Robotics Stack Exchange
Robotics Stack Exchange

Most Popular

more tags
1500 questions
91
votes
4 answers

Why are Mars rovers so slow?

Mars rovers are typically very slow. Curiosity, for example, has average speed of about 30 meters per hour. Why is it designed so slow? Is it because of some specific power restrictions or for other reasons? What is the top reason why it is so slow?
sharptooth
  • 1,191
  • 1
  • 8
  • 7
81
votes
9 answers

What are good strategies for tuning PID loops?

Tuning controller gains can be difficult, what general strategies work well to get a stable system that converges to the right solution?
Felix
  • 1,327
  • 2
  • 12
  • 12
70
votes
5 answers

Why do I need a Kalman filter?

I am designing an unmanned aerial vehicle, which will include several types of sensors: 3-axis accelerometer 3-axis gyroscope 3-axis magnetometer horizon sensor GPS downward facing ultrasound. A friend of mine told me that I will need to put…
Rocketmagnet
  • 6,457
  • 5
  • 29
  • 54
60
votes
2 answers

Why are capacitors added to motors (in parallel); what is their purpose?

I've seen many motors having capacitors attached in parallel in bots. Apparently, this is for the "safety" of the motor. As I understand it, all these will do is smoothen any fluctuations--and I doubt that fluctuations can have any adverse effects…
Manishearth
  • 1,833
  • 2
  • 21
  • 28
44
votes
4 answers

What is stall current and free current of motors?

What are the stall and free currents of an electric motor? For example, this Vex motor lists its stall and free currents at the bottom of the page. I think I understand the general idea, but a detailed description would be helpful.
golmschenk
  • 1,564
  • 3
  • 16
  • 25
44
votes
11 answers

Programming Robots with JavaScript

As somebody who is spending the majority of his time programming in JavaScript, what's the best route to get into small-robotics without needing to deviate too much from my current language focus? Are there any project kits or tools that make use of…
Sampson
  • 681
  • 6
  • 6
44
votes
2 answers

How to choose the right propeller/motor combination for a quadcopter?

There are many sites which explain briefly this problem and even propose combinations. I however would like a much more detailed explanation. What is going to give my quad the most agility? Do I need bigger motors/props in a heavy quad to achieve…
klonq
  • 543
  • 1
  • 4
  • 6
43
votes
4 answers

What is the difference between Kinect for Windows and Kinect for XBox?

As I see there is a huge price gap between the two \$223 vs \$99 (at amazon). My intention is to use one of those from Ubuntu linux to perform depth sensing, navigation etc. and naturally I prefer the cheaper. However I am not sure if I miss some…
rics
  • 846
  • 1
  • 6
  • 9
39
votes
11 answers

Preventing leaks in motor shafts for underwater bots

Whenever building an aquatic bot, we always have to take care to prevent leakages, for obvious reasons. Now, holes for wires can be made watertight easily--but what about motors? We can easily seal the casing in place (and fill in any holes in the…
Manishearth
  • 1,833
  • 2
  • 21
  • 28
37
votes
4 answers

Quadcopter liPo battery weight/capacity trade off

I'm trying to find where additional battery capacity becomes worthless in relation to the added weight in terms of a quadcopter. Currently with a 5500 mAh battery, 11.1V, I can get between 12 minutes and 12:30 flight time out of it. My question,…
Chris
  • 1,005
  • 1
  • 10
  • 17
33
votes
2 answers

How to fuse linear and angular data from sensors?

My team and I are setting up an outdoor robot that has encoders, a commercial-grade IMU, and GPS sensor. The robot has a basic tank drive, so the encoders sufficiently supply ticks from the left and right wheels. The IMU gives roll, pitch, yaw, and…
Robz
  • 2,162
  • 4
  • 22
  • 28
32
votes
1 answer

Why are Servo Motors so noisy?

I was working on a project to make a bedside night light out of a stuffed butterfly or bird. I was making a mechanism to make the wings flap with a servo motor and some small gears. The servo motor was very loud as it moved. And this was whether or…
Michael
  • 423
  • 4
  • 5
32
votes
6 answers

Which type of actuator will be suitable for a very strong robot arm?

I wish to build a robotic arm that can lift a useful amount of weight (such as 3-6 kg on an arm that can extend to approx 1.25 meters). What actuators are available to accomplish this? The main factors and design points are: Not Expensive 5 to 6…
Mark W
  • 420
  • 1
  • 4
  • 6
32
votes
14 answers

Can ROS run on a Raspberry Pi?

Can ROS run on a Raspberry Pi? ROS is resigned to run on a network of machines, with different machines, even different cores on the same machine doing different jobs. Can one of those machines be a Raspberry Pi? I am considering using an R-Pi as…
Rocketmagnet
  • 6,457
  • 5
  • 29
  • 54
31
votes
3 answers

What is a suitable model for two-wheeled robots?

What is a suitable model for two-wheeled robots? That is, what equations of motion describe the dynamics of a two-wheeled robot. Model of varying fidelity are welcome. This includes non-linear models, as well as linearized models.
ronalchn
  • 3,084
  • 4
  • 24
  • 36
1
2 3
…
99 100