Help to choice a linear actuator for 2dof

Hello everyone,
I'm Marco from Italy,
are weeks that I read and I am looking for information to build a 2dof and go upgrade my static simulator. I have not yet a well-defined project, I'm considering price and quantity of work / results and viewing it based on your experiences. Let me start by deciding which engine to use for the movement and I think I have figured out that the best solution are the actuators Scn6 (are 1.96 meter tall and 105 kg weight) and I have to move the one sitting and not the entire station, scn6 are fast and aesthetically pleasing enough but have a prohibitive cost, so I wanted to ask you experts if it was possible to replace these http://www.microbot.it/en/product/81/Linear-Actuator-IP54-200mm-12V-1.5cm-s-50Kg.html actuators with much more economic, but they seem to have good load capacity and good speed (150mm / s vs 200 mm / sec scn6). finalizing these actuator is valid for a project? can be interfaced easily and can have similar or better performance than a wiper motor? sorry for bad Inglese but I use a translator. Thank you



original: ciao a tutti, sono Marco dall italia, sono settimane che leggo e cerco informazioni per costruire un 2dof e andare a fare upgrade del mio statico simulatore. non ho ancora un progetto ben definito, sto valutando prezzi e quantitá di lavoro/ risultati in basandomi e visionando le vostre esperienze. Vorrei iniziare decidendo quale motore usare per il movimento e mi pare di aver capito che la soluzione migliore sono gli attuatori Scn6 ( sono 1,96 meter alto e 105 kg peso) e devo spostare la sola seduta e non la postazione intera, scn6 sono veloci abbastanza ed esteticamente gradevoli ma hanno un costo proibitivo, volevo quindi chiedere a voi esperti se era possibile sostituire con questi attuatori molto piú economici, ma che sembrano avere buone capacitá di carico e buona velocitá (150mm/s vs 200mm/sec di scn6). finalizzando la domanda é sono validi per un progetto? sono interfacciabili facilmente e possono avere prestazioni simili o migliori di un wiper motor ? scusate per bad english ma utilizzo un traduttore. grazie

Hi @wDOCw , I think you have made an error. The quoted speed for the actuators you are looking at is "1.5 cm/s which is 15mm/s not 150mm/s. They are too slow.

Mike

Sorry omg , you're right, thanks for your help, it was too good to be true ....
unfortunately I see no alternative except the wipers motors but am not very good with the electrical part, so there is no linear actuators cost a little bit more?

there is a solution, but you have to build them yourself
http://bffsimulation.com/linear-act.php

@eaorobbie is working on putting a pair together when he gets time.
http://www.xsimulator.net/community/threads/diy-actuators-plans-by-ian-bff-shortened-by-me.5279/ I got the parts and then sent them to him as my level of expertise is not quite there.

As for DC motors, you can use the 12v 200 watt worm gear motors most of us use these days with great success. Theres several variants and styles around.
If you are not familiar with electronics, use the Pololu JRK 12v12 control board. A bit expensive at $99 US each, but simple to setup.

well, thanks for the explanation, I'm a beginner and starting with the build a linear actuator seems to me too, I might try it with the motor you suggested, following some post I might be able to do something good. I would take the cards Pololu jrk, which if I understand correctly perform the function of a one arduino + motomonster right? only that need 2, one for each motor. but if i purchase the Pololu krk x2 and then decide to convert the project with actuators scn5 the jrk can be used to drive the actuators ?


Original text: bene , grazie per le spiegazioni, sono un principiante e partire con il costruire un attuatore lineare mi sembra troppo, potrei provare con i motori che mi hai consigliato , seguendo qualche post potrei riuscire a fare qualcosa di buono. vorrei prendere le schede pololu jrk, che se ho ben capito svolgono la funzione di un arduino one + motomonster giusto? solamente che ne servon 2 , una per ciascun motore. ma in caso acquisto le pololu krk x2 e poi decido di convertire il progetto con attuatori scn posso usare le jrk per pilotare gli attuatori?

Yes JRK replaces ard and monter, but you need 2 jrks, one per motor. Cost more, but better performance.
No JRKS will not run SCN actuators, they use their own controller.

ok I understand, maybe we employ more time but I think that working on this project can entertain me and give satisfaction. But now I need more advice, I would not go OT and when I start with my work I will open a topic, just let me know if proceeding with these purchases are on track to achieve a good result.

So if you buy this engine (x2) http://www.ebay.co.uk/itm/12V-DC-Ge...al_Components_Supplies_ET&hash=item19f0dd7b66

two of this Jrk http://www.pololu.com/product/1393

power supply (x2 or only 1?)

and two of this to mount rear the motor http://www.robot-italy.com/it/alps-10kohm-potentiometer-9mm.html


i need to move only seat for a complessive 120-125 kg of structure and my weight, can be ok , what u think?

I forgot, you may have told us already, what sort of sim frame did you have in mind? Seat mover? Full frame?
With the motors, try to get one left and one right hand. It will make it easier to set them up.
Yes 2 JRks, and look at 2 power supplies so each motor has 12v 40 amps at its use.

The project is to start with 2dof Seat mover , later maybe add a 3 dof for traction loss.

The motors that i have linked are good enougth or u have other better to link ?

Motors are a little slow, 65rpm. But would still produce a good result, the 60:1 gearboxes can be changed over and 25:1 gear boxes could be fitted and you will then have 150-160rpm which is what both Dave and I use. But on the other hand 85mm centre to centre levers and only using 60 - 70 degrees of the usable 180 deg would still result in fairly quick motion plus handle a heavy seat and driver too.
Worked out to approx. to - 85mm lever on 70 deg is about 100mm , lever takes 0.923 sec to do 1 rev (360 degrees) so to do 70 degrees it takes 0.179 sec approx. Now in that time it travel 100mm linear (overall, not exactly) so in theory under the best circumstances the sim should push around the the 500mm/sec mark and push way more weight then the scn5 or 6 can.
Now that's all theory , in real situation it will equal them and even better them for about the cost of one of them. Just don't look as pretty, but surely kick like a mule.

Hope that translates ok.

well ty rob, I asked the seller and he told me that it can send the modified engines with ratio 25: 1. course by paying a little extra .
now I have to understand if it is ok or if you told me to apply the conversion ratio later with a further gear. I get the same rpm / torque if it is modified directly or externally ?

What I was trying to show, even thou the motors are a lot slower, with a slight longer lever and a smaller angle of rotation you will still in the end have enough speed to equal the SCN5 setups and with the slower boxes you gain more torque meaning the sim will handle more weight and move very nicely.

But if not satisfied later on you can change the gearboxes out for 25:1's , they can be bought cheaply separately for about 14 pound in the UK and I have seen them as low as $25 US on EBay for a pair and the 60:1 unbolt and the 25:1 bolt back on. Most of that gear is fairly interchangeable , many people supplying the products that come from the one Chinese manufacture

hey wDOCw, for Power supplies. Look into Server Power supplies off Ebay.

I got My dps 600pb 575w 47A supplies for 12.50$ a pop IN Canada so shipping was cheap. No need to buy from China and pay excessive shipping.

@Rob

off topic, but... have you ever seen a nice cheap motor alterntive in china?... i have been searching for a while but havent find anything... have you?

fer

Not unless your buying a hundred of them at once, stuck with going to suppliers. Actually nearly cheaper to buy from the UK and have them shipped to Australia when comparing prices.

Hi guys
I have collected a bit of material, I hope to have taken everything that I need, now I have to solder the jrk and make cable connections to test the components, then proceed with the construction / modification of my simulator. Ps: the motors are labeled 60: 1 65 rpm but in the shipping document contains the technical specifications of 5000 rpm with gear 60: 1 should be about 83rpm .. or not?

Looks good , if you have a decent car battery to quickly hook up the motors to test, I don't believe manufactures specs they produce, until I prove or disapprove by manually testing them. Like my motors state they do x Rpm once tested under 13.8v I get a constant 160 Rpm.

Well that's all the electronics sorted out, time to build a sim. Cool

I' ve test it with a power supply, without load seem make 85~ Rpm , at this speed 8-9 cm (centre-centre) of cranck can be enougth? What u think?

1 minute rotation...

thats fine, I have a mates sim that has 60:1 boxes on his with 80mm CTC, and it moves quick enough. Then again, he is using a lot of travel of the lever, like 150 deg of turn though.

They will be fast enough for decent vibrations in movements.
Ok so the maths,
Lets be conservative and guess under normal load they will reach 80rpm
At 80 rpm it will do 1.4167 rev per sec so to do 1 rev (360 deg) it takes 0.7059 secs.
Ok but we don't use 1 rev (360 deg) I use 80 deg on my seatmover most use anywhere from 90 - 120 deg.
So lets pick 100 deg to be an average or mean, then time it will take to travel this angle is 0.1960 secs.
Now to work the approx. linear speed when setup correctly - 80mm lever moving 100 deg will travel 140mm.
So we can now say using a 80rpm motor with an 80mm c/c lever travelling 100 degree will travel 140mm in 0.1960 secs.
Therefore a total of 714mm/sec but what we actual feel and use on the sim the 100 deg equates too 122mm of linear movement.
Therefore the feasible total speed would come in around 600mm/sec or once loaded beat an scn5's unloaded speed.

Been asked this question a lot I hope that helps to clear it up for more people.