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Thing Used in This Project
- PHPoC Blue
- PHPoC Stepper Motor Controller
- Step Motor Car http://www.smartarduino.com/view.php?id=94504
- Ultrasonic distance sensor
- Jumper wires
The Idea
The main idea was to control a step motor-based robot by drawing route on web-based map, making the robot carry your goods to destination just by touching your finger on mobile screen.
In this project, I make a simple car without using feedback sensor. Therefore, position error is accumulated over time.
This project may inspire someone to make a perfect carrier robot by using some kind of feedback sensors to correct position error. This will be more convenient if it is combined with a routing algorithm such as Dijkstra algorithm.
How It Works
We need an image of office's map. The map's size must have the same aspect ratio as real size.
Tip: drawing map will be more exact in term of aspect ratio if it is drawn based on then floor bricks.
Map image is scaled to fit the mobile screen. When finger touch on web-based map:
- The XY coordinate (in pixel) is rescaled to image's coordinate, and then is sent to PHPoC as target position.
PHPoC converts the pixel coordinate to real coordinate (in millimeter).
PHP Code:
//pixel to millimeter
$ratio = MAP_IMG_WIDTH / MAP_REAL_WIDTH; //pixel / millimeter
$target_x /= $ratio;
$target_y /= $ratio;
MAP_IMG_WIDTH is width of map image in pixel unit.
MAP_REAL_WIDTH is real width of your office in millimeter unit.
- PHPoC calculates the direction (rotated angle) and distance based on: current position, previous direction and target position
PHP Code:
// calculate the rotate angle
$vector_x = $target_x - $pre_x;
$vector_y = $target_y - $pre_y;
$length_1 = sqrt($pre_vector_x * $pre_vector_x + $pre_vector_y * $pre_vector_y);
$length_2 = sqrt($vector_x * $vector_x + $vector_y * $vector_y);
$cosin_alpha = ($pre_vector_x * $vector_x + $pre_vector_y * $vector_y) / ( $length_1 * $length_2);
$angle = acos($cosin_alpha) * 180 / M_PI;
$dir = $pre_vector_x * $vector_y - $pre_vector_y * $vector_x;
//save new values
$pre_x = $target_x;
$pre_y = $target_y;
$pre_vector_x = $vector_x;
$pre_vector_y = $vector_y;
// calculate the distance
$dist = sqrt($vector_x*$vector_x + $vector_y*$vector_y);
- PHPoC converts the rotated angle to number of step the motor has to move and send command to step motor controller to move the motor.
PHP Code:
//angle to step
/* Theory
$chord = $angle * M_PI / 180* TRACK;
$dist_per_step = HALF_STEP_ANGLE * M_PI / 180 * WHEEL_RADIUS;
$step_num =round($chord / $dist_per_step);
*/
// Simplify
$step_num = round(($angle * TRACK) / (HALF_STEP_ANGLE * WHEEL_RADIUS)/2);
HALF_STEP_ANGLE is angle per a step in haft-step drive mode (since motors is operated under this mode).
WHEEL_RADIUS is radius of wheel.
- PHPoC converts the distance to number of step the motor has to move and send command to step motor controller to move the motor.
PHP Code:
//distance to step
$step_num = $dist / WHEEL_PERIMETER * HALF_STEP_NUM;
WHEEL_PERIMETER is perimeter of wheel
HALF_STEP_NUM is number of step per a revolution of motor in haft-step drive mode (since motors is operated under this mode).
A distance sensor is added to detect obstacles.
Source Codes
user interface <index.php>
PHP Code:
<!DOCTYPE html>
<html>
<head>
<title>PHPoC - Step Motor</title>
<meta name="viewport" content="width=device-width, initial-scale=0.7">
<style>
body {
text-align: center;
background-color: #33C7F2;
}
#cvs_frame {
margin-right: auto;
margin-left: auto;
position: relative;
background-color: #FFFFFF;
}
.canvas {
position: absolute;
left: 0px;
top: 0px;
overflow-y: auto;
overflow-x: hidden;
-webkit-overflow-scrolling: touch; /* nice webkit native scroll */
}
#layer_1 {
z-index: 2;
}
#layer_2 {
z-index: 1;
background: url(map.png) no-repeat;
background-size: contain;
border: 1px solid #000;
}
</style>
<script>
var CMD_MOVE = 2;
var RESOLUTION = 20;
var IMAGE_WIDTH = 1140, IMAGE_HEIGHT = 1562;
var ws = null;
var layer_1 = null, layer_2 = null;
var cvs_frame = null;
var ctx1 = null, ctx2 = null;
var canvas_width = 0, canvas_height = 0;
var x = 0, y = 0; //position in image coordinate (pixel)
var touch_x = 0; touch_y = 0; //position in canvas coordinate (in pixel).
var cvs_pos_x = 0, cvs_pos_y = 0;
var pre_cvs_pos_x = 0, pre_cvs_pos_y = 0;
function init()
{
//initial position
x = 16 * IMAGE_WIDTH / 25.0;
y = 22 * IMAGE_HEIGHT / 34.0;
cvs_frame = document.getElementById("cvs_frame");
layer_1 = document.getElementById("layer_1");
layer_2 = document.getElementById("layer_2");
layer_1.addEventListener("touchstart", mouse_down);
layer_1.addEventListener("touchend", mouse_up);
layer_1.addEventListener("touchmove", mouse_move);
layer_1.addEventListener("mousedown", mouse_down);
layer_1.addEventListener("mouseup", mouse_up);
layer_1.addEventListener("mousemove", mouse_move);
ctx1 = layer_1.getContext("2d");
ctx2 = layer_2.getContext("2d");
canvas_resize();
}
function canvas_clear()
{
ctx1.clearRect(0, 0, canvas_width, -canvas_height);
ctx2.clearRect(0, 0, canvas_width, -canvas_height);
}
function event_handler(event, type)
{
var pre_x = x, pre_y = y;
// convert coordinate
if(event.targetTouches)
{
var targetTouches = event.targetTouches;
touch_x = targetTouches[0].pageX - cvs_frame.offsetLeft;
touch_y = targetTouches[0].pageY - cvs_frame.offsetTop - canvas_height;
}
else
{
touch_x = event.offsetX;
touch_y = event.offsetY - canvas_height;
}
var temp_x = Math.round(touch_x / canvas_width * IMAGE_WIDTH);
var temp_y = Math.round((-touch_y) / canvas_height * IMAGE_HEIGHT);
if(type == "MOVE")
{
var delta_x = temp_x - pre_x;
var delta_y = temp_y - pre_y;
var dist = Math.sqrt(Math.pow(delta_x, 2) + Math.pow(delta_y, 2));
if(dist < RESOLUTION)
return false;
}
x = temp_x;
y = temp_y;
return true;
}
function ws_onmessage(e_msg)
{
var arr = JSON.parse(e_msg.data);
var pos_x = arr[0];
var pos_y = arr[1];
pre_cvs_pos_x = cvs_pos_x;
pre_cvs_pos_y = cvs_pos_y;
cvs_pos_x = Math.round(pos_x * canvas_width / MAX_X);
cvs_pos_y = -Math.round(pos_y * canvas_height / MAX_Y);
ctx1.clearRect(0, 0, canvas_width, -canvas_height);
ctx1.beginPath();
ctx1.arc(cvs_pos_x, cvs_pos_y, 7, 0, 2*Math.PI);
ctx1.fill();
//ctx2.lineTo(cvs_pos_x, cvs_pos_y);
//ctx2.stroke();
}
function ws_onopen()
{
document.getElementById("ws_state").innerHTML = "OPEN";
document.getElementById("wc_conn").innerHTML = "Disconnect";
}
function ws_onclose()
{
document.getElementById("ws_state").innerHTML = "CLOSED";
document.getElementById("wc_conn").innerHTML = "Connect";
ws.onopen = null;
ws.onclose = null;
ws.onmessage = null;
ws = null;
}
function wc_onclick()
{
if(ws == null)
{
ws = new WebSocket("ws://<?echo _SERVER("HTTP_HOST")?>/step_motor_car", "csv.phpoc");
document.getElementById("ws_state").innerHTML = "CONNECTING";
ws.onopen = ws_onopen;
ws.onclose = ws_onclose;
ws.onmessage = ws_onmessage;
}
else
ws.close();
}
function mouse_down()
{
if(event.targetTouches)
{
event.preventDefault();
if(event.targetTouches.length > 1)
return;
}
event_handler(event, "DOWN");
if(ws == null || ws.readyState != 1)
return;
ws.send(CMD_MOVE + " " + x + " " + y + "\r\n");
//console.log(x + ", " + y);
console.log(touch_x + ", " + touch_y);
ctx2.lineTo(touch_x, touch_y);
ctx2.stroke();
}
function mouse_up()
{
if(event.targetTouches)
{
event.preventDefault();
}
if(ws == null || ws.readyState != 1)
return;
}
function mouse_move()
{
if(event.targetTouches)
{
event.preventDefault();
if(event.targetTouches.length > 1)
return;
}
if(!event_handler(event, "MOVE"))
return;
if(ws == null || ws.readyState != 1)
return;
ws.send(CMD_MOVE + " " + x + " " + y + "\r\n");
ctx2.lineTo(touch_x, touch_y);
ctx2.stroke();
}
function canvas_resize()
{
var width = window.innerWidth;
var height = window.innerHeight;
canvas_height = height - 100;
canvas_width = Math.round(canvas_height / IMAGE_HEIGHT * IMAGE_WIDTH);
cvs_frame.style.width = canvas_width + "px";
cvs_frame.style.height = canvas_height + "px";
layer_1.width = canvas_width;
layer_1.height = canvas_height;
ctx1.translate(0, canvas_height);
ctx1.lineWidth = 5;
ctx1.fillStyle = "green";
layer_2.width = canvas_width;
layer_2.height = canvas_height;
ctx2.translate(0, canvas_height);
ctx2.lineWidth = 5;
ctx2.strokeStyle = "blue";
var touch_x = Math.round(x * canvas_width / IMAGE_WIDTH);
var touch_y = Math.round((-y) * canvas_height / IMAGE_HEIGHT);
ctx1.beginPath();
ctx1.arc(touch_x, touch_y, 3, 0, 2*Math.PI);
ctx1.fill();
ctx2.beginPath();
ctx2.lineTo(touch_x, touch_y);
}
window.onload = init;
</script>
</head>
<body onresize="canvas_resize()">
<div id="cvs_frame">
<canvas id="layer_1" class="canvas"></canvas>
<canvas id="layer_2" class="canvas"></canvas>
</div>
<p>WebSocket : <span id="ws_state">null</span></p>
<button id="wc_conn" type="button" onclick="wc_onclick();">Connect</button>
<button type="button" onclick="canvas_clear();">Clear</button>
</body>
</html>
Main task <task0.php>
PHP Code:
<?php
if(_SERVER("REQUEST_METHOD"))
exit; // avoid php execution via http request
include_once "/lib/sd_340.php";
include_once "/lib/sd_spc.php";
include_once "/lib/sn_tcp_ws.php";
define("TRACK", 191); //in mm
define("WHEEL_RADIUS", 48.2); // in mm
define("WHEEL_PERIMETER", 2*M_PI*WHEEL_RADIUS); // in mm
define("FULL_STEP_ANGLE", 1.8); //degree0
define("HALF_STEP_ANGLE", 0.9); //degree
define("FULL_STEP_NUM", 200); //step per round
define("HALF_STEP_NUM", 400); //step per round
define("MAP_IMG_WIDTH", 1140); //pixel
define("MAP_REAL_WIDTH", 25*450.0); //millimeter
define("STATE_FREE", 0);
define("STATE_PAUSE", 1);
define("STATE_MOVE", 2);
define("INF_DISTANCE", 1000); // 1000cm
function step_cmd($sid, $cmd)
{
$resp = spc_request($sid, 4, $cmd);
if($resp)
{
$resp = explode(",", $resp);
if((int)$resp[0] != 200)
echo "step_cmd : '$cmd' request error ", $resp[0], "\r\n";
if(count($resp) > 1)
return $resp[1];
else
return "";
}
else
return "";
}
function car_goto($target_x, $target_y)
{
global $pre_x, $pre_y;
global $pre_vector_x, $pre_vector_y;
global $target_step_1, $target_step_2;
global $car_state;
// calculate the rotate angle
$vector_x = $target_x - $pre_x;
$vector_y = $target_y - $pre_y;
$length_1 = sqrt($pre_vector_x * $pre_vector_x + $pre_vector_y * $pre_vector_y);
$length_2 = sqrt($vector_x * $vector_x + $vector_y * $vector_y);
$cosin_alpha = ($pre_vector_x * $vector_x + $pre_vector_y * $vector_y) / ( $length_1 * $length_2);
$angle = acos($cosin_alpha) * 180 / M_PI;
$dir = $pre_vector_x * $vector_y - $pre_vector_y * $vector_x;
//save new values
$pre_x = $target_x;
$pre_y = $target_y;
$pre_vector_x = $vector_x;
$pre_vector_y = $vector_y;
$step_num = ($angle * TRACK) / (HALF_STEP_ANGLE * WHEEL_RADIUS) /2;
if($dir < 0)
{
$target_step_1 += $step_num;
$target_step_2 += $step_num;
}
else
{
$target_step_1 -= $step_num;
$target_step_2 -= $step_num;
}
$pos_1 = round($target_step_1);
$pos_2 = round($target_step_2);
step_cmd(13, "goto $pos_1 400 1600");
step_cmd(14, "goto $pos_2 400 1600");
while((int)step_cmd(13, "get state"))
usleep(1);
while((int)step_cmd(14, "get state"))
usleep(1);
$dist = sqrt($vector_x*$vector_x + $vector_y*$vector_y);
//millimeter to step
$step_num = $dist / WHEEL_PERIMETER * HALF_STEP_NUM;
$target_step_1 += $step_num;
$target_step_2 -= $step_num;
$pos_1 = round($target_step_1);
$pos_2 = round($target_step_2);
step_cmd(13, "goto $pos_1 400 1600");
step_cmd(14, "goto $pos_2 400 1600");
$car_state = STATE_MOVE;
}
function sensor_setup()
{
// setup trigger pulse timer
ht_ioctl(0, "set mode output pulse");
ht_ioctl(0, "set div us");
ht_ioctl(0, "set repc 1");
ht_ioctl(0, "set count 5 10"); // 10us pulse width
// setup echo capture timer
ht_ioctl(1, "reset");
ht_ioctl(1, "set div us");
ht_ioctl(1, "set mode capture toggle");
ht_ioctl(1, "set trigger from pin rise");
ht_ioctl(1, "set repc 4");
}
function sensor_read()
{
ht_ioctl(1, "start"); // we should start capture timer first
ht_ioctl(0, "start"); // start trigger pulse
usleep(100000); // sleep 100ms
ht_ioctl(1, "stop");
// 1st capture value ("get count 0") is always zero.
// we should get 2nd capture value;
$us = ht_ioctl(1, "get count 1");
if($us == 0)
$dist = INF_DISTANCE;
else
{
$dist = $us * 340.0 / 2; // us to meter conversion
$dist = $dist / 10000; // meter to centimeter conversion
}
return $dist;
}
function car_loop()
{
global $target_step_1, $target_step_2;
global $car_state;
if($car_state == STATE_FREE)
return;
$pos_1 = round($target_step_1);
$pos_2 = round($target_step_2);
if(sensor_read() < 5)
{
if($car_state == STATE_MOVE)
{
$car_state = STATE_PAUSE;
step_cmd(13, "stop");
step_cmd(14, "stop");
}
return;
}
else if($car_state == STATE_PAUSE)
{
$car_state = STATE_MOVE;
step_cmd(13, "goto $pos_1 400 1600");
step_cmd(14, "goto $pos_2 400 1600");
}
$cur_step_1 = (float)step_cmd(13, "get pos");
$cur_step_2 = (float)step_cmd(14, "get pos");
if($cur_step_1 == $pos_1 && $cur_step_2 == $pos_2)
$car_state = STATE_FREE;
}
function network_loop()
{
if(ws_state(0) == TCP_CONNECTED)
{
$rbuf = "";
$rlen = ws_read_line(0, $rbuf);
if($rlen)
{
$data = explode(" ", $rbuf);
$target_x = (int)$data[1];
$target_y = (int)$data[2];
//pixel to millimeter
$ratio = MAP_IMG_WIDTH / MAP_REAL_WIDTH; //pixel / millimeter
$target_x /= $ratio;
$target_y /= $ratio;
car_goto($target_x, $target_y);
}
}
}
sensor_setup();
ws_setup(0, "step_motor_car", "csv.phpoc");
spc_reset();
spc_sync_baud(460800);
step_cmd(13, "set vref stop 2");
step_cmd(13, "set vref drive 14");
step_cmd(13, "set mode half");
step_cmd(13, "set rsnc 120 250");
step_cmd(14, "set vref stop 2");
step_cmd(14, "set vref drive 14");
step_cmd(14, "set mode half");
step_cmd(14, "set rsnc 120 250");
$pre_x = 16*450.0;
$pre_y = 22*450.0;
$pre_vector_x = 0;
$pre_vector_y = 1;
$target_step_1 = 0.0;
$target_step_2 = 0.0;
$car_state = STATE_FREE;
while(1)
{
car_loop();
if($car_state == STATE_FREE)
network_loop();
}
?>
For more detail instruction, visit https://www.hackster.io/phpoc_man/dr...e-s-map-0c356d