Robotics Stack Exchange
Robotics Stack Exchange

Most Popular

more tags
1500 questions
5
votes
4 answers

Controlling a system with PID that resists backdrive

I'm controlling the angular position of a pendulum using a DC motor with a worm gearbox. Mechanically, worm gears are impossible to backdrive. Using a PID controller on a pendulum system with a regular DC motor (no worm gear), the integrator would…
Dan Laks
  • 151
  • 2
5
votes
2 answers

Different Particle Filter min and max particle numbers give almost the same result

I'm using amcl package in ROS to localize a mobile robot. I've changed min_particles and max_particles several times then calculated the output difference with odomotry to evaluate these parameters. The table below demonstrate results; As you see,…
Maysam
  • 345
  • 3
  • 11
5
votes
3 answers

Mahalanobis distance between 2 line features

I am implementing the ATLAS SLAM framework for a ground robot, using EKF Slam for local maps and using line segment features. The line segment features can be abstracted to their respective lines [d,α] where d and α represent the distance and angle…
crystalbass17
  • 51
  • 3
5
votes
2 answers

"Smooth" inverse kinematics model for 2-wheeled differential drive robot

I have been reading about kinematic models for nonholonomic mobile robots such as differential wheeled robots. The texts I've found so far all give reasonably decent solutions for the forward kinematics problem; but when it comes to inverse…
xperroni
  • 1,353
  • 9
  • 18
5
votes
1 answer

How to make one robot follow the other in parallel formation

This is quite a basic question. I'm practising robot programming with VRep. I have 2 K3 robots in the scene. One robot follows a predefined path. I want the second robot to move "in parallel" with the first one so they keep same orientation and same…
Archer
  • 153
  • 2
5
votes
2 answers

Does it matter if my electronic speed controllers are close to my brushless motors?

I have built several quadcopters, hexacopters, and octacopters. Between the flight controller (I use 3DR APM2.6 or Pixhawk) and the motors I use heavy duty power wires as well as a servo-style cable carrying a PWM control signal for the ESC. Three…
foobarbecue
  • 643
  • 5
  • 15
5
votes
3 answers

Can I reuse the hall sensors in a brushless motor as an encoder?

I have upgraded the motors in my robotic arm to sensored, brushless RC car motors. The hope was to reuse the Hall sensors to double as a rotary encoder, by tapping 2 Hall sensors and treating the 2 bits as a quadrature signal (a crude quadrature…
Yale Zhang
  • 241
  • 1
  • 5
5
votes
5 answers

How does a robot efficiently store a map it makes?

From what I understand, you can create a map using sensors and storing values in an array. For example, the array can have 0's for places not visited, and 1's for places visited, or 0's for open spaces and 1's for occupied spaces, etc. The map…
Alligator
  • 153
  • 4
5
votes
2 answers

Can you identify the construction material/system used in the pic?

What's the name of the "big meccano" used in the photo below to construct all the cabinets and racks? It appears to be an aluminium cut-to-length system of 4-way rails. I've seen it used many times and assume it has a well-known brand-name to those…
Luke Puplett
  • 153
  • 4
5
votes
4 answers

Why linkage-based haptic devices are much more common than cable (tension)-based ones?

According not only to this link, but in my humble opinion to common sense as well, cable-based haptic devices have got lower inertia and are less complicated mechanically. I also believe that controlling them is not that big deal - the inverse…
Antek
  • 163
  • 5
5
votes
2 answers

What kind of motor control can I implement if I cannot use an Encoder?

Every time I see a PID control for a motor, it involves an Encoder, so the algorithm knows the real position of the motor or wheel. But with the robot I have, I cannot use an encoder. I only have ONE optocoupler per wheel which can count how many…
Chirrin Dul
  • 51
  • 2
5
votes
3 answers

How much should I expect a Kalman filter to converge?

I am learning about Kalman filters, and implementing the examples from the paper Kalman Filter Applications - Cornell University. I have implemented example 2, which models a simple water tank, filling at a constant rate. We only measure the tank…
Rocketmagnet
  • 6,457
  • 5
  • 29
  • 54
5
votes
4 answers

What are the advantages of optimal control as opposed to control theory?

For a robot, say path planning in particular, what are the pros and cons of choosing classical control theory or optimal control (LQR for example) ?
Raaj
  • 195
  • 2
  • 7
5
votes
4 answers

What is the minimum number of RC channels required to control a Quad Copter?

Most of the blogs/website say we need a minimum of four channels for a quadcopter (pitch, roll, throttle, yaw): One channel for throttle A second channel for turning right and left. A third channel for pitching forward and backward. A fourth one…
user1474918
  • 51
  • 1
  • 1
  • 4
5
votes
1 answer

Quadcopter Throttle and PID mixing to Motor Speed

I've been writing some quad copter software and I am not sure what the best way is to map the throttle and PID inputs to ESC power. My throttle range is 0-1 and my PID outputs are 0-1. My ESC's have a range of 1060us to 1860us. I have mapped the…
Joseph Roberts
  • 227
  • 3
  • 8
1 2 3
…
99 100