All Questions

4
votes
0answers
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 ...
3
votes
0answers
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 ...
3
votes
0answers
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 ...
3
votes
0answers
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 ...
3
votes
0answers
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 ...
3
votes
0answers
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?
3
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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). ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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'...
2
votes
0answers
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&...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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, ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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) ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 (...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
190 views

Holonomic constraint forces using Lagrange multipliers

Consider a multibody robotic system with Lagrangian $ L = \dot{q}^{T}M\dot{q} + V $ and equations of motion of the form $$M(q)\ddot{q}+C(q,\dot{q})\dot{q}+A^{T}(q)\lambda+N(q)=0 $$ where $N=\frac{\...
2
votes
0answers
68 views

How do CAD programs solve for Inverse/Forward Kinematics problem in Assembly?

I am trying to solve for the Forward kinematics of a spatial parallel manipulator. Its loop closure (LC) equations are pretty long, and are being solved using numerical methods. As I am adding more ...
2
votes
0answers
69 views

Consitent Scale in Monocular pose estimation

I just wanted to know if scale is conserved across multiple images, when doing a process such as monocular odometry. I know in reality the scale tends to drift over time due to accumulation of small ...
2
votes
0answers
61 views

How unique are Quarternions and what about the sign?

I want to track a robot's orientation in space and wanted to choose quaternions for their many advantages. However I have a few questions that I haven't found to be solved anywhere. The method I use ...
2
votes
0answers
137 views

Simple inertial 2d path planning library for arduino

I have a pretty simple 2d manipulator which uses an arduino to control a payload weighing about 2kg. I want to implement a simple 2d path planner which takes as input: Current position, velocity, ...
2
votes
0answers
383 views

real-time stereo vision system for long range (up to 100m) depth estimation

I want to implement a FPGA-based real-time stereo vision system for long range (up to 100m) depth estimation. Also, I want to use two ip cameras in the system. I have calculated depth error using the ...
2
votes
0answers
106 views

LQR for Inverted pendulumn

I'm studying an optimal control for the inverted pendulum in the following figure the state and the output of the system are defined as $$x=\begin{bmatrix}r & \theta & \dot{r} & \dot{\...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
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 ...
2
votes
0answers
399 views

How to properly calibrate a magnetometer in IMU for precise yaw?

EDIT: Moved to ElectricalEngineering StackExchange Community I'm using Sparkfun Razor IMU 9DOF sensor which incorporates accelerometer, gyroscope, and magnetometer, for giving the Euler's angles (yaw,...
2
votes
0answers
231 views

Triangulation from calibrated stereo rig

I am using a stereo rig to do SLAM, calibrated using the MATLAB Calibration Tool. I need to compute the 2D coordinates of a landmark using the observation model obtained from triangulation (the images ...

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