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1500 questions
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2 answers

Having a hard time understanding this equation in monocular EKF SLAM

Reading this paper on visual odometry, where they have used a bearing vector to parameterize the features. I am having a hard time understanding what the state propagation equation for the bearing vector term means : The vector N is not mentioned…
rookie
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why is quadrotor motion planning hard?

With introduction of incremental sampling algorithms, like PRM and RRT planning in higher dimensional spaces in reasonable computation time has become possible though it is PSPACE-hard. But why is a quadrotor motion planning problem still difficult…
boon
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Suggestions on object types (features) to track from ARDrone 2 camera

UPDATE I have aded 50 bounty for this question on the StackOverflow I am trying to implement object tracking from the camera(just one camera, no Z info). Camera has 720*1280 resolution, but I usually rescale it to 360*640 for faster…
fiz
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Are operational space and joint space dependent on each other?

Some questions about this, my friends and I argued with this problem. Are operational space and joint space dependent on each other? I know that $x_e$ (end effector's pos.) and $q$ (joint var.) can be expressed by an equation with non-linear…
david
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Pure Arduino Quadcopter

I recently bought a set of escs, brushless outrunner motors and propellers. I'm trying to perform a calibration on the esc, but I can't find how I can do that without using components other than the arduino uno itself. The setup I've managed to make…
Petros
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Syncing camera with other signals

I am not sure if this is the best place to ask this question, but hopefully someone here can give me some advice. I have a device hooked up to a data acquisition system that can provide sync out signal and record sync in signals. I need to…
James
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Programming 4-digit seven segment display using interrupts only

I have to program an autonomous bot (using an ATmega2560). It has a 4-digit seven segment display attached to it. I have to make the bot traverse through arena while continuously displaying the time in seconds on the seven segment display. I can't…
Shivendra
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How to align solidworks global origin with assembly origin while exporting in solidworks to urdf

I have created a robot model in solidworks and exported in solidworks to urdf plug-in. When exporting the co-ordinates of the model is misaligned which is causing problem while using in ROS. As you could see in picture the Z-axis is horizontal in…
user3725099
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What is the best way to attach a 3D printed part to a servo for robotics use?

I am trying to make custom parts that fit directly onto a servo. Doing this has proved more difficult than I've expected so far. I was hoping to avoid incorporating the provided servo horns into the 3D printed part, so I've been trying this method…
HlfShell
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Multi-Rate Sensor Fusion using EKF

Context: I have an IMU(a/g/m) + Wheel Odometry measurement data that I'm trying to fuse in order to localize a 2D (ackermann drive) robot. The state vector X = [x y yaw]. I'm using the odometry data to propagate the state through time (no control…
AKag
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Inverse kinematics after calibration

I am working on a 6DOF robot arm project and I have one big question. When I first derived the inverse kinematics (IK) algorithm after decoupling (spherical wrist), I could easily get the equations based on nominal DH values, where alpha are either…
David Lin
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Choosing the state vector for an EKF

Could someone help me understand the logic behind choosing a particular state space vector for an EKF? Context: Say there is a 4 wheeled robot that operates only in 2D. It is equipped with an inertial unit (a/g/m) and wheel encoders (I understand…
AKag
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Reference request: Path accuracy algorithm in the joint angle space

I am currently reviewing a path accuracy algorithm. The measured data are points in the 7 dimensional joint space (the robot under test is a 7 axes Robot, but this is not of importance for the question). As far as I know path accuracy is measured…
Johannes Trost
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Is there an alternative to manifolds when using quaternions for orientation representation in Pose Graph SLAM?

I want to implement my own pose graph SLAM following [1]. Since my vehicle is moving in 3D-space i represent my pose using a 3D-translation vector and a quaternion for orientation. [1] tells me that it's necessary to adapt their algorithm 1 by using…
morph
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PID Tuning for an Unbalanced Quadcopter: When do I know if the I-gain I've set is too high?

Good day, I am working on an autonomous flight controller for a quadcopter ('X' configuration) using only angles as inputs for the setpoints used in a single loop PID controller running at 200Hz (PID Implementation is Here: Quadcopter PID…
user123456098
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