21 votes

Effective ways to drive a single shaft with multiple motors?

While a mechanical differential does what you ask, you don't really need it. You can connect two identical electric motors together on the same shaft. There is no "slipping out of sync" because ...
  • 11.3k
21 votes

Effective ways to drive a single shaft with multiple motors?

A differential is a mechanical device designed to do exactly what you propose. It will allow the two motors to spin at slightly different rates while still combining the power. The most common use ...
9 votes
Accepted

Units for rotational impedance

Radians and unit analysis The comment by MrYouMath is correct. For the purposes of dimensional analysis, the radian is considered a dimensionless quantity and therefore does not need to be included. ...
7 votes
Accepted

Does any know what kind of pump "Colossus" used for saving the Notre Dame Cathedral?

This is not a definitve answer, but since I went to the trouble to look it up I thought i might as well post what I found: Pretty sure there's no onboard pump As you can see this is a normal firehose,...
  • 4,651
6 votes

Knowing how many times the rear wheels have rotated, and the angle of the front wheels at every time interval, how do I find the location of a car?

The main problem which I can see in your idea, that your system will have a cumulative error. Only calculating this won't be enough, you will have to find alternate solutions, too. In similar (but ...
  • 2,374
6 votes
Accepted

Knowing how many times the rear wheels have rotated, and the angle of the front wheels at every time interval, how do I find the location of a car?

Taking this in stages, initially lets consider only a single front wheel, with no slip in any direction, where we have an accurate continuous measure of both rotational position and absolute angle. In ...
  • 488
5 votes
Accepted

Are precision pneumatics possible?

While pneumatic systems can be controlled in a non-discrete manner as GisMofx mentioned, that is generally not the norm because the control system to achieve that movement is more expensive that ...
  • 7,499
4 votes

How do robots maintain stability?

PID, LQR, and LQG feedback control laws are only small pieces of the solution. Alone, these methods generally cannot solve the problem of balanced bipedal walking. The reason why is because these ...
  • 2,579
4 votes

How to design a vacuum climbing robot

You do not need full vacuum to accomplish your goal. A small amount of vacuum pressure adds up really quick over a large surface area. Try to make the entire footprint of your robot under vacuum; your ...
  • 7,499
4 votes

How to sense displacement without using any camera?

I can say using accelerometers to detect displacement won't work. These devices have so much of inherent noise that discerning very slow acceleration from remaining immobile is about impossible. You ...
  • 6,133
4 votes

Knowing how many times the rear wheels have rotated, and the angle of the front wheels at every time interval, how do I find the location of a car?

The correct way to do this is by using what is known as a particle filter. The maths for estimating your next position is quite simple and other answers have already provided that, but this is how ...
  • 5,960
4 votes
Accepted

Torque Problems vs Motor Problem?

The motors have a rated speed of 2750rpm. It doesn't look like there's much of a gear ratio, so at the moment the motors spin at the same speed as the wheels. With 16" wheels, 2750rpm is about ...
  • 156
3 votes

How to sense displacement without using any camera?

I think going optical is the only best solution. How about handheld interferometer? The reflection from interfoerometers are the best, as they give nanometer precision. If you could mount reflective ...
3 votes

Knowing how many times the rear wheels have rotated, and the angle of the front wheels at every time interval, how do I find the location of a car?

The basic equation would be $$\text{Distance traveled}=2 \pi r \times n$$ where $r$ is the radius of the wheel and $n$ is the number of revolutions of the wheel. This assumes, though, that there's no ...
  • 2,485
3 votes

Knowing how many times the rear wheels have rotated, and the angle of the front wheels at every time interval, how do I find the location of a car?

Knowing the diameter of the wheels and the number of times the wheels turn over in a time interval will give both distance travelled and average speed for that time interval. You would have to have a ...
  • 9,527
3 votes

How to design a vacuum climbing robot

An important point in the fluid dynamics design is about control points. A simple experiment - hold your hand over a hose on the vacuum cleaner, you'll notice a light vacuum pulling on it, but hold ...
  • 5,323
3 votes
Accepted

Artificial Intelligence in manufacturing machines

In general terms what you really want from CNC machines is to repeat the same actions exactly the same every time, while you may need to monitor and account for things like tool wear, temperature ...
  • 15.1k
3 votes

Are precision pneumatics possible?

Yes, it's possible. See here: Position Control of a Pneumatic Actuator and this youtube video here: Pneumatic Actuator With Position Control on YouTube Many solutions use a servo controlled ...
  • 1,578
3 votes

Can CO2 produce energy to drive a bot

Potentially yes. There are a lot of homemade toys which use a reaction between vinegar and bicarbonate of soda to make simple CO2 jet engines. However if you want to use this sort of reaction to ...
  • 15.1k
3 votes
Accepted

4 Gears in a Circular Pattern - Calculating the Proper Distances for Meshing

Let’s consider gears as being represented by a pitch circle on which lie several equally spaced dots with a number equal to the number of teeth. These dots can either represent the teeth or the gaps ...
  • 1,307
3 votes

How can I implement S-curve motion profile on mobile robotic platform / wheeled robot?

There are many ways to create a trajectory between two points using a sigmoid function. It's not a simple question, and the math is a little involved. Here's how I would do it. Short Answer You can ...
3 votes
Accepted

Small scale manufacturing

I believe the key here is not the material, but the manufacturing method. I would not recommend a small cnc machine, which seems to be what you're considering. Those are cool and fun, but you will ...
  • 1,663
3 votes

How can I calculate a robotic arm's maximum reach?

Total reach is usually the straight line length of each member added together, do work centre to centre. The manufacturer will specify the total load at a spcific configuration so check the detail.
  • 14.2k
2 votes

Steering wheel torque when car is turning

It heavily depends on the caster that the suspension is set at. Caster makes the wheels go back to neutral position. The more caster, the more torque is needed to keep the wheel at a position. Scrub ...
  • 1,164
2 votes
Accepted

DC brush geared motor: coast vs brake effects on motor/gearhead lifespan

The forces of breaking a motor by shorting its electrical connections are the same as starting the motor with full voltage applied. Actually, they'd only be the same in a ideal motor. In any real ...
  • 11.3k
2 votes

How do robots maintain stability?

The robot likely has a body accelerometer & integrates it to use a velocity tracking controller with some sort of explicit or implicit proportional & integral control for the body. - This ...
2 votes

How do robots maintain stability?

Clearly there are a lot of different potential solutions to this depending on the application and design approach. Also, as is clear from the video, bipedal robots are still a long way from achieving ...
  • 15.1k
2 votes

Strength of human hand compared to robot

I find I have to make a pretty large device to have anywhere near the same power as the human hand. Is the human hand, cubic centimeter for cubic centimeter just really strong compared to a machine? ...
  • 1,845

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