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United Kingdom
Asked — Edited

Controlling A Kangaroo With The V4

For Dave and Richard and anyone else who is interested, here is fully working and tested code for using the Kangaroo (with bi-directional comms) via the UART on the V4 with encoder feedback.

I am still quite new with EZ scripting so the code may not be as elegant as I would like, I could not find an ASCII to decimal function in ARC so I had to write a block of code to do this DJ maybe I am missing something here?

Anyway I think this does show how fantastic and versatile the V4 is, well done DJ and team!

Tony

Code:


# -------------------------------------------------
# Name : V4_Roo_serial
# Author : Tony Ellis
# Date : 01/07/2014
# Version : 1.0
# -------------------------------------------------

definearray($byte,10)
$wheel_turn=63890
$dly=50
$FLAG=0
uartinit(0,0,19200) # initalise UART

# ***** Initalise Kangaroo
uartwrite(0,0,"D,start",13) # drive channel start
uartwrite(0,0,"T,start",13) # turn channel start
uartwrite(0,0,"T,p0",13) # this is also needed at start

#goto(START)

$val=2*$wheel_turn # load position
$COMM_CHR="DF3" # D=drive channel - F=move forward - 3=speed 3
goto(INC_POS)
halt()

:START

$val=$wheel_turn-500
$position=0
$unit=round($val/8)
$str="4000"
$x=1
goto(RAMP)
$str="7000"
$x=2
goto(RAMP)
$str="10000"
$x=3
goto(RAMP)
$str="7500"
$x=6
goto(RAMP)
$str="5500"
$x=7
goto(RAMP)
$str="2500"
$x=8
goto(RAMP)
uartwrite(0,0,"D,s0",13)
halt()


:RAMP
uartwrite(0,0,"D,s"+$str,13)
$v=$unit*$x
REPEATUNTIL($position>$v)
goto(GET_POS)
ENDREPEATUNTIL
print("position="+$position)
print("speed="+$str)
return

# -------------------------------------------------
# Subroutines

# ***** POSITION commands *****

:INC_POS # increment position subroutine
$str=tostring($val) # convert variable to string
$COMM="pi" # determine direction
IF (getcharat($COMM_CHR,1)="R")
$COMM="pi-"
ENDIF
goto(SEND_DATA)
goto(GET_POS)
REPEATUNTIL($FLAG=1)
goto(GET_POS)
ENDREPEATUNTIL
print("POSITION = "+$position)
return

:GET_POS # get current position subroutine
uartwrite(0,0,"D,getp",13)
sleep($dly)
goto(GET_DATA)
print($position)
return

# -------------------------------------------------
:SEND_DATA
$M_SPEED=(getbyteat($COMM_CHR,2)-48)*1200
$string=(getcharat($COMM_CHR,0)+","+$COMM+$str+"s"+$M_SPEED) # build data packet
uartwrite(0,0,$string,13) # send packet
sleep($dly) # delay required
return

# -------------------------------------------------
:GET_DATA
$num_bytes=uartavailable(0,0)

$data=uartread(0,0,$num_bytes)

$byte1=getbyteat($data,0) # byte 1 = command
$byte2=getbyteat($data,1) # byte 2 = ","
$byte3=getbyteat($data,2) # byte 3 = command completed status

# ***** Convert ASCII digits to decimal number
$total=0
$multiplier=1
$x=$num_bytes-2
REPEATUNTIL($x=3)#$num_bytes-7)
$byte[$x]=getbyteat($data,($x-1))
$byte[$x]=($byte[$x]-48)*$multiplier
$total=$total+$byte[$x]
$multiplier=$multiplier*10
$x--
ENDREPEATUNTIL

# ***** Determine byte 3
# $FLAG=0
IF ($byte3=80)
$FLAG=1 # "P" returned so move completed
ELSEIF ($byte3=112)
$FLAG=2 # lowercase "p" so move not completed
ELSEIF ($byte3=83)
$FLAG=3 # "S" returned so speed reached
ELSEIF ($byte3=115)
$FLAG=4 # lowercase "s" so still accelerating
ENDIF

IF ($FLAG<3)
$position=$total
ELSEIF ($FLAG>2)
$speed=$total
ENDIF
return

AI Support Bot
Related Content
Synthiam
United Kingdom
#1  
That is strange something in the UBB code is forcing a "click to watch video" piece of text in my listing? That part should read as below.

:RAMP
uartwrite(0,0,"D,s"+$str,13)
$v=$unit*$x

Thats even odder I cannot write that line of code down even outside the UBB code, it always converts it to that text note?

As I cannot give the line of code here, anyone that wants a full listing just send me a email.

Tony
PRO
Synthiam
#11  
Tony, what do you mean by Ascii to Decimal?

This will send a single byte with the value of 123...

Code:


$x = 123

uartWrite(1, 0, $x)
United Kingdom
#12  
Hi DJ

The Kangaroo returns large numbers (just 10 wheel revolutions would be 638900) in an ASCII string for position (> a byte and would require a Dword var) and I want to convert this into a single decimal number so I devised the routine (***** convert ASCII digits to decimal number) in my listing to do this. I was just not sure if their was a better way? I really like your scripting language and want to use it efficiently.

My code listing got corrupted when it was pasted into the code view. I have looked through and there are a number of omissions/problems caused by pasting it in via the code view, complete lines missing and "<" and ">" directives are even extracted from some lines.

Apologies to anyone trying to use the code but with the corrupted parts its probably unusable, as I said before I am happy to sent the script to anyone that wants it.

Tony
#13  
@Tony, the code I've been using is the one you sent me through the web.
United Kingdom
#14  
Dave, I know you have the full code, but the omissions made my script look completely wrong and it then did not make sense in places so I wanted to alert other forum members. Below is a video that shows the script working, the first demo calls for the Kangaroo to drive forward 2 wheel revolutions at slow speed (3) "DF3" you can see the returned positions from the Kangaroo (in decimal) on the screen. The second demo (on the video) is a kind of course ramp up to speed and then ramp down. I will not be using the V4 to control my Kangaroo as I have a dedicated locomotion PIC that sits as an interface for the V4 so it does not to get "bogged down" with controlling, this is why this script/demo are a bit limited as I just knocked it up quickly to help you guys on the forum.

Cube World sold all over the World, it was huge in the States and also Japan, here is a very cool Japanese TV advert
youtu.be/AotdNHrk0iM
Here is my favorite US TV advert for series 4 (sports)
youtu.be/fToQbGUT-s8
With our new cubes characters can now jump out of their cube into a tablet device.



Tony
#15  
Thanks Tony for the video. Good luck with your cube project. I hope you keep us informed of its progress.
United Kingdom
#16  
Dave, I have spent a hour and modified my rig to "independent mode" and modified my script and got it to work now in independent mode. I will spend another hour tomorrow (refine the code a bit) and send you the revised script.

Tony
#17  
@Toymaker

Rather than just sending the script to individuals, can I recommend that you put it in an EZ-B project (with nothing else) and attach the project to a post? That way months/years from now, users will still be able to download and work with it without you needing to respond to every request.

Alan
#18  
@Tony, I know how valuable and limited your time is. Your truly an exceptional and top quality person to do this for me and others here. I can't properly express how much this is appreciated. With your workload and a family life I never expected this so quickly. Thanks my friend. I hope that someday, somehow I can return the favor. :)
United Kingdom
#19  
Dave, here is the script for independent mode it works fine here, you will need to set the SPEED_MULTIPLIER var (it probably will be double my value), also wheel_turn will be half. I will send you the project file by email.

The example first goes forward 2 revolutions (at speed 9) and continues to report positions back from the Kangaroo until it reaches the target position. It then goes in reverse for 1 revolution (at speed 3) again reporting back the position. You will see a slight lag in the position printout on the script window, this is because the V4 cannot fully keep up with the Kangaroo at these baud rates so it over-runs a bit, the position will still be got to accurately though.

For channel 2 just change the command string to something like "2F7" etc

As this is a tutorial I will post the script here so all can see.

Code:


# -------------------------------------------------
# Name : V4_Roo_independent
# Author : Tony Ellis
# Date : 01/08/2014
# Version : 1.0
# -------------------------------------------------

definearray($byte,10)
$wheel_turn=63890
$dly=50
$FLAG=0
$CHANNEL=1
$SPEED_MULTIPLIER=1200
uartinit(0,0,9600) # initalise UART

# ***** Initalise Kangaroo
uartwrite(0,0,"1,start",13) # drive channel start
uartwrite(0,0,"2,start",13) # drive channel start
uartwrite(0,0,"1,p0",13) # this is also needed at start
uartwrite(0,0,"2,p0",13) # this is also needed at start

#goto(EXAMPLE_2)

# ***** Example for CHANNEL 1
$val=2*$wheel_turn # load position = 2 wheel turns
$COMM_CHR="1F9" # 1=drive channel - F=move forward - 9=speed 9
goto(INC_POS)
print("position attained")
sleep(2000)
$val=$wheel_turn # load position = 1 wheel turn
$COMM_CHR="1R3" # 1=drive channel - R=move forward - 3=speed 3
goto(INC_POS)
print("position attained")
halt()


# -------------------------------------------------
# Subroutines

# ***** POSITION commands *****

:INC_POS # increment position subroutine
$str=tostring($val) # convert POSITION variable to string
$COMM_CHR,0=tostring($CHANNEL) # convert CHANNEL variable to string
$COMM="pi" # determine direction
IF (getcharat($COMM_CHR,1)="R")
$COMM="pi-"
ENDIF
goto(SEND_DATA)
goto(GET_POS)
REPEATUNTIL($FLAG=1)
goto(GET_POS)
ENDREPEATUNTIL
print("POSITION = "+$position)
return

# -------------------------------------------------

:GET_POS # get current position subroutine
uartwrite(0,0,$CHANNEL+",getp",13)
sleep($dly)
goto(GET_DATA)
print($position)
return

# -------------------------------------------------
:SEND_DATA # assemble data packet and send to Kangaroo
$M_SPEED=(getbyteat($COMM_CHR,2)-48)*$SPEED_MULTIPLIER
$string=(getcharat($COMM_CHR,0)+","+$COMM+$str+"s"+$M_SPEED) # build data packet
uartwrite(0,0,$string,13) # send packet
sleep($dly) # delay required
return

# -------------------------------------------------
:GET_DATA # get data back from Kangaroo
$num_bytes=uartavailable(0,0)

$data=uartread(0,0,$num_bytes)

$byte1=getbyteat($data,0) # byte 1 = command
$byte2=getbyteat($data,1) # byte 2 = ","
$byte3=getbyteat($data,2) # byte 3 = command completed status

# ***** Convert ASCII digits to decimal number
$total=0
$multiplier=1
$x=$num_bytes-2
REPEATUNTIL($x=3)#$num_bytes-7)
$byte[$x]=getbyteat($data,($x-1))
$byte[$x]=($byte[$x]-48)*$multiplier
$total=$total+$byte[$x]
$multiplier=$multiplier*10
$x--
ENDREPEATUNTIL

# ***** Determine byte 3
# $FLAG=0
IF ($byte3=80)
$FLAG=1 # "P" returned so move completed
ELSEIF ($byte3=112)
$FLAG=2 # lowercase "p" so move not completed
ELSEIF ($byte3=83)
$FLAG=3 # "S" returned so speed reached
ELSEIF ($byte3=115)
$FLAG=4 # lowercase "s" so still accelerating
ENDIF

IF ($FLAG<3)
$position=$total
ELSEIF ($FLAG>2)
$speed=$total
ENDIF
return
#20  
@Tony, I said this to you privately in my last e-mail but I'd like to repeat it here publicly;

I hope I'm not starting to sound too mushy or scripted but I really do appreciate this. I'm honored to be using scripts in my B9 crafted by a designer of your caliber and fame. I really look up to you and respect and amazed at what you can do. I'm looking forward to digging into this script and seeing if I can figure it out and apply it. I'm sure I'll have a question or two. Please don't feel like you need to respond right away and help figure it out. We both have busy lives and lots to do.

I've been showing my family your Cube World commercials and some of them remember them. My 40 yr old son (I was very young when he was born ;-) ) members clearly and got real excited. He says he really wanted to buy a set when they were available but didn't have the opportunity or cash. Good luck on the new roll out when it ready. I hope you are able to let me and others on the forum know when that will be. These and your little dinosaurs would make excellent gifts for my grand kids (and me too).
#21  
Thanks, Tony for sharing this code with us.
Mel
#22  
BTW, what is the purpose of the Kangaroo? Is it just for serial communications? Or does it do something else?

thanks,
#23  
Jeez Mel.... have you been under a rock for the last 6 months lol.... What it is a how to use the kangaroo has seen a couple of major threads on the subject (including this one).... just do a search here (Dave stated a major one for his B9)...Also go to Dimension Engineering's web page to read up on it.... Why don't you take the time to read up on it.... then ask the questions...
United Kingdom
#24  
Mel, the Kangaroo is an ingenious device that converts the Sabertooth motorcontroller into a fantastically versatile closed-loop dual motor dive system (closed-loop = feedback of position etc - open loop = no feedback), so a servo is a closed-loop device as it has a feedback potentiometer. The Kangaroo also allows for encoder feedback and I use this (see my threads on it) to make my robots go in totally straight lines and precise distances. It uses an algorithm known a PID (Proportional-Integral-Derivative) which is normally quite difficult to tune, the genius thing about the Kangaroo is that it has an "autotune" function that does the tuning for you. Here is a link

en.wikipedia.org/wiki/PID_controller

Tony
#25  
Hey Mel, The auto tune on the Kangaroo X2 make set up of it very easy. It's important however to have your motor attached properly, have a feedback device like a pot or encoder attached to it and everything wired correctly. If any of these are not present the Kangaroo will sense this and shut down. This can be both good and bad as it's frustrating trying to find what's not working properly but it will also sense a catastrophe situation like a runaway or short and shut it's self down. The auto tune is a wonder and a lot of fun to watch. I love watching my robot twist and turn at different speeds while the tune is going on. Here's a few Ytube vids I found of this:





#26  
Nice , kangaroo sounds like it is an excellent add on for the sabertooth. I should pick on up after ezbs arrive.
#27  
@Joeh, I highly recommend this combination. It would be a snap and a no brainer for a guy with your talent.
United Kingdom
#28  
Josh, I second Dave's comments the Kangaroo/Sabertooth combo is an excellent PID motor controller, look at my earlier parts in this thread where I show coding the Kangaroo from EZ-Script it covers pretty much all you need to know about fully controlling motors and analysing feedback from the encoders etc.

I have though discovered a problem with the Kangaroo in that you cannot use high resolution encoders (of the type I use) in mixed mode (dual motor locomotion), I am having to design a circuit that divides the encoders outputs to get it all to work. With a single motor with high res encoder (independent mode) you should be ok, its just when the Kangaroo has to deal with 2 motors simultaneously it cannot keep up with the counts.

Tony
#29  
OK, I sort of understand now. Thanks , Guys! And, I do crawl under a rock from time to time to rest my eyes and brain.
#30  
@Tony, I can confirm that the kangaroo works perfectly in independent mode useing the high resolution encoder. That's how I'm controlling my motors and they function fine.