Stepper Motor For Forklifts

Hello , I need some advice for my project work where i am required to create a forklift to left some boxes of light weights.I have seen some youtube videos where they are using stepper motors to create such lifts.
As for my forklift do i need a stepper motor to control a pulley or something else ?

Tell us more about your project.
A model forklift or a real one?
How much weight?

kazezx:
As for my forklift do i need a stepper motor to control a pulley or something else ?

You need to determine the mechanical design. Then we can help with the programming.

Post a diagram of the machine you want to make.

As well as answering @vinceherman's questions.

...R

kazezx:
As for my forklift do i need a stepper motor to control a pulley or something else ?

There are lots of options. Ask 10 engineers, and they'll give you 12 answers.

You have to make decisions on how to do it, and what the requirements are. You can use any kind of motor there is. It makes no sense to use a hydraulic motor capable of moving tons, where a 6VDC electric micro motor would do.

Figure out what you want.

  • How heavy is "some boxes of light weights"?
  • How big is that box?
  • How far do you want to move it?
  • How many axis do you need? An actual forklift works on at least 3 axis (2 linear, 1 rotary).
  • How do you want to do the lifting? Real forklifts can use pulleys, chain or belts, rack and pinion, and/or electric or hydraulic linear actuators.
  • What is the desired result? Just to change the elevation, or to put the box into a warehouse pallet-rack slot?
  • Is this a school assignment, or something you need?

A stepper motor may be exactly what you need. It could be totally wrong too. it may be a harder solution, where the micro motor would be easier. Steppers are primarily used for precision, but if your precision points are just "top" and "bottom", the little motor and limit switches would be much easier.

I (and most) don't mind helping, even if it is for school. Learning is good. Asking questions in the right place is an excellent skill to learn. It sounds like you're asking in exactly the right place.

belt drive or leadscrew are the commonest drive techniques - leadscrew gives more force, lower speed.

Perhaps its time for some numbers, “some”, “light” are vague terms that mean nothing definite,
how many boxes, how much weight, lift how far, lift how fast…

It will be a model forklift that I’m going to forge myself though it should be able to withstand utmost 500 grams.
The forklift will be attached to a stand where it can move horizontally for a distance of 30 centimetres.
I believe it should be holding 1 or maximum 2 boxes at a time.

Actually it is for my final year project where I am building a warehouse robot that will read a box RFID tag and send that code to a server which contain a database,the server then reads from the database to send location for placing the package onto a Shelf Location(Row,Column).The Robot is suppose to move to that location while avoiding any obstacle and holding the box.

Arriving at the location , the forklift should move up or down on a vertical level depending on the Column number ( time to lift should be 2 seconds )
The robot will have 2 layers separated(to place the Arduino board and other modules) by at least 8 cm with the upper layer 4 cm less than the lower one,this will allow the forklift stand to incline by an angle [in both directions : stand incline up + move forward = hold package onto fork , stand incline down + move backward = drop package](I already found out how to do it ).

Then after placing the package box , the robot should send the location status of the item as “Storage” to the database before moving back to the other boxes to loop the process as long as their as there are items inside the database that needs to be placed onto the shelf.

So I searched online and found that a stepper motor could be use for such lifts but will it hold with such weight ?
here is an example of the design I found online that I can make or use as a base :

I know this is not the section for this question but feel free to redirect to any threads : how to move to a coordinates indoor ? I read on google that gps modules ain’t good indoor…

My only 2 problems are the indoor positioning and the weight lifting of the robot.
Your ideas for further improvement are kindly welcomed.

how many boxes, how much weight, lift how far, lift how fast... I really can't be bothered to read
an essay to extract these values! [ sorry, but some folks are busy... ]

Boxes = 1
Weight per box = 250 grams
Lift how far = 20 cm
lift how fast = 0.1 metres/second

Great description of your project. Have you determined the total number of stepper motors required for all the movements you described?

A real warehouse system will have identifiers to confirm every movement stops at where it was supposed to be. Perhaps bar codes, or something similar. Also need a way to determine is a box is already in the storage spot, but not in your data base.

Paul

Pololu has steppers with lead screws in various lengths, e.g. 38cm

These will lift a few kg and rated for 1.7 Amps/phase, so their DRV8825 driver would be suitable.

jremington:
Pololu has steppers with lead screws in various lengths, e.g. 38cm

These will lift a few kg and rated for 1.7 Amps/phase, so their DRV8825 driver would be suitable.

Is there a cheap mechanism that can be implemented with DRV8825 , the project must be cost effective since the lead screws stepper of 38cm you mention is high in value. A system below 20$ would be appreciated.

Paul_KD7HB:
Great description of your project. Have you determined the total number of stepper motors required for all the movements you described?

Suppose i used the pulley mechanism from the diagram i mentioned above in the description but instead of just 2 i shall use 4 with each ones at the 4 end corners of the stand and form a rectangular like shape...will it work that way and be strong enough or using 2 lead screws the 2 end sides of the stand work better ?

Paul_KD7HB:
A real warehouse system will have identifiers to confirm every movement stops at where it was supposed to be. Perhaps bar codes, or something similar. Also need a way to determine is a box is already in the storage spot, but not in your data base.

Paul

I read online that RFID can be also used for positioning the items as well as the robot and seems complicated...but is it feasible to the warehouse or there is something much more efficient?

kazezx:
Is there a cheap mechanism that can be implemented with DRV8825 ,

What about attaching a piece of screwed rod to the shaft of a cheap motor and a nut on the rod to do the lifting? The brass insert from a large chocolate-block connector could be used to connect the shaft of a Nema17 motor to the screwed rod.

An alternative “left field” suggestion … what about using a sail-winch servo to wind a cord that does the lifting? Servos are very simple mechanically, electrically and from a programming point of view.

…R

Will a 28BYJ-48 Stepper Motor do the lifting job with the help of belt techniques?
or it is better to stick with the nema 11 + drv8825 driver .
I dont want to increase the weight of the robot with the nema motor since it seems to increase in terms of weight as the series increment.
Nema 8 = 60 g
Nema 11 = 110 g
Nema 17 = 700 g

Linear movement Track

None of the descriptions in Reply #13 is meaningful as far as suitability is concerned. The NemaXX numbers just describe the front face of the motor. For each size of front face there is a wide range of motors with different torques.

You need to figure out the torque you require and then find a motor that provides that torque, with a bit in reserve.

...R
Stepper Motor Basics
Simple Stepper Code

Robin2:
None of the descriptions in Reply #13 is meaningful as far as suitability is concerned. The NemaXX numbers just describe the front face of the motor. For each size of front face there is a wide range of motors with different torques.

You need to figure out the torque you require and then find a motor that provides that torque, with a bit in reserve.

...R
Stepper Motor Basics
Simple Stepper Code

Sorry i forgot to edit my first replied.I was looking at some videos from youtube base on your suggestion and found a perfect idea that uses 2 screwed rod, 1 belt , 2 pulleys and a stepper motor that moves a plane in linear motion

Example here

I will be using the Nema 11 as the stepper since its holding torque is 600 g-cm and the DRV8825 driver.

kazezx:
Sorry i forgot to edit my first replied.I was looking at some videos from youtube base on your suggestion and found a perfect idea that uses 2 screwed rod, 1 belt , 2 pulleys and a stepper motor that moves a plane in linear motion

Example here

I will be using the Nema 11 as the stepper since its holding torque is 600 g-cm and the DRV8825 driver.

You REALLY need to get out of the classroom and see how forklifts and other elevator mechanisms are made and work. What you are describing keeps getting more complicated all the time.

As long as you are fabricating stuff, look at building a cage with rollers holding it to either a pair of channel shaped or angle shaped uprights. Use rollers to keep the cage on the uprights and able to move vertically.

Then all you need is a pulley at the top, a DC motor at the bottom and a cable to attach to the cage or carriage, through the pulley and back to the motor to wind/unwind the cable. Simple!

Use micro switches to tell the controller when carriage is at top, bottom and various stops in between.

The whole mechanism can be mounted on a track for horizontal movement that is completely controllable.

Paul

Paul_KD7HB:
Then all you need is a pulley at the top, a DC motor at the bottom and a cable to attach to the cage or carriage, through the pulley and back to the motor to wind/unwind the cable. Simple!

That's exactly what I had in mind when I suggested using a sail-winch servo. You have explained it properly.

...R

A final year project that has to cost less than $20?

Consider forgoing a couple of lattes with extra whipped cream next week.

Robin2:
That's exactly what I had in mind when I suggested using a sail-winch servo. You have explained it properly.

...R

Do they have a "holding" capability? Or a brake?

Paul