# All Questions

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6 views

### how to use ROS navigation stack with 4 wheeled robots

I have a 4 wheeled toy car, with 5 motors, one on each wheel and one is used for steering. How can I use ROS navigation stack with this robot since navigation stack is used with differential drive ...
9 views

### Best practices for quad-copter designing

What are the some of the best practices for placing the components (including battery, GPS, flight-controller, wires, receiver etc.) on the air-frame of an 'X' quad-copter to ensure the minimum power ...
10 views

### Why 3DR Power Module has two 5v and GND output

Why are there two 5V and GND output in 3DR Power module (https://www.instructables.com/id/Safetly-use-CLONE-APM-Power-Modules/) (https://www.youtube.com/watch?v=M6OSp05Y5b8). Can we power up an APM 2....
13 views

### What is the max linear acceleration of Husky A200?

I am not experienced in doing robotics. I have been trying to find the max linear acceleration of Husky A200 in order to set real constraint for simulation purposes. What I did was to find out the ...
10 views

### Have artificial muscles achieved the level for the practical use, e.g. in InMoov robot?

https://iopscience.iop.org/article/10.1088/1361-665X/ab0d9b is article about manipulator that uses artificial muscles. My question is - have the articial muscles achieved the maturity for some ...
9 views

### How does TTS TacTile Code Reader work?

This is the TTS TacTile Code Reader: https://www.tts-international.com/tactile-code-reader/1010494.html?cgid=Primary-Computing_--_ICT-Bee-Bot_Blue-Bot_--_Pro-Bot There aren't any connection pins, I ...
16 views

### Definition of robotics manipulator?

I'm new to robotics, I don't understand the way wikipedia defines robotics manipulator. If there is no any direct contact how could the robot move things within his work envelope. In robotics a ...
20 views

### Build real-time wireless camera trap [migrated]

I am looking to build a camera trap for wildlife viewing, able to capture pictures (or even videos) in decent quality to be able to identify distinct features. I do however need to be able to see the ...
14 views

### Move two DC brush motors at the same time using Kangaroo and Sabertooth

I had been doing a project which we are using kangaroo and sabertooth 2x32 to move two brush motors with an encoder. There are many obstacles that we overcome. from different signal, tuning etc., ...
16 views

### Slowly pushing mechanism [on hold]

im kinda new into this so help would be needed. So i want to create a slowly pushing mechanism. I have a vertical hollow tube (there are items inside) and i want to create slowly pushing mechanism at ...
52 views

### Sequence of rotation [on hold]

I have a question about the basic of rotation. If you have a sequence of rotations, why does the first rotation get multiplied at last, as below? 45 deg. rotation around x 70 deg. rotation around x ...
14 views

### Angular Velocities of CoM in Global Coordinate

The block diagram of the robot is shown as above. Here, $\phi$ is the angle between $X_v$ and $X_0$ (Yaw angle of the robot), and $\psi$ is the angle between $Z_b$ and $Z_v$ (pitch angle of the robot'...
11 views

### how to integrate apm 2.8 and raspberry pi 3 for object tracking

Please I want to carry out a project on object tracking, I have an APM 2.8 and a raspberry pi 3 how do I command the flight controller to takeoff directly from my pi interface?, any advice on how I ...
27 views

### How to extract the servo motors of a Digital Micromirror Device?

The good news is, that modern DLP projectors are sold for a low price. Each of the projectors is equipped with a so called digital micromirror device, which is an MEMS array. It contains millions of ...
17 views

### Building trac_ik_python for Windows 10 using VisualStudio2019

I’m trying to build TracIK-python with Microsoft Visual Studio 2019 for Windows 10 and am making use of the available trac_ik_wrap.i file in the swig folder to ...
18 views

### HD Map Creation in Real Time [closed]

I have a robot that I want to navigate through a complex environment. I want to make an accurate 360 degree surround view map of the robot's environment. How can I do this? I have 2 180 degree lidars ...
21 views

### Best Sensors/Upgrades for mBots? [closed]

So i have regular mBot with black/white line follower & ultrasonic sensor. What would be the best thing to upgrade it with? Also is there something that is similar to those blue metal rods? I ...
34 views

### Complementary filter for gyroscope and accelerometer

I am trying to understand how the complementary filter works. I did some research and i found this: I am confused about the noise and drift before any filter is applied. I have 2 questions: In the ...
44 views

### Fusing Multiple Lidars Into 1 Point Cloud

I have a car with 8 lidars, each with a field of view of 60 degrees. My car looks like this How can I merge all the lidar readings into 1 point cloud?
33 views

### feedback linearization for a quadrotor

I am trying to develop a controller for a quadrotor using dynamic feedback linearization technique, but I am not sure I am doing thigs correctly. I know that for designing such controller I have to ...
5 views

### What is the ~tf_prefix parameter does?

I have a TurtleBot3 Robot and when I’m trying to do this command to start the nodes (The ROBOT is real) roslaunch turtlebot3_bringup turtlebot3_robot.launch I’m ...
30 views

### Old toy robot - anyone remember this? [closed]

Apologies if this is not the right place, but.... Does anyone know what this toy robot might be? I was given it years ago when I first started robotics courses, now it has become a favourite with my ...
18 views

### Any alternative to finding singularity of Puma 560 than differentiating the Jacobian and putting the Det=0?

Any alternative to finding singularity of Puma 560 than putting the Jacob Det=0? Also when it says the axes intersect, which axes do they mean? The z?
13 views

### How to create an artificial muscle in Gazebo? [closed]

I am looking for a function in Gazebo to shrink an object related to two other objects. The artificial muscle will have a mount on the rotating element to increase the available angles of rotation of ...
12 views

### Velocity obstacle method in joint space [on hold]

The velocity obstacle (V0) method and it's variants such as the reciprocal velocity obstacle and optimal reciprocal velocity obstacle method have been deployed for multi-agent reactive navigation. By ...
16 views

### how to implement a wall following controller for a TurtleBot3? (ROS - python)

I want to implement a wall following controller for my TurtleBot3 (with ROS system). sensors which I have on the robot: lidar(360) and optional 2 ultrasonic sensors on the side (1 on left and the ...
5 views

### Dynamixel MX - Open CM 9.04 + Open CM Exp - Issue With Bootloader

I am using Dynamixel MX 64 AR with Open CM 9.04 + Open CM Exp using Arduino IDE. I am using the following code to find Dynamixel ID and Baud Rate: ...
11 views

### Trying to make a map with gmapping but Rviz shows nothing

I'm trying to visualize and create a map using a Lidar and Rviz. I have a Lidar that publishes the LaserScan data on /scan and that is visible in Rviz. That is working fine. I also have installed ...
24 views

### Gazebo GUI doesn't show up

I tried Gazebo 9 and 10 on Ubuntu 18.04 MATE and it quits in a few seconds without showing Gazebo GUI. I'm running it on 32-bit Intel CPU with 950 Graphics chipset (pretty old). Here is what I see in ...
25 views

### Why Drone flips over while taking off?

Noob here. Response is very much appreciated. I have built a drone based on apm 2.8. however, it doesn't lifting up and flip over when it start to fly. Can you please guide what could be the possible ...
10 views

### rtk-gps faster (60Hz) and cheaper?

The below rtk-gps measures position to about 1.5inches for \$1500 and an update rate of 5Hz on gps, and it measures 12.6mm x 4.6mm so that it would easily fit inside of a 20mm-diameter tube-shaped ...
33 views

### Servo motor torque

I am confused with the torque ratings of servo motors, or I guess it is general while choosing any motor. For example a servo's torque is rated as 10kg-cm, so does that mean it can handle a 100N ...
13 views

### VFH/VFH+ Axis Orientation & Sensor Angles

I have been struggling with trying to get the VFH+ implementation working correctly using Orca-Robotics implementation which seems to be the same implementation used in the ROS package and MATLAB and ...
21 views

### RC controlled underwater robot [duplicate]

I am working on a project to build a remotely controlled underwater robot to work in pure water tank. The max depth the robot has to dive is 40cm, and the robot has no over-the-water antenna. I ...
21 views

### Coupled joints limimit

I have 6dof articular robot. All joints are revolute. The limit of 3rd joint depends on the position of 2nd joint. I need to write function which returns 0 if 3rd fits limits with respect to 2nd joint ...
39 views

### RC transmitter/receiver for underwater robot [closed]

I am working on a project to build a remotely controlled underwater robot. The max depth the robot has to dive is 40cm. I tested the 2.4GHz RC transmitter and receiver and it could work only up to ...
36 views

### Fusion multiple LaserScans to PointCloud

I am currently trying to do 3D SLAM with two 2D Lidars and possibly additional IMU in ROS. However, there seems to be no ROS package available to meet my needs. The closest one would be laser_pipeline ...
32 views

### Moving clock arms individually

I have as project to build something like this ( using arduino if possible ): http://clockclock.com The one modelization that came across my mind is to take 2 sticks ( as clock arms ) and command ...
26 views

### how to rotate a small metal part, precise (0.01 Deg) and repeatable?

For rotating a (90 grams metal, 30mm*30mm*15mm) part in a system, I need a mechanism with these constraints: The part (and other attachments) can rotate with about 0.01 degree or less precision. In ...
24 views

### How can I break down this easily to find out the homogeneous transformation for 3 jointed robot?

I am a beginner at this and, I am trying to find the best way understand how to do this. I have tried youtube but, to no avail. I appreciate any tips.
41 views

### Localize a Mobile Robot on a Mirror

I am currently busy with a project which requires me to construct a robot capable of cleaning a heliostat (movable mirror used to redirect sunlight). Heliostats are basically large flat mirrors that ...
21 views

### Is there a table of DC motors in relation to weight/mass? I want to find the fastest for my build

I am building a line follower robot for a science competition, i have the weight of the components but i don't know what would be the fastest motor i could use to reach the best avg speed of the robot....
24 views

### Odometry heading and laser scan heading not point to same direction

please help, after so much research still cant find a single solution from google. some say offset, but there is no offset in the configuration. problem: odom direction and laser scan heading didnt ...
28 views

### How to convert serial data to sensor_msgs/Range Message

I have a ROS node which manipulates a serial frame, the frame contains ultrasonic measurements, I have to extract this measurement and publish it as ...
30 views

### Formation control for ground vehicles

I am working on a project where I am aiming at connecting multiple vehicles in a formation and allowing hive control of the formation. The robots (husky-like) use ROS and so I was hoping to ...
31 views

### Having trouble getting correct homogeneous transformation matrices for my robotic arm

I am working on a project to build and program a robotic arm. And, no, this is not a HW problem. I have watched a ton of tutorials on the HTM, but its still not fully clicking. The image shows my ...
43 views

### In path planning, what kind of path is feasible for a nonholonomic robot?

For a car-like nonholonomic robot, What kind of path is feasible? Is it right that a path is feasible for a car-like robot if it's curvature continuous, and the curvature on any point doesn't exceed ...
33 views

### Mobile Antenna question

I have a rocket-shaped (tube-shaped) mobile 20mm in diameter. From a base-unit, 600yards away, I want to be able to send two floats (call it x and y) every 1/60th of a second (60Hz data rate [or ...