This servo system Zhiyun make, MIGHT work with the bmpcc ...but dont listen to me .... you need to find someone who has actually tried it....

r/https://www.amazon.com/Zhiyun-Follow-Controller-Supports-Panasonic/dp/B07DH6LPGW/ref=sr_1_3?s=electronics&ie=UTF8&qid=1540751208&sr=1-3&keywords=Zhiyun++Servo+Follow+Focus