msgid "train401:Program a progressive deceleration in order to avoid the mines right behind the goal."
msgstr "train401:Запрограммируйте постепенное снижение скорости, чтобы избежать мины прямо перед целью."
#. type: \b; header
#: train401-help/tdragst.txt:1
#, no-wrap
msgid "Exercise"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:3
#, no-wrap
msgid "Reach the finishing pad (25m in front of you) as fast as possible, using the instruction <code>motor( , )</code>. You will have to slow down progressively at the end of the move, otherwise the bot will get blown up on the <a object|mine>mines</a>."
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:5
#, no-wrap
msgid "You could very well write no more than <c/><a cbot|move>move</a>(25);<n/>, this would work perfectly well. However, the aim of this exercise is to learn how to use the instruction <code><a cbot|motor>motor</a></code>."
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:7
#, no-wrap
msgid "This instruction asks for two values:\n"
msgstr ""
#. type: Bullet: '1)'
#: train401-help/tdragst.txt:7
#, no-wrap
msgid "The speed of the left-hand motor."
msgstr ""
#. type: Bullet: '2)'
#: train401-help/tdragst.txt:8
#, no-wrap
msgid "The speed of the right-hand motor."
msgstr ""
#. type: \s; block (usually verbatim code)
#: train401-help/tdragst.txt:11
#, no-wrap
msgid "<c/>\tmotor( left, right );"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:13
#, no-wrap
msgid "The values must range between -1 and 1:\n"
msgstr ""
#. type: Bullet: '-'
#: train401-help/tdragst.txt:13
#, no-wrap
msgid "1 = full throttle backward"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:16
#, no-wrap
msgid ""
" 0 = stop\n"
" 1 = full throttle forward"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:18
#, no-wrap
msgid "For example, <c/>motor(0.5, 0.5);<n/> will move the motor forward with half-speed, until new instructions are given to the motors."
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:20
#, no-wrap
msgid "With the instruction <c/>motor(0.5, 0.6);<n/>, the bot will move forward with half-speed, turning at the same time slightly to the left: the right-hand motor moves a little faster (<code>0.6</code>) than the left-hand motor (<code>0.5</code>)."
msgstr ""
#. type: \b; header
#: train401-help/tdragst.txt:21
#, no-wrap
msgid "General principle"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:24
#, no-wrap
msgid ""
"In order to move forward for exactly 25 meters and not more, you must move full speed during the first 23 meters, then reduce the speed of the motors progressively during the last two meters.\n"
"The <a cbot|var>variable</a> <a cbot|object>position</a> gives you at any moment the current position of the bot, and the instruction <c/><a cbot|dist>distance</a>( , );<n/> returns the distance between two points. The best way to know where you are consists in saving the current position before the start into a <a cbot|var>variable</a>, for example a variable called <code>start</code>. Then you can calculate the distance between the starting position and your current position with <code>distance(position, start)</code>."
msgstr ""
#. type: \b; header
#: train401-help/tdragst.txt:25
#, no-wrap
msgid "The program"
msgstr ""
#. type: Bullet: '1)'
#: train401-help/tdragst.txt:26
#, no-wrap
msgid "declare the variables"
msgstr ""
#. type: \s; block (usually verbatim code)
#: train401-help/tdragst.txt:29
#, no-wrap
msgid ""
"<c/>\tpoint start;\n"
"\tfloat len;"
msgstr ""
#. type: Bullet: '2)'
#: train401-help/tdragst.txt:30
#, no-wrap
msgid "save the starting position"
msgstr ""
#. type: \s; block (usually verbatim code)
#: train401-help/tdragst.txt:32
#, no-wrap
msgid "<c/>\tstart = position;"
msgstr ""
#. type: Bullet: '3)'
#: train401-help/tdragst.txt:33
#, no-wrap
msgid "start full throttle :"
msgstr ""
#. type: \s; block (usually verbatim code)
#: train401-help/tdragst.txt:35
#, no-wrap
msgid "<c/>\tmotor(1, 1);"
msgstr ""
#. type: Bullet: '4)'
#: train401-help/tdragst.txt:36
#, no-wrap
msgid "Perform an infinite <code><a cbot|while>while</a></code> loop:"
msgstr ""
#. type: \s; block (usually verbatim code)
#: train401-help/tdragst.txt:45
#, no-wrap
msgid ""
"<c/>\twhile ( true )\n"
"\t{\n"
"\t\tlen = distance(position, start);\n"
"\t\tif ( len > 25-2 )\n"
"\t\t{\n"
"\t\t\tmotor( less than before ! );\n"
"\t\t}\n"
"\t}"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:47
#, no-wrap
msgid "As long as the distance between the start and the current position is smaller than 23m, the instruction in braces after the <code><a cbot|if>if</a></code> instruction will not be executed, so the motors keep their maximum speed as they were told by the <c/><a cbot|motor>motor</a>(1,1);<n/> instruction."
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:49
#, no-wrap
msgid "In order to slow down progressively, the speed of the motors must be proportional to the remaining distance:\n"
msgstr ""
#. type: Bullet: 'o'
#: train401-help/tdragst.txt:49
#, no-wrap
msgid "<code>2.0</code> meters left -> speed = <code>1.00</code> (maximum)"
msgstr ""
#. type: Bullet: 'o'
#: train401-help/tdragst.txt:50
#, no-wrap
msgid "<code>1.5</code> meters left -> speed = <code>0.75</code>"
msgstr ""
#. type: Bullet: 'o'
#: train401-help/tdragst.txt:51
#, no-wrap
msgid "<code>1.0</code> meter left -> speed = <code>0.50</code>"
msgstr ""
#. type: Bullet: 'o'
#: train401-help/tdragst.txt:52
#, no-wrap
msgid "<code>0.5</code> meter left -> speed = <code>0.25</code>"
msgstr ""
#. type: Bullet: 'o'
#: train401-help/tdragst.txt:53
#, no-wrap
msgid "<code>0.0</code> meter left -> speed = <code>0.00</code> (stop)"
msgstr ""
#. type: Image filename
#: train401-help/tdragst.txt:55
#, no-wrap
msgid "tdragst1"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:57
#, no-wrap
msgid "You can use the following <a cbot|expr>expression</a> <code>(25-len)/2</code> in order to calculate the value for the speed instruction that must be given to the motors."
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:59
#, no-wrap
msgid "It is now up to you to put everything together and to test the program."
msgstr ""
#. type: \b; header
#: train401-help/tdragst.txt:60
#, no-wrap
msgid "Remark"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:62
#, no-wrap
msgid "You can use values greater than 1 for the instruction <c/><a cbot|motor>motor</a>();<n/>, but the bot will not move any faster."
msgstr ""
#. type: \t; header
#: train401-help/tdragst.txt:63
#, no-wrap
msgid "See also"
msgstr ""
#. type: Plain text
#: train401-help/tdragst.txt:64
#, no-wrap
msgid "<a cbot>Programming</a>, <a cbot|type>types</a> and <a cbot|category>categories</a>."
