# All Questions

569 questions
371 views

### How does one implement a third order complementary filter for estimating altitude using data from an accelerometer and a barometer?

I am working with the CJMCU build of cleanflight on a small drone. As of now, the algorithm for altitude hold uses a first order complementary filter to combine data from the barometer and the ...
111 views

### Matlab: Simulate received signals of sonar sensors

StackExchange community! I need the guidance what to use for the generation sensor data in Matlab. My purpose is to optimize the exploration process of unknown environment using the multi-robot ...
125 views

### Examples of Zeno Behaviour in the Real World

Zeno Behaviour or Zeno Phenomenon can be informally stated as the behavior of a system making an infinite number of jumps in a finite amount of time. While this is an important Control system problem ...
621 views

### ROS MoveIt!, virtual joints, planar joints, prismatic joints

I do have a robotic application, where a 7Dof robot arm is mounted on a omnidirectional mobile platform. My overall goal is to get MoveIt! to calculate a sequence of joint movements, such that the ...
105 views

### Maximum ball screw speeds

What is the maximum rotational velocity of miniature ball-screw (diameters up to 12mm) for approximately 1000 thrust cycles, and which type/brand would that be, if the speed is limited by the ball ...
130 views

### On-board monocular odometry for quadcopter stabilization

Has anyone done this with EKF/PID on a small microcontroller? Or know of code snippets to help implementing this?
99 views

### choose ZigBee modules for full wireless mesh

What is the most common ZigBee IP Modules to create full wireless mesh mode? I know that it should be 1) coordinator and 2) router to create full-mesh But I am interesting about what kind of modules ...
25 views

### Any way to program a robot remotely?

So Udacity, Kuka and KIT are/were offering a Kuka challenge. Basically, the participants got to write code and run it remotely on a Kuka robot based in the KIT labs in Germany and submit their code ...
21 views

### Explanation of the error correction mechanism used in the Mahony filter

I’m trying to better understand how the Mahony filter works, which I believe (after much google searching) is a typical approach used to provide AHRS (Attitude Heading Reference System). I’m tying to ...
21 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 ...
13 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). ...
34 views

### Yaw drift when implementing AHRS filter fusion

I am using the Matlab AHRS filter fusion algorithm with an InvenSense ICM-20948 to determine object orientation. I seem to be obtaining reasonable results however I am getting what appears to be ...
28 views

### Overcoming or managing deadband in vehicle steering controller

I found out there is a deadband in my steering controller after several runs. The transfer function for it in the $s$-domain is $$H(s)=\frac{270\cdot e^{-0.03s}}{0.015\cdot s + 1}$$ To overcome this ...
75 views

### How to handle sensor data for a sensor-fusion algorithm

I am implementing the explicit complementary filter(see below) with a 9DOF MEMS sensors (accelerometer, magnetometer and gyroscope) for attitude estimation. Currently, the gyro and accel update rates ...
22 views

### Stereo Rectification when Extrinsics are known

Suppose I have two cameras $C_1$ and $C_2$ arranged in a stereo configuration. Let us assume that the camera is free of distortion with ideal intrinsics and that the camera extrinsics $R$ and $t$ are ...
61 views

### CNC stepper motors are loud and slow after decreasing the steps/mm from 250 to 5

I'm making a drawing robot and have hooked up my steppers to each axis. I'm using the grbl shield with arduino and nema 17 steppers. Initially the firmware was set at 250 steps/mm but with my setup ...
89 views

### Magnetometer Calibration

I'm looking at using a magnetometer in a project and I'm struggling to understand the proper procedure for calibration of the sensor. I understand that magnetometers need to be calibrated to ...
17 views

### Fiducials in conjuction with AMCL

I'm having some trouble getting fiducials (using aruco_detect) to work alongside amcl. The goal here is to use normal amcl localization when a fiducial is not present, and to switch to localization ...
29 views

### Create path with minimum curvature for Ackerman drive

I'm trying to create a trajectory between two given poses for an Ackerman drive. The poses are defined as follows: Current Pose position $(x_0, y_0)$ rotation on z-axis $\theta_0$ Final Pose ...
58 views

### Wheeled Mobile Robot State Estimation Model Using Odometry

I have a process model update that follows the form: $$\mathbf{x}_{k|k-1} = \mathbf{x}_{k-1|k-1} + \delta \mathbf{x}_k,$$ where $\mathbf{x}_{k-1|k-1}$ is the posterior estimate from the last ...
41 views

### OpenRAVE “fast-forward” physics simulation?

I am working with OpenRAVE simulator and I am using ODE Physics (OpenRAVE plugin to support ODE). I have a robot in an environment and multiple other objects that are subject to the physics engine. I ...
51 views

### How rational is it to use Intel Realsense for my affordable indoor autonomous robot?

Right now, I am using ESP32 for the motors and planning to add either Raspberry Pi Zero or ARM Cortex-M4 (STM32) and use ROS with Intel RealSense RGBD camera. How sensible is it? I am not expert in ...
43 views

### Strategy for 3D path planning over large distances with kinodynamic constraints

I was hoping to pick your brains about a problem that even after much reading has left me baffled. My Application: For the sake of simulating underwater scenarios in very large environments (up to ...
60 views

### Is there a Kinfu version that runs with ROS on an Odroid?

I have a ROS-based robot that runs on an Odroid with a 3d Camera (Openni-based) and would like to use Kinfu (or something similar) on it. I'm not sure if the Mali-GPU is fast enough, but so far I didn'...
86 views

### Position-Attitude Kalman filter with Quaternions

I want to design an EKF to estimate the position of a UAV. If I were doing this with Euler angles then I would have a state vector that would look like \begin{bmatrix}north&east&down&...
138 views

### How does marginalization of variables effect least squares SLAM energy function?

Consider a simple example of Bundle Adjustment where I have robot and landmark poses $x = \left[ x_p \text{ } x_m\right]^T$ and measurements given by $z$, such that a simple factor graph can be ...
99 views

### Multiple antenna styles on FPV without true diversity

I did a search and couldn't find a site that stood out as RC. I was hoping you guys would be closest. Here's my question. I bought a set of Eachine EV100 FPV goggles. Every resource I've looked at ...
90 views

### How to properly initialize every new pose in a Visual SLAM algorithm (namely DSO)?

My question is a bit specific, because it is linked to a certain algorithm. Therefore I didn't find any other solutions on how to go about this problem. If you could refer me to research papers, ...
29 views

### Torque commands for velocity reference motor

I have a controller board for a motor, where I can read the motor current (to transform to torque), the position, the velocity and I can give a velocity command. There is not really a torque mode on ...
641 views

### ROS Gazebo Odometry Issue

I am setting up a Gazebo model for use with the navigation stack. I have been reading the Navigation Tuning Guide and am confused about the lidar data in the odom frame. I would think that the tuning ...
99 views

### Monocular SLAM depth reconstruction

I am trying to derive the inverse depth equation used in monocular SLAM algorithms. Specifically the equation 8 of the ORB SLAM paper I am very close, except I do not understand where the (u_j-c) ...
64 views

### From a linear force actuator that spans multiple links and joints to the equivalent motor torque

I am programming/using a rigid body joint-space dynamics solver for robots in which I want to implement linear force actuators between links with their equivalent torque sources that are 'spanned' by ...
85 views

### VREP - Attaching Baxter manipulators

Trying to add manipulators to the VREP Baxter robot, I can add the gripper easily enough by adding the manipulator object in a scene to the appropriate arm tip and setting its position and rotation to ...
24 views

### Robotic vessel navigation using GIS datasets

I am trying to build an autonomous vessel able to plan the best route to a certain waypoint or to follow a pre-defined route. Currently, I have imported Esri GIS files containing elevation data (...
61 views

### Effectiveness of visual odometry algorithms (CPU usage)

My robot needs to obtain visual odometry, with a condition that the used algorithm has to have as low computational requirements as possible and the used camera/sensor shouldn't be very expensive. The ...
25 views

### Gyroscope modeling parameters

Well im trying to model a gyroscope which is MPU-6050 and i am stuck in getting the missalignment and scale factor parameters from its datasheet ... And there is another problem that the names in ...
190 views

320 views

### Are there any open source path planning libraries that implement Voronoi diagram techniques?

I've been looking into path planning for a non-holonomic robot with 3 DOF in a 2D plane and recently learned about Voronoi diagrams but I cannot find any open source planning libraries that use this ...
205 views

### Visual SLAM for wheeled robot

I would appreciate your help for choosing the appropriate real-time SLAM algorithm. I am interested in having autonomous robot, thus a SLAM component is needed for autonomous navigation. The ...
155 views

### Geometrical solution to an IK problem for a humanoid robot leg

On the attached figure, I show a graphical representation of the problem I am facing. I have developed a humanoid robot with a thigh which makes an angle with respect to the leg. It means that there ...
45 views

### What is the effect that the size of the correlation window (in pixels) has on the matching performance of stereo algorithms?

While stereo algorithms perform matching, they usually compare pixels within a region around the feature. I would like to know what effect the size of that search window has on the matching ...
160 views

### Introducing new particles in particle filters for localization

Standard particle filters can produce bad localization result if the initial particle generation step produces no particle that is close to location (and bearing) of tracked object. The accuracy ...