Asked
— Edited
V1.1.2 available on page 3
Taking on board some of the comments made recently regarding autonomous roaming, plus a few improvements I wanted to make I have updated the Ping Roam script (which if I knew it would be so popular I would have made more of an effort the first time around).
I've done some quick testing with it however my testbot runs on 4 modified servos with wheels on which isn't the best method of driving it so it may still have some bugs in... that's where you come in
Let me know if there are any bugs, anything that doesn't work quite like it should, any further improvements you want...
I did have a bug in the escape routine, which I think I have now solved. Where it has a loop in the routine to continue turning until the sensor reading is above the setpoint I think that was throwing off the return at the end of the routine, not returning to where it came from but returning to when it was told to loop. Solved with additional labels and it seems to be working now...
Changes
Boxed In check added
Escape from Boxed In added
Avoidance of left/right/left/right loops
Automatic calculation of sweep servo center position
Tidied up code
More comments added
Almost completely made with labels and gotos
And, here is the code
# Ping Object Avoidance
# Using Ultra Sonic Ping Sensor on servo for avoidance
# Version 1.1.0
# Configuration Settings
# Adjust values below for port configuration
$pingport = D0 # Change for Ping Port
$echoport = D1 # Change for Echo Port
$sweepservo = D2 # Change for sweep servo port
# Adjust values below for movement control
$reverseturn = 1 # Reverse before turn? 0 = no, 1 = yes
$maxdistance = 30 # Change for maximum distance from object before avoiding in units
$boxedindistance = 20 # Change for maximum distance for boxed in detection
$turnamount = 500 # Change for how long to turn for in ms
$reverseamount = 500 # Change for how long to reverse for in ms (if applicable)
$movementspeed = 255 # Change for movement speed
$slowturn = 127 # Change for slow turn speed
# Adjust values below for sweep configuration
$sweepmin = 10 # Change for min limit
$sweepmax = 90 # Change for max limit
$sweepservodelay = 500 # Change for delay between sweep servo movements and readings
# Testing Options
$testmode = 0 # Change to 1 if testing without PING sensor
# Do not adjust these values
$sweepcenter = $sweepmin+$sweepmax
$sweepcenter = $sweepcenter/2
$sweepcenter = Round($sweepcenter,0)
$sweepprevious = $sweepmax # Do not change
$sweepcurrent = $sweepcenter # Do not change
$SweepErrorFlag = 0 # Do not change
$BoxedInErrorFlag = 0 # Do not change
$BoxedInRun = 0 # Do not change
$SweepCenterRun = 0 # Do not change
$EscapeRun = 0 # Do not change
$ScriptErrorFlag = 0 # Do not change
$isboxedin = 0 # Do not change
$penultimatemove = "none"
$lastmove = "none"
# ------- The Script --------
# Set the start point for any loops
:begin
# Center the sweep servo
Servo($sweepservo, $sweepcenter)
# Start moving forwards
FORWARD()
# Start the detection
Goto(detect) # This line is redundant
# Detection code
# Set a label for loops and gotos
:detect
# Use random numbers if in test mode
IF ($testmode=0)
$currentdistance = GetPing($pingport, $echoport)
ELSE
$currentdistance = GetRandom(0,255)
ENDIF
# Check the current distance against the max allowed distance
IF ($currentdistance <= $maxdistance)
# If the current distance is below the max distance start avoiding
GOTO(avoid)
# Set label for avoid return to avoid return errors
:avoidreturn
ENDIF
# Run the sweeping servo code
GOTO(sweep)
# Wait
SLEEP ($sweepservodelay)
# Loop back to the start of detection
GOTO(detect)
# Avoidance code
# Set a label for loops and gotos
:avoid
# First check if boxed in
Goto(boxedin)
# If the robot is boxed in run the escape code
IF ($isboxedin = 1)
Goto(escape)
# Avoid return error after escape loop by setting a label for a goto
:escapereturn
ENDIF
# Check to see if to reverse before turning
IF ($reverseturn = 1)
# If the option of reverse before turning is set reverse
Reverse($movementspeed,$reverseamount)
ENDIF
# Check the servo position
# Check if it's to the left
IF ($sweepcurrent = $sweepmin)
# If the servo is in the lowst position (left) move right
Goto(moveright)
# Continue moving forwards
FORWARD()
# Else check if it's to the right
ELSEIF ($sweepcurrent = $sweepmax)
# If the servo is in the highest position (right) move left
Goto(moveleft)
# Continue moving forwards
FORWARD()
# Else assume it's in the middle
ELSE
# If the servo is in the center position check which side is closest to the object and move the other way
# Move and check the left side
Servo($sweepservo,$sweepmin)
# Use random numbers if in test mode
IF ($testmode=0)
$pingmin = GetPing($pingport, $echoport)
ELSE
$pingmin = GetRandom(0,255)
ENDIF
# Wait
Sleep(400)
# Move and check the right side
Servo($sweepservo,$sweepmax)
# Use random numbers if in test mode
IF ($testmode=0)
$pingmax = GetPing($pingport, $echoport)
ELSE
$pingmax = GetRandom(0,255)
ENDIF
# Wait
Sleep(400)
# Move and check the center
Servo($sweepservo,$sweepcenter)
IF ($pingmin > $pingmax)
Goto(moveright)
FORWARD()
ELSE
Goto(moveleft)
FORWARD()
ENDIF
ENDIF
# Return to the main code
Goto(avoidreturn)
# The sweep code
# Set a label for loops and gotos
:sweep
# Move in the correct direction and store previous position
# Check what the current position is
# Check if left
IF ($sweepcurrent = $sweepmin)
# Save the current position as the previous
$sweepprevious = $sweepcurrent
# Move to the next position
Servo($sweepservo, $sweepcenter)
# Save the current position
$sweepcurrent = GetServo($sweepservo)
# Else check if its center and where it was before
# If it is center and was left before
ELSEIF ($sweepcurrent = $sweepcenter and $sweepprevious = $sweepmin)
# Save the current position as the previous
$sweepprevious = $sweepcurrent
# Move to the next position
Servo($sweepservo, $sweepmax)
# Save the current position
$sweepcurrent = GetServo($sweepservo)
# If it is center and was right before
ELSEIF ($sweepcurrent = $sweepcenter and $sweepprevious = $sweepmax)
# Save the current position as the previous
$sweepprevious = $sweepcurrent
# Move to the next position
Servo($sweepservo, $sweepmin)
# Save the current position
$sweepcurrent = GetServo($sweepservo)
# Else check if right
ELSEIF ($sweepcurrent = $sweepmax)
# Save the current position as the previous
$sweepprevious = $sweepcurrent
# Move to the next position
Servo($sweepservo, $sweepcenter)
# Save the current position
$sweepcurrent = GetServo($sweepservo)
# Else something has gone wrong
ELSE
# Set an error flag for debugging purposes
$SweepErrorFlag = 1
ENDIF
# Return back to the main script
Return()
# The sweep center code
# Set a label for loops and gotos
:sweepcenter
# Set a flag so we know it has run for debugging purposes
$SweepCenterRun = 1
# Move the servo to the left position
Servo($sweepservo,$sweepmin)
# Use random numbers if in test mode
IF ($testmode=0)
$pingmin = GetPing($pingport, $echoport)
ELSE
$pingmin = GetRandom(0,255)
ENDIF
# Wait
Sleep(200)
# Move the servo to the right
Servo($sweepservo,$sweepmax)
# Use random numbers if in test mode
IF ($testmode=0)
$pingmax = GetPing($pingport, $echoport)
ELSE
$pingmax = GetRandom(0,255)
ENDIF
# Wait
Sleep(200)
# Move the servo back to the center
Servo($sweepservo,$sweepcenter)
# Check which side has the closest object
# If the object to the left is further away than the object to the right
IF ($pingmin > $pingmax)
# Move to the right
RIGHT($movementspeed,$turnamount)
# Move forwards again
FORWARD()
# Else if the object to the right is further away than the object to the left
ELSEIF ($pingmin < $pingmax)
# Move to the left
LEFT($movementspeed,$turnamount)
# Move forwards again
FORWARD()
# Else they are both the same
ELSE
# So move left - this can be customised
LEFT($movementspeed,$turnamount)
# And move forwards again
FORWARD()
ENDIF
# Retyrn to the main code
Return()
# The boxed in code
# Set a label for loops and gotos
:boxedin
# Set a flag so we know it has run for debugging
$BoxedInRun = 1
# Get distance to the side
# Move the servo to the left
Servo($sweepservo,$sweepmin)
# Use random numbers if in test mode
IF ($testmode=0)
$side1scan = GetPing($pingport,$echoport)
ELSE
$side1scan = GetRandom(0,255)
ENDIF
# Get distance to the other side
# Move the servo to the right
Servo($sweepservo,$sweepmax)
# Use random numbers if in test mode
IF ($testmode=0)
$side2scan = GetPing($pingport,$echoport)
ELSE
$side2scan = GetRandom(0,255)
ENDIF
# Get distance to the front
# Move the servo to the center
Servo($sweepservo,$sweepcenter)
# Use random numbers if in test mode
IF ($testmode=0)
$centerscan = GetPing($pingport,$echoport)
ELSE
$centerscan = GetRandom(0,255)
ENDIF
# Check if boxed in by compairing the results against a fixed boxed in distance
IF ($side1scan < $boxedindistance and $side2scan < $boxedindistance and $centerscan < $boxedindistance)
# If any are true set the boxed in flag
$isboxedin = 1
ENDIF
# Return to the main script
Return()
# The escape code
# Set a label for loops and gotos
:escape
# Set a flag so we know it has run for debugging
$EscapeRun = 1
# Reset the boxed in flag
$isboxedin = 0
# Center the sweep servo
Servo($sweepservo,$sweepcenter)
# Turn slowly
Left($slowturn)
# Set up a loop
:escapeloop
# Scan until clear
# Use random numbers if in test mode
IF ($testmode=0)
$escapescan = GetPing($pingport,$echoport)
ELSE
$escapescan = GetRandom(0,255)
ENDIF
# If the scan result is below the boxed in distance loop
IF ($escapescan < $BoxedInDistance)
# Go back to the start of the escape loop
Goto(escapeloop)
ENDIF
# Continue forwards
FORWARD()
# Return to the main script
Goto(escapereturn)
# Move Right code
# Set a label for loops and gotos
:moveright
# Check the last 2 moves to avoid left right left right loops
IF ($lastmove = "left" and $penultimatemove = "right")
# If it has been right then left dont move right again but escape from a loop
Goto(escape)
# Reset the last move
$lastmove = "none"
# Else just move right
ELSE
RIGHT($movementspeed,$turnamount)
# Save the penultimate move
$penultimatemove = $lastmove
# Save the last move
$lastmove = "right"
ENDIF
# Go back to the main script
Return()
# Move left code
# Set a label for loops and gotos
:moveleft
# Check the last 2 moves to avoid left right left right loops
IF ($lastmove = "right" and $penultimatemove = "left")
# If it has been left then right dont move left afain but escape from a loop
Goto(escape)
# Reset the last move
$lastmove = "none"
# Else just move left
ELSE
LEFT($movementspeed,$turnamount)
# Save the penultimate move
$penultimatemove = $lastmove
# Save the last move
$lastmove= "left"
ENDIF
# Go back to the main script
Return()
# End of scripts
It's also on the cloud PingAvoidanceV1.1.0
And for ease of copying and pasting (in case the forums decide to add in some emoticons) it's also on pastebin
Any and all feedback is greatly appreciated no matter how trivial. Feel free to make your own improvements and modifications (let me know what they are too - believe it or not I'm still learning too).
@McJeff0125, That's the problem with a lot of the ping sensors, the one in Melvin often reports back 255 when it isn't. That's the main reason I use IR sensors and am rewriting the above script to use 3 IR sensors in fixed positions rather than 1 ping on a servo. I have read that the voltage and current to a sensor is crucial and can have negative effects if not just right.
@derrick that sounds odd, I'll take another look at the code just in case but the reversing part shouldn't get stuck in a loop. If you open the script up and run it with the script showing it'll show you down the right hand side what's happening, and why it's getting stuck in a reverse loop - but doing this does mean no access to the Movement Panel to stop the robot so be aware of that.
my batterys were going dead, after a full charge the script seems to work well!.....lol
LOT of times using a sonar is the material,thats the reason for bad reading,same with IR can only detect certain materials.
For a good design you need both,and sometimes thats not enough.
Plus orientation of the sensor,plus size of the cone detection.
I just trying this with my BV4113 H bridge and it works then for some reason like @Derrick says it can get stuck reversing forever. Also it would be good if the robot stopped like it was thinking and then reversed
Certainly shows the power of ARC that we can simply mod a few parameters and then run it on completly different platforms
I'm getting odd issues though like the laptop connects and I can control the robot except any movement with my movement panel
I noticed my ping sensor would randomly spike to 255 when i charged the battery it went away.low voltage to the ping sensor, so i think the script would start looping...?
I'll look into it all. I just set testbot going again and it had the constant reverse problem (something that hadn't happened before). In fact, it seems it's just doing a few things not quite as it should... things that hadn't happened first time around. I'm not sure if it's connected to the fact my PC is currently bogged down by other processes too, very possibly. I will have a dedicated EZ-Robot PC sometime in the next week or so which will eliminate that.
@winstn60 is it just this project/script that is giving you the Movement Panel problems or is it a general problem you are having?
I've added in some stops in the V1.1.1 code but need to check the reversing problem, it shouldn't reverse without turning afterwards although it may be running the escape code which then doesn't get chance to run if the sensor reports > the minimum distance, so if a spurious 255 pops in it'll exit the escape and go on forwards.
The low voltage/ping sensor issue is good to know and also exactly the reason why I need to get testbot off of the box and AA batteries and on to a decent platform with the 2S LiPo (which should eliminate any voltage issues since I don't let them run below 6v)
All good things to know so thanks for testing it out. Any more problems please post about them, I'm sure there are other things that could be made better or that don't run quite right.
Hi Rich its a general problem which I never had before. I have to reboot the EZ-B board to get control back on the movement panel. But if I get your script running it works well fror a few seconds then ARC locks up or the robot goes into permanent reverse I just floormap error InvalidOperationException: Object is currently in use elswhere. Very frustrating
Are you on Skype btw I'm neil.winstanley st albans if you want a chat
I received that error for the first time tonight, never had it before and didn't pop up when it was in test mode running from random numbers with no EZ-B connected either.
No I don't have skype anymore, the latest update sent my PC a little nuts, failed to install so decided to remove it completely since I barely use it.