https://github.com/mattvenn/servo

https://github.com/mattvenn/servo

Last synced: about 2 months ago
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• Host: GitHub
• URL: https://github.com/mattvenn/servo
• Owner: mattvenn
• Created: 2016-05-11T09:08:35.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2016-05-12T09:24:30.000Z (about 9 years ago)
• Last Synced: 2025-04-01T18:09:55.562Z (about 2 months ago)
• Language: Arduino
• Size: 1.09 MB
• Stars: 1
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Servo testing

![setup](setup.jpg)

[video of servo following](https://www.youtube.com/watch?v=cL2WiDrB8N4&feature=youtu.be)

## Zeigler-Nichols method

https://en.wikipedia.org/wiki/Ziegler%E2%80%93Nichols_method

![oscillation.png](oscillation.png)

* ku = 8

* tu = 64 ms

So for no overshoot:

* p = 4.8

* i = 0.032

* d = 0.008

![large move](ziegler 400.png)

![small move](ziegler 20.png)

## Alternative PID alg  + tuning while loaded

* ku = 7.5

* tu = 61 ms

* p = 2.47

* i = 0.03

* d = 0.02

![large move](ziegler2 400.png)

![small move](ziegler2 20.png)

## BOM

* 12v DC brushed motor with 80:1 gearbox

* 400 ppr encoder (1600 cpr) mounted on output of motor's gearbox

* L298 H bridge

* ATMEGA328p

## Firmware

* PID loop running at 100Hz

* PWM running at 32kHz

# PSU

* 12v, current limited at 0.5A.

* Typical draw while static is 0.1A

* PSU is not going switching to constant current while moving.