Long Range UGV
I've been contemplating hacking a kid's Power Wheels style vehicle into something autonomous for a long time. I found this one for $20. I like it because the rider area is lower than most, lowering CoG for stability. It's hard to beat a robot chassis for $20 so I'm going to look at it today. I hope it has two motors for the rear wheels, and I hope the steering mechanism isn't too crazy. The battery is dead, and it doesn't come with a charger but that is fine with me.
End Goal: If it is reliable, and waterproof I'd like to leave it out in the desert, like a real rover. I think if I coordinate this with the Park Patrol in this area I can get away with it. I would like to leave it out there for at least 1 month, possibly longer. It would be interesting to see how long it lasts out there, and what happens to it.
Brains: Propeller MCU(s), likely SPIN, possibly C, maybe both.
Sensors: We can rule out PING, unless we can find some waterproof PINGs. I will go with Sharp IR, IMU, GPS and some other ADC sensors like light and sound. It will need motion detection when sitting still, especially to wake it up if anyone comes near it. Then an MP3 player to play some message about how it is GPS tracked, don't mess with it because the onboard reactor is running away, etc etc.
Navigation: I would like to get it to be able to follow a magnetic heading, while avoiding obstacles. I don't think GPS waypoint navigation is needed, but this would afford me the chance to play around with it.
Comms: XBee Pro 900Mhz radios and/or something cellular. I need suggestions on the cellular part. We'll need to do telemetry as well as the images.
Steering: I don't know what to expect inside of the buggy. I can possibly use the Dynamixel MX-28 I have to steer it. If not I will try to salvage a windshield wiper, or a drill motor and clutched chuck, unless someone has a better suggestion. Cheaper is better because we may never see it again.
Power: I plan to use small 12v SLA batteries for now. I have 2 solar panels I might be able to put on it, that can provide up to 150 watts. If that works out I'd be really happy. If I cannot mount the panels due to their size, maybe I can find someone that would trade 2 large panels for 2 smaller panels. I don't think I'd ever use 150 watts, if there are cloudy days it would come in handy. If there are a lot of cloudy days there will need to be a deep sleep mode. It will be impossible to completely kill this thing. I'm not driving 4 hours (round trip) to pick up a bot with dead batteries.
Camera: We have to figure out how to send images using XBee and the 3G modem, hopefully using the same camera. It would be great if the camera was IR sensitive for night shots. I have a nice IR illuminator for it. This wouldn't be any fun without the images to go with the telemetry.
Thoughts and suggestions are much appreciated.
End Goal: If it is reliable, and waterproof I'd like to leave it out in the desert, like a real rover. I think if I coordinate this with the Park Patrol in this area I can get away with it. I would like to leave it out there for at least 1 month, possibly longer. It would be interesting to see how long it lasts out there, and what happens to it.
Brains: Propeller MCU(s), likely SPIN, possibly C, maybe both.
Sensors: We can rule out PING, unless we can find some waterproof PINGs. I will go with Sharp IR, IMU, GPS and some other ADC sensors like light and sound. It will need motion detection when sitting still, especially to wake it up if anyone comes near it. Then an MP3 player to play some message about how it is GPS tracked, don't mess with it because the onboard reactor is running away, etc etc.
Navigation: I would like to get it to be able to follow a magnetic heading, while avoiding obstacles. I don't think GPS waypoint navigation is needed, but this would afford me the chance to play around with it.
Comms: XBee Pro 900Mhz radios and/or something cellular. I need suggestions on the cellular part. We'll need to do telemetry as well as the images.
Steering: I don't know what to expect inside of the buggy. I can possibly use the Dynamixel MX-28 I have to steer it. If not I will try to salvage a windshield wiper, or a drill motor and clutched chuck, unless someone has a better suggestion. Cheaper is better because we may never see it again.
Power: I plan to use small 12v SLA batteries for now. I have 2 solar panels I might be able to put on it, that can provide up to 150 watts. If that works out I'd be really happy. If I cannot mount the panels due to their size, maybe I can find someone that would trade 2 large panels for 2 smaller panels. I don't think I'd ever use 150 watts, if there are cloudy days it would come in handy. If there are a lot of cloudy days there will need to be a deep sleep mode. It will be impossible to completely kill this thing. I'm not driving 4 hours (round trip) to pick up a bot with dead batteries.
Camera: We have to figure out how to send images using XBee and the 3G modem, hopefully using the same camera. It would be great if the camera was IR sensitive for night shots. I have a nice IR illuminator for it. This wouldn't be any fun without the images to go with the telemetry.
Thoughts and suggestions are much appreciated.
1333 x 597 - 2M
Comments
I'm going to work on the motors first. Pull the gearbox apart and check everything out. I'd like to check the brushes on the motor, but they look hard to reassemble.
I had no idea there wasn't any ramping with these things. It's either on or off, there are two speeds accomplished by two motors. In low only one motor would turn on.
Here are some pics. Not bad for day one. After the motors I'll move onto the steering mechanism.
Now what else did you need? A Power Wheels?
Never forget Hitchbot in the City of Brotherly Love!
http://www.cnn.com/2015/08/03/us/hitchbot-robot-beheaded-philadelphia-feat/
Yes... humans are a bad crowd... that's the reason why the mars rovers live(d) longer than Hitchbot!
What is this desert, the one in sothern California?
The one with high white sand dunes?
The one with four wheelers trying to get some air at the top of the next rise.?
If that is the place, street treads are not going to get very far. Not sure if it will be left alone for a month. Shame to put a lot of time and parts on a bot someone may run over.
Good luck finding a secluded spot, if you find it, there will be a lot of satisfaction in a project like this. Logging day/night temperature's, balancing power in vs power expended. Just the whole idea of the bot being self sufficient and on it's own, is pretty cool.
If your bot will be twenty minutes away, that might just as well be on another planet. There isn't any good way of getting FPV from that distance. Unless you have a plan, which you usually do. :thumb:
Thanks, I ordered a couple. "Good-Module" can't go wong. That is one blinky power wheel!
Sure, the biggest reason not to leave it in the desert is other people. For once in my life I'm not going to let it bother me. I can't think of anything else to do with it once it is ready for such a thing. It could end up like HitchBot
Yeah SoCal, here's the link.
Not by the white sand dunes. The criteria for the spot is that is must be similar to Mars and also have 3G, okay that sounds funny. I have secluded spots. The tough part about secluded spots is that they're not as sunny and the 3G takes a few minutes to send SMS.
The traction is something I plan to test once it's running, which should be next weekend if I can put feedback on an actuator I bought on Amazon for $40. Actually it was free, thanks to leftover gift cards.
There is a funny thing about Power Wheels and traction. They have hard plastic wheels, and the motor control is a simple on/off system. People are adding rubber to the tires to get traction, then burning out motors, because the motor relied on the slippage so it could turn at full RPM when you hit the gas. So everyone got mad at the people selling the rubber mod. Then, someone smart figured hey, we can have the rubber mod if we use a proportional speed control. So now all is well in power wheels land, traction and proportional speed control. I still cannot believe these things do not have proportional speed control out of the box.
It's not going out there without sending back pics. So far I've found a couple of expensive ways to do it. I will keep searching.
Here's a pic of the steering actuator. I hope that cap comes off the end of the motor! I plan to use one of those magnet encoders. A friend of mine has donated that and two beefy motor controllers. Otherwise I'm mounting a pot on the pivot point of one of the front tires.
Also, a shot of the gearbox, in very good shape. I will repack it anyway.
The Boy Scouts had Scout: http://www.nbcnews.com/technology/after-2-500-miles-atlantic-scout-ocean-drone-missing-sea-2D11603748
And this Brit Robin keeps at it: http://www.tsogpss.co.uk.gridhosted.co.uk/
The robot will need to get inside their head. Something for everyone! It will be covered in stickers the indigenous species can relate to. I'm working on a detector that can sense nearby RF, that could trigger an MP3 player, "No disassemble!!"
Isn't it? The exciting part is putting it out there. The scary part is that I haven't tried mounting the solar panels yet.
I'm trying to come up with a name. I'm not good at it, someone bail me out already.
Kickstarter would be awesome, but not this round. I'd rather have this under my belt, team up with a large group, and build an actual rover.
If I had a lot of land around me I would have an outdoor robot. Living in a condo forces me into these things. I'm thinking a 1 week trial run in someone's back yard. I need to pick the most secure yard and it has to be at least a few miles away. It would probably be good if they didn't have dogs
Good news! I got 2 brand new motors and gearboxes for it today. $40 on eBay. Same cost as the motors without the gearbox elsewhere.
You could be liable.
I have no idea how to mount it, it's waterproof but not very durable. I put it outside charging an SLA and it seems like it's overkill.
Make a frame out of aluminum angle stock and some pop rivets. Strong, light and weatherproof, The frame can stay attached to the body, and you can remove the panel to work on the robot.
Jim
That's a good idea, I will look into that. I bet they would. Thanks.
I was thinking of picking up some square tube today. I can build a frame under it. Then figure out how to attach that frame to the rover once the body is ready.
I was planning to bring the chassis to a place that wraps cars, but they said it will be up to a month to get it wrapped and the price was too high anyway. Spray paint it is...
I hope not, it's not really between any points of interest. I have a pretty good spot planned, it's one of few with decent data coverage.
The battery I planned to use for this project is dead. The best thing is weight is not a factor, I can put something heavy in there. I plan to use two 12 v batteries, and a UPS between them. The UPS also trickle charges the second battery. It's a neat little circuit for in-car computers. http://www.mini-box.com/picoUPS-100-12V-DC-micro-UPS-system-battery-backup-system?sc=8&category=1264
Propulsion Battery: 12V / 26Ah SLA (not sure about the NB terminals)
9.1 hours @ 2A everything on, motors at "full speed" (speed will be efficient, not fast, TBD)
Motors, LEDs, anything that uses 12V and lots of current.
https://www.amazon.com/Amstron-26Ah-Sealed-Battery-Terminal/dp/B002L9CN3K
Accessory Battery: 12V / 7 Ah SLA
9.8 hours @ 500mA sensors, comms and MCU(s). This could change with cooling fans.
The rest of the electronics.
https://www.amazon.com/Battery-Replacement-Interstate-Patrol-BSL1075/dp/B00K8MQHK2
The solar panel will directly charge the large battery, and the UPS will charge the smaller battery. The large battery will be connected directly to the motor controllers. The UPS will not provide power to the motors, only electronics. They may be some relays involved, but that also adds more points of failure.
The cool factor would be having a bank of relays that could re-route power, but I don't think we need it, and it could end up having issues. I have one of those eBay relay banks and I get a funny feeling thinking about using it to control everything. I'm going to stick to KISS.
The robot should be able to easily manage with that amount of power. The worst case scenario is not moving and going into sleep mode. I don't know what the sleep mode drain will be until we figure out the modem. I think the GSM modems are very power hungry, and I'm hoping that can run 24/7.
The only way I can see this happening is to setup a 3G router with Ethernet on the robot. Wifi would be much easier, and the power could be reduced to save battery, but it seems cheesy and problematic to use wifi.
I can add this $40 USB dongle to my current data plan at no extra monthly cost.
https://3gstore.com/device/126_att_huawei_usbconnect_900_e1815.html
Connect with a short USB extension to the $30 TP Link router -
https://www.amazon.com/TP-Link-Wireless-Portable-Router-TL-MR3020/dp/B00634PLTW
The router would unfortunately need to connect to a 10/100 switch.
Connected to the switch will be an IP Camera, and some kind of interface to the Propeller.
I see that the Spinneret is discontinued, too bad I sold mine. If someone has one to sell or trade let me know, I think that would be easy. If there are better/other options than the Spinneret I'm all ears, and appreciate the help.
I would like to control the robot using Telnet commands.
The shared data plan I'm on can easily support another 4 GB of usage per month. That means we can do 800x600 @ 1fps while driving, providing the signal is strong enough. This is all very good news to me.
Yes, picking up spray paint today. The red is driving me nuts... I have a digi-camo stencil, but I think I'll go old school. Semper Fi! http://www.krylon.com/products/fusion-for-plastic/ Some nice colors in there.
I hope to borrow a sand blaster, if not it will be elbow grease and sandpaper. I'm waiting on some parts that will take around 10 days to arrive so I have plenty of time before stuff gets mounted.
@NWCCTV probably still has Spinnerets, pls see this link: http://forums.parallax.com/discussion/165177/have-to-give-it-up-for-a-while
I will use angle brackets to attach everything. What do you think of this?
Each panel weighs 12 lbs. I'll probably go with 1" tube.
I have a Spinneret that I'm not using. PM me with offer and where to send it.
Dave
I'm going to attempt to set up a serial link between home base and the rover. I hope to be able to remotely program the rover's 2nd Propeller, which will handle the autonomous modes.
Initially I'd like to be able to send a move command that will expire in x amount of time. So if you tell it to go forward, it will until a sensor trips, or the amount of time expires. This should stop any runaway bots. Being able to program it in the field also means getting it to the field faster.
Another thing I overlooked, and is rather important, is the RSSI of the 3G modem. I hope I can get that from the TP Link router, since the 3G modem is plugged in via USB. If I can't, I'm not sure what to do about that. We can't be roaming in no coverage areas.
From http://www.radioraiders.com/gsm-at-commands.html (via WayBackMachine):
Probably a way like this will work with most other modems too...
Starting with connecting the batteries, this Prop would automatically boot. It would check both batts, and if conditions are good it would then turn on the other busses, using relays. If conditions are not good, it will keep everything off, go to sleep and check again later. This is known as deep sleep mode, and there are no comms on during this time. This should protect the batteries. During this time the rover would be inaccessible.
Another reason why we need this power control is that sensor code can hang by just turning off the sensor. This would allow everything to come up fresh.
I may include some anti-theft in the essentials bus, and a momentary e-stop button, possibly a shock sensor and loud alarm, but that would be added toward the end.
None of this is set in stone until I can do some real testing. Here's my list of chores...
1. Measure current of all devices
2. Choose batteries (48 hours of deep sleep mode or 2 hours of driving/communicating + 24 hours of deep sleep)
3. Field test for at least a few days, I can simulate everything in my garage