Published June 28, 2017 © GPL3+

Drawing Route For Car On The Office's Map

This project helps control a step motor-based robot by drawing route on web-based map, making the robot carry your goods to destination.

IntermediateFull instructions provided5,245

Things used in this project

Hardware components

PHPoC Blue

PHPoC Stepper Motor Controller (S-type or T-type)

Step Motor Car

DIYables Ultrasonic Sensor HC-SR04

DIYables Jumper Wires

DIYables DC Power Jack Connector

Story

Demo

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 the 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).

//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

// 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.

//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.

//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.

Hardware Setup

Step motor controller setup

Since the car use two step motor, it needs to use two step motor controller. The command is sent from PHPoC to step motor controller in particular (smart expansion board in general) via a dedicated port and a protocol, called SPC protocol. But we don't need to care about it. The library takes care all.

What we need to do it stack two steps motor controllers on PHPoC.

Additionally, Since there can stack up to 14 smart expansion boards on PHPoC, in order identify each boards, we need to give address (called slave ID) for each boards. Addressing for each board is done by setting a dip switch. (see image)

In my case, I set address (slave ID) for two step motor controller is 13 and 14. you can look into source code, you will see some command with these slave ID, for example:

step_cmd(13, "goto $pos_1 400 1600");  
step_cmd(14, "goto $pos_2 400 1600");

Note that, the order is not important.

Connecting Step motors to Step motor controllers

Firstly, connect each motor to each controller according to this instruction. (don't care about which motor connect to which controller). When we runs source code, if the direction is inverted, just switch slave ID (13-> 14 and 14 -> 13).

In this case, I did not use Digital input port. So, ignore it

Connecting distance sensor to PHPoC

Ultrasonic distance sensor is used to detect and avoid obstacles.

Parameters Setup

Now look into source code and see which parameters we need to change to suit to your car.

Parameters of your car

in task0.php

define("TRACK",				191); //in mm 
define("WHEEL_RADIUS",		48.2); // in mm 
define("WHEEL_PERIMETER",	2*M_PI*WHEEL_RADIUS); // in mm

You need to manually measure the parameters.

TRACK : see a above images

WHEEL_RADIUS is radius of wheel.

WHEEL_PERIMETER is perimeter of wheel

Parameters of motors

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

You will get FULL_STEP_ANGLE from specification of motor. and then we can calculate the the remaining value

HALF_STEP_ANGLE = FULL_STEP_ANGLE /2

FULL_STEP_NUM = 360 / FULL_STEP_ANGLE

HALF_STEP_NUM = 360 / HALF_STEP_ANGLE

Parameter of map

in task0.php

define("MAP_IMG_WIDTH",		1140); //pixel 
define("MAP_REAL_WIDTH",	25*450.0); //millimeter

MAP_IMG_WIDTH is width of map image in pixel (check property of the image)

MAP_REAL_WIDTH is real with of your area corresponding to map. it need to be manually measured. Tips: just measure size of brick and count number of brick in your area.

in index.php

var IMAGE_WIDTH = 1140, IMAGE_HEIGHT = 1562;

Initial position of car

Initial position is position of car when PHPoC boots or resets. It must be the same among: real position (where you put your car), position setting in task0.php and index.php

In my setting, I set my car at position (15th brick, 20th brick) (see below image)

in task0.php (line 227, 228), initial position is in millimeter (450 is width of brick)

$pre_x = 15*450.0; 
$pre_y = 20*450.0;

in index.php (line 59. 60), initial position is in pixel (25 and 34 is number of brick in width and height, respectively)

//initial position 
x = 15 * IMAGE_WIDTH / 25.0; 
y = 20 * IMAGE_HEIGHT / 34.0;

If you have any question, please feel free to leave a comment!

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();
}

?>

<!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>

Credits

phpoc_man

62 projects • 406 followers

Drawing Route For Car On The Office's Map

Things used in this project

Hardware components

Story

Demo

The Idea

How it works

Hardware Setup

Parameters Setup

Schematics

car

car

Code

Main task (task0.php)

User Interface (index.php)

Credits

phpoc_man

Comments

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Drawing Route For Car On The Office's Map

Drawing Route For Car On The Office's Map

Things used in this project

Hardware components

Story

Demo

The Idea

How it works

Hardware Setup

Parameters Setup

Schematics

car

car

Code

Main task (task0.php)

User Interface (index.php)

Credits

phpoc_man

Comments

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