Robotics Stack Exchange
Robotics Stack Exchange

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1500 questions
22
votes
2 answers

Visualizing and debugging an EKF

I am currently debugging and tuning an EKF (Extended Kalman Filter). The task is classical mobile robot pose tracking where landmarks are AR markers. Sometimes I am surprised how some measurement affects the estimate. When I look at and calculate…
r0nald
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21
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6 answers

What is the difference between path planning and motion planning?

What are the main differences between motion planning and path planning? Imagine that the objective of the algorithm is to find a path between the humanoid soccer playing robot and the ball which should be as short as possible and yet satisfying the…
Pooya Sagharchi
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21
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3 answers

How to rotate covariance?

I am working on an EKF and have a question regarding coordinate frame conversion for covariance matrices. Let's say I get some measurement $(x, y, z, roll, pitch, yaw)$ with corresponding 6x6 covariance matrix $C$. This measurement and $C$ are given…
automatom
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21
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4 answers

How can I use the Arduino PID library to drive a robot in a straight line?

I would like to create an Arduino based robot with 2 wheels, quadrature encoders on each wheel, a H-bridge driver chip (or motor controller) and a caster. I want to use the PID library to ensure the speed is proportional to the distance to travel. …
Robert
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20
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10 answers

How mature is real-time programming in robotics?

Edit: I don't know why, but this question seems to be confusing many people. I am aware of when/where/why/how to use real-time. I am interested in knowing whether people who have a real-time task would actually care enough to implement it in…
Shahbaz
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19
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7 answers

Robot never goes straight

I am using 2 identical DC motors and a castor wheel. The motors are connected to L293D motor driver and are controlled by RPi. The robot is not going straight. It veers off to the right. I am running both the motors at 100% PWM. What I tried to…
Mouse
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19
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7 answers

What good robotics software platforms / operating systems are available?

My company will soon be starting a brand new robotics project, and we are still trying to decide whether we should design and code a robotics software platform from scratch, or if there are any good existing ones. It would be very useful if there…
Rocketmagnet
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19
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2 answers

How To Determine Heading Without Compass

Lets say I drop a robot into a featureless environment and any magnetic field based sensors (magnetometer/compass) are not allowed. What methods are there of determining where north is? Tracking the sun/stars is an option but not reliable enough…
user65
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19
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4 answers

Computing the Jacobian matrix for Inverse Kinematics

When computing the Jacobian matrix for solving an Inverse Kinematic analytically, I read from many places that I could use this formula to create each of the columns of a joint in the Jacobian matrix: $$\mathbf{J}_{i}=\frac{\partial…
xenon
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19
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3 answers

What's the most effective type of rechargeable battery when taking into account size / weight / Ah?

I'm looking to build an underwater glider robot that will need to remain autonomous for long periods of time, perhaps even months. Power draw should be minimal, and I'm thinking of including some form of charging device (such as a solar charger)…
berry120
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19
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3 answers

What is the best way to power a large number (27) servos at 5 V?

I apologize if this question may sound a little vague. I am working on a robotics project that will contain 27 servos of various sizes and I am having trouble figuring out how they should be powered. I was hoping to use several (3-6) 5 W 18650…
user428
19
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1 answer

ROS: Best practices?

I'm going to build a small robot system, and it seems like that ROS serves a nice framework to control and program the system. However, I am wondering which is the best practice to manage the components of my robot. Does it make sense to put all…
manf
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19
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2 answers

How to choose a good IMU for a wheeled robot?

At our lab, we have a several "Kurt" type robots (about the size of a Pioneer, six wheels, differential drive). The built-in gyroscopes are by now really outdated; the main problem is that the gyroscopes have a large drift that increases as the gyro…
Martin
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18
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3 answers

Calculating the efficiency of Mecanum wheels

I'm part of a FIRST Robotics team, and we're looking into using Mecanum wheels for our robot. What are the advantages and disadvantages of using Mecanum wheel versus regular ones? From looking through Google, it looks like Mecanum wheels give more…
Michael0x2a
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18
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4 answers

What is inverse depth (in odometry) and why would I use it?

Reading some papers about visual odometry, many use inverse depth. Is it only the mathematical inverse of the depth (meaning 1/d) or does it represent something else. And what are the advantages of using it?
Mehdi
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