# All Questions

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31 views

### Force controller with feedback issues

I'm implementing a force controller on a robotic arm, where the force input comes from torque sensors in the joints. I have calculated the cartesian force on the end-effector from the joint torques, ...
22 views

### Mission Planner: How to create a custom Waypoint Command

I am trying to set up a waypoint in Mission Planner that causes the drone to hover, take sensor data from a custom sensor, then either land or continue hovering based off of what the sensor data says. ...
69 views

### 3D mapping with octomap

I want to use octomap and while I tried this out I had some problems. When I started octomap_server and rviz I realized that the sensor is looking only in one way, even if I rotate my robot (my fixed ...
23 views

### Stuck pneumatic cylinder

I've just received a baomain pneumatic cylinder from amazon (50 mm bore 100 mm stroke). When I tried to move it back and forth by hand, it wouldn't budge. Ive never used pneumatic cylinders for ...
49 views

### Feedback linearization of a nonlinear MIMO system

I have to design a feedback linearization for the model of a car with a single trailer. This picture shows the system: And this is the kinematic model I got, where ...
79 views

### How to read data from the VN100 IMU on Ubuntu?

Hi I have a VectorNav VN100S Development kit, which has VN100 IMU unit. I want to set it up with Ubuntu 16.04 and ROS Kinetic, but unable to read anything from the VN-100. So far I have been ...
73 views

### Given an initial position, a goal position and a duration find a trajectory

I have an initial position $X^R_{init}$ of the robot ($x$, $y$ and yaw) and a goal position $X^R_{goal}$ I need to create a trajectory of duration $T$ with $n$ waypoints to move the robot from its ...
41 views

### Kalman Filter: Do we need to measure each entry of the output-sequence, or can we derive them?

A Kalman-Filter gets applied to a state-space model in order to obtain estimates of the state-vector. Example: Assume a car moving on a straight line in x-direction (this is a 1-dimensional problem)....
14 views

### Standard Kalman Filter applied to non-Gaussian noise data

A Kalman-Filter could be applied to sensor-readings in order to smooth them. The Kalman-Filter, however, assumes Gaussian distributed sensor-noise with zero-mean. Now, I found that my sensor-noise ...
19 views

### Question about EKF SLAM (w/ unknown correspondence) update step

In Probabilistic Robotics, page 322, the EKF SLAM update step is shown below. My question is, why is for every observed feature, $\bar{\mu}_t,\bar{\Sigma}_t$ are overwritten in lines 23,24 by the ...
24 views

### Combining gyroscope and compass to navigate in cities?

I am developing a navigation app which combines compass and gyroscope to withstand magnetic field disturbances which can be found in cities. I am able to know what the magnetic field is supposed to ...
30 views

### Questions about customized stereo camera

I am designing my robot and I have quite design issues with the available stereo cameras on a market. For the prototype I am using ZED M but it is too expensive and quite large. The question is, do ...
42 views

### What sort of dev boards or standalone microprocessors are used for controlling robotics projects?

I've been using arduino boards for powering my robotics projects, however I want to move towards a more professional method of controlling electronics. I am not sure whether standalone microprocessors/...
8 views

### How to define a massless collisionless visualless keypoint in a Gazebo simulation model (SDF)

Say I have a sdf model: ...
14 views

### Information filter sensor fusion

I am struggling with a basic implementation of the information filter. I have the equivalent Kalman filter working. The information filter appears to be harder to debug. This is mostly because we ...
84 views

### Calculate Roll Pitch Yaw from Modified Denavit Hartenberg

I'm using modified denavit hartenberg to represent my robot end-effector. But i couldnt find equation to calculate rpy if im using mdh. Below my MDH. I try use rpy equation for dh paramater(from ...
23 views

### How to derive the CoG Jacobian for biped robot?

I'm trying to derive the Center of Gravity Jacobian of a biped robot. I think that the Jacobian has a method of obtaining by partial differentiation and a method of obtaining it geometrically. This ...
94 views

### Building a stationary robot. ROS the right tool for me?

I'm wondering if ROS is the right system for me. I'm currently involved in a project which consists of building a device that has the purpose to take spectroscopic measurements using a laser and a ...
36 views

### Manipulability Measures of Serial Robots?

I need to create a dataset of dexterous workspaces for a significantly large number of serial robots with varying DoFs. My question is if there is an efficient way of measuring a robot's ...
30 views

### How to identificate uav's roll and pitch model and control to track object?

I'm building a drone distance controller for parrot mambo. I need to track a colored page with given distance and given heigth. I can get the yaw information from parrot mambo with 0.5 sec. Since I ...
32 views

### Why does singularity condition for a serial manipulator never involve the first joint variable

In planar 2R the singularity condition involves the second joint variable. In spatial 3R, singularities involve second and third link lengths and angles. Why does the first joint parameter never ...
25 views

### Task Space Control Parameters for 6-Dof Manipulator

I'm developing a Task Space controller based on speed for a Universal Robot 5. I've already calculated the Jacobian, position and rotation error for the classic control method: The method works fine ...
52 views

### Kinematics with Product-of-Exponentials terminology: not forward, not inverse

I'm working on a kinematic estimation algorithm, and am trying to come up with the right terminology. I'm using the Product-of-Exponentials formulation for kinematic chains (and ignoring position ...
45 views

### Hand-Eye calibration of a 2D barcode scanner and a robot

I have a Keyence barcode scanner that can give me the coordinates of a detected barcode in pixels. I have a 6 DOF robot whose end effector pose I know at any given time. My ultimate goal is to place a ...
22 views

### Library for GPS

Is there any difference between "tinyGPS++.h","tinyGPS.h", and "Adafruit_GPS.h"? Can I use the same code to extract the current GPS location for all these libraries?
23 views

### Observed position update after motion of the robot

The equation (14) in this paper, $$P_{Cj}=RP_{Pj}+T+e_j$$ where $P_{Cj}$ and $P_{Pj}$ are the observed positions of feature $j$ prior to and after the current robot motion, $R$(otation) and $T$(...
24 views

### Does anyone have documentation for a CoroWare Explorer?

I have inherited a CoroWare Explorer from someone who used it for their PhD research years ago. They have no documentation on the robot, and I cannot find any online. Does anyone have a user's manual ...
49 views

### How to use a map created with odometry

I'm using ROS Melodic with Gazebo 9 in an Ubuntu 18.04.2 LTS. I'm studying a robotics subject at the university and I have to create a map of a closed room with one obstacle using only odometry. The ...
15 views

### Undo pitching effect of camera when pose (y-axis) is near 90 degrees?

I am using KITTI odometry dataset whereby the camera's axis is pointing X (east), Y (down) and Z (north). It also contain the frame to frame poses of the camera (first pose is fixed as the map frame). ...
18 views

### Create a torus in SDF

How do I create a torus geometry shape in SDF? I assume I need to do it manually using the <mesh> tag but am unsure of how to proceed. Note that I am NOT ...
52 views

### Drone Mapping Project

I'm mapping my college campus with a drone (as part of an approved science project). I want to film, measure the temperature, and take infrared video at the same time. What drones are good for ...
96 views

### How to convert PointCloud2 message to a grid?

I'm using a Velodyne sensor which publishes on /velodyne_points topic, and its class type is PointCloud2. Now I want to convert ...
44 views

### How can i connect to AWS Robomaker simulation job using ros_bridge?

We have a web app which we are using to show details of robot on including video, position and feeds like lidar feed. We are using http://wiki.ros.org/rosbridge_suite Rosbridge for this successfully ...
23 views

### Robot rolls and rotates with different parameters

I am currently trying to build a robot with ackermann steering. As an example I found https://github.com/trainman419/ackermann_vehicle-1 for this robot. It works pretty well with the set parameters ...
59 views

### Electronic Speed Controller

What should be the specification of ESC that I should use for a 320KV 1820W brushless DC Motor?. Is it necessary to use an 80A ESC?, Basically, How can I choose the required ESC for a motor?
15 views

### Calculating acceleration relative to ground using an accelerometer in a drone

I use a gyroscope and an accelerometer to measure the rotation of my drone and now I would like to measure it's acceleration along the Z (Vertical) axis. Problem is I need this relative to the ground ...
55 views

I'm trying to build an Autonomous parcel delivering rover using GPS.So after giving destination coordinates, I don't know how to make the robot understand to which direction it should move. Basically, ...
140 views

### Do I need a camera along with LIDAR for SLAM?

Equipment: Pi 3 B Mega 2x Encoder Motor 12VDC 299RPM MPU 6050 12V bat 2000mAh LIDAR or Kinect ? I want to implement EKF SLAM. I have referred bot NOX ROS wandering robot, Hussarian CORE and Robotics ...
35 views

### How can I perform localisation without using LIDAR?

I want to make a self driving (autonomous) wheelchair where I want to create a map for localisation of the wheelchair. I do not want to use LIDAR as it is very expensive. Also, I do not mind if the ...
24 views

### What is an axial and polar vector?

In Robot Kinematics and Dynamics by Herman Bruyninckx, it states: Axial vectors have an inner orientation, i.e., the direction of the vector indicates the positive orientation. For example, a unit ...
99 views

### Aliexpress bought BNO055 UART connection

I bought a BNO055 module from Aliexpress which is shown in the picture below. I am able to read the IMU data in an Arduino nano from this BNO055 via an I2C connection. Now, I want to connect it to a ...
28 views

### Robot trajectory generation; path-paramerization

I have a differential drive robot, and it's supposed to drive on a parabolic function $(f(x) = x^2)$. But for all control algorithms, you have a trajectory given as $f(s)$ or $f(t)$. I want to use ...
16 views

### How to do mechanical calculations for a towing robot?

I am making an automated guided vehicle AGV will tow standard shopping carts each will weighs 20-30kg I hope to use 12V DC gear motors 100rpm torque 20kg.cm (assume the floor is smooth and flat) I ...
28 views

### Sensor complement in Drone

I saw a question posted by @Rocketmagnet (Why do I need a Kalman filter?) about the need for a Kalman filter. In that question, he says he's designing an UAV and lists the following sensors he will ...
34 views

### Roomba Create 2: how to convert steering angle to radius?

I want to set the steering angle for Roomba Create 2, and as far as I understand I can do this by setting a turning radius for the Roomba Create 2. My question is: How to convert steering angle to ...
25 views

### What is the motor that move like an elbow called

I'm trying to make wings that fold in and open. I want to have the joint of the wing controlled by a motor of some sort but I don't know what I'm looking for is called.
24 views

### Roboclaw node on ROS error: “Encoders None None”. Encoders can't be read properly. What might the cause be?

My two wheels robot was working properly with ROS Roboclaw node before changing a burnt Motor. After changing this motor with a similar motor, I reconfigured it as usual without touching the node or ...
9 views

### Using SPDT Relay for Voltage shifting in Arduino UNO and ESP8266 combination

I'm using the tinkercard.com online Arduino simulator and I have an issue. I'm trying to use the ESP8266 WiFi module with the Arduino UNO board and as the WiFi module operates on a maximum of 3.5V ...