# All Questions

4,425 questions
12 views

### Does Create 2 have a built in optical interface (IR remote) using the Open Interface Spec

I was starting to work on the Arduino interface (and Raspberry Pi) using the USB serial cable for the Create 2 , as a baseline to build other outer loop controls. My wife asked me why I would do that,...
77 views

### Jacobian of a 6DOF arm

I have a robot with 6 DOF. I read a lot of tutorial on how to compute the Jacobian, but usually all examples are for planar robots with 2DOF. I don't understand how can I get the Jacobian of a 6 DOF ...
60 views

### Raspberry Pi Robot Car won't drive straight, right wheel is faster [duplicate]

My Raspberry Pi car bot will not drive straight at all. After examining and listening to the two motors, I noticed that the right wheel is a lot faster. I have matching wheels and the same code ...
69 views

### what is the algorithm to get position (Linear displacement and linear velocity ) using IMU (Like MPU6050)?

So I have been working on a drone project for a very long time, now I decided to work on Kalman filter which is used widely nowadays like Ardupilot. I looked at the source code so basically understand ...
168 views

### python code for closed form inverse kinematics solution

I solved the inverse kinematics of a 4DOF robotic arm (which is not planar) and I wrote this code bellow in python. The coordinates for each joint is: I considered the first three joints as a wrist ...
48 views

### Doubt with linearization and discretization process - Ekf

In the paper "State Estimation for Legged Robots - Consistent Fusion of Leg Kinematics and IMU", the authors describe the application of an extended kalman filter to estimate states of a quadruped ...
63 views

### Incremental (on-the-fly) smooth trajectory interpolation algorithm from waypoints?

short version (TL;DR): I'm receiving x(t) waypoints "online", which I must travel through at the specified times. I need an algorithm that would plan a smooth trajectory in-between them without ...
36 views

### What is the front mechanism of this robot's track called?

What is the mechanism on the front of the tracks of this robot called? They are also tracks, but they are able to be moved by the operator, and they are able to function as tracks. I've only seen ...
64 views

### smooth robot 3D trajectory using graph optimization

I want to solve a trajectory smoothing problem using graph optimization. I have asked questions on how to solve this problem in a previous post and got directed towards using graph optimization. I ...
57 views

### How to cope with an optical window limitation on 2D LiDAR?

I have a very small and cheap robot and I wanted to mount a 2D LiDAR on a bottom of it (3cm above the ground). It seems to be great as during the mapping the lidar will detect even small elevations ...
43 views

### State Space Model of Brushless DC

I am working on a project in which I want to use State Feedback Control to position control a BLDC motor in combination with a motor controller. I want to do this since translating time domain ...
41 views

### How do I compute the translation and rotation velocities of a robot

I am stuck at computing the translation and rotation of a robot moving onto an ellipse given by: $$p(t) =(m) + \cos(t)∗a + \sin(t)*b$$ where m = center of ellipse and the two axes a (horizontal) ...
39 views

### Transformation matrix between a 2D and a 3D coordinate system

I have 2 sensors : one has 2D coordinate system and the other has a 3D coordinate system (not same origin). Knowing the positions of some corresponding target points (used as fixed reference) in both ...
53 views

### Map initialization problem in Mono SLAM

I'm reading and trying to implement the paper Monofusion(V. Pradeep, C. Rhemann, S. Izadi, C. Zach, M. Bleyer and S. Bathiche, "MonoFusion: Real-time 3D reconstruction of small scenes with a single ...
78 views

### Is a printer a robot? [closed]

While formulating an answer to this question let us consider the parts and the function of the printer during its basic process. We tell the printer what we want it to do, "print this". The printer ...
58 views

### How to calculate shortest path between multiple pick and drop destinations

I have a scenario where I have multiple robots, and they have to pick and drop some items at specified locations as shown in Figure. There are 4 jobs to be done for this particular instance. How can ...
106 views

### smoothing the robot poses inbetween two known poses

I have a set of N robot poses between point A and B. I use a global localization technique to estimate poses at point A and B. As a result, I have a new corrected pose B'. Please see the figure below. ...
48 views

### What is the rectangular-shaped joint in this diagram?

What is the rectangular-shaped joint under the M1? What does it do, and what is its DOF?
40 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 ...
31 views

### How to derive the Jacobian for a floating base linkage?

I am trying to determine the Jacobian for a planar bipedal robot. I'm modeling it as a floating base system with 5 links (floating base and 2 two-link legs), which seems to be the common approach. I ...
78 views

### How to add a magnetometer in an Extended Kalman filter for innovation update?

I can't find out the response so I am posting here. My post kind of follow this one : Adding magnetic field vector to a Kalman filter but I already know that I don't have to put the magnetometer in a ...
103 views

### Noisy magnetometer data

I’m looking to develop an AHRS for which I’m using a magnetometer to correct for heading errors. I wanted to check that the magnetometer I'm using is functioning to the level of accuracy (+- 1 degree) ...
20 views

### time to Initialise or start sensor after power given [closed]

I am working on a time critical project. I use an optical sensor. I would like to know the initialisation or boot time the sensor after power given which will be in µS. How could I measure that?
58 views

### Spherical (Ball) Joint in Robot Model not Working in Gazebo

I'm having trouble including a spherical/ball joint in my robot model. I have tried using the 'ball' joint type defined by sdf (http://sdformat.org/spec?ver=1.6&elem=joint#joint_type) but the urdf ...
64 views

### Simulating the robot using moveit with ROS

I'm an absolute beginner in this field so I request you to help me although the question seems very silly. I want to send the robot (in simulation) pose goal from ROS node. I want to use to moveit ...
35 views

### How to calculate effort/torque values of a joint

I have a robotic arm with 6 DOF. For each joint, I get get the Joint Wrench, which is composed by the force and torque of the parent and child links of the joints. In other works, for joint 1 I can ...
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### How to interpret the passivity criteria equation?

In Passivity-Based Control and Estimation in Networked Robotics (among others), a passive system is defined as one that: $$\int_0^t y^T(t)u(t) dt \geq -\beta$$ for output $y$ and input $u$. I have ...
33 views

### Robotics and Software defined radio

From time to time here in the forum are messages gets posted about radio communication with quadcopters. So called “radio modems” are used for a “robot to groundstation”-communication. But the more ...
22 views

### EKF singularity problem when measurement noise R is zero

my Extended kalman filter (EKF) program works well, my estimated state vector is same as real state vector when I give any positive definite number to measurement noise R. But I want to make ...
83 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 ...
47 views

### Controlling the robot with joystick values [closed]

I struggling days with this problem : I have joystick values 0~FF for each axis. So the higher this value, the faster the axis moves. I am trying to find a way to control a robot with these values. ...
58 views

### Motor controller for two Hitec D845WP servos

I am undertaking a project using two Hitec D845WP servos running at 8.4 V. Hitec's website lists idle current of 30 mA, no load operating of 1600 mA, stall current of 10 A and ...
33 views

### Why is the contact force of the rigid-body robot model ks*xr?

In the paper "On Dynamic Models of Robot Force Control", which is written by Steven D. Eppinger and Warren P. Seering, there is a model 'rigid-body robot model'. The model is like below. In the ...
34 views

### Why information filter called information filter

We all know Information Filter is a dual representation of kalman filter. The main difference between information filter and kalman filter is the way the Gaussian belief is represented. In kalman ...
37 views

### Data Driven Modelling for Motor Position Control

I am trying to identify a plant model for a motor position control using MATLAB System identification toolbox. If it is a speed control example the data set can be generated easily. In this a case ...
75 views

### DH parameters for lynx robot

Can anyone help me out with DH parameters and axis placement for below kinematic chain?
36 views

### Forward kinematics: Findling the positions of points on lynx robot

I have a task to find position of 5 points on lynx robot. I need to write below function. This function takes theta values as input. function [ pos ] = lynx_fk( theta1, theta2, theta3, theta4, ...
21 views

### Will a change of motor driver improve motor performance?

I have this motor, from datasheet it works on the 6-12V range and has a no load current of 0.52A, and a stall current of 20A. I want to test the motor before buying an expensive motor driver. I have ...
20 views

### Naze32 flight controller not connecting to RC

Cleanflight reads my Naze32, but the RC values aren't responding at all. Everything is connected and double checked that the wires were connected properly and firmware was flashed. Just not getting ...
39 views

### project to create a lighter wall [duplicate]

We are working in a project to help blind people cross the street alone .so ,Can I create a Virtual reality wall or a holographic 3d one that is visible in the Street and in all day times ?? ( morning ...
61 views

### Arduino based quadcopter flipping problem [closed]

I have built an Arduino DUE based quadcopter and I am using HC-12 as a transmitter and receiver between my laptop and the quadcopter. What am I doing is just send a speed value from my laptop and ...
89 views

### Inverse kinematics with end effector orientation?

I'm trying to implement an inverse kinematics solver, but this time even with the end effector's orientation. I succeeded with the case when the end effector only requires the position. I learned ...
18 views

### Pnumatic sulinoid with multiple outputs

I can't figure out what solenoid I would use. Everything I search for comes up with cylinders. Not sure if it's even a sulinoid that I need. I'd like to have 8 hoses connected to a compressor. I'd ...
402 views

### ROS: catkin_make vs. catkin build

When using ROS: Why use catkin build from catkin_tools instead of catkin_make? I've been told catkin build is better but no one who tells me this can give me a reason why.
294 views

### Control a DIY Robot Arm Kit Educational Robotic Claw Set with ROS

I've just started robotics and ROS and I wondering if I can control a DIY Robot Arm Kit Educational Robotic Claw Set (I think its motherboard is arduino). You can find the kit here. Can I use ROS to ...
10 views

### What's the brand of this acoustic speaker whose operation range is 10-100 kHz?

In this paper A fully autonomous terrestrial bat-like acoustic robot - PLOS the robot that is being presented is equipped with an acoustic speaker that can generate 10-100 kHz sound waves. I want to ...
18 views

### Which algorithms to locate a static 3D object relative to a moving camera/IMU?

I am using typical setup with camera and IMU as found on a smartphone. Using this, I would like to estimate the relative pose between the camera and an object (for simplicity, let's say a cube). The ...
56 views

### Reachable Position with endeffector robotic arm

I have a 7 DOF robotic Arm. All the 7 Joints are rotational and have upper and lower joint angle limits. Now assume my end effector has a certain Pose $x = [X, Y, Z, a, b, c]$. My Question now is ...