Probably not (but it does not hurt to ask).
RyanAir as actually a Q/A section that answers the question "can i book a seat for my luggage". If taken verbatim this seems to apply almost exclusively to musical instruments, you would need to ask if your CP30 falls under those exceptions. However they give maximum dimensions, so if your robot exceeds those you already have your answer.
From Ryanair's website.
Sporting or musical equipment including but not limited to large
fishing rods, golf clubs, bikes* (bikes have a weight limit of 30
kilos), scooters, fencing equipment, boules, pole vaults, javelin,
surfboards, bodyboards, snowboards and skis and large musical
instruments including but not limited to harps, double bass and drums
are inherently unsuitable for carriage by airlines operating fast
turnarounds such as Ryanair. However, these items may be carried in
the hold of the aircraft in addition to your personal checked baggage
allowance up to a limit of 20 kilos per item. Fees apply, click here
Any sporting and musical item weighing over the 20 kilos allowance
will be charged for the excess at the applicable excess baggage rate
- Bicycles - MUST be contained in a protective box or protective bike bag in order to be accepted for travel. Electric bicycles cannot be
transported by plane.
Smaller musical items such as a guitar, violin or viola which exceed
our cabin baggage dimensions may be carried in the cabin if a seat for
it has been reserved and the appropriate fare paid. There is no
checked or cabin baggage allowance associated with the purchase of an
To book an extra seat for an item the word "ITEM SEAT" must be entered
as the surname and "EXTRA" must be entered at the first name. EXTRA
ITEM SEAT will then be displayed on the reservation and online
boarding pass. The accompanying passenger's travel document details
must be entered during the online check- in process. Reserved seating
in emergency rows 1,16 and 17 may not be purchased if you have
purchased an extra seat for item/comfort.
For health and safety reasons Ryanair does not accept for carriage any
individual item exceeding 32 kilos or with combined dimensions of more
than 81cms (height), 119cms (width) and 119cms (depth). This weight
limit does not apply to mobility equipment.