Simple Node.js PID controller.
$ npm install node-pid-controller
Let's take the example of a car cruise control. We want the car driving at 120km/h.
k_p
, k_i
and k_d
are the proportional, integral and derivative terms. dt
is the interval of time between two measures. If not set, it will be automatically calculated.
let Controller = require('node-pid-controller');
let ctr = new Controller({
k_p: 0.25,
k_i: 0.01,
k_d: 0.01,
dt: 1
});
You can also pass options as arguments:
let ctr = new Controller(0.25, 0.01, 0.01, 1); // k_p, k_i, k_d, dt
ctr.setTarget(120); // 120km/h
let correction = ctr.update(110); // 110km/h is the current speed
Normally, you use the correction to a measure, in a closed loop.
let goalReached = false
while (!goalReached) {
let output = measureFromSomeSensor();
let input = ctr.update(output);
applyInputToActuator(input);
goalReached = (input === 0) ? true : false; // in the case of continuous control, you let this variable 'false'
}
k_p
,k_i
,k_d
: the PID's coefficientsdt
: interval of time (in seconds) between two measures. If not provided, it will be automatically calculated.i_max
: the maximum absolute value of the integral term (optional)
mocha test
Philmod <[email protected]>