Guy Sirton
  • Member for 8 years, 6 months
  • Last seen more than 4 years ago
  • British Columbia, Canada
How do robotics startups work?
11 votes

I can share my experience at a startup where we built what was essentially special purpose robots. I'm sure there's a wide spectrum though. A lot depends on the complexity of your robot or machine ...

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Polling or Timer interrupt?
8 votes

The processor has to execute something. You will always have an "endless" loop even if you're doing some work in an interrupt handler. The best solution depends on exactly what you're trying to do. ...

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For robot wheel control : Brushless DC motor or Servo Motor?
Accepted answer
7 votes

Let's try and clear things up a little bit... "RC Servo" motors These can be found in radio controlled cars and airplanes to e.g. turn the wheel or actuate various controls in the airplane. They ...

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What is meant by a speed profile?
Accepted answer
6 votes

Think of a motion profile as a graph of speed vs. time. If you drive your car down the road: Your initial speed is zero. You start pressing the accelerator pedal. The car starts moving slowly. You ...

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How to explain bandwidth of a measurement to a noob?
6 votes

2pietjuh2's Mom: Are you familiar with dog whistles? Dog whistles make a sound at a frequency that dogs can hear but humans can not. The sound it makes has a higher frequency than the maximum ...

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Quadcopter PID tuning
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6 votes

It looks like your proportional gain is too high. You seem to be constantly increasing RPM on one motor while locking in the other one to make the system rotate. This isn't a good control strategy as ...

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Reducing motor speed without jamming up
5 votes

When you PWM the voltage to the motor you are effectively controlling the current to the motor which is related to torque (acceleration). The "jamming up" that you notice is basically the inability ...

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Low speed control of bldc motors
Accepted answer
4 votes

Brushless DC motors should have excellant lower speed performance. Your problem is probably not the motor but rather the electronic speed controller. Those sensorless controllers generally don't ...

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Localizing a swarm of robots
Accepted answer
4 votes

Some ideas off the top of my head... Generally you can either have each robot sense it's own position or have some sort of system find the robots and send them information about their position (or a ...

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What are good strategies for tuning PID loops?
4 votes

I'll try to expand a little from my experience for those who may be interested. I think the problem is we have a lot of control theory that is somewhat inaccessible (and sometimes not useful) and ...

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How to machine aluminium on a low budget?
3 votes

As John Williams points out you can find desktop metal milling machines that are reasonably priced. However if you want to work with metal make sure the machine you're buying is designed for that. ...

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WHY are there no operating torque specifications on steppers?
3 votes

I have never seen a stepper motor manufacturer not specify the torque vs. speed. I'm not sure where you've looked but a lot of people re-sell various random equipment to hobbyists without providing ...

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

When the string isn't under tension you have a non-linear system (i.e. you're pushing on a rope) which may also make this harder to control. The stiffness of your string is going to limit your ...

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proper tuning method of an cascade controller?
2 votes

A cascaded controller simply has the output of one controller acting as the input to another. A good example of this would be in a motor control application where you typically have a current loop ...

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How Can I Measure the torque applied by a servo motor?
2 votes

There are lots of ways of measuring torque from first principles. Obviously the first problem is that you need a sensor, you have lots of options: You can use a torque sensor. ( e.g. imada.com/...

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PID control against sine wave error
2 votes

One observation is that this is a slightly different situation than the classical control problem. Your sensor is looking ahead so you're not measuring the current (or past error) but rather you're ...

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Find the difference between two consecutive sensor readings in real-time in C
2 votes

You need to store the previous value somewhere, e.g. in a static: void ... { static int previous_value = 0; int current_value = Sensor1; diff = current_value - previous_value; previous_value =...

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Choosing correct power supply for Stepper Motors
Accepted answer
2 votes

As long as the steppers are running relatively slowly, let's say a few hundred steps per second, you should be fine. Your driver uses PWM to control the current through the motor windings. In ...

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Smooth servo movement for a crawling robot
2 votes

I think the question refers to this sort of device: RC servo Those usually aren't very high performance so they're not going to be able to track a generated motion profile very well. Most commercial ...

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Why can Humans single out audio in a crowd? What would it take for a robot to do the same?
2 votes

I think there are at least three things going on: Filtering that is dependant on the location the sound is coming from. Our stereo hearing combined with certain attributes of how our ears are built ...

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SCARA Arm Lead Screw Choices
1 votes

There are a bunch of mechanical considerations but as far as the screw/motor combination is concerned you want to look at the top speed and torque requirements. Your torque requirements are a ...

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What's the difference between CAN's Motor Max Velocity vs. Profile Max Velocity?
Accepted answer
1 votes

Max Motor Speed is used to protect the motor against being driven over it's maximum speed. The units for this are RPM. Max Profile Velocity is given in same units as the profile velocity and applies ...

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differential drive PID controller
0 votes

Nice robot. The +/- 5 threshold in your code is a red flag to me. This introduces a non-linearity/discontinuity which shouldn't be needed. What is the rationale for that? If you have enough memory ...

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Benefits of the Number of Propellers
Accepted answer
0 votes

Four fixed pitch propellers is one of the simplest configurations. The motors are mounted rigidly and the control of the vehicle is 100% electronic through controlling the speed of the propellers ( ...

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Connecting a Raspberry Pi to a roomba via an FTDI cable
0 votes

Try: ser = serial.Serial('/dev/ttyUSB0', 57600) (though from a quick look at the docs your way should work too). A very common mistake is switching RX and TX. The TX from your board need to go ...

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