Squirrels have fuzzy tails.
0 Members and 1 Guest are viewing this topic.
2. The on-board controller will consist of a COTS XP Embedded computer linked to the remote controllers through WiFi. It will be responsible for agglomerating and scrubbing all sensor data, and eventually executing autonomous programs.
3. DIO will be from a PCI controller card (http://www.accesio.com/go.cgi?p=../pci/pci_dio_24d.html). I plan on using a few of the outputs to drive H-bridges with PWM (Iím a bit leery that handling PWM from the central processor will drain too many computer cycles; can anyone confirm or deny this?).
5. The power source for these beasts will be 2 Hawker Odyssey PC680s, wired in series for 24 VDC at 32 AH (I believe these should provide me with at least 30 min of cruise time, no?)
6. The tread is a point of contention currently.
flames (Iím sure I can get one for not using Linux or a RTOS)
I agree with dunk, use a microcontroller to handle the low level stuff and let your PC interface with it. The microcontroller would have the motor drivers and I/O that you need.
Cost . . . how much money do you have for it? Guessing by the components you are using, it will come out to over $1000 . . .
Consider using timing belts or assembly belt material for treads instead. Basically you get grooved wheels, stretch the belt onto them, and your done. But I think you would be better by using a 4 wheel robot, where the wheels on either side drive together. Basically a 4 wheel differential drive system - I have made one before that worked really nice (see image). Remember that treads are not only harder to make, but less energy efficient, make turning a lot harder, and reduce your forward speed. A wheel can climb over anything lower than it's radius, perhaps using large wheels might be easier?
And design your bot 100% in CAD (perferably 3D CAD)! A badly planned robot is a badly built robot.
I've budgeted $2500 for "phase 1"
minimizing my ground pressure and maximizing my "bite" into the ground is advantageous.
I'm currently designing it in AutoCAD (3D model). I'm hoping this can avoid the need for a prototype
i think the best bit of advice i could give would be to build a prototype before you start spending money on the final components.
have you thought about power supply for your on-board computer? i have used these with good results: http://www.mini-itx.com/store/?c=10#p1835.
i would hope that these cards will be able to handle PWM in hardware. the specs talk about "Counter/Timers (Optional)" but i don't see PWM functionality mentioned anywhere which would be disappointing.i suspect you will run into problems if you try to get accurate PWM controll from a windows program. when the system gets busy you will have longer pulses than when it's resources are free. i'm not saying it won't be possible (or that i know much about windows programming, (that's your field right?)) but it would be far easier if you used a I/O device that could handle the timing for you.i am working on a very similar project. i am using a microcontroller for a motor controller, attached to the PC via a USB port. (a serial port would be *far* easier but i'm using USB for fun.) all the PWM stuff is handled by the microcontroller. the PC just has to send device_number and pulse_width info.
the 2nd highest power draw will be from your on-board computer.the higher performance a computer you use, the higher the power draw. once you get things up and running, consider removing all unused components. memory uses a lot of power. downclocked CPUs will use less power than ones running at full speed. laptop hard disks will not only put up with bumps better but use less power too. (linux, not needing a GUI to run, will be less CPU intensive, therefor use less power than windows....)i think you should be able to get a PC with limited components, running a limited OS drawing less than 500mA @ 24Volts. so it would be possible to get quite a long standby life out of this thing.(i'm nearly ready to test power draw on a mini ITX mobo at home. i'll let you know how i get on.)
dam right. what's that windows stuff doing on there......
Please tell us your secret in getting robot funding!
Phase 1 sounds like a huge project in itself . . . what are the other phases? Usually when I build a robot, Phase 1 is designing it, Phase 2 is building the mechanical parts, and Phase 3 is electronics/programming/testing . . .
What about really wide tires? And/or tires with deep groves in them (sorta like a gear)?
No matter how much you design, there will always be mistakes. Its more about minimizing mistakes and the loss of money/time to correct them . . .
My assumption is that your system will be semi-autonomous, and work under a similar structure as the Predator (that flying drone blowing up the crazies in Iraq) - the robot handles everything except target ID and the firing button. Correct?
I'm located in north Dallas, TX.
2 ft wide, 5 ft long,