Model Yacht Hoist

Hi all,

I have rather ambitious project I would like to share and get some advice on.

I am planning to build a scale model (Maybe 1:20 or 1:30) of this 600t yacht hoist. See photo

https://www.ascom-italy.it/products/1/1/7/30.html

Components
2 x independent wheel drive motors (May need 4)
8 x steering servos 180deg
4 x winch motors
8 x fall up position switches
2 x fall cable brake - for independent fall control during sling setup
2 x load cells

Remote control matching layout of the real thing - iPad if possible or I will build arduino controller

I think I will need 2 arduinos to run all this plus remote.
Master to receive commands from remote and drive wheel motors and steering servos
Slave to run winches, cable brakes and load cells.

I currently own 1 x MKR1000 and 1 x Leonardo so would like to use these. Or would I be better off buying a MKRZero or something else?

The real hoist is powered by a diesel engine driving 3 hydraulic pumps. I would like to program my model motors the behave in a similar way - bogging down if steering and driving with low revs.

I plan to make the structure out of water jet cut steel that I will TIG weld. Scale will be controlled by how small I can get the wheel units. Any recommendations for wheel/steering units?

Thanks
Will

I'm not familiar with the MKR Arduinos but it seems to me you could easily control all of that with a Mega. However the question is where to put it within the confines of the model.

How big will the model be, and approximately how heavy?

The small N20 gear motors may be useful. They are available in a wide range of gear ratios and with different gearbox orientations. They are widely available. This link may give you some ideas.

...R

Thanks Robin,
I looked at the Mega but I think I need at least 20 PWM pins for all the speed control.
I don’t know if I’m better off with a shield instead of master slave setup?

I would like to keep it about 0.5m x 0.5m x 0.5m and hopefully less then 5kg. Able to lift 10kg. There is an engine bay on one side that will use hide all the control and batteries.
Thanks
Will

Sorry can’t seem to update photos from my iPad

I don't see anything in your list that needs PWM pins.
Servo's do not PWM pins. A Mega can drive 48 Servo, so PWM is definitely not needed.

Maybe the winch motors and wheel drive motors, but for a model you can likely use (small?) stepper motors and have better control. The Stepper.h library does not need PWM pins. I have a stepper motor running right now on A3-A0 and they are definitely not PWM.

Thanks CrossRoads,

I thought Servo position signal was from from PWM. Now that I have sorted out that misunderstanding A mega looks like an option.
I hadn’t really thought about using stepper motors but load independent speed control would help a lot.

Wilas89:
I thought Servo position signal was from from PWM.

Unfortunately the acronym PWM is used for two quite different things - the signal that the Servo library produces is different from the signal produced by analogWrite() and which is only available on the Arduino PWM pins. analogWrite() is used to control the speed of DC motors (through a suitable motor driver) and to control the brightness of LEDs.

...R

Photos of real thing. Getting 8 wheel units to steer is will be fun to program but cost a lot in hardware. I do have access to a 200t hoist with only 4 wheel units but I like the spectical of 8.

Images from Reply #6 so we don't have to download them. See this Simple Image Posting Guide

...R

Are you dead set on making a model of that particular hoist? it seems to me the wheel units would be very difficult to miniaturise.

Smaller versions of the same sort of hoist only have one wheel at each corner which would make life a lot easier.

...R