I have access to a lot of surplus 7.5 volt radio battery packs. They put out about 8.5vdc when fully charged and I want to use them to supply power for my project.
Can I use some 7806 Voltage Regulators in parallel with a big Capacitor after them to drop the supply down for the axon, sensors, and the servos?
No, unfortunately you can not
Your batteries are probably 6 cell NiMH (or NiCd).
Nickel-based cells are charged to close to 1.45V and is considered flat when they reach 0.9V if high discharge currents are used and 1.1V if low discharge currents are used (and something inbetween for currents inbetween).
That means that your batteries will vary in voltage from up to 8.7V freshly charged and down to 5.4V.
An 7806 needs 8.5 to 9V in to provide a regulated 6V out.
With a Low Drop Out (LDO) regulator, you can get by with a bit less than 6.5V at the input for 6V regulated out, but that is not really too helpfull.
As I see it, your best option is to select matching pairs of batteries to get the voltage in the range 10.8V to 17.4V and then use a switching regulator to get the low voltages you need. The motors can be run from a battery of their own, or switched down too for a more stable approach, but the motors won't care either way.
A place to start for cheap switchers is http://www.romanblack.com/smps/smps.htm
Any idea what amount of current the [...] I have not been able to find a data sheet for the ir sensors so if anyone has the current usage on them it would help [...]
Strange, that datasheet is all over the net. The GP2D12 has an average current dissipation of 33 mA (50mA max.).http://www.google.com/search?hl=en&safe=off&rls=com.microsoft%3A*%3AIE-SearchBox&rlz=1I7GGLJ_en&num=100&q=GP2D12+filetype%3Apdf