# All Questions

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15 views

### What is the baseline of a RGBD camera?

I'm looking at some ORB SLAM2 settings where there's a parameter for "IR projector baseline times fx". Could someone here explain what exactly is the baseline of an IR projector? Is it the distance ...
26 views

### Unlabelled pins on this L293D dual DC motor driver

I've got this board from a local store. It's an L293D based dual DC motor driver. All the pins are labelled except the 5 on the bottom as shown in the picture below. Couldn't find any datasheet or ...
33 views

### Understanding the SICK S300 RS422 data output

I'm using a SICK S300 safety scanner connected via RS422 -> USB and I'm trying to decode the lines of data into meaningful values, however looking at the data compared to the Telegram Listing it seems ...
49 views

### 360 Continuous Rotation Servo only goes 180 degrees

I bought the following servo: D DOLITY High Speed 360 Degree Continuous Rotation Servo for Robotic(15kg/cm) Metal Gears Servo I'm trying to get it to spin in one direction continuously, but it looks ...
14 views

### AlphaBot2 run / migrate to .NET Core

Bought this robot called AlphaBot2. Has sample code here: https://www.waveshare.com/wiki/File:AlphaBot_Demo.7z What I am interested in knowing is how do I convert these Python samples to C# with .NET ...
48 views

### Calculate ticks with three encoders?

I have a question regarding calculating the ticks in a sensored BLDC. The BLDC has three hall effect sensors with slightly differing phasing and there are 30 magnets in 360 degrees of wheel rotation. ...
44 views

### What exactly is a nodelet?

I am new to ROS. I tried to read the documentation regarding nodelets on ROS wiki. But I couldn't understand it very well. I would like to know what is a nodelets in simple and intuitive terms
25 views

### Autonomous quadcopter: How to transform setpoint into motor inputs?

I would like to know how to transform a setpoint to inputs for the motors of a quadcopter. I would like a function like that: ...
33 views

I am new to the art of building quadcopters and am looking to build a camera platform with a payload of 250g. With the following setup would that be possible or could someone point me in the direction ...
60 views

### teleop_twist_joy with Logitech F710 Joystick force feedback error

I am using a Logitech F710 joystick game controller in ROS Kinetic Kame. I was able to perform jstest testing, and can see my joystick works well. But when I try ...
34 views

### Path planning algorithm to run my floor cleaning robot/zig zag path travel

I am creating a floor cleaning robot with obstacle detection as my final year project. The basic task of the robot is to clean the floor while avoiding obstacles using an ultrasonic sensor. The ...
25 views

### Problem with moving heavy computation into ISR's (dspic33E)?

I am controlling a robotic system using a dspic33E. I have a few PID control loops for motor control, several SPI slaves, and an I2C master that I communicate with. Currently, I use interrupts for ...
52 views

### Variables that Improve SLAM

I have a general question regarding SLAM as I am not an expert on the topic. What are the variables that can improve map generation? The ones I can think of are: A higher resolution camera ...
20 views

### Decrease minimum depth of a RGBD camera

I have a Kinect camera which has a minimum depth of 0.5m and I'm trying to find a way to decrease it to around 0.2m for near-depth detection. Does anyone know how this can be done? Can a macro lens be ...
60 views

### What is the purpose of these grey balls on the drone?

Are these used for position tracking? Are there any papers
31 views

### Relation between PWM frequency and torque

I am using Pololu G2 18v15 to drive a maxon motor. The motor is supposed to drive a load in a sinusoidal trajectory against gravity with maximum torque of 0.0634 NM with max speed of 5 rpm. I am using ...
19 views

### Selection of motor and Calculating the torque for 6DOF robot Arm

I am trying to select the motor for a robot arm with six degrees of the freedom robot arm. What should I do to select the motors and which type of motor I should select?
54 views

### How to synchronise data for fusion in Kalman from multiple sensors with different timestamp information?

I'm using Kalman filter to track the position of a vehicle and receive position data from 2 sensors: A GPS sensor and an Ultrasonic sensor for which I want to implement sensor fusion into the Kalman. ...
51 views

### Null space of the Jacobian matrix for a robotic arm

I have doubts on how to find all the joint velocities that don't produce any linear velocity, so are in the Null space, when we are in a singular configuration. For example, suppose we have a 2R ...
85 views

### Why is behavior-based robotics not as popular as deep learning or reinforcement learning?

I am a master student in Germany and one of our professors is doing robotics research but with a different paradigm - the behavior-based robotics based on Subsumption Architecture developed by prof. ...
33 views

### Data structure to store a robot map

I'm studying robotics at the university and I have to implement on my own SLAM algorithm. To do it I will use ROS, Gazebo and C++. I have a doubt about what data structure I have to use to store the ...
14 views

### ROS rqt_plot and rqt_multiplot font change

I am trying to plot my gazebo simulation data in rqt_plot or rqt_multiplot. However, after plotting is done I would like to change the font size/style on the plot. So far I could not find a way how ...
83 views

### Inverse kinematics of a sun tracker with swapped axes

I am realizing a sun tracker based on latitude, longitude, and date-time. The system calculates the azimuth and elevation angles to track the sun. In a classic sun tracker, the azimuth axis is ...
34 views

### For what step disturbance value the system will become unstable?

I am new to control theory and have difficulties about this question R is the input, Td is the disturbance, C is the output Given that G1=K/(s^2+A*s), where K is the gain and A is a parameter greater ...
41 views

### Working with large bag files efficiently

I'm running into issues playing large rosbag files (over 50 Gb which exceeds my RAM size) consisting of several chunks. It seems that the file is processed sequentially in chunks, and reading a ...
17 views

### How to make x variable change each time and read its value from txt file

I am working on my undergraduate project and this is my first time in using use python to control parrot bebop 2 drone and use BCI or BMI technology. I have x variable (int) and I want to read its ...
26 views

### effect of three terms of PID controller on output response? [duplicate]

What is the effect of each of the three terms on output response of a pid controller? i mean how will P term shape/effect the output response similarly what is the effect of I and D terms on output ...
62 views

### Confused about I and D in PID controller?

I am trying to learn PID controllers from basics and i came to know that "P" term looks for current error "I"term looks for past error "D"term looks for future error I have some how understood "P" ...
27 views

### Do I have to use the CAN protocol that the motor controller uses in order to communicate with it?

I have a question about using the CAN bus to control motor controllers. Do I have to use the CAN protocol that the motor controller uses, e.g. CANopen CiA DS 301 CiA profile 402, in order to ...
6 views

### 2 NAO robots and a human interacting and exchanging an object

I need to solve the following scenario between 2 NAO robots and one human. Maybe you have advice which NAO accessory or builtin sensor is accurate enough to measure such a distance of 0,5 meters and ...
27 views

### why we need both vel and acc contribution for actual position?

I was trying to understand multiwii quadcopter code. I started with understanding GPS code. Here is a section of the code where I have doubt. Why actual position = pos + velocity contribution + ...
36 views

### Fuzzy logic controller for controlling a four-bar linkage

I am trying to design a control system to move a joint of four bar linkage according to desired trajectory. A dc-motor is used to move the joint. Can fuzzy logic controller be used to solve this ...
35 views

### Plot a map using wheel encoder and IMU data

I want to plot a map( with matplotlib or any other library ) using a wheel encoder and IMU data. Eg:- For every 10cm robot moves it should draw line (in a graph) and draw angles depending on the data ...
22 views

### Basic question about Markov Localization, probability and belief distribution shift

I am starting in robotics, and reading about Markov Localization, I have one doubt, probably very stupid, but, well, I want to solve it. Let's take the CMU Website example: https://www.cs.cmu.edu/afs/...
50 views

### Libraries to calculate kinematics using Screw Theory

Most kinematics libraries/packages use the conventional transformation matrices (DH parameters). However, I'm looking for something that uses Screw Theory principles to set up the Product of ...
26 views

### ORB-SLAM pose estimation

I've been reading about ORB-SLAM and ORB-SLAM2, but I can't quite figure out how pose estimation is done. I see that it uses a bag-of-word method for loop detection, but how are current features ...
20 views

### How to configure a DC power distribution bus

If you have a distributed system of DC motors, sensors and microcontrollers, is power usually distributed over a single high volt bus, using DC converters where needed? Or is it typical to implement ...
24 views

### How to get the accurancy of the position system?

I want to build a system for positioning objects. It should be driven by a DC motor and a sensor should control the rotation angle. For the positioning I want to design (calculation) the accuracy. ...
58 views

### Simple explanation of PID control [duplicate]

I tried reading and searching different books and links for understanding PID control but not much progress Can some one please give me simple explanation of PID control?or atleast links where easy ...
115 views

### Control VS artificial intelligence?

I have heard of both the terms AI (artificial intelligence) based robots and control based robots. Although they are both different fields, what is the difference between AI and control in regards to ...
36 views

### Does the Create 2 have the roomba room mapping software?

My understanding is that the Roomba has a sophisticated room mapping capability. Does the create 2 include that capability and is it usable by the hobbyist?
42 views

### How does sensor fusion related to SLAM

How does sensor fusion affect the slam process?, if we have stereo camera with GPS and Imu, how does sensor fusion benefit the SLAM? Do we use sensor fusion to enhance localization phase of SLAM, and ...
19 views

### what is ultrasonic based slam

i am confused about SLAM implementation, and i need your advise to organize my mind. Fist let me say that i have to generate 2D map, what is in this case the SLAM input? is it like (x1,y1),(x2,y2)...(...
58 views

### IMU based joint angle measurement

Let us assume we have a two 2-DoF robot. Both axes rotate around x. And the goal is to measure the joint angle values with the roll value from IMUs attached on each link. However, the problem is that ...
20 views

### Controlling Actuated Robot Hand in Underactuated Manner

We have an allegro hand in our robot, and it is in actuated behavior. In other words, each joint is controlled one or more than one actuator, that is motor. There are 3 actuators for each finger, ...
44 views

### Jumping motion in point to point movement

I have one question about point to point movement. Let's say the end-effector is placed at $(0,0,0)$ and the goal position is at $(10,0,10)$. The corresponding joint angle value changes $d\theta$ can ...
61 views

### Path Planning algorithm

The broad question is this; given an occupancy grid and the robots current pose (x,y,theta,theta'(first derivative)) how should I plan motion for my robot with the following constraints: shortest ...
25 views

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

I am confused between 3D rigid affine(with scale, without shear) transformation and Lie group's sim(3) matrix. 3D affine would be [sR|t; 0 1]. we rotate, scale and then translate a 3D point using ...