Robotics Stack Exchange
Robotics Stack Exchange

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Counterweight in arm designs

I wonder why most robotic arms use large J2 (shoulder) motors rather than counterweights. What sort of complexity do they add to the design beside increase in overall weight? In fact, rather than using extra weight as counterweight, the J3 (elbow)…
John M.
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Assistance in finding correct LIDAR for short-range object detection task

I am working on a task that involves finding a distance of a moving object going a static linear object, e.g a long pole. After trying some approaches (mostly involving stereo vision), I have come up with the idea of building an array of 1D Lidars…
xen20
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Fake localization using bag file in ROS

I have a bag file that contains couple of topics needed for localization, odometry data, kinect data and /tf. What I want is watching robot's movement path in rviz after initializing robot position (even I don't know how to initial it). Any…
Maysam
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Arduino Uno getting a type of "HANGED" while runing samll code of switc debounce and Serial print

I am using Arduino UNO to read a push button every time it is pressed.Earlier i was simply reading the Digital IO pin to read the count and then i faced the condition of switch debounce regarding which i had asked a question here and get to know…
shailendra
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Implementation of a particle filter algorithm

How do you calculate the likelihood of making an observation ? Does someone have a link to a book or article that explains the math that you need to do to implement a PF algorithm? Conceptually i understand the implementation but I'm having a hard…
Shawty
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Recommendations for system to repeatedly force contact between head and desk

I frequently bang my head on my desk after performing a task poorly. I would like to eliminate the unnecessary middle step of actually performing a task poorly. As such, I would like to design a system to hold my head and repeatedly strike it…
Jason C
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given position and orientation of two coordinate frames, how to transfer a vector from one to another

given position and orientation of two coordinate frames, how can transfer a vector from one frame to another. The position is given in Cartesian space and the orientations in quaternion or Euler angels.
Alejandro
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How do I compute the derivative of the Jacobian with Matlab?

I am studying robotics, and I am trying to write a Matlab code for computing the derivative of the jacobian matrix. The formula for computing the derivative of the Jacobian is the following: so it has been done a derivation with respect to time and…
J.D.
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How do I assign the origin of the frames in the Denavit Hartenberg convention?

I am studying the Denavit Hartenberg and to practice I am using the following manipulator: I have been able to assign some of the frames almost correctly, but i did some mistakes I cannot understand. First of all, the correct solution for this…
J.D.
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where can I find a good source to study robotics kinematics and trajectory planning relative to robotic arm manipulator?

I am a student, and I have to study for a Robotics exam which consistes mainly in kinematics for a robotic manipulator and trajectory planning also for a robotic manipulator. In the part relative to kinematics, I have found many sources to study,…
J.D.
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Odd L293D behavior: Pin 16 seems to act as enable

I have a chip that is labeled L293D with a small 'ST' logo, which does not behave like I believe a L239D should: I have the chip on a breadboard with pins 4,5,12 and 13 connected to the ground rail. The positive rail gets 6V from a battery pack. A…
Juergen
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Robot - Wall Avoiding (Plinko Robot)

I am looking to build a robot that will travel and zig-zag down the hallway.It will be headed towards a wall at roughly 45 degrees and then use a IR LED to detect when a wall is nearby. From there, the robot will rotate and head towards the other…
CPK
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Choosing correct power supply for Stepper Motors

I am building a machine and need 2 Stepper Motor for that. The motors are driven using by a 3.3v arm device. I have made the following selections regarding the stepper motor, stepper motor driver and the power supply. Power Supply 12 Volt Power…
SteveIrwin
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How do "process gain" and "proportional gain" affect the Steady State Error in a PID Controlled machine?

I came across this doubt while reading the Wikipedia page on PID Control. The section on Steady-state error states: Steady-state error (SSE) is proportional to the process gain and inversely proportional to proportional gain. First of all I'm…
TheReal_Skywalker
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Rocker bogie suspension stability

From the designs usually shown of rocker bogie systems, the whole weight of platform seems to be supported by only one rod, be it differential bar or gear. Isn't this a bit unstable system because if we have arms of rover at one end we will have a…
Shivam
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