2DOF simulator based on CKAS Thruxim

[Riton]

I'm not sure to understand ... translation is difficult for me, but
it seems to me complicated, VM140 not work in 2 ms:


Caractéristiques:
- 8 entrées analogiques avec une résolution de 10 bit: 0…5 ou 10Vcc / 20Kohms
- 8 sorties analogiques avec une résolution de 8 bit: 0…5V ou 10Vcc / 47ohms
- 8 entrées numériques: compatible avec des sorties à collecteur ouvert (connexion à GND=0)
- 8 sorties numériques à collecteur ouvert (max. 50V/100mA)
- Indication à Leds pour toutes les entrées/sorties
- Une sortie PWM de 10 bit: sortie à collecteur ouvert de 0 à 100% (max. 100mA / 40V)
- Délai de réaction général: 4ms par commande
- Port USB: compatible: 2.0 et 1.1 compatible.
- Consommation via port USB: +/- 60mA
- Possibilité de connecter jusqu'à 8 cartes à l'ordinateur
- Alimentation à partir d'un adaptateur: 12VCC / 300 mA (PS1205)
- Fréquence MLI: 15.6kHz
- Temps d'exécution standard: 48mS (utilisez les pilotes Microchip et K8061D.DLL drivers)
- Temps d'exécution accélérée: 21mS (utilisez K8061_C.DLL V1.0 par RE Applications)
- Dimensions: 195 x 142 x 20mm


use 0 ... 10v of VM140, does not in my view to control of frequency, Thanos knows the problem!

Perhaps the programing with your controller will be different and will fix the problem of speed control drives


use 0 ... 10v of VM140, does not work to control frequency inverters,
(From my point of view)
Thanos knows the problem!

Maybe with your PLC programming will be different and solve the problem of speed control of frequency inverters.

I also see that you are using 24v relays, it is not so quick and practical the map can velleman switching example.
There is also a function in the frequency that avoids the use of relays.
a simple open collector output that will be very well
on the map as VM140.

It is in my opinion much easier to directly control frequency inverters with a PC interface and a PC.
Although I do not know about your stress and your educational need on this point.

I realized my simulator with much less resources and it is probably as effective.

[Mertensbart20]

Hello Riton,

I can understand your remarks. The 2ms refresh rate comes from a question I posed on the Velleman-forum about the refreshrate of the VM140. This was the answer:

"The minimum refresh interval is 2ms."

Since we use the VM140 only to change a gamevalue to a voltage I assume this refresh rate is correct. Again, the VM140 isn't programmed, doesn't do any calculation. It just puts out six 0V to 10V signals that change along with the game-values.

From there on the simulator is only controlled by the PLC (a very fast PLC that reacts within 10ms). So there is no feedback to the PC or VM140. The main reason we work this way is because the students have to use a PLC in their study.

For the relays, you are right but they are only used to switch on the brake of the motor so that the motorinertia is directly stopped. But indeed, most new invertors can do it directly. Maybe the G120C can do it. But we have to switch 230V for the motorbrake. And I don't think you can switch 230V directly with an invertor, so we'll probably have to use a relay.

In any case we will be using the VM140. Changing the project now is to late for my students. And as I said, our first simulator works fine using the same principle. So I don't see problems with the new one.

Greetings,
Bart

[Riton]

ok, thanks or this information !

[Mertensbart20]

Hello everybody,

Quick update about the encoders. These are two industrial Sick incremental rotary encoders (including couplings) with following signals:

- 1024 pulses per revolution
- A, B and Z signal
- 5V pulses
- more information can be found in de datasheet I included
- price: 109 euro's a piece

With the right encodermodule you can get 4084 positions per revolution. For our simulator this means that we can measure the position of the platform up to 0,0225 degrees accurately. I hope the students can finish their holders soon en couple them to the motors. Once there we can start testing the movement of the motors.

In the meanwhile the woodshop has started sawing al the pieces for the cockpit that will be mounted on the platform.

Greetings,
Bart

[Mertensbart20]

Hello everybody,

It has taken a while but we (the students) finally made good progress. We coupled the encoders onto the motors as can be seen in the picture.
Now testing can begin. Plans are to have a working simulator by the beginning of march. I will keep progress up to date.

Greetings,
Bart

[Mertensbart20]

Hello everybody,

We have made some steps forward. The cockpit has been build (you can see some pictures below). Paintjob will be done soon.

The mechanical structure is almost finished. I also included some pictures. First tests should start within three weeks.

Greetings,
Bart

[vicpopo]

Hi,

It looks really like CKAS 2DOF.Same frame , same motor manufacterer...
Impatient to watch it in motion.

[Riton]

what will happen if there is a bug with electronics?
If the motor running without stopping?

I think it's dangerous, you may break the encoder and the cams if they tap against the structure.

But, it's a good simulator, nice motors , and nice frame!

[Mertensbart20]

Hello Riton,

Good remarks and ofcourse we have taken this in consideration. The simulator is protected by the invertors in two ways:

1. Should the motors overheat a thermal safety will open in the motor which will interrupt a signal to the invertors. The invertors are programmed to stop the motors once this signal has been interrupted.
2. Should the motorarms move beyond the extreme points the motorarms will hit a positionswitch (these are not installed yet). This positionswitch will interrupt another signal to the invertor. And again the invertor will stop the motor once the signal is interrupted.

The safeties above will also work when there aoccurs a cable-break.

The design looks a like the Thruxim but our motors are bigger because we want to have a pitch- and rollangle of 18°. But I don't think they use wormgearmotors for the Thruxim. I think they use a motor with an axial reduction which is better for the lifetime of the motor and the energy efficiency. But these type of motors are far more expensive. And SEW assured us the motors will last a lifetime since it is a simulator for private use. And energy efficiency is not really a big deal for a device that will be used maybe half an our each day.

At this moment anothers student has started working on adding a yaw-axis by placing the whole simulator on rotating point directly driven by a motor. But since it is a schoolproject it will take about a year to finish .

Greetings,
Bart

[vicpopo]

Hi ,

Yes you're right for the Thruxim that is helical gear box type R27 or R37 .
But with Ckas new 6 dof plateform " low cost " there are not the same gearbox as you that is helical-bevel gearbox unit.
When you look at the technical specification for the same power wanted (0,25 kW for example) with the the same gear ratio ( output shaft gearbox 12rpm) you've got the same amazing torque (between 150 and 180 Nm).
The efficiency is a little better with helical gear units but the torque is the same.
The big advantage for the helical bevel is the space you can win with the output shaft at 90° to the motor shaft.the design is compact and all the motors are under the plateform, nothing go outside from the lift plateform ( security advantage also).
And the last advantage is that the use a hollow shaft.One side there is the arm to lift the plateform and the other side you find the angle encoder .This solution is compact (room saved) and 100 % safe for the encoder.

Edit : I don't really saw your gearbox is it a helical bevel gearunit or helical-worm gear units?
Seems to be helical worm gear units.
The helical worm gear unit is possible also but with less efficiency.

Edit :
Helical gear units

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Helical

Helical bevel

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Helical bevel

Helical worm

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Helical worm