# Tag Info

### 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 ...
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### 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 ...
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### 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 ...
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### 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....
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### 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" [IĆ±aki Navarro and Fernando ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 - ...
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### 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 ...
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### 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 ...
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### 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.
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### 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 ...
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### 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. $H_2$ ...
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### 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 ...
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### 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 ...
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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 ...

### 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 ...
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### 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 ...
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 ...
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