design trolley on tracks

[leonardo000333]

Yes, but as data I have speed at regime and the final one, I miss both time and acceleration... I have two unknowns in an equation or not?

 

[meccanicamg]

Yes, but as data I have speed at regime and the final one, I miss both time and acceleration... I have two unknowns in an equation or not?

You know the speed.
Final speed is zero.
for the calculation of time you have to impose it you or rather the stop ramp will have to be done respecting what you think is the useful space range for braking.
If you want his snapshot, let's try to bet 100 milliseconds or 0.1 seconds.
♪[ \Delta{V}=\frac{\Delta{s}}{\Delta{t}} \]then by reverse formula you will get the braking space, which will be evaluated on short strokes.

example: if we want to get about 0.1ms of ramp to reach 250mm/s except roundings (usually I use the excel sheet on other scale of values) we are around 3m/s2 of acceleration however in 10 mm of stroke I stopped.
However making the stops with precision variable load is a nice casino because it would be necessary to calculate the couple that serves on each trip....and to do it or you know how much loads or you have to have load cells on the cart....poi make the "recept" in the plc.

 

[leonardo000333]

ok it is too complicated for my application, what I do not understand is if space and time I imposed them...after in the relay will be really like this? ? '
Anyway I thought it was easier and as the engine will be operated and turned off manually maybe I should think of a different system to move this cart.
One thing that had come to my mind is, since I have low friction with the linear guides, I could put two winches one to the right and one to the left of the cart, when I have to move it on one side turn a winch when I have to let it go on the other side I release a veracello and I use the other even if it is more Moroccan. (obviously manual winches

 

[PIETRO2002]

ok it is too complicated for my application, what I do not understand is if space and time I imposed them...after in the relay will be really like this? ? '
Anyway I thought it was easier and as the engine will be operated and turned off manually maybe I should think of a different system to move this cart.
One thing that had come to my mind is, since I have low friction with the linear guides, I could put two winches one to the right and one to the left of the cart, when I have to move it on one side turn a winch when I have to let it go on the other side I release a veracello and I use the other even if it is more Moroccan. (obviously manual winches

If it is so that you don't complicate your life, apply a flyer at the entrance of the reducer and turn!! Have we made a trip to pindaric for nothing?

 

[meccanicamg]

ok it is too complicated for my application, what I do not understand is if space and time I imposed them...after in the relay will be really like this? ? '
Anyway I thought it was easier and as the engine will be operated and turned off manually maybe I should think of a different system to move this cart.
One thing that had come to my mind is, since I have low friction with the linear guides, I could put two winches one to the right and one to the left of the cart, when I have to move it on one side turn a winch when I have to let it go on the other side I release a veracello and I use the other even if it is more Moroccan. (obviously manual winches

three questions:
1) your boss in the office what does he say?
2) What did your business sell to the customer?
3) we have a cart that must move quickly and accurately, stop with error 5 mm, we are risking to mount a vector motor and we went to the winch....carrucola....by hand? Someone must have beaten his head... are we sure of all this?

 

[leonardo000333]

no boss, no business, my first project without a match iva, no security only the hope that it will be accepted and financed. If I put the flyer on the reducer can be a good idea but still I have the inertia then to fight.
I thought to put a driving system like what's in the screw lathe trapeze even though this way would not stop instantly

 

[meccanicamg]

no boss, no business, my first project without a match iva, no security only the hope that it will be accepted and financed. If I put the flyer on the reducer can be a good idea but still I have the inertia then to fight.
I thought to put a driving system like what's in the screw lathe trapeze even though this way would not stop instantly

I'm sorry, but I'd like to throw away my head by reading this post... I'm sure you're looking for luck with the bear's skin...

the use of an endless screw I would exclude it a priori, although instead a screw recirculation of spheres could be much more consonant and precise in itself. But there is the disadvantage that you have the long run and if you want very accentuated acceleration ramps, you will find that the screw will go in resonance and you will not manage the axis and you will have to reduce the performance a lot (personally I replaced a vertical axis made with ball screws with a pinion and rack just for impossibility to manage high acceleration and speed, in addition to having other mass balancing problems).

returning to our system made with pinion and rack..... seen that we know that going at low speed you need less power and if we stop we are more precise you can do as follows:
- three-phase motor with inverter.
- encoder on the rack to determine the running space in absolute (can be wire encoder or absolute rotating)

at each stop position will correspond to an early position of a few hundred millimeters where we decelerate. so I leave, making acceleration ramp in about 100mm... constant speed.... slowing rate....at least 100mm at low speed and stop in position in about 10mm. so doing you get a step motion where accelerations are more gradual. if the encoder on the pinion will have 1024 pulses/turn you have enough to stay in the 5mm positioning.
However to do everything, i.e. mechanics of the wagon, electronics, programming drive and everything, declaration etc. you need a good team of competent people....ke in mind what this means ... risks and responsibility as well as ability.

 

[leonardo000333]

I understand perfectly, I'm thinking as an alternative to disconnecting the pinion from the rack at the time of the stop so he stops when he wants and does not transmit the bike

 

[meccanicamg]

I understand perfectly, I'm thinking as an alternative to disconnecting the pinion from the rack at the time of the stop so he stops when he wants and does not transmit the bike

You don't have to disconnect anything....it's not a bomb....when you slowed down leftovers at low speed and you stop in place by pairing the engine up to zero speed, insert the electric brake controlled separately and then current to the engine.
all this you have to handle with a plc by force of things.

 

[brn]

but as the first project, something with less risk of harming?

 

[leonardo000333]

alternatively I could use a two-speed motor with 2 n different poles, when I miss 20mm step to reduced speed

 

[meccanicamg]

but as the first project, something with less risk of harming?

is the unconsciousness of youth....

 

[PIETRO2002]

I still don't know if he can move it manually with a flyer on the gearbox, the speed will be very low, and so the inertias, we're talking about different planets.
I talk about the age of stone and mechanicsmg speaks of a lunar rocket! What's good at the end?

 

[meccanicamg]

alternatively I could use a two-speed motor with 2 n different poles, when I miss 20mm step to reduced speed

If you use a two-winding engine you have to have all double switches, both in one sense and in the other....it is more than having an inverter to be able to program completely flexible. However you need an inverter... you can't go straight.

then the wagon takes of those blows with the two windings exchanged on the fly... .

 

[meccanicamg]

I still don't know if he can move it manually with a flyer on the gearbox, the speed will be very low, and so the inertias, we're talking about different planets.
I talk about the age of stone and mechanicsmg speaks of a lunar rocket! What's good at the end?

we started from 30m/min and we went down to 15m/min....but here if we go hand crank we make 1m/min. You know, dear leonardo, we're talking about different things?
I don't want to look like wand.... but maybe it's better to do a little bit of a little bit of a tit before you get into these things. Are you sure you can do this?
are coming out solutions to say little embarrassing...

 

[leonardo000333]

in fact moving it by hand with the flyer would go too slowly

 

[leonardo000333]

I have a week to think about it.

 

[meccanicamg]

just to resume a concept said a few posts before....but maybe not sufficiently explained.... skates.

a 3 meter long wagon with three rows of three skates with over 10ton....they make almost 1ton to skate. You should mount a ridiculous skate ....small ... but on a ride so it wouldn't hold because not aligned correctly.
I also have to make two very well milled bases: the mobile wagon and the fixed ground part.

anti-economic.

According to me it takes turned c45 wheels, two tracks drawn from 20x20 or 30x30 threaded to be soldered inside a c iron with the open part above "u"...so thicknesses in the yard and costs little.
the crazy wheels all with two ball bearings inside the wheel and a threaded passer pin. ideal 4 wheels....max 6. very cheap.

ground rack welded and lined in yard next to the drawn track.

sprocket mounted on parallel axle reducer (which costs less than the epicycleidal) on the wagon, motor with brake, encoder and at least soft start inverter with 3 programmable ramps. steel cable chain kabelschlepp series s.

absolute encoder on pinion or wire encoder or laser keyence that pulls up to 5 meters to read the position. mini plc siemens or other.

then ....security: sensitive edges in head and tail, flashing and mermaid when moving. If sensitive edges are touched, stop the carriage. very cheap.

we try to deal with material spans:
- engine and gearbox 2500€
- iron frame 7000€ welded, milled and painted
- wheels and bearings 800€
- rack and pinion 3000€
- rail and iron threaded at 3000€
- cable chain 1000€
- complete electric picture and sensors and a few buttons on the electric panel 3000€
- mechanical design with complete drawings 80 hours to 35€/h= 2800€
- hours masonry + carpenter that weld installation binary ....1000€
- plc programming 1200€

estimated estimated estimated approximate cost = 25000€.

- manual use and maintenance, risk analysis, trademark and various..... another 5000.

- and the schematics? Other 2000€

cost car keys in hand = 32000€.


and hope that there is no need to cut the floor to cash out the tracks on the zero floor.... otherwise go another 3000€ extra bricklayer.

and the electric cable to the picture....who puts it? Is the cockpit nearby? or should we intervene? without knowing or reading or writing I would put another 2000€ of trouble.

 

[leonardo000333]

we say that in regards to welding milling drawing and most other things I do in the workshop I, cost 0 certification, installation binary there are always me, for the electrical part I will need a hand, for painting I also have the sandblaster therefore no problem but it is the last of the thoughts.

 

[leonardo000333]

I predict that with 7000 euros I can make it, the problem of the wheels is always what they skate on the surface when it is unloaded, that I have about 2500n per wheel if it is okay, when I have also 10000 to load.