Demag H135

[Emilus]

Hello,

I`d like to introduce my newest construction –strongly inspired by DEMAG H135 LEGO digger

Here I wish to say thank you to friends who were there for me with their advice and information. So thank you Zbik, Gen… and others, as well as a certain digger operator from Canada. My special thanks to TT for his overall help and lending me his NXT air pressure sensor (more about it here:

The original:

Here I intend to change the traditional way of Mocs presentation, because I don`t think it`s possible to combine a technical description of a digger and avoid yawning from those who are not really into technical stuff but rather videos/snapshots. This is the reason why I`m going to have a two-part description. The first part (Digger in a nutshell) is going to deal with the basics, snapshots and videos. It`s intended for those who are not really into how it`s constructed or how it works. The other part (Digger-making of) is going to include the description of the way the digger is built, how it works and about the software used and written on my own. Also, there`s going to be VIP`s snapshots.

Welcome to the first part – Digger in a nutshell:

My Demag H135 is likely to be the first remote controlled (Bluetooth and NXT) pneumatic digger. All the sections of the boom move smoothly, which is possible partly thanks to the software I wrote. The software is the latest version which enables the remote control of Lego pneumatic valves with pressure above 30 PSI)

A couple of snapshots:

What is unique about this model is the way it is steered. My aim was to make it as close to reality as possible. To achieve this goal I took a short digging course in a real digger (the footage here:

. Having gained new knowledge I equipped my digger with a steering console (and wrote the software). The console has two joysticks which operate on two axes and which have the same functions as their real counterparts.

Basic data:

Weight:

Length (the boom extended maximally)

Width:

Height: (the boom lifted maximally)

Items I used in my model (the digger and steering console)

-4 NXT

-1 battery box

-1 battery box SMALL (with AAA batteries, it`s on the other side of the cabin from the front, imitates the conditioning-cooling assembly and functions as counterweight to the heavy cabin). It has AAA batteries but remains disconnected electrically, it`s just for the weight)

-1 IR turret

-1 regular remote control IR

-3 NXT sensors

-1 pneumatic pressure sensor (more about it: http://translate.google.nl/translate?hl=en&sl=pl&tl=en&u=http%3A%2F%2Fwww.lugpol.pl%2Fforum%2Fviewtopic.php%3Fp%3D208965)

-3 NXT motors(serva)

-3 XL motors

-2 medium motors

-10 big new type pneumatic servo mechanisms and 4 big old type ones

-4 pneumatic valves

-6 old type pneumatic pumps

-1 compressed air pressure measuring manometer

-scores of other items

Video of my digger driving:

Video showing my digger operating with the steering console visible:

Video showing the digger lifting:

Video showing the digger digging:

Video showing the digger digging from operator's cab:

I`d like to accentuate that the software I wrote for the digger steering is designed in a way which enables smooth steering sensitivity changing and the tempo of the boom`s movements. Obviously, the operator`s skills and the right joysticks manning add up to enhancing the smooth movement of the boom. In the video you can see me maneuver the boom faster or more slowly on purpose. I`m satisfied with the joysticks` movements because it enables the operator to operate them slowly or fast, exactly as he wishes.

When it comes to the looks, I tried my best to make the construction and the boom characteristic for MT. Some units (eg. The cabin) have already been built as MT. In the cabin there is a rubber chair (intact for 3 years) and openable door, so typical of me. Hopefully you`ll like the looks of it.

Demag Brickshelf Gallery:

http://www.brickshelf.com...gi?f=491020&n=0

VIP Demag Brickshelf Gallery):

http://www.brickshelf.com...ry.cgi?f=491025

Thank you for attention. I`d like to inform that the rest of the text is going to be dealing with the way the digger was built, so those not really fond of technical stuff can quit reading now.

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Welcome to the other part of my description – The digger – Making of:

The model is the crowning of all my efforts to construct a system combining smooth remote operation of pneumatic pressured valves. I`m going to start with focusing on the machine mechanics just to continue with the description of the steering console. My descriptions are going to deal with both the mechanics and the software.

First the undercarriage:

The undercarriage is created as a carrier of two NXTs (containing 6 batteries), which I used in my model. The NXT in the undercarriage operates the Xl that in turn operates the turret turning (program reduction) and the sensor of pneumatic pressure (which turns the compressor on or off). Also, the NXT propels two Xls which drive the compressor. The additional function of the NXT in the undercarriage is to emit the sound signal (horn).

In the undercarriage you can also find two PF medium Motors. These drive tracks using 24:1 reduction (worm on 24 teeth). There are four cables linking the undercarriage with the turret. Together with one pneumatic wire they are connected to the turret through a turntable. Because of this there is no possibility of endless turret turning around the undercarriage)

Turret:

Inside the turret there are: NXT brick with 6 batteries, a compressor (made up of six small pneumatic pumps, propelled by two PF XL motors with acceleration of 1:2), three electrovalves (LEGO pneumatic valves steered by NXT-servo motors), a batterybox, an IR turret and a pneumatic manometer. The turret is also a frame on which three modules of casing are mounted.

Electrovalves construction is based on NXT motor, which not only operates the valve but also constitutes its frame:

The NXT brick put in the turret propels 3 electrovalves. Being geometrically mounted it also functions as counterweight together with the batterybox placed above it. If the brick hangs or its battery discharges it is possible to exchange it without disconnecting the turret. All you need to do is turn the turret by 90 degrees in any direction around the undercarriage and you get access to the battery from the bottom of the turret.

The boom:

My intention was to make the boom as realistic as possible when it comes to the visual side and the movement range. The whole boom can carry 6 big pneumatic new type servo mechanisms, II section four big pneumatic new type servo mechanisms. The bucket is steered by 4 big pneumatic old type servo motors. Geometry and movements range:

Bucket:

I tried to achieve both realistic shape and size by means of liftarms, plates and flat plates. Did I make it? Well, you are to decide.

And now the steering console:

As mentioned before, my aim was to make my digger as close to reality as possible as far as operating, use and looks go (two two-direction paddles)

The console consists of two NXT bricks, 3 buttons (built on the basis of sensors) and an IR remote control. The IR remote control steers driving and it uses the IR turret placed on the digger turret to steer two PF medium motors which propel the tracks.

The left joystick serves to move the boom of the II section (forward-backward movement) and to turn the turret around (leftward-rightward movement). As far as the boom rotation goes, deflection +/-10 degrees doesn`t render the turret rotation. The joystick`s deflection +/-10 degrees within +/-10 - +/-35 degrees causes the turret to rotate at a smaller speed (20% of the XL motor power – reduction by means of software). The joystick`s deflection above +/-35 degrees causes the turret to rotate at a greater speed (35% of the XL motor power - reduction by means of software). Pressing the orange button on the brick renders setting 0 for the current joystick deflection on the axis of the turret rotation.

The right joystick serves to lift/lower the whole boom (forward-backward movement) and to move the bucket (+/-10 degrees leftward-rightward movement).

The button on the right joystick serves to set the working mode block/digging. After pressing the button by the block position you go to the digging mode. If press the button again, you set all the valves to the 0 position and go to the block mode. This is the moment when you can lower the paddles without influencing the boom movements.

The button on the left joystick serves to set all the electrovalves to 0 position (in the digging mode) at the current paddles deflection (3 axes which enable digging)

. The black button, placed between the bricks, serves to launch the sound signal – the horn.

The left NXT brick placed in the console connects (via Bluetooth) with the NXT brick in the turret and they exchange the following info:

-current setting of each of the three electrovalves

-seeting electrovalves to 0 position

-the battery level in both bricks

-signal to remote switch off of the turret brick when the left console brick is switched off

-working mode signal: block/digging

-manual 0 position setting on each of the electrovalves

The right NXT brick placed in the console connects (via Bluetooth) with the NXT brick in the undercarriage and they exchange the following info:

-information about the current compressor condition (on or off), current PSI pressure

-current condition of the turret rotation drive (stop, movement at speed 1 or speed 2)

-the battery level in both bricks

-signal to remote switch off of the undercarriage brick when the right console brick is switched off

–-signal launching/turning off the sound signal-the horn.

At this point I`m going to discuss the menu in the two console NXT bricks. In the left NXT brick, after you load the software, you can see the following menu:

"blokada" means „block” – working mode (block/digging). The caption above "inactive" stands for lack of connection with the turret brick. A couple of seconds later the connection automatically starts and you can see “active” caption.

If you press the button on the right joystick, you go to the digging mode:

The shown numbers are deflections of 3 joysticks axes, represented in degrees. After you press the button on the left joystick you can see:

All the 3 electrovalves are set to 0 position. If you press the button on the right joystick (setting the “block” mode)and press the right arrow on the NXT brick, you can see the menu of the battery level in both the console and turret NXT bricks

Now if you press the bottom brick button 3 times, at short time intervals, you can see:

The brick is switched off. Simultaneously it remotely switches off the NXT brick in the digger turret it was connected with by means of Bluetooth (a moment before being switched off, all the electrovalves are set to 0 position). However, if you mistakenly press the brick button twice then to switch off the brick you need to wait a while and repeat the whole sequence of pressing the button 3 times.

Still if you don`t switch off the brick and you press the left arrow twice (once to get to the menu with “block” caption) then you can see the first of 3 menus which serve to manual calibration of electrovalves (to get to the next two you need to press the left arrow on the brick once or twice):

Pneumatic electrovalves are made up of the NXT motor and pneumatic valve that is placed on the angle liftarm. This connection isn`t perfectly fixed. Additionaly, LEGO pneumatic valve is always a little inactive (you need more strength to move it than to move it by the same angle once it has already been moved).This is why although I wrote the software to partly eliminate nonlinear resistance of the valves, calibration of the turret valves is necessary occasionally. The console is used to do it. First you need to take away the covers on the turret to be able to see the valves (however, having had experience and observing the working boom movements, I can already well say by how many degrees I should reset 0 point of each of the 3 electrovalves without the need to take away the covers).

Next, when you are in one of the 3 menus:

Being in each of those menus and pressing button on either left or right joystick, you can reset manually valves by 1 degree:

Next you repeat the sequence of switching off in the last menu of manual valves setting (the bucket). You press the bottom brick button three times and switch off both bricks, but this time the program remembers the setting of the manual regulation and when you switch the bricks on again, the valves are already well-adjusted.

In the right NXT brick, after you load the program, you can see the following menu:

The caption above „inactive” stands for lack of connection with the turret brick. A couple of seconds later connection automatically launches and the caption “active” appears. If you move the left joystick sideward you can start steering the turret rotation. In this menu, with the turret rotation at speed 1 you can see:

Now if you deflect the joystick by more than 35 degrees, you can see the following on the screen:

By pressing the orange button on the NXT brick you set 0 on the axis of the left joystick. If in this menu you press the left arrow you can see the compressor menu which enables you to see the current condition of the compressor (stop or work) and the current air pressure (expressed in PSI) in the digger pressure structure.

The compressor is switched on when the air pressure in the installation is below 30 PSI and switched off above 30 PSI.

If you press the horn button and you are in the menu of the turret rotation or the menu of the compressor, you will hear the sound of a horn. The turret rotation takes place when both the rotation and compressor menus are active. If you are in the compressor menu and press the right arrow twice (or once for the rotation menu), you enter the menu of the battery level and see:

If you press the bottom brick button three times at short time intervals, you can see:

The brick is switched off and it remotely switches off the NXT brick in the undercarriage with which it was connected via bluetooth. However, if you mistakenly press the brick bottom button twice then to switch off the brick you need to wait a while and repeat the whole sequence of pressing the button 3 times at short time intervals.

Inevitably the most troublesome when building the model was finding a way to construct the electrovalve which would ensure fast operation necessary with high pressures. Also, I needed to achieve the right precision and create the smallest possible size. I searched for different solutions, and the one I used eventually proves out to be the best. Obviously, the electrovalve mechanism is just a part of success, the other one being the software. It turns out that valves are different when it comes to the matter of precision. Each is unique and each has a different “range” of the zero point as well as different values of deflection causing the “beginning of permeability” (air flow). The software is quite complex. The first joystick angle deflection is converted 1:2, which means that one degree of the joystick deflection causes the electrovalve to deflect by two degrees. After certain value the conversion rate changes to 1:0,2, which means that one degree of the joystick deflection causes the electrovalve to deflect by 0,2 degrees. This ensures operational precision and prevents too rapid flow of compressed air to each of the digger circuits.

Here is an exemplary fragment of a program code which serves to move and calibrate the bucket:

if(messageParm[2]<50){

rr1=messageParm[2]*p2;

rr2=messageParm[2]*p1+22;

rr5=messageParm[2]*p1-29;

if(messageParm[2]<=11&&messageParm[2]>=-16){rr3=1;}

if(rr3==1){

if(nMotorEncoder[iIsekcja]>(rr1+2)){motor[iIsekcja]=(-50);}

if(nMotorEncoder[iIsekcja]<(rr1-2)){motor[iIsekcja]=(50);}

if(nMotorEncoder[iIsekcja]<=(rr1+2)&&nMotorEncoder[iIsekcja]>=(rr1-2)){motor[iIsekcja]=0;}

}

if(messageParm[2]>11&&messageParm[2]<50){rr3=2;}

if(rr3==2){

if(nMotorEncoder[iIsekcja]>(rr2+1)){motor[iIsekcja]=(-50);}

if(nMotorEncoder[iIsekcja]<(rr2-1)){motor[iIsekcja]=(50);}

if(nMotorEncoder[iIsekcja]<=(rr2+1)&&nMotorEncoder[iIsekcja]>=(rr2-1)){motor[iIsekcja]=0;}

}

if(messageParm[2]<-16){rr3=3;}

if(rr3==3){

if(nMotorEncoder[iIsekcja]>(rr5+1)){motor[iIsekcja]=(-50);}

if(nMotorEncoder[iIsekcja]<(rr5-1)){motor[iIsekcja]=(50);}

if(nMotorEncoder[iIsekcja]<=(rr5+1)&&nMotorEncoder[iIsekcja]>=(rr5-1)){motor[iIsekcja]=0;}

}

rr4=messageParm[2];

if(m==0&&n==-6){

eraseDisplay();

if(bt!=19){nxtDisplayCenteredTextLine(0,"NIEAKTYWNE");}else{nxtDisplayCenteredTextLine(0,"AKTYWNE");}

nxtDisplayCenteredBigTextLine(2,"LYZKA");

if(SensorValue[zerowanie]==1){II=II+1;}

if(SensorValue[aktyw]==1){II=II-1;}

nxtDisplayCenteredBigTextLine(5,"%d st",II);

if(nNxtButtonPressed==0&&ww==0){ww=1;}

if(ww==1&&nNxtButtonPressed==-1){ww=2;}

if(nNxtButtonPressed==0&&ww==2){ww=3;}

if(ww==3&&nNxtButtonPressed==-1){ww=4;}

if(ww==4&&nNxtButtonPressed==0){III=500;}

if(III==500){

n=-8;

eraseDisplay();

nxtDisplayCenteredBigTextLine(1, "KONIEC");

nxtDisplayCenteredBigTextLine(4, "PRACY");

nxtDisplayCenteredTextLine(7, "MILEGO DNIA");

wait10Msec(50);

nMotorEncoder[isekcja]=0;nMotorEncoder[iIIlyzka]=0;nMotorEncoder[iIsekcja]=0;

wait10Msec(500);

powerOff();

}

wait10Msec(10);

}

All the software in the digger (for 4 NXT bricks) are made up of circa 640 code lines and were written in C (RobotC).

Additionally in the digger turret there is a manometer and an extra pneumatic valve. The first one is meant for optical pressure checking. The latter serves to eg. dispose of the pressure remnants after switching off the digger.

Again photos:

Gallery:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=491020&n=0

Gallery VIP:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=491025

That is all, thanks :)

Edited December 31, 2011 by Emilus

[Alasdair Ryan]

Great excavator,I like how you used nxt motors for the valves.It looks just like the real thing what a great end to the year.

Edited December 31, 2011 by Alasdair Ryan

[Finntech]

One of the best MOCs I have ever seen. Thanks for sharing it! Nice ending for the year 2011.

And because the operation is so realistic, I would build it in a bigger scale (just a thought), and used it for demo purpose in some construction exhibition. it would be great to attach ie. this system to it:

http://www.topcon-positioning.eu/30/Machine_Control/Excavator/46/528/3D%20GPS/product_details.html

Put the GPS in a demo mode, and show to the customers how it works. Well, just a wild idea, but it would be cabable for doing it.

Edited December 31, 2011 by Finntech

[basbase]

This is an awesome MOC! I really love how you are able to accurately control the pneumatics. All those NXT bricks must have cost you a fortune.

Looks:

Performance:

Innovative:

Great job!

(btw the link to the pneumatic pressure sensor does not work, here is a working one with translation)

[timslegos]

That model is FANTASTIC! The control of the valves is beautiful and super realistic looking. I am thoroughly impressed!

tim

[jacobkristensen]

That is a very great model, and I think you have reached(or is close) to the limit of LEGO. Befor they desiced to clean up their systems(unified power systems of nxt and PF, at least same connector - I am fine with two kindes of motors(servomotors and normal motors)).

Also the realism of your model is really great, but again you are nearing the limit, to my experince of to how much pressure you can put into un-drilled lego pneumatics, witch is somewhere between 3 and 4 bars, depending on the hose.

Edited January 3, 2012 by jacobkristensen

[_bIG_fM_]

Wow.

Just Wow.

At first i was wondering why a "normal" excavator was mentioned on the frontpage, but after your post i fully understand why. This should be one of the most complex builds ever made in Lego. You put an incredible amount of effort in this. Well done!

And a great usage of nxt for the joysticks!

Felipe

[Surly]

What an awesome build!

Did you consider adding non Lego options like the mindsensors Pneumatic servos or PS2 controller?

cheers

Surly

[allanp]

Well now i've got to go to the 2011 round up topic and say THIS is by far my favorite MOC of the year!

[Badger]

Amazing !

[parda]

Epic MOC!! I'm going to read it again

Like the controls.

[grohl]

What I love most is the way how you control it. It has to be really different experience to have the joysticks that look so close to the real ones.

[Larrynautik]

A great representation of the legendary Demag machine, notably used in diamond mines such like the Ekati Diamond Mine in the North of Canada, close to the Artic Circle. This machine resists well at extremely cold temperatures.

You have an excellent video documentary about this Demag machine in MegaStructures Season 2, "Diamond Diggers" (known in french as Les Constructeurs de l'Extrême, S2, Forages Extrêmes, on Direct8 channel)

Excellent job Emilus

[DLuders]

You have an excellent video documentary about this Demag machine in MegaStructures Season 2, "Diamond Diggers"

in RUSSIAN:

[Smrgol]

That is sweet. Just been watching the cab view video and the movement is so smooth and life like.

Watching these sorts of projects only makes me want more stuff sooner haha

[jorgeopesi]

My dreams come true with this machine, awesome creation...

[LEGO Train 12 Volts]

This is the best technic MOC I've ever seen!

The driving system is absolutely impressive ...TOP WORK!

[cfc]

WOW! thats one of, if not the best MOC i have ever seen! Pure Genius!!

[alex54]

I'm not a Technic expert neither a Mindstorm one, but it seems that you have passed some times to make this outstanding MOC!

The design of the vehicle is very well done and clever. It's great to see a Technic moc with a more standard System look, it works very well.

And last but not least, the NXT controler! Wow! I have recently tried a Mindstorm set, and I have to admit that it's not that easy to master. I am not familiar with informatic codes, so I used the LEGO Mindstrom software. And it's not that easy! I've spend about 10h to make a 9V train layout controled with one NXT. So making such a command for your Demag just blows me!

It really gives us to "play" with your creation!

[Emilus]

I'm glad that you like it.

Thanks for your appreciation, in future i will post some of my other interesting MOCs.

Greetings:)

[Cri2fast]

What is the use NXT air pressure sensor?

[Aris]

Excellent work! Is the air source external?

[fosamax]

Are you going to bump every ten years old topic ? 

[Maaboo the Witch]

26 minutes ago, fosamax said:

Are you going to bump every ten years old topic ? 

Me too, me too! Wheeeeeeeee!