garry glen chalk (born february 17, 1952) is an english-canadian actor and voice actor. he has provided the voices for optimus primal of "beast wars: transformers" and "beast machines", as well as optimus prime in the anime english dubs of "transformers: armada", "transformers energon", and "transformers: cybertron", and also was the third american voice of dr. robotnik for "sonic underground". he has lent his voice to over 30 animated television series and has been in films such as "the fly ii", "godzilla" and "freddy vs. jason". he played the recurring role of col. chekov on "stargate sg-1". he is perhaps best known for his recurring role as inspector andrew pawlachuk on "cold squad".