How to insert data into database using a custom php MVC with ajax

I want to store data into database.

I tried this:

In the View I created this form:

<form id="addData" action="<?php echo URL ?>controles/addControl" method="POST">
    <input type="text" name="text1">
    <input type="text" name="text2">
    <input type="text" name="text3">
    <input type="submit" name="Add">
</form>

Then I created a Model

controles_model.php

public function addControl(){
    $text1  = $POST['text1'];
    $text2  = $POST['text2'];               
    $text3  = $POST['text3'];

    $stmt = $this->db->prepare("INSERT INTO `controles` (field1, field2, field3 ) VALUES(?,?,?)");
    $stmt->execute(array($text1,$text2,$text3));

    if($stmt == true){
        return "good";
    }else{
        return "wrong";
    }
}

Then I created a Controller:

controles.php

class Controles extends Controller {    
    function __construct(){
        parent::__construct();
    }
    public function index(){        
        $this->view->render('controles/index');
    }
    function addControl(){
        $this->model->addControl();
    }
}

and finally, for the JS file I created this:

$("#addControl").on('submit', function(e){
    e.preventDefault();

    var url     = $(this).attr('action');
    var data    = $(this).serialize();

    $.post(url, data, function(response) {
        if(response == "good"){
            $("#insertedSuccessfully").show();
        }else if(response == "wrong"){
            $("#notInserted").show();
        }   
    });
});

All this doesn't work. How can I fix it?

NB: the database connection is OK, it work fine sine I can retreive data from database.