8
votes
Accepted
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 ...
- 963
8
votes
Accepted
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 ...
- 15.7k
5
votes
Accepted
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 ...
- 15.7k
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 ...
- 314
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 - ...
- 236
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 ...
- 1,029
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, ...
- 218
3
votes
Accepted
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 ...
- 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 ...
Ben♦
- 5,780
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 ...
- 1,345
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 ...
- 1,981
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 ...
- 4,335
3
votes
Accepted
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 ...
3
votes
Accepted
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 ...
- 6,612
3
votes
Accepted
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,...
- 1,236
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 /...
- 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 ...
- 1,981
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 ...
- 1,031
2
votes
Accepted
Why does it require more force to turn a servo if it is electronically connected to another servo?
The other servo, being an electrical device, has some finite resistance.
When the servos are not electrically connected, the output of the manually turned servo is an open circuit, meaning that ...
- 15.7k
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.
2
votes
Accepted
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 ...
- 1,377
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 ...
- 446
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 ...
- 633
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 ...
- 6,612
2
votes
Accepted
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 ...
- 6,612
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 ...
- 597
2
votes
Which motors are used in boston spot robot
I had the chance to play with Spot this afternoon and it is not hydraulic.
I bet for a stepper motor with cycloidal gears and position encoders. But I not really sure which kind of motor. They didn't ...
- 121
2
votes
Mounting on servo horn
While all sorts of things get used in experiments, screws really intended to tap into plastic have larger more aggressive threads than those intended to go into a pre-tapped hole in a harder material ...
- 121
2
votes
Why are some motor shafts stiff while others spin freely when not powered?
IMHO it depends on two factors:
if there is gear on the servo (so to motor rotates fast, the result is slow precise motion with high force), then moving it manually even little means to rotate the ...
- 453
2
votes
How to program a continuous servo motor? (Arduino)
I believe by continuous rotation servo you mean servos similar to TowerPro MG-995 or Winch Servo HS-785HB.
For such servo, the normal Arduino code for servo motors won't work.
You have to define
<...
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