My first programmable robot "WSTR1.3" [and videos]

[Windt H.J.]

Hello, sorry for the English!
This is my first programmable robot called W.S.T.R.1.3.
I built this robot purely for experimentation and also because it was something I had always wanted to do!
The tracked vehicle is the well known Catweasel.
I modified the insides of the Catweasel to take other drive motors because I was not happy with the plastic gearwheels and the amount of noise the drive produced.
It also houses the drive motor batteries.
The drive motors are controlled by an MD22.
The upper part of the robot is all aluminum and houses the controller, some of the electronics and a battery for them.
The upper part is also easily removable for maintenance and upgrading.
On the very top I mounted a steppermotor with an SRF08 and CMPS03 which gives the robot an ability to scan 360°.
MD22, SRF08 and CMPS03 are connected to a C-Control I v2.02 via an emulated I2C bus, I have provided examples in the download area.

The robot is not really finished yet and future upgrades I would like to do is add wheel encoders for measuring distance and maybe an SP03.

One problem the robot still has is that it will not detect objects close to the ground, I am still working on this.

A few videos --> https://www.roboternetz.de/phpBB2/dload.php?action=category&cat_id=10

Greetings,
H.J. Windt

W.S.T.R.1.3
Environment: Indoors.
Programming language: CCBasic.
Controller: C-Control I v2.02 with Application Board 2.0
Steppermotor Controller: My own design.
I2C Sensors/ devices: MD22 / SRF08 / CMPS03 / PCF8570.
Mechanical: Catweasel / steppermotor / drive motors / timing belts / pulleys / ball bearings and housing all ordered from Conrad.
Aluminum: local hardware store and Conrad.
Dimensions LxBxH: 40,5cm x 30cm x 36cm
Weight: Not yet known.
Speed max.: Fast enough.
Speed min.: Slow enough.

[PicNick]

Good Job ! looks pretty.
One fundamental question:
W.S.T.R.1.3
What does it mean ?

[tobimc]

HI

I have just one comment:
- WOW -

Did you use a CNC-milling-machine?

best regards,
Tobi

[Manf]

The whole construction looks very well.
The construction with own gears and belts shows experience in this field.
The three hole adjustment at the side of the tower promises a lot of futher extensions. More mounting holes in the main plate will be useful.

As the shelters do not really protect the construction for outdoor use I wonder why chains instead of wheels were choosen for the cassis, it always needs a lot more power to drive.

Can you tell a little more about the objects near the ground that are not detected? If that is essential the sensor could be bent down a little and the motor for the sensor head could be placed lower, inside the tower.

Please do also tell whether answers in German are ok for you.
Manfred

[michaelb]

Hi
it looks great!
I've one question: What is a MD22?
That robot looks a little bit like this robot (http://www.wiesolator.de/)
nice greetings michael

[Windt H.J.]

Hello,
Thanks for the great comments!

@PicNick
I’m not very good at coming up with names so I thought:
I use “Windt Systems” in my programs
The Catweasel is a tracked vehicle for traveling (or roaming) rough terrains
So I just put them together: Windt Systems Terrain Roamer v 1.3.

@Tobimc
This was all done by hand.
A lot of measuring, checking, measuring…… and then sawing and drilling.
A friend at work did the 45° on the tower.

@Manf
I have always liked vehicles with chains and when I came across the Catweasel I thought “This is the vehicle I want to use!”.
In the future I want to do an outside version with independent suspension on all 8 wheels (this will also create more ground clearance and a more stable platform).

Thanks for your suggestions, I am certainly going to try placing the motor lower!
I’m using a SRF08 with the gain register set so that I get a narrower beam, but because the SRF08 is so high and the beam is narrow, objects close to the ground and close to the robot are missed.

Answers in German are okay, I may not be able to understand everything but I have found a translation website.

@michaelb
The MD22 is a 50V 5A H-Bridge Motor Driver for 2 motors with I2C, servo and analog interface.
Have a look at http://www.robot-electronics.co.uk/shop/Motor_Controllers2008.htm

Greetings,
H.J. Windt

[raoul4]

by the way where are you from?
best regards, raoul

[PicNick]

..when I came across the Catweasel I thought “This is the vehicle I want to use!”.
big decisions always come from the belly. :-)
obstacle sensing: wonder, if it makes sense to have one sensor for both long and short distances. for short dist. I'd try out GP2D12 (iR) or stuff like that.

[tobimc]

Hi!

Oh. This was shure a lot of work...
But is the MD55 not a bit too big for this motors?
I think a L298 would also be possible....

Why is your bot not outdoor-usable?
It looks so ... "outdoor"... ;)

Again: Gratulations

Best regards,
Tobi

[Florian]

Hallo Windt H.J.!
I think that my english wont be the best but I'll try it ... ;o)
Your robot looks quite good and it seemed to be hard-worked.
Now my questions:
How large is the angle of rotation of the sensor tower?
How quickly can it turn around?
Do you only use this sensor tower with the SRF08 to look around?
Is it possible to nod the tower for looking around in an other vertical angle?

I hope you all understood me ... ;o)

[Windt H.J.]

Hello again!
Thanks for the interest!
I’ll try to answer the questions the best I can.

@PicNick
Versions 1.0 to 1.2 did use the GP2D12 sensor but the beam of this sensor is really narrow which means that scanning an area takes a lot of time (the robot must move slowly or the scan could miss a object).
I was hoping to speedup the time needed for scanning by using the SRF08, which it did.
The SRF08 has a really wide field of view (~ 65° @ ~26,5cm) which can be adjusted to give a narrower field of view (~39° @ ~26,5cm).
The narrower field of view gives a much better scan resolution but also means that objects close to the ground are missed. #-o
Maybe by lowering the head and or adding a 2nd SRF08 aimed at an angle will solve this problem.

@tobimc
One motor running at full speed on a flat surface will pull about 1 amp but can peak to about 3 amps depending on the conditions (surface/ turning/ climbing).
This is still within the 5 amps that the MD22 can handle.
The MD22 has also an I2C interface which I really like, I love the I2C protocol! \:D/

The robot is not really for outdoor use because the electronics are exposed, maybe on a nice dry and sunny day I could test it outside.

@Florian
The angle of rotation is 360° in steps of 1.8°.
A full turn of 360° without scanning takes about 1,4 sec.
I only use the sensor tower to look around but I might need to add a sensor due to a problem explained above.
I have also mounted a CMPS03 on top of the head, this to keep it as far away from any magnetic fields from the drive motors ex. as possible.
The vertical angle is fixed.
I wanted to keep the head and tower as clean and simple as possible but still be interesting. 8)

Greetings,
H.J. Windt

[Florian]

Hello H.J. Windt!
Thank you for these very interesting information! :o)

[tobimc]

HI!

Ah - Oh. Okay. ;)

My problem whith these steppers is, that they can be turned when they are switched off.
Do you have a stop to callibrate the stepper?
Or how was your solution of the Problem?

Why do you turn the CMP whith the SRF?

best regards,
Tobi

[Windt H.J.]

Hello tobimc,

My problem whith these steppers is, that they can be turned when they are switched off.
Do you have a stop to callibrate the stepper?
Or how was your solution of the Problem?

Why do you turn the CMP whith the SRF?


You are correct; I use a micro-switch for calibrating the stepper.
The CMPS03 was placed on top because this is the highest point on the robot and also the middle of the bot and to keep it away from the drive motors.
The CMPS03 is only used for turning the bot.
Greetings/ Grüße,
H.J. Windt

[Dirk]

Hallo H.J.,

tolles Teil, dein Roboter!

Das wäre genau die Art von Roboter, den ich mir als Nachfolger des CCRP5, das war bei mir der Einstieg, vorstellen könnte.
Für mich käme dann der Umstieg von C-Control auf das RNBFRA Board in Frage. Ich werde wohl bald zum AVR wechseln. Nicht, weil der uC prinzipielle Vorteile gegenüber z.B. der CC2 hätte, sondern weil die Entwicklung eines ähnlichen Boards auf C-Control-Basis von CONRAD verschlafen wurde. Stattdessen gibt's da halbherzige (und teure) andere Roboter-Bausätze.

Also noch einmal: Tolle Leistung! Für mich sicher ein Vorbild für eine eigene Lösung.

Gruss Dirk

[raoul4]

hehe
ich bezweifle, dass dich Windt H.J. verstehen kann.....
mfg

[Windt H.J.]

Hello,
I can read some of the German language and I also use a translation website for Words that I don’t recognize. :wink:
Someday Conrad will probably stop with the C-Control system altogether and I will have to step over to something else I guess.
Here is also another picture of the “inside” showing the position of the drives and drive batteries.
Thanks for all the interest, comments and suggestions!
Greetings,
H.J. Windt
Glückliches neues Jahr zu jeder!

[sulu]

Hi,
this robot looks really good.
One question:
What kind of batteries did you use?

Thanks

[tobimc]

Hi!

Ah yes I see!
Is the switch exact enough to callibrate it exactly?
I'm a bit sceptic about these switchens...

Did you use any kind of tranceiver in your bot?

I think you used lead-acid batteries (is that the correct word?)?
I'm just trying Lithium Polymaer-Batteries. I bought one for 18€. It has 1200mAh, and is much smaller and lighter than my equivalent lead-acid battery.
The major disadvantage of this types of battery is, that you have to controll them all the time. But if the programm is written once (it is simple), they're fun.

best regards and a happy new year
Tobi

[Windt H.J.]

I’m using 2X 6V 3,0Ah Sonnenschein dryfit A300 lead-acid batteries connected for 12V.
I had these batteries lying around in my “laboratory”.:cheesy:
The motors can take 6V normal 9V max and I have a software restriction in place to prevent using the motors above 9 volts.

The micro switch is exact enough to calibrate the stepper but I must mention that I am using the stepper with full steps (no half steps or micro stepping).

I’m not using a transponder (have no need for it yet) but maybe in the future. :-k

Until next time, Greetings,
H.J. Windt

[tobimc]

Hi!

How long does the Bot work whith this giant power-reserve?

Hm.

best regards, Tobi

[techboy]

Hi, nice Bot!

Mfg.techboy

[Windt H.J.]

How long does the Bot work whith this giant power-reserve?

Hello,
I’m not exactly sure but I think it is around 1,25 hours.
Greetings,
H.J. Windt

[tobimc]

Hi!

Ah! not bad, not bad.

Are these bearings of the two motors directly screwed (mounted ??) onto the plastic?

best regards Tobi

[Windt H.J.]

Are these bearings of the two motors directly screwed (mounted ??) onto the plastic?

Hello,
The bearings are held in place with bearing blocks and the bearing blocks are mounted to the plastic using M3 rings, nuts and bolts.
Greetings,
H.J. Windt

[solo]

Yes its a nice one! Where did u get the Catweasel from?

[Windt H.J.]

Hello,

Where did u get the Catweasel from?

Here :arrow: www.conrad.com :-$

Greetings,
H.J. Windt

[Windt H.J.]

Hello,
I have not had very much time to work on my bot but I was able to make some short videos.
The “Just Run” video shows the bot using a program to just ride around without hitting anything.
https://www.roboternetz.de/phpBB2/dload.php?action=file&file_id=287
The “Wall Hugger” video shows the bot using another program making the bot follow a wall on its right side trying to keep a certain distance from the wall.
https://www.roboternetz.de/phpBB2/dload.php?action=file&file_id=288
Greetings,
H.J. Windt

[tobimc]

HI

This is very good!
You implimated the PWM (Pulse Width Modultaion ?? ) very well!

How do you calculate the radien in the wall-following-algorithm, and how do you convert them into PWM?

have fun,
Tobi

[Windt H.J.]

Hello,
The drive motors are connected to an MD22 (dual motor driver) and the C-Control communicates with the MD22 via my E-I2C bus.
To control the motors the controller sends 3 bytes of information to the MD22 control registers (of course the address and command bytes ex. are also sent) and the MD22 does the rest.
The bytes send are speed1 (drive speed right), speed2 (drive speed left) and acceleration.
Speeds control the direction and speeds of the motors:
0 = fast reverse…….128 = stop……..255 = fast forward
Acceleration controls the pull up time:
0 = pull up fast……………………….255 = pull up slowly.

The Wall Hugger program only uses 3 scan angles and 4 movement directions:

Scan angles:
Forward scan (front): stepper motor at position 50/ fire and read the SRF08
Corner scan (front right): stepper motor at position 35/ fire and read the SRF08
Side scan (right side): stepper motor at position 20/ fire and read the SRF08

Movement directions:
Turn left
Bear left
Forward
Bear right

No calculations are done, its just a few IF THEN’s and a few subroutines, but it would be very interesting to try calculation instead of the IF THEN’s .
Here is also a portion of the Wall Hugger code.

#start

#front_scan
steppermotor_start_position = 50 : gosub steppermotor_control
gosub get_srf08_range
if srf08_actual_range < 45 then goto turn_left

#corner_scan
steppermotor_start_position = 35 : gosub steppermotor_control
gosub get_srf08_range
if srf08_actual_range < 45 then goto turn_left
if srf08_actual_range < 55 then goto bear_left

#side_scan
steppermotor_start_position = 20 : gosub steppermotor_control
gosub get_srf08_range
if srf08_actual_range < 45 then goto bear_left
if srf08_actual_range < 55 then goto forward
goto bear_right

#turn_left
drive_speed_right = 150
drive_speed_left = 106
drive_acceleration = 255
gosub set_md22_speeds
goto start

#bear_left
drive_speed_right = 170
drive_speed_left = 144
drive_acceleration = 255
gosub set_md22_speeds
goto start

#forward
drive_speed_right = 160
drive_speed_left = 160
drive_acceleration = 255
gosub set_md22_speeds
goto start

#bear_right
drive_speed_left = 170
drive_speed_right = 144
drive_acceleration = 255
gosub set_md22_speeds
goto start
Greetings,
H.J. Windt

[Windt H.J.]

Hello,
Just for fun I added an SP03.
The SP03 is a small text to speech synthesizer with an I2C interface.
Now the bots speaks!
Greetings,

[Superhirn]

Hi,

super bot. it looks great.
But why are you registered in a german forum wehn you only speak english?

[Andun]

Maybe there is no good english speaking roboter forum in the net? :D

See how great we are .... höhöhöhöhö .... ohh ... kann you read the ö (=oe) or ist this only a confusing sing? :D

But, back to topic: Very nice Bot and the idea to speak :D What does the robot has to say? (This was my baddest english, I think ...)


Andun

[michiE]

looks great !!!

another question : how old are you ???

greets
michi

[hacker]

Perhaps...are you able to record the bot while he´s speaking on video? It might be really fun.

[tobimc]

Hi

Oh yes I also wanted to ask wether you could record a bit.
Is this synthesizer based on the (nearly) famous SpeakJet ( http://www.speakjet.com/ ) or is it completely different (of course there has to be an I²C - to - serial - converter, when the SpeakJet-case matches)?

Best regards,
Tobi

[Windt H.J.]

Hello,
@Superhirn / Andun / michiE / hacker / tobimc

Roboternetz is one of, if not THE, best sites I have ever seen and it helps that I can read some of the German language.

I can’t find my microphone but information and samples can be found here -> http://www.robot-electronics.co.uk/shop/Speech_Synthesizer_SP032006.htm

http://www.robotikhardware.de/ also imports the SP03.

Greetings,
H.J. Windt

[BiGF00T]

Well done, great job. Would a little bit more light mess with the sensors? I can't see much in the videos... :( With full contrast I can recognize your bot but still not see too much. (my digital camera has the same problem and the light in my room is too dark to compensate..)
But it's a bit like all those UFO recordings. We can't be sure if this is real. Might all be a big conspiracy of a foreign government to make us believe that foreign bot-technology is far more advanced than our own ;)