Hello all, I’m very new to the robotics area and have just started reading through tutorials and am looking to build my first robot. What I’m about to describe might seem a bit ambitious at first, so I’m hoping that some folks will be kind enough to provide suggestions and guidance. Thanks in advance for reading!
I’m looking to create a unmanned ground vehicle (UGV) that I can deploy in Southern CA to roam the desert. Here’s my wish list of things that I need to be able to do:
1.Be extremely agile. It must climb, descend, and traverse fairly steep angles. It must crawl over rocks, and go around ones that it can’t maneuver over.
2. It needs to be durable, weatherproof, not necessarily waterproof though. It needs to be able to sustain wind, dust, dirt, gravel, insects, etc. and be able to operate in a range of temperatures from 20-110 degrees Fahrenheit
3. It needs to be able to send and receive GPS, and tracking information to show where it has been, video feed, data, pictures, video, etc. I want to be able to control this remotely from my home sitting on the couch when this thing is 400 miles away in the middle of nowhere, and I also want to be able to flip on the “auto pilot” switch too! Ha!
4. It doesn’t need to be fast all the time, but it’d be nice to go from a ft/sec to ~10ft/sec if I wanted to move it from one location to another. More torque is preferred.
5. It needs to have a decent amount of clearance height.
6. Ideally I’d like a solar panel to charge the batteries. I’m hoping that I could find a power supply that would allow this ting to run during the evening hours through the night and charge during the day. I’m also concerned about FIRE when operating in a high temperature environment.
7. Maybe a hot swappable battery pack to run during day?
8. Most of all, I want to be able to tell it an area that I want it to grid and traverse every possible inch, like a robotic lawnmower.
I’ve been looking at the GEARS Surface Mobility Platform and that seems fairly close to what I’m looking for, but any suggestions, advice, guidance, do’s or don’t would be helpful. Oh yeah, I’m hoping to spend less than $5k. That’s kinda the upper limit of my “fun” budget.
Thank you everyone for any comments and/or feedback!! I hope I was specific enough. (Also taking volunteers within a few hours of San Diego to mentor me, LOL)
The gears frame is not weather proof - you’ll need to enclose the motors and the electronics.
The electronics will thank you.
If it’s a smart phone where you can send/receive serial signals, then you’re set. You’d need to create your own code though.
Definitely possible - it’s all in the coding.
Nope - nothing new and cutting edge; heat sinks and fans work best.
Suggest adding the solar panel and charging only after you have the navigation and mechanics down pat. Ideally a retractable solar panel is best (protects it from wind, sand etc). Whatever you do, you’ll need to do your best ot protect it from sand, dust and (possibly) rain.
That’s certainly possible. A few points that stood out:
You’ll need to determine the maximum obstacle size you want it to try to climb over. Normally this is not too large - it’s preferable to move around an object than risk getting stuck or flipping over.
It sounds like you’ll need to customize a frame no matter which you choose in order to make it weather resistant and able to withstand high temperature. The harder you run the robot, the more the components will heat up.
How do you plan to do this from over 400 limes away? Is there a cellular signal? This will be the hardest part.
10’ /s is quite fast. You’ll need to compromise between speed and torque.
It’s less about a fire, than chips simply overheating and stopping. You’ll need heat sinks and fans - which means parts of the robot will be open to the elements - you’ll need to find ways to cool it without opening it up too much.
There is of course the concern about theft / vandalism… but that’s up to you.
The main question you’ll need to ask yourself is if you want a full mini PC or a microcontroller. Not many people have used satellite phones in their robotics projects, so take a look to see what you need to interface with that (and is it even possible?).
Since speed, distance and location are important, we’d suggest the SMP with encoders. The body has many holes so you’ll need to either cover those or cover the entire body to prevent dust from getting in, but also let excess heat get out (fan and vent system with filter perhaps, controlled by the microcontroller which is connected to an onboard temperature sensor?).
Microcontroller approach:
]Arduino MEGA or related/*:m] ]GPS / GPRS / GSM Arduino Shield/:m] ]GPS antenna/:m] ]Motor shield (12A+ per channel) or related/:m] ]MEGA IO Shield (ease of connection)/:m] ]Distance sensors - you’ll likely need to shield them from dust./:m] ]IMU for tilt and additional feedback for orientation/:m] ]Tilt-compensated compass for heading/:m] ]High capacity 12V battery (we’ll be adding 12V, 10Ah NiMh batteries soon - you’d need at least two)./:m] ]Solar panels and charging circuit/:m] ]Camera (how this will connect to the system is a different issue)/:m] ]Misc parts (like LEDs, wiring, connectors etc)./:m]
Please note that we have not tried this combination of products together - they are only to give you an idea of what you need. It’s important that you read through the specifications to see if they are all compatible. Pay special attention to whichIO pins are used and if multiple shields need to same pin.
You’ll need enough IO to handle:
Motor controllers: 2x PWM + 2x Digital pins
Encoders: 2x Digital per encoder
GPS / GPRS: 1x serial +
Sensors
So in your vast experience what would be a quick and dirty chopping cart assuming that I wanted to go with the GEARS platform? It sounds like I’ll need a microcontroller, motorcontroller, power source, etc… Would you please suggest a line-up of both compatible parts, etc.? Also, in case it makes a difference, I have a Mac operating system, so that’d be nice to be able to use rather than having to go purchase a PC to experiment with. I’d rather spend the money with you! ha!
Thanks Coleman! Here are a few clarifying points to your comments:
I definitely don’t want to risk getting stuck or flipping over, but at the same time, I need it to be able to climb and traverse various gradients and slopes. If I had to guess, I’d say that Id like it to be able to go over a rock that is 4-6 inches tall, and go around one that is any larger. More importantly, I’d like it to be able to make a 360 degree sweep around the rock that it can’t go over. I know that’s alot of turning possibly, but that’s a requirement.
Why do you think that I’ll need a customized frame? The GEARS frame that I say seemed like it might do the job. What am I missing? I’m also completely open to the idea of just having this thing run at night, or when temperatures are under a certain threshold. This is not a mission critical to be able to run during the day in the dead of summer. If you’re not familiar with the desert, here are the basics. From October -May, temperature at night is about 35 degrees and around 75 degrees during the day. From April-September the nights are about 75 degrees and the days can get as hot as 110 degrees. I think only running at night during the summer is most feasible and then a just stopping all movement of the rover during the day or when it’s too hot to charge from solar, or maybe even wind! (It blows pretty hard sometimes.)
That is the tricky part. There is cellular in some places. I’d be open to just going with cellular communications to keep things simple at first. It’s not a very strong signal at times, but it’s there and if it made things easier to get ‘proof of concept’, I’d settle for that. In this scenario, I think is where the autonomy part comes in. If it loses signal, I still need to be able to have it continue it’s mission and then report back to a location where it last had signal to report its location and information from the mission. (Sound’s complicated to me, but hoping there is a solution). However, if you’re telling me that all I need is an iridium sat phone, and it’s that easy, then great! Is there a hybrid of cellular and sat phone, so it could use the cellular as primary and sat phone in those "OH CRAP"moments?
I was taking a guess at speed. I need it to crawl, and then I need it to move into a higher gear. If I drop it off on a roadside and say “fetch” to a location that is 3 miles out in the desert, I don’t want to have to wait a year for it to get there. I think I’d prefer torque.
I see your point on the overheating. I remember heat sinks from the RC car days that sat on top of speed controllers. I’m sure they have something better now. Hopefully the time of day and season that it operates will offset some of the heat/cooling requirements.
As far as vandalism and theft goes, my friends have said the same thing. I’d normally agree with them, but where I’m talking about going is so remote and so few people, I can’t think that anyone would mess with it, let alone steal it. As a backup plan, I plan on painting it desert sand brown to minimize view. Moreover, I’ll put letters that say US GEOLOGICAL SURVEY, PROPERTY OF US GOVERNMENT, or US MILITARY. DO NOT TOUCH. STAY BACK 100 FEET. And then put a nuclear energy sticker on the side and chemical hazard signs as deterrents! LOL I’m serious. And as a backup to that psychological backup plan, it’ll have GPS, so I’ll know where it is, right? Anyone that is going to steal it is going to at least bring it back into cellular range.
