big AFAIK. I have some limited experience with RC electronics and don't know anything about industrial servos, and other simillar stuff :-) BLDC motors (...
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2 votes

How do I control a servo using a beaglebone black running ubuntu

It's python but easy to install: https://learn.adafruit.com/setting-up-io-python-library-on-beaglebone-black/pwm. Otherwise you can fopen files in the device tree and write to them, or you can open /...
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  • 217
2 votes

Building industrial-like robotic arm

A machinedesign.com article, “Exclusive interview: Gill Pratt on how compliant actuators revolutionized robotics”, includes a close-up picture of an SEA (series elastic actuator) mechanism developed ...
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2 votes

Building industrial-like robotic arm

A series elastic actuator is really just a motor/gearbox with passive compliance built in (hence the spring). A google search finds http://ihmc.us/groups/sea/ (with links to some specs and ...
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2 votes

Finding a light load high precision servo motor

Since you didn't state your accuracy requirements in terms of degrees, I assume you want it to be accurate enough to the eye. Pretty much any RC servo motor will do the job. These can easily support ...
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2 votes
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Lifting robotic leg with only one servo

The linkages suggested by jwpat7 are great, and I would probably prefer to use something like that. But, if you want something really simple, then you might be able to get away with a four-bar linkage ...
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  • 1,357
2 votes

Steering using different speeds in DC motors or using a servo?

Automotive style steering can actually be simple. The conventional car has just one motor that powers two rear non-steering wheels through a differential. The differential solves the problem of how ...
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2 votes

Granite devices IONI servo drive

Although the Analog setpoint resolution isn't documented on the Granite Devices Wiki, the ADC in IONI is 12 bits.
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2 votes

How to test how much current 9 servos can draw at a time?

I assume that all the servos are identical, so it is enough to measure only one, and multiply the result by 9. The best would be if you could use a lab bench variable power supply, like this. With one ...
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2 votes

How to power this servomotor?

No. If there is no {installation, electrical, maintenance, etc} manual/description etc. (and maybe add also quality certificate also here) it is not fair to assume anything. Buying something without ...
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  • 6,437
2 votes
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Calculating screw breakaway torque

You can approximate the breakaway torque by considering static friction only. From the static friction coefficient of the lead screw (by knowing the maximum load on the spindle, coming from the ...
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  • 6,437
2 votes

How to calculate battery size for servo motors?

This typically requires a bit of testing with your actual payload. You can try to model it mathematically, but it's easier and more accurate to just plug it in and measure the current draw. Current ...
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