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5 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 ...
sempaiscuba's user avatar
  • 1,074
5 votes
Accepted

How can a coaxial stepper motor be used to drive the Z axis effector of a SCARA robot?

i found out that it is called an RZ tool ... google scara RZ tool there is a captive rotating "nut" on the threaded shaft that causes the shaft to move linearly ...
jsotola's user avatar
  • 570
5 votes
Accepted

Why do series elastic actuators have more accurate and stable force control?

Series elastic actuators tend to have more stable force control because the spring filters out the high-frequency motion of the mechanism. A low frequency in the system dynamics means that you can use ...
hauptmech's user avatar
  • 4,445
4 votes
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What types of actuators do these industrial bots use?

Actuation is a complex subject that cannot be reduces to 1 component alone. It is the interaction of software electronics and mechanics. "Toy" servos tend to incorporate everything in one small ...
50k4's user avatar
  • 6,682
3 votes
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Does MIT Cheetah uses Series Elastic Actuator?

It seems that the answer is that it doesn't actually use either of those designs. According to the paper Proprioceptive Actuator Design in the MIT Cheetah: Impact Mitigation and High-Bandwidth ...
sempaiscuba's user avatar
  • 1,074
3 votes
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What is an "actuation state"

after reading this ... there are mentions of task-space, state-space, configuration-space, etc https://www.researchgate.net/publication/...
jsotola's user avatar
  • 570
3 votes

What types of actuators do these industrial bots use?

A robot like the one you refer to probably has a mix of transmission types that increase in power-to-weight ratio and decrease in size and stiffness as you move outwards on the kinematic chain. The ...
DXM's user avatar
  • 106
3 votes
Accepted

What is the typical intro example for control systems for a spherical joint?

The best example I can think of would be the spherical pendulum. Albeit, this is not exactly the easiest thing to regulate as you have two degrees of freedom and a frictionless contact (well depending ...
DrMrstheMonarch's user avatar
3 votes

What are the pros and cons of Zip Chain Actuators in robotics?

The primary feature of a zip chain actuator is that it does not need extra depth to retract into. A standard linear actuator has a slider that will travel back behind the point of actuation. It will ...
Tully's user avatar
  • 25.1k
3 votes
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Is it worth designing your own components to mount a ball screw?

The general answer I would give anyone, working on any project, who asked this question: Should I buy commercially available, off-the-shelf (COTS) parts, or make my own? would be to always buy off-...
Chuck's user avatar
  • 16k
2 votes

How to get started on making a dispenser for Indian spices?

You should have a look at small screw conveyors. Either experimentally find out how much you have to turn for your spices or make a feedback loop with a scale.
FooTheBar's user avatar
  • 1,375
2 votes

Can't Read current on Pololu Dual MC33926 Motor Driver Shield for Arduino

I know this thread is old but it's high on Google results and I would like to clarify for anyone who stumbles upon it in the future an answer not yet listed: this chip is not designed to read current ...
athoesen's user avatar
2 votes

How can I turn a bowl/glass upside down?

Here's an idea Explanation Instead of the servo bearing the weight, there is an axis through the bowl that the servo is attached to. This takes all of the strain off of the servo. The servo arm is ...
iamPres's user avatar
  • 41
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 ...
nowox's user avatar
  • 121
2 votes
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State of the art trajectory for fine precision robots

For very high-precision applications such as finishing, milling by CNC machines, jerk-bounded trajectories (that is, trajectories comprising polynomials of degree 3 of higher) are often used. If you ...
Petch Puttichai's user avatar
2 votes

Control method of large linear actuator

The LAS3 actuator draws a current of 2.5 Amps @ 24Volts and has a DC motor, so the H-Bridge in the link can be used to control it. It is even a bit overdimensioned. You can link the Ardunio to the H ...
50k4's user avatar
  • 6,682
2 votes

Design a robot that can apply hot glue to paper

The problem I see is that after a while of holding the trigger, you have to let go of the trigger and then squeeze again. This is because the trigger has advanced the stick of glue as far as the ...
sa_leinad's user avatar
  • 207
2 votes

Controlling Actuated Robot Hand in Underactuated Manner

I don’t think underactuated is the proper term. You are trying to control multiple actuators with a single DOF. That is redundancy resolution. I have used the Simplex Method to compute stable ...
SteveO's user avatar
  • 4,396
2 votes
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Output power of an actuator - General definition

It reads to me like the author is stating that a stiffer material means it could make an actuator with more output power, which doesn't make a lot of sense to me. Maybe they mean a more efficient ...
Chuck's user avatar
  • 16k
2 votes
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Why Hydraulics and Not Motors?

Hydraulics and pneumatics let you separate the mechanical power generation component (compressor, hydraulic power unit, etc.) from the actuator. In the case of something like a robotic arm, this means ...
Chuck's user avatar
  • 16k
2 votes

What type of actuators are needed for a high accuracy, low load weight robotic arm?

Ask yourself if you really need accuracy or precision. Because I think precision is easier to achieve than accuracy for most arms. I am not sure I would be as worried about the actuator as the gear-...
Ben's user avatar
  • 5,865
2 votes
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Controlling motion of single link

I believe all of the above is correct, but if someone thinks otherwise I would welcome the correction. Yes, it's correct. The boundary conditions now include (I think) $\ddot{\theta} = 0$ at $t=0$ ...
JRTG's user avatar
  • 1,999
1 vote

What do the model numbers in Harmonic Drive gear drives represent?

It is the pitch diameter of the flex spline in inches/10. You can see it used it their equations for thrust force on the wave generator.
hauptmech's user avatar
  • 4,445
1 vote
Accepted

Potentiometer as pressure sensor in linear actuator?

Yes, you'll see the position become fairly stable when you've hit a rock (assuming that your bot is heavy enough to stall your actuator). Measuring current will also tell you if you've stalled/are ...
Kyler Laird's user avatar
1 vote

Are scissors what I want for moving straight up and out?

a robot that could get items out of the dishwasher and put them away This is an active research topic. Toyota has a whole division working on assistive robotics, close to Stanford in Palo Alto. It is ...
Jon Watte's user avatar
  • 720
1 vote
Accepted

Rotary Serial Elastic Actuator

For an arm with series elastic actuators I'm not aware of an open source design. There are many mechanisms you can find in research papers if you search for them. For force control you have a few ...
hauptmech's user avatar
  • 4,445
1 vote

Rotary Serial Elastic Actuator

There was a paper describing a rotary series elastic actuator for human-assistive systems in IEEE/ASME Transactions on Mechatronics, Vol. 17, No. 2 (April 2012). The paper included diagrams of the ...
sempaiscuba's user avatar
  • 1,074
1 vote

Replace screws with motors!

You are best off using the servo's horn/hub (the plastic or metal disk or arm that you attach to the servo), and screwing the arm to the hub. You get buy some larger horns for fairly cheap, and that ...
user3685427's user avatar
1 vote

Electronic Spring Vibrating Spheres

The term for the electrical component that actuated (vibrates) at a selectable frequency is "Piezoelectric actuator". You can also examine vibration motors, like in the mobile phones or in the ...
Gürkan Çetin's user avatar

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