Mecanum Vehicle

@joeyb416 Given you said

Unfortunately, I am somewhat technologically illiterate. 

maybe you should start with something less ambitious? Scaling a small vehicle such as Bill assembled requires advanced engineering, physics, mechanical, and electronic skills. Also, 500 lbs at 5 mph should not be done in a public area without first consulting a lawyer and obtaining the required insurance which will likely be very expensive.

Getting back to basics, 5 mph is 132,000 ft /hr is 440 ft/min and 7.3 ft / sec. That is actually quite a distance in 1 sec. I don't know how to calculate the brakes needed for that to reduce the 7.3 ft / sec to 0 ft /sec in X ft. If there is a risk of human contact I would want X to be less than 1" or 0.083 ft. Someone with better math skills will know how to calculate the energy to be dissipated but brake design will be a major undertaking.

Recording the movement of the vehicle whether it be GPS or controller data or both is actually quite trivial compared to the other tasks.

Most of the weight will actually be the batteries to propel the device unless you use Lithium then the initial cost will be significantly higher. Basically a 6V FLA golf cart battery weighs 65lbs and you need 4 for 24V. That will provide roughly 50 amp hours or 1,200 WattHours at a weight of 260 lbs. The 2 LiFePO4 12V batteries weigh a total of 66 lbs and deliver 100 amps or 2,400 WattHours.

I think I will leave it there, but as I said, this could be a very big challenge if you are not skilled in a bunch of fields.

FYI, in another life I often did risk assessment for a fortune 5 company and occasionally outside agencies including government.

Hi @joeyb416,

  Sorry, Ron (@zander) is right ...500 lbs at  5 mph, which is a 'gentle' running pace, is a potentially lethal weapon in a populated area.

But, the good news is the same small, lightweight camera can be attached to a much more modest platform - and you can use that to safely develop your product and your personal skills. 

When you have that, a second phase would be transfer your technology to a larger platform... but that is a different story for the future

Best wishes and good luck, Dave 

@zander and @davee

I can’t thank you enough for your input. You are both right, I would have been over my head going into this project. I am thankful I came here before doing anything!

I will go on to build a small (much less dangerous) RC mecanum car. There are plenty of videos to start wrapping my head around these things. 

The only question I have left is about recording controller data for the vehicle. After I build my small RC model, how would I go about recording data from a controller? Anything you can point me to would be greatly appreciated! 

Thanks again for the responses!

@joeyb416 Start with what Bill did, if that doesn't do exactly what you want then modify it to your needs. If you get stuck, come back and ask.

Hi @joeyb416,

   Good luck with your project, which I hope proves more manageable.

As for data recording, there are numerous answers, but it is a bit like asking 'How long is a piece of string?'.

The answer depends on lots of factors, which in turn depend upon your aspirations.

I would recommend starting with making a list of EXACTLY what you want to record and what you want to do with the data.

This should include (approximate) format, rate of collection, how long you are recording for and so on, possibly as a small spreadsheet. Then you can get a better idea of how much and how quickly data must be stored.

Also, do you want to collect it on the robot, or maybe send it 'live' to a local base station?

Also, when you have the data ... will it be in the right place for any subsequent processing, viewing etc.?

In other words, think through the logistics of the whole process, and put some estimates with quantities and times together.

Armed with this information, you can begin to map the hardware, and accompanying software requirements for the whole process.

It is likely you will change your plans as you go through your project, but a few hours initial planning will probably save weeks of going round in circles!

Best wishes, Dave

@joeyb416 FYI @davee I just wanted to try to add some additional information. Make the collection routines a separate procedure with a case statement triggered from one of the (probably 1st) parameters. Then as many procedures internal to that to do the required collection of data. That way if you change your mind or discover new requirements there is likely only one piece of code to change instead of dozens. Like Dave said, spec it out first. I would even consider a somewhat radical approach and do this (two statements on one line)

variable = read controllerA ;        recordStats("controllerA", data, data, etc);

by putting the data collection procedure calls on the same line you minimize code volume and the non collection code can be read per usual. I think it's a valid application of KISS.

Food for thought.