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1500 questions
18
votes
3 answers
Why do Mars rovers designers prefer wheels over tracks?
Typically Mars rovers use wheels and not tracks. I guess Spirit would have better chances getting out of that soft soil should it have tracks. In general, Mars surface structure is not known in advance, so it seems wiser to be prepaired for…
sharptooth
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18
votes
2 answers
Wheels vs Continuous Tracks (Tank Treads)
I'm building a small robot using some cheap Vex Robotics tank treads. However, my choice of picking tank treads is almost purely based on the fact that they seem like more fun than wheels. I don't actually know if they really have much of an…
golmschenk
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18
votes
3 answers
Quadcopter Localization Beacon
I want to use an RF beacon to localize my quadcopter for autolanding, when GPS is not precise enough, for example, when my driveway is only 10 feet wide, and the GPS is only showing 20-30 ft. accuracy (with a proverbial lake of lava on either side).…
Chris
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18
votes
3 answers
What are good methods for tuning the process noise on Kalman filters?
Most often tuning the Kalman filter noise matrices is done by trial and error or domain knowledge. Are there more principled ways for tuning all the Kalman filter parameters?
Chris Mansley
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18
votes
4 answers
Single camera vision and mapping system
Some time ago I saw a demo of a small 'toy tank' with a single camera mounted on it. This tank was able to drive around the floor and detect objects and then move/steer to avoid them.
The interesting part was that it used a single camera vision…
Ben
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18
votes
5 answers
How to detect when a stepper motor has stalled?
How can I detect when a stepper motor has stalled?
A google search led me to some people who say that
when the stepper motor stalls, the current spikes up,
which is easily detectable with a Hall sensor.
(Or, I suppose, by any of the other current…
David Cary
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17
votes
4 answers
Will connecting two servo motors double the torque?
For my robot, I am using two continuous rotation servos to spin a threaded rod. I am trying to make this project as cheap as possible. Here are the servos that I can find:
Servo #1: This is a very cheap option and it has half of the torque I…
Anonymous Penguin
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17
votes
2 answers
covariance matrix in EKF?
I'm struggling with the concept of covariance matrix.
$$
\Sigma
=
\begin{bmatrix}
\sigma_{xx} & \sigma_{xy} & \sigma_{x \theta} \\
\sigma_{yx} & \sigma_{yy} & \sigma_{y \theta} \\
\sigma_{\theta x} & \sigma_{\theta y} & \sigma_{\theta \theta}…
CroCo
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17
votes
2 answers
How do robotics startups work?
In software engineering startups, you generally go to a room with a computer or bring your own laptop, and write code. I'm interested in how robotics startups work: Is there a separate location for designing the robots? Take for example, Anki. Do…
George Newton
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17
votes
6 answers
Mathematical prerequisites for beginning graduate student in robotics
A beginning graduate student in robotics asked me the areas of mathematics that he should brush up on (prerequisites) to begin a masters research program in robotics. What are some good materials/books that are indispensable for a research student?…
hAcKnRoCk
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17
votes
3 answers
Position Control vs Velocity Control vs Torque Control
Please can somebody explain to me the difference between Position Control, Velocity Control, and Torque Control? Specifically, I am thinking in terms of a robot arm. I understand that position control tries to control the position of the actuators,…
Karnivaurus
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16
votes
3 answers
Extended Kalman Filter using odometry motion model
In the prediction step of EKF localization, linearization must be performed and (as mentioned in Probabilistic Robotics [THRUN,BURGARD,FOX] page 206) the Jacobian matrix when using velocity motion model, defined as
$\begin{bmatrix} x \\ y \\ \theta…
zSt
- 343
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16
votes
2 answers
What's an efficient way to visit every reachable space on a grid with unknown obstacles?
I'm trying to create a map of the obstacles in a fairly coarse 2D grid space, using exploration. I detect obstacles by attempting to move from one space to an adjacent space, and if that fails then there's an obstacle in the destination space…
Ian
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16
votes
2 answers
Optimal Control for a simple pendulum
I'm studying various optimal control methods (and implements them in Matlab), and as test case I choose (for now) a simple pendulum (fixed to the ground), which I want to control to the upper position.
I managed to control it using "simple" feedback…
Francesco
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16
votes
1 answer
How is a brushless gimbal motor different from a regular brushless motor?
How are the brushless motors in a gimbal assembly designed?
Obviously it doesn't need continual rotation, but it does need accurate control of precise position. I've noticed that the motors in my gimbal don't have the usual magnetic 'snap' positions…
Octopus
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