Robotics Stack Exchange
Robotics Stack Exchange

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1500 questions
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2 answers

Accelerometers in a self-balancing robot, can't we do better?

I'm currently reading on self-balancing robots that use an IMU (gyroscopes + accelerometers) to estimate their current tilt angle. Most documents that I have found say the same things: You can't just take the arc-tangent of the accelerometers data…
Julien
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What rail material is best used for linear bearings?

For the 3d printer RepRap Prusa there are several rails (smooth rods) that guide the printer head on the different axises. The printer head uses several linear bearings to glide along the rails. There isn't any specification on what kind of…
DogEatDog
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How can I improve the map in my Mobile Autonomous Robot using KINECT

A little background of my aim I am in the process of building a mobile autonomous robot which must navigate around an unknown area, must avoid obstacles and receive speech input to do various tasks. It also must recognize faces, objects etc. I am…
Shreyas Kapur
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Robotics Location Following and Tracking?

I am building a robot that will follow a target as the target moves around. I would like some help with the setup for tracking the target. The most obvious solutions are Ultrasound or Infrared sensors, but for this application, they won't work.…
RJackson
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Shedding light on "cyber-physical systems"

These days, one often hears of cyber-physical systems. Reading on the subject, though, it is very unclear how those systems differ from distributed and/or embedded systems. Examples from Wikipedia itself only make them look more like traditional…
Shahbaz
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Understanding and implementing belief space planning

I am currently working on state estimation/navigation for a system with multiple robots. As of now, what I have is each robot localizing itself with a Kalman filter, given vision based measurements. As next steps, I am aiming to do two…
HighVoltage
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Do multiple LIDAR systems in same area interfere?

LIDARs use a pulse of light to measure distance, usually from the time of flight to reflection and back. With a collection of these measurements they can determine their surroundings in two or three dimensions. LIDARs are used as one of the sensor…
Hrulga
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3 answers

What is the actual physical actuated quantity when controlling the position of a servo?

I'm trying to learn about servo control. I have seen that the most generic position control method for servos is PID, where the control input is position error. However, I am not sure about what is the actuated quantity. I am guessing that it is one…
Ayberk Özgür
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4 answers

What connectors are most reliable?

If you have used connectors for signal wiring for any length of time, you may find that they are unreliable. Specifically, I find these to be unreliable when used for a long time, with a number of disconnections and re-connections: This is due to…
ronalchn
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For servos, can it be implied that `Holding Torque = Operating Torque * 2` like with steppers?

I am following a guide that recommends using stepper motors and it has an approximate holding and operating torque. It says that if you don't know the operating torque, it is often half of the holding torque. I am adapting this to use with a servo…
Anonymous Penguin
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Motors response different with high-frequency PWM

We are making a junior soccer robot and we just got our brilliant motors from Maxon. Setting the PWM timer to low-frequencies (around 39kHz or 156 kHz ) the robot acts as expected. But this produces some problems. It puts a heavy current on…
Miro Markaravanes
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Solving Inverse Kinematics with Gradient Descent

I am trying to implement my own inverse kinematics solver for a robot arm. My solution is a standard iterative one, where at each step, I compute the Jacobian and the pseudo-inverse Jacobian, then compute the Euclidean distance between the end…
Karnivaurus
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Dropping PWM on Ardrone Parrot 2.0

I am having some issues with the ARDrone Parrot 2.0 and hope someone else may be running into the same thing. While hovering, the drone is (seemingly) randomly losing altitude then recovering . It is doing so while not being commanded any velocity…
Daman
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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 to do a complete 360° spin, provided the…
Ramast
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What to do when position control with trajectories is interrupted?

What are strategies used when trajectories, which are applied to a robotic joint, are interrupted? Say a robotic arm hits an obstacle, the controller just keeps applying the trajectory. Then at the end, the error gets so large, the torque can get…
drerD
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