# All Questions

4,456 questions
33 views

### Real-time python reinforcement learning library

I'm looking for a reinforcement learning library that can be used for real-time robot control. What I first had in mind was ROS to describe the robot, Mujoco to simulate physics, and OpenAI gym to ...
20 views

### RGBD Camera Eye in Hand Calibration

Hello I am new to robotics. So far I have a basic understanding of the camera calibration. One would need rotation and transformation matrices to convert a point from camera coordinate system to robot/...
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### Control Algorithms for Kinesthetic Teaching

There are several algorithms for post-processing of kinesthetically demonstrated motions for manipulators learning a task. However, I have failed to find papers/research work on modeling the ...
26 views

### How can robots communicate, locate and identify each other?

I'm planning to build some simple robotic boats. They will be travelling some distance alone but should also be able to group and physically connect together to form one boat. When they are near each ...
65 views

### Inverse Kinematics “Can not converge” issue

I'm a complete beginner with LabView and I have been practicing forward kinematics with the help of a tutorial I found. It's been a learning curve but I've managed to understand a few things. However,...
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### How is this bicycle model in Robotics Vision & Control derived? And is its equation missing something?

I'm reading Robotics, Vision and Control, on page 108 it has following equations: $$\rho=\sqrt{\Delta^2_x+\Delta^2_y}$$ $$\alpha = \tan^{-1}\frac{\Delta_y}{\Delta_x}-\theta$$ \beta = -\theta-\alpha\$...
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### Gazebo crashes and burns launching empty world in new package [closed]

I'm launching empty_world copied into my package with the command roslaunch my_package empty_world.launch. Here is ...
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### vision guided robotic arm always required 6d pose of object? [closed]

I have an object like attached in image. It is hanging vertical (its position may change but static object) and I want to grasp it using 6DOF Robotic arm. I am Using camera to detect object. I am ...
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### Looking for a model in a gazebo

I have a small world file, say ...
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### How can i do message packet signing using javascript/node js for MAVLink v2 messages

I am trying to control ardupilot using nodejs. My requirement is to use Javascript solution instead of Python/C. The mavlink.io page for supported languages shows javascript generated library has ...
47 views

### Any slam simulator without using ROS?

I found there are STDR and Stage simulators on ROS for SLAM and mobile robot simulation. But I’m trying to run simulations on my laptop that has really limited space, when I tried to install Stage, it ...
37 views

### Adjusting the PWM frequency and duty cycle to achieve the desired angular velocity in differential drive robots

I am practicing C++ and intro to robotics using a simple differential drive robot and a raspberry pi. Also following along the GA Tech course on control of mobile robotics. The implementation I am ...
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### Short range stereo vision

I am designing a stereo vision system for short depth range (15 cm to 35 cm) and I have some problems about baseline, focal length and depth range. My application is to scan an animal tissue (meat, ...
40 views

### DH parameters for a PPP arm

I found this picture on the web and was working through it to make sure I understood the derivation for a PPP arm. I believe for link 2, alpha_2 ought to be -90 and not +90. Additionally, I don't ...
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### Roomba stops responding to commands on the OI

So I just received my roomba create 2. I have managed to read and send commands to the roomba using the OI and an Arduino. I also got it to move using the USB cable provided by iRobot and the tethered ...
49 views

### 3D Direction Sensor - Question from a Neuroscientist

I'm posting here on the advice of r/diydrones, who said you're the people to ask. I'm hoping you might be able to help out with a problem i've come across in my research? I'm a Neuroscientist working ...
34 views

### How to drive a curve in a maze

im currently programming a robot with 2 wheels and i got the task to let it drive alone for a few minutes in a maze. I just managed to programm a controller that controls the distance to each wall ...
28 views

### Robotics flag at start of maze

Just to give u a little background of what I am doing, I am currently programming my vehicle to wall-hug a maze. My idea is that my vehicle does a check at start whether or not it will move in ...
43 views

### Line following robot mathematic model

I'm trying to improve the speed my line following robot. I have made this chassis designs. This is the main prototype I'm working on. Look at the following image. I'm driving the robot with PID, and ...
16 views

### Is there a Java or mathematical algorithm for Pure Path Pursuit?

I was building a robot which I wanted to have smooth consistent motions and pathways. I am somewhat familiar with Pure Path Pursuit and wanted to know if someone could point me towards a mathematical ...
22 views

After some research Robotic hand simulation in MatLab? After some motivation, I have tried to go inside Matlab Simulink and was able to do this :- https://drive.google.com/open?id=...
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### How can Denavit-Hartenberg representation with only 4 variables describe rototranslations with 6 DOF?

I am wondering how the Denavit-Hartenberg representation is able to describe rototranslations with 6 DOF with only 4 parameters? Some context: Denavit-Hartenberg representations can be used to ...
20 views

### Accuracy of the NEO-6M GPS module

For an autonomous bot, I wanted to use a NEO-6M GPS module with an Arduino. How much accuracy can I expect from this specific GPS module?
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### Can P gain too high cause roll of death?

I've been sperimenting with PIDs on my quadcopter and I've noticed that pitch P = 65 causes double front and back flips which looks like a roll of death (or in this case a flip of death) and lowering ...
31 views

### Python, Universal Robots, Ethernet problem

This is in regards to a UR 10 running 3.5.3.10825. For the script urx_get_robot.py ...
25 views

### Image based visual servoing for quadrotor forward flight

I'm still trying to understand how to implement image based visual servoing (IBVS) for quadrotor. The control laws seem straightforward if you want to use IBVS to track a feature in the image space at ...
24 views

### Improving PID gain constants

I have started building and programming my own quadcopter. I used stm32 f103 and right now I'm testing PID controller. The issue is getting right gain constants. I have build a swing and attached ...
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### Technical books on autonomous cars?

What are some technical books specifically geared towards software/hardware designs or algorithm designs for autonomous cars? Not just books like Probabilistic Robotics or Planning Algorithms.
41 views

### Dropping a box from a quadcopter

I am trying to estimate when and where to release a box carried by a delivery UAV such that it falls on a given target. I need to take the wind speed/direction into account. (See the visual below for ...
31 views

### rostopic list not showing topic

When I use the rostopic list commands, the output is only returning /rosout & /rosout_agg...
23 views

### For pose estimation, what is the typical range of the rotation values that are estimated? Is it from -180 to 180 degrees?

I am currently working with the Rutgers APC 2015 data set for pose estimation, and see that the pose estimates, specifically the rotation estimates, have seemingly been rescaled to range between -1 ...
54 views

### How are shells for robotic arms made?

I wonder how the shells of robotic arms are usually made. By the shell, I mean this: This is taken from the project here, which is a University project. If the shells were injection moulded, how ...
33 views

### What is the best adaptive controller for robotic arms?

I have a question that lays on practical experience. What is the best adaptive controller for a robotic arm? Self Tuning Regulator (STR) Model Reference Adaptive Controller (MARC) Adaptive Model ...
37 views

### Technologies needed for indoor and outdoor navigating robot

Before I begin, I should add that I am a complete beginner in robotics and hope that I can figure out where I should start by asking this question. I am trying to make a robot that is able to ...
60 views

### Controllability of a car with a single trailer

I'm studying the kinematic model of a car with a single trailer. This picture shows the system: I started from the following statements: With these constraints, I got the Pfaffian form: And then ...
34 views

### Driving a gearbox with another?

I'm trying to find a 1:1000 gearbox for NEMA 17, but the highest (affordable) one I've found is 1:100. Is it a good idea to drive a 1:100 planetary gearbox with a 1:10 planetary box? Is it common to ...
43 views

### Making a motor controlled joint passive

Anyone know of a good (and economical) way to make a motor controlled arm become a passive link on trigger? That is, the joint can be active (motor controlled) or passive (rotate freely). The tip of ...
49 views

### What the best roadmap to learn building and programming drones in the deepest level? [closed]

I want to learn how to program the drone in C without using the available libraries and platforms. I want to be able to understand how everything is set at a fundamental level(SRAM). Also, I want to ...
25 views

### How do angular velocities make sense for a quadcopter pid controller?

If I have a quadcopter that I am programming, how do angular velocities for the pid controller make sense. If I set my sticks to move with a certain angular speed in one direction and then bring them ...
27 views

### Maze wall hugging both clockwise and anti-clockwise

So I did the algorithm for the vehicle to go in a clockwise direction(Refer to my pseudocodes below). But now that my school had said there will be an anti-clockwise direction as well, I'm not sure ...
80 views

### Finding correct RPY for approaching a known point on a plane

I have a robot with 6 DOF that I want to use to grab a hanging sheet at a specific point near its edge. The grip needs to be perpendicular to the edge and co-planar with the point of course. I have ...
55 views

### ROS Theoretical Question - How does work properly a node

I'm new at ROS and I'm trying to figure out how does the node works with a pyton/C++ code. I have two codes for the same situation: Use a Xbox Controller to move the turtle in turtlesim FIRST - ...
49 views

### Navigation - GPS + IMU; how to make it more accurate?

Currently, I am trying to navigate a small robot car to point A from my current position. The car has a GPS sensor and a BNO055 IMU(Gyro + Mag + Acc). I know the GPS co-ordinates of point A. Using the ...
29 views

### Why my stepper motor doesn't move when I attach a blade?

I wanted to use the NEMA 17 stepper to drive a blade/flapper that I have custom made for some physical application.As soon as I tighten the screw,the motor stops rotation in the usual way. Don't have ...
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### How can a motor be run at higher voltage for longer?

A 12V windshield wiper motor to run at 24V for more speed but near-equal driving force. Testing with a variable DC supply between 21.6V & 26.4V showed the current maxes at 3.72 - 3.90A, as ...
108 views

### Interference caused by multiple robots during task completion

Suppose there is an area to survey. If we deploy one robot it takes time T to sweep the area. Now if we deploy 2 robots, we would expect it to take time T/2. However in reality, because we are sending ...
24 views

### How to balance a long vertical bar

I have a mobile base (1400x1800x400 mm) which has a vertical bar (1) mounted on its geometric center; this vertical bar has a length of 2500 mm and a diameter of 100 mm and I need to keep it always in ...
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### How do I calculate the direction robot is facing, pose from velocity and yaw rate?

I have a simple car robot with four wheels moving relatively slowly (5~10 mph). The robot has a velocity magnitude and yaw rate sensor and the sensor samples about every 0.1 seconds. I want to map the ...