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11 votes

What is the difference between a holonomic and an omnidirectional robot?

Holonomic is a precise mathematical term; one definition is velocity constraints can be integrated into the form $$\begin{align} f(q1,q2,...,t) = 0. \end{align}$$ Roughly, that means the ...
ryan0270's user avatar
  • 2,814
9 votes
Accepted

How exactly does sensor fusion work in Kalman filters?

I realize this question already has an accepted answer, but I'd like to provide some additional input. The question of sensor fusion is a good one, but, depending on the application, you don't ...
user96966's user avatar
  • 126
8 votes

Alternative to ROS?

I think you are getting confused between the basic ROS possibilities and some more advanced libraries which are integrated but do not need to be used by users without 'advanced' requirements. If you ...
N. Staub's user avatar
  • 1,412
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
  • 4,445
7 votes
Accepted

How many robots is considered to be a robotic swarm not a group of robots?

A robot swarm is defined by its behaviour, rather than the number of robots it contains. Swarm robots: "... are coordinated in a distributed and decentralised way" [IƱaki Navarro and Fernando ...
sempaiscuba's user avatar
  • 1,074
6 votes
Accepted

Stabilising an inverted pendulum

There are lots of ways to solve this problem, which falls into the category of Control Engineering. There are two standard approaches: Classical Control: The control command has to be proportional ...
Paul's user avatar
  • 1,278
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
  • 15.9k
6 votes

Is there any robot stability control equation that describes the relation between velocity of the robot and its orientation?

That's not obvious. If I'm in a tank, going 0.5 km/h, I don't need to slow down at all. If I'm in a bobsled going 100km/h and the track banks, I don't need to slow down at all. When you steer, you ...
Chuck's user avatar
  • 15.9k
6 votes
Accepted

How to measure pull force on a (kite) rope?

The component you highlighted is called a tensile load cell. You could buy one from a supplier, but it probably would be cheaper to buy a cheap digital hanging scale and taking the sensor out of it - ...
Pete Kirkham's user avatar
6 votes

Which is a good and cheap 3D LIDAR or other options?

There are now some sub and around ~1000USD 3D Lidars available. I wanted to provide an answer for future reference if anyone else comes looking for "cheap" Lidars. LeddarTech M16 ~500 USD ...
Andreas Klintberg's user avatar
6 votes
Accepted

In SLAM loop closure, What does a sim3 matrix do?

Sim3 is just the lie group associated a similarity transform which is the exact same thing as your 3D Affine transform. If you work out the multiplication for your two matrices you would find that ...
edwinem's user avatar
  • 1,881
6 votes

What's the difference between Pose Measurement and Position Measurement?

what you are looking for is written in the paper. Position refers only to x,y,z translational measurements while pose means position and orientation.
jdios's user avatar
  • 497
5 votes

Biped Robot not getting on one foot

You got the second picture by physically manipulating the robot to get the center of mass above the rotated foot. What you need to do is to get the robot to shift its own center of mass in a similar ...
Chuck's user avatar
  • 15.9k
5 votes

What's the diffrence between $H_2$ and $H_\infty$ control?

In short answer: yes Kalman filter is a special case of an $H_2$ observer Yes Yes ... LQG is just Kalman filter + LQR controller, which are both special cases of $H_2$ Depends on the use case. $H_2$ ...
ryan0270's user avatar
  • 2,814
5 votes
Accepted

What is the difference between the pose of a robot and the configuration of a robot?

Do "configuration" and "pose" means the same thing? No. One of the most clear definitions of 'pose' that I've heard is in Peter Corke's Robotics, Vision and Control (RVC). It states that: "The ...
sempaiscuba's user avatar
  • 1,074
4 votes
Accepted

How to know the payload of the chassis from its motors?

If I told you my truck has 200 horsepower, could you tell me the cargo weight capacity? Not really. There are more factors than just the motor specs that play into your assessment. You might be ...
SteveO's user avatar
  • 4,396
4 votes
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Regarding Kalman filter and estimating heading with magnetic compass

I encountered this problem myself when making an extended Kalman filter for a quadrotor. You have to check if the estimate goes above or below +/- pi, and then correct it if it does. You can do this ...
trudesagen's user avatar
4 votes

How can we solve the problem of robot size in sensor based motion planning?

If you are able to sense obstacles with a sensor pattern that is circular (eg laser scanner, contact sensors on a circular body, etc), and you can rotate the robot pose without translation, then you ...
hauptmech's user avatar
  • 4,445
4 votes

How does fast slam creates grid maps?

Grid based FastSlam relies on the same principle that Landmakr based FastSlam. The difference is that we are not working with each grid cell as a landmark, but the whole gridmap itself. For Grid ...
Guille Sanchez's user avatar
4 votes
Accepted

Biped Robot not getting on one foot

You might be able to use the the opposite foot to begin the rotation of your chassis, but it will be dependent on your chassis and foot geometry. Using your photos for reference, the left foot would ...
kaliatech's user avatar
  • 562
4 votes

Process noise and Measurement noise in Kalman filter

Basically, the relative magnitude between process and measurement noise determines how much to trust a new sensor measurement. In one extreme, if the process noise is zero the kalman filter will ...
ryan0270's user avatar
  • 2,814
4 votes

Quicktron company - Mobile robots (Equivalent of Kiva Systems?)

The company is called Flashhold, here is the link to the website: http://www.flashhold.com/ They raised more than 29M$ in aseries B funding recently and seem to gain a lot of traction https://www....
Alex's user avatar
  • 41
4 votes

Alternative to ROS?

Arduino is not really relevant since its output is a bare-metal microcontroller code. You can gain experience with more complex microcontroller systems by using a realtime OS on your arduino board. I ...
hauptmech's user avatar
  • 4,445
4 votes

What is the best adaptive controller for robotic arms?

The given strategies can be divided into two groups: model-based and model-free control. The AMPC and MARC suggestions are model-based the other are model-free. Theoretically, a pid controller can be ...
Manuel Rodriguez's user avatar
4 votes
Accepted

Problem understanding a paper about visual odometry

So SVO works a bit differently then other VO systems as it uses dense image alignment. You need to understand this concept first before understanding SVO. Look up Lucas and Kanade image alignment. The ...
edwinem's user avatar
  • 1,881
4 votes

Occupancy grid maps

As the wikipedia page of Occupancy grid mapping explains, the result of the mapping process is a binary 1 or 0, occupied or not, the decision itself may be based on noisy data, which involves the ...
50k4's user avatar
  • 6,682
4 votes
Accepted

Some doubts regarding SLAM and its technical terms

Q1) Online SLAM vs Offline SLAM. Can "Online" SLAM be also called "real-time" SLAM? What is the use of offline SLAM if it can't be used on a real robot in real-time? Yes, online ...
badmistersquirrel's user avatar
3 votes
Accepted

Mobile robot algorithm implementation error

So I'll point out what might be some problems, at-a-glance, but wow this is one of the longest questions I've seen here. I'm pretty swamped with real-life stuff at the moment, so I'll just point these ...
Chuck's user avatar
  • 15.9k
3 votes
Accepted

Meaning of s_last in D star Lite algorithm

$s_{last}$ does change. Looking at the pseudo code, $s_{last}$ is updated upon each iteration of the while loop in main(), in ...
Greenonline's user avatar
  • 1,627
3 votes

Linearize a non linear system

The short answer to this question is that linearization won't work, and here's why: Differential drive robots can be modeled with unicycle dynamics of the form: $$\dot{z}=\left[\begin{matrix}\dot{x}\\...
JSycamore's user avatar
  • 926

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