Hydraulic Hexapod, control, theory, etc...

Paul Sherman

Got my BOE, and have been going thru the books and generally having a ball with it.

I realize I'm jumping the gun, but I want to start thinking in terms of controlling my machine...some background before the question:

Transmitter is a Futaba, receiver is a 7 chan. Futaba, and I have some small servos to experiment with.

Transmitter will be for forward/rev & steering. Servos will control two big-ish hydraulic pumps, then motors to drive the legs. I plan on using a Hall effect sensor to keep the alternating tripods in sync.

But right now I want to understand the logical relationships between transmitter, receiver, BOE, and servos.

Transmitter sends a signal to BOE via receiver (BOE listens for PULSIN). Would the software (info from Hall effect, position sensor, etc.) then intercede, and in turn send PULSOUT to the servos?

Also, the physical connections; I think right now for the servos will use Vss & Vdd for power, and assign the third white wire to a pin for PULSOUT, correct?

Would the receiver be the same deal, white wire to a pin to await PULSIN (power will come from th ereceiver battery here)


Clear as mud?
Any help appreciated-
Paul

Project pics so far:
http://personalpages.tds.net/~ksteuer/machine/

allanlane5

Yes, the way a BS2 is typically used in this scenario is as you have described.

The 7 'output's of the Reciever will be routed to 7 BS2 pins. The BS2 will use "PULSIN" on each pin to measure the commanded pulse width. The BS2 can then do some logic in itself (if desired) to determine what pattern of pulses it should give out to the Servo's.

The BS2 will then output those PULSOUT values of appropriate width (for the appropriate position) to the output servo's.

A 'brute force' check program for the BS2 would merely 'copy' the values from input pin to output pin -- PULSIN InPin1, PulseVal· :· PULSOUT OutPin1, PulseVal

And the power and signal wires are as you have called out. Though you must insure that Vss, the Reciever ground, and the Servo grounds, all are attached together somewhere. This gives you a "common ground" for all the devices to reference their control signals against.

Paul Sherman

Thanks Allan.

Ah yes, they all need to reference common ground...would that be as easy as running jumpers connecting the neg. side of the devices?

Thanks again-
Paul

allanlane5

Yep, it is that simple.