# All Questions

4,460 questions
12 views

### Problem with UKF weights when calculating predicted state

I'm having troubles implementing a UKF during the calculation of $\overline{\mu_t}$, specifically in this step: $$\overline{\mu_t} = \sum_{i=0}^{2n}w_m^{[i]}\chi_t^{*[i]}$$ My problem I'm facing is ...
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### I need to read a lot of analog signals without any analog pins

I have an nvidia xavier with gpio running linux. It should work very similarly to raspberry pis. I need to connect a bunch of pressure sensors, thermistor, potentiometers, and vibration sensors to my ...
23 views

### Accuracy of hall sensor encoders on Raspberry Pi

I have 2 motors (JGA25-370) with hall-sensor encodes. They emit about 90-100 interrupts every 100ms, so 1000 a second. Which means I have an interrupt happening every 1ms. The motors are driven by ...
22 views

### Combining data from 9DOF IMU

My team and I are building an AUV and are planning to replace the existing 6DOF MPU-6050 sensor with a 9DOF Adafruit BNO055 sensor. However, we're unable to figure out how to combine the data from the ...
33 views

### Which sensors can be used to feel breeze blowing by the robot?

Am faced with a situation where my robot needs to feel breeze blowing by over its artificial skin. While there exist many types of tactile sensors, nothing seems to fit the bill. I might abandon the ...
32 views

### How many encoders should I have?

I'm planning a robot vehicle and plan to get one or more motors that have encoders built in. How many encoders do I need I really need in order to gather solidly accurate information about speed ...
36 views

### How to calculate observation matrix Jacobians in EFK based mono slam? What are projection Jacobians?

I have been trying to understand an implementation of monoSLAM 1. But my question is generic to EKF based single camera SLAM. My Jacobian calculation leads to complex and lengthy expressions while ...
48 views

### Why can't motors be as elegant as human muscles? Why do we have to use electromagnetism to create movement?

Pretty much as the title says. Why isn't it possible to build motors as microscopically and simply as they're built in humans? Why can't we recreate electronic nerves and muscles?
41 views

### FastSlam2.0: ICP Scan Matching vs Odometry? What is the typical time step?

When working with a FastSlam2.0 algorithm, ICP Scan Matching is supposed to give more accurate measurements than odometry. The problem is, that given some noisy measurements from the laser scanner, ...
20 views

### message_filters doesn't call the callback function

I'm trying to use the message_filters in order to subscribe to two topics. Here's my code ...
57 views

### How can I preserve a high framerate while using at least 1280x720 resolution on 2 USB cameras on the same computer?

To expand on this, I have a down-facing camera using the whycon ROS node on Ubuntu 16.04 Kinetic on a quad-core computer with 640x480@60fps MJPG video. I'm also using the ...
125 views

### Convert local coordinates of a moving IMU to global coordinates

I am trying to compare the performance of an IMU in motion against an optical tracking system. The IMU has an accelerometer and a gyroscope and gives output in the local IMU coordinate frames. The ...
46 views

### Quaternion error in one degree of freedom

I would like to control a system which orientation I measure with as quaternion based EKF in one degree of freedom. Obviously the simplest thing would be to convert the quaternion estimate to euler ...
18 views

### Compile webots for Python 3.6 for Windows

I would appreciate if someone could assist me in compiling webots source for Python 3.6 to allow me and others to use TensorFlow with it. I already tried but apparently there is something not ...
43 views

### ABB Object Oriented RAPID language

How do I create something like a class and have instances of it in ABB RAPID language?
60 views

### Microcontrollers and Python

So I am fairly new to robotics however I do have some background with the python coding language. Recently I set myself the task of learning some basics for robotics just to increase my knowledge base....
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### State Space model for bouncing ball

In lecture 5.5 Bouncing ball, slide 26, Coursera's Control of Mobile Robot course, how are the state space equations formed in "Equations of motion in-between bounces"? Why is [0 -g] added? And how ...
175 views

### Is rospython subscriber thread safe?

I'm trying to write a python node, which has one class and two member functions as callback functions. so a TimeSynchronizer and Subscriber in a node. I saw in this link and tested that python ...
75 views

### Libraries to simulate path planning in a dynamic environment for a 2D space

I need to simulate a path planning approach for a 2D space where the obstacles are moving. Initially, I need to implement probabilistic road map, D* lite, A* and Bug2 algorithm. The robot needs to be ...
42 views

### Arm path planning with obstacle avoidance in Unity

My application is not specifically in Robotics, but the problem that I'm trying to solve seems to have been studied primarily from the viewpoint of Robotics, so I am hoping to get an answer here. ...
33 views

### How can i find and install (acspid) python PID library

How can i find and install (acspid) python PID library in the folowing code import acspid pid=acspid.pidcont(1.2,0.02,0.01,5,-5)
18 views

### Can I combine BEAM robotics with fuzzy control?

Beam robotics invented by Mark W. Tilden is about analog circuits for controlling robots. The idea is to avoid microcontrollers and software and use instead resistors, breadboards and capacitor for ...
24 views

### Localization in box using rangefinders

Let's say I have a robot, located in a box. The robot can move in the x and y and rotate. The robot has 4 rangefinders, mounted 90 degrees apart, that measure the distance to the walls of the box (I ...