Community Digest

Top new questions this week:

Compute Maximum End Effector Velocity Along Path

Let's say I have a 2-link planar robot arm. The motors in both joints have maximum angular speeds that limit how fast they can spin. If I plan a path from point A to point B with a constant end ...

robotic-arm inverse-kinematics path-planning  
asked by Jacob G 3 votes
answered by Ugo Pattacini 1 vote

Range of a heading angle [0,2π) or [−π,π)

Consider the unicycle dynamics in 2D plane: $$\begin{array}{l} \dot x = v\cos \varphi \\ \dot y = v\sin \varphi \\ \dot \varphi = \omega \end{array}$$ What is the range of the heading angle $\phi$? ...

mobile-robot kinematics dynamics coordinate-system  
asked by sci9 2 votes
answered by C.O Park 2 votes

Are all micro-nanorobots are 4D printed (TPP)?

I wanted to ask if there is another way to fabricate micro-nano soft robots apart from 4D printing. What are other fabrication methods can be used to build a soft microrobot?

asked by Mirroyal Ismayilov 2 votes

Difference between CHOMP and DRL

in terms of motion planning, what are the difference between gradient-based motion planning (for instance, CHOMP and deep reinforcement learning? ...

mobile-robot robotic-arm motion-planning reinforcement-learning  
asked by Joe 2 votes

What should be my spray handle-servo interface for pull mechanism?

I am an electronics engineering student who recently started working on Arduino. As part of my efforts to wake up on time, I decided that I should make an automatic water spray alarm clock. I have all ...

servomotor mechanism  
asked by Prasanjit Rath 1 vote

Calculate Torques & Forces From Jacobian Matrix

Dear Robotics Stack Exchange, I am trying to calculate the torques and forces for a 2DOF robot. I’m used the partial differentiation method to find the Jacobian matrix. I managed to find the ...

robotic-arm kinematics torque jacobian force  
asked by Neamus 1 vote
answered by SteveO 0 votes

Uniform and non-uniform cost maps

I can not find a clear answer on the internet about the difference between a uniform and non-uniform cost map. I am interested in getting an answer in the context of grid maps for robot navigation.

mapping occupancygrid  
asked by bluegreen 1 vote
answered by Manuel Rodriguez 0 votes

Greatest hits from previous weeks:

Particle filters: How to do resampling?

I understand the basic principle of a particle filter and tried to implement one. However, I got hung up on the resampling part. Theoretically speaking, it is quite simple: From the old (and ...

localization particle-filter  
asked by Daniel Eberts 25 votes
answered by DaemonMaker 20 votes

How to rotate covariance?

I am working on an EKF and have a question regarding coordinate frame conversion for covariance matrices. Let's say I get some measurement $(x, y, z, roll, pitch, yaw)$ with corresponding 6x6 ...

asked by TheWumpus 11 votes
answered by ryan0270 8 votes

Is configuration space same as joint space?

For robotic manipulator like the one on the picture: are the configuration space and joint space equivalent? I am trying to understand difference between the two...

kinematics motion-planning forward-kinematics  
asked by Slaven Glumac 7 votes
answered by Slaven Glumac 7 votes

Simple equation to calculate needed motor torque

Suppose I have a DC motor with an arm connected to it (arm length = 10cm, arm weight = 0), motor speed 10rpm. If I connect a 1Kg weight to the very end of that arm, how much torque is needed for the ...

motor torque  
asked by Ramast 8 votes
answered by Chuck 8 votes

Which type of actuator will be suitable for a very strong robot arm?

I wish to build a robotic arm that can lift a useful amount of weight (such as 3-6 kg on an arm that can extend to approx 1.25 meters). What actuators are available to accomplish this? The main ...

mobile-robot robotic-arm actuator  
asked by Mark W 29 votes
answered by Mark Booth 28 votes

How do I calculate the required loop frequency for a servo controller?

I have a motor which drives a string connected to a load cell. I would like to implement a closed loop controller to control the load applied by the motor to the string. How do I go about determining ...

control motor force  
asked by Rocketmagnet 11 votes
answered by embedded.kyle 4 votes

Quadcopter liPo battery weight/capacity trade off

I'm trying to find where additional battery capacity becomes worthless in relation to the added weight in terms of a quadcopter. Currently with a 5500 mAh battery, 11.1V, I can get between 12 minutes ...

battery quadcopter power  
asked by Chris 35 votes
answered by embedded.kyle 41 votes

Can you answer these questions?

Convert ECEF Velocity to NED Velocity

My GNSS modules gives me one NMEA packet with ECEF velocity. My doubt is about how i convert these 3 vectors to NED frame. Can i use the conventional matrix rotation MathWorksRef. If yes, i use the ...

navigation frame gnss  
asked by Bruno Otavio 1 vote

Use 2 Cameras as 1 Stereo Camera

I have one Picamera and one normal USB Webcam and would like to use them together as one stereo camera. Is this even possible as the 2 cameras aren't exactly the same? I would like to use them in ROS ...

ros slam cameras stereo-vision monocular  
asked by DragonflyRobotics 1 vote
answered by C.O Park 0 votes

Self localization for 3 wheeled omnidirectional robot

I am trying to self localize a 3 wheeled omni directional robots using just motor encoders I followed the odometry method mentioned in equations 5,8,9 of

localization odometry  
asked by Abhinandan K 1 vote
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