Frequent Questions
788 questions
84
votes
9
answers
350k
views
What are good strategies for tuning PID loops?
Tuning controller gains can be difficult, what general strategies work well to get a stable system that converges to the right solution?
- 1,357
31
votes
3
answers
10k
views
What is a suitable model for two-wheeled robots?
What is a suitable model for two-wheeled robots? That is, what equations of motion describe the dynamics of a two-wheeled robot.
Model of varying fidelity are welcome. This includes non-linear models,...
- 3,104
7
votes
3
answers
9k
views
What iRobot products support the open interface besides the iRobot Create?
I have read that certain iRobot products support or can be hacked to support something close to the open interace. There is even a book about hacking Roomba. What Robots have this capability?
- 123
1
vote
3
answers
4k
views
ros2 spinning problem[SOLVED]
i'm trying to transform ego-planner-swarm founded in:
https://github.com/ZJU-FAST-Lab/ego-planner-swarm
to ros2...
the problem was in one of the subscription's callbacks there was a function in which ...
70
votes
5
answers
12k
views
Why do I need a Kalman filter?
I am designing an unmanned aerial vehicle, which will include several types of sensors:
3-axis accelerometer
3-axis gyroscope
3-axis magnetometer
horizon sensor
GPS
downward facing ultrasound.
A ...
- 6,449
16
votes
2
answers
19k
views
Calculate position of differential drive robot
How do you calculate or update the position of a differential drive robot with incremental sensors?
There is one incremental sensor attatched to each of the two differential wheels. Both sensors ...
- 405
19
votes
7
answers
8k
views
Robot never goes straight
I am using 2 identical DC motors and a castor wheel. The motors are connected to L293D motor driver and are controlled by RPi.
The robot is not going straight. It veers off to the right. I am ...
- 313
9
votes
2
answers
7k
views
Line Follower optimization
I'm working on building a line follower robot and want to optimize its performance. It was suggested that I use a PID algorithm. I read a lot about PID but am confused a bit regarding following:
I've ...
- 221
7
votes
1
answer
1k
views
understanding the PID controller
I am trying to understand the effects of P, I and D constants in a PID controller on a system.
As far I've understood, P and I make the system 'faster', and D makes it 'slower'(which I read in books),...
- 345
38
votes
11
answers
58k
views
Preventing leaks in motor shafts for underwater bots
Whenever building an aquatic bot, we always have to take care to prevent leakages, for obvious reasons. Now, holes for wires can be made watertight easily--but what about motors? We can easily seal ...
- 1,833
32
votes
6
answers
63k
views
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 ...
- 420
28
votes
8
answers
19k
views
Absolute positioning without GPS
Using an IMU a robot can estimate its current position relative to its starting position, but this incurs error over time. GPS is especially useful for providing position information not biased by ...
- 2,192
22
votes
4
answers
7k
views
What frequency does my quadcopter output-sense-calculate-output update loop need to stay stable?
With a 600 mm (2 foot) motor-to-motor quadcopter, what frequency does my output-sense-calculate-output update loop need to stay stable?
I'm estimating a total takeoff weight of very roughly 2 pounds (...
- 4,565
21
votes
5
answers
21k
views
How can I use the Arduino PID library to drive a robot in a straight line?
I would like to create an Arduino based robot with 2 wheels, quadrature encoders on each wheel, a H-bridge driver chip (or motor controller) and a caster. I want to use the PID library to ensure the ...
- 361
19
votes
3
answers
3k
views
What is the best way to power a large number (27) servos at 5 V?
I apologize if this question may sound a little vague. I am working on a robotics project that will contain 27 servos of various sizes and I am having trouble figuring out how they should be powered.
...
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