Hot answers tagged

30 votes
Accepted

Robot never goes straight

I'm posting this as an answer because it is the answer. You can't. As @BendingUnit22 mentions, you are attempting "open loop" control. Noise and variations will mean that your robot will never ...
Chuck's user avatar
  • 16k
10 votes
Accepted

Simple equation to calculate needed motor torque

How quickly do you want to go from stopped to 10rpm? This will define your angular acceleration. Regarding calculations, first you should convert to standard units, so meters instead of centimeters ...
Chuck's user avatar
  • 16k
8 votes
Accepted

Harmonic drives in hobby projects

The core reason for choosing harmonic drives is desire for zero backlash. Moreover, regarding mass and size, they become more beneficial for higher gear ratios as their size and mass do not scale for ...
JJM Driessen's user avatar
7 votes

Motor Choice given size constraint and load requirement

If you have some budget for your project, both Maxon and Faulhaber have good DC motors and motor-gearhead combinations. Maxon publishes a nice set of formulas and background theory on electric motors....
hauptmech's user avatar
  • 4,385
7 votes
Accepted

Using brushless motors for very high torque

Your expectations are rather aggressive for a DC motor. First - 40Nm (350in-lbs) is A LOT of torque! Ex: A max rated torque for 1/4-20 bolt is only 75 in-lb (8.5Nm). Second - The mechanical power ...
markshancock's user avatar
6 votes

Robot never goes straight

Since the open-closed loop issue is already mentioned, I will give a comment to the "I once tried to run a dc-motor without a load". Yes you might damage your motor with this but you can also damage ...
TobiasK's user avatar
  • 1,657
6 votes

Motor Choice given size constraint and load requirement

20kg is a mass. It makes a force on Earth (20*9.81 = 196N), but that's not a torque. Motors make torque - what is your maximum torque specification? Once you know how much torque you need (that will ...
Chuck's user avatar
  • 16k
6 votes

What are some ways to estimate torque/load on a robotic arm joint

Model Based: Low cost solution is always software: Develop a dynamic model which computes the load on the motors based on the motions (e.g. with Recursive Newton Euler Algorithm or Lagrange-Euler ...
50k4's user avatar
  • 6,652
6 votes
Accepted

What is the difference between DC motor with encoder and DC with out encoder?

As @szczepan mentions, the difference is one of feedback. There are many ways to get feedback regarding the motion of a dc motor. People implementing a control system will often put a mark on the ...
SteveO's user avatar
  • 4,386
6 votes
Accepted

How much weight can DC Motor carry?

Well, to answer this question for your special case, one needs more information about the motors. Maybe, you can supply a product code. And one needs more details of the involved mechanics... is it a ...
SDwarfs's user avatar
  • 301
5 votes
Accepted

Length and Width of a Line Following Robot

Actually, the caster wheel has ideally no effect on the kinematics of the vehicle. In reality there will be some resistance from the caster wheel that does impact the vehicle motion, but we can still ...
Brian Lynch's user avatar
  • 1,377
5 votes
Accepted

Quadrature encoder signal from dc motor is very noisy

Conceptually everything was set up correctly, but a number of basic mistakes affected the signal. Here is the set-up which should be used to record the signal from one of the encoder outputs: A set ...
neuronet's user avatar
  • 233
5 votes
Accepted

Why to combine a Raspberry Pi (or similar board computer) and an Arduino for controlling motors?

The reason is Clock on the Raspberry Pi. Note that the raspberry is powerful but not that powerful that it can run an OS and simultaneously give you precisely timed PWM outputs. I assume that you'll ...
Kartik Madhira's user avatar
5 votes
Accepted

Equations of motion in matrix form and energy consumption

Can you set up the problem so that the quantities you care about (e.g. power) are more explicitly represented? Reasoning physically, where could the power go? Accelerating masses, including rotation ...
r-bryan's user avatar
  • 1,271
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 ...
Jim's user avatar
  • 314
4 votes
Accepted

Which USB interface for Android device I can use for motor driver

What you want cannot be simply done by using an Android device and a USB cable. You will need a micro controller to process the instruction sent from your mobile device and then control the motor ...
Parthiv P's user avatar
4 votes
Accepted

DC Motor to open a door

While there are other H-bridges that handle higher current and it might be cost-effective to just buy a higher-amperage pre-packaged ESC (electronic speed controller), you might also consider using ...
James Waldby - jwpat7's user avatar
4 votes

Relationship between motor torque and acceleration

1) but the more torque, the faster the robot's acceleration: YES $$ F=\frac{Torque}{wheelradius} $$ and robot's acceleration is $$ a=\frac{F}{m} $$ so, from that equation you can see that linear ...
galtor's user avatar
  • 470
4 votes
Accepted

Relationship between motor torque and acceleration

Based on the calculations, it seems that any amount of torque can get the robot moving That is true only for a theoretical robot moving in vacuum without any friction in its mechanisms. Normally if ...
mactro's user avatar
  • 953
4 votes
Accepted

Can too much input current destroy my motor driver?

You are approaching the problem from wrong side. Current capability of a battery (25C) has nothing to do with that how much current will it actually source. It is the load (motors in that case) what ...
mactro's user avatar
  • 953
4 votes

Question about what motor to use for opening window

The other answers advocate the use of stepper motors. They can be easy to control by just sending a certain number of pulses to the stepper controller. However, they do not guarantee that you will ...
SteveO's user avatar
  • 4,386
4 votes
Accepted

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
  • 6,652
4 votes
Accepted

Need super-basic help with motor encoder

The "Green (Ground), Brown (Channel B), Yellow (Channel A), and Orange (Sensor Voltage +)" wires connect to the encoder on the back of the motor and allow the use of quadrature to detect the number ...
James Waldby - jwpat7's user avatar
4 votes

What is the torque/force required to rotate the base of a robot arm?

You need enough torque to overcome friction, and to accelerate the load. If you know the friction torque ($\tau_f$), and the mass moment of inertia along the motor axis ($I$), then the minimum motor ...
Christo's user avatar
  • 385
4 votes

Should I use an arduino to control my balancing robot's motors?

If you want to have a good balancing, PID loop timing is very important. Standard Raspberry OS, like Raspbian can't guarantee you any precise timing, so once your loop period may be 10ms, once it can ...
mactro's user avatar
  • 953
4 votes

What are the equations of a s-curve position path?

The S-Curve profile can have several divisions along the time axis 7 divisions as per this image. This example has a constant positive jerk zone, a constant acceleration zone, a constant negative ...
Akshay Kumar's user avatar
4 votes

No electric motors can handle being stalled for even short periods of time, even at low power. Is this statement true in all cases?

Electric motors designed for stall torque can handle stall torque just fine. One giveaway sign of high stall torque motors is forced cooling (cooling with a powered fan and not just a fan mounted ...
50k4's user avatar
  • 6,652
4 votes

Impact of using PID Output as a Change (Delta) vs Absolute

All PID controllers are relative in the sense that they act on a reference error, which is the difference between the reference signal and the sensed signal. Assuming the integral error starts at the ...
Chuck's user avatar
  • 16k
4 votes
Accepted

Will increasing voltage on brushless DC motor increase torque, if speed is kept constant?

It depends on various other factors as well. If the motor outputs 60RPM @24V under load, given the motor is rated for 12V - 60V and the load is kept the same, then by doubling the voltage from 24V to ...
S10's user avatar
  • 71
3 votes

How can I increase the resolution of a PWM signal?

You won't ever get 'exactly' 2042.8878 RPM, so going with your measurement accuracy I will assume you mean 2042.8878 +/- 0.0005 RPM. This is approximately an error of 1 part in 4 million. So let's ...
Pete Kirkham's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible