Six titans of industry stood onstage at MIT’s Kresge Auditorium yesterday, assembled to speak on a panel about artificial intelligence (AI), including David H. Koch Institute professor Robert Langer; Helen Greiner, cofounder of iRobot, the Bedford-based company perhaps best known for its line of autonomous vacuum cleaners; Xiao’ou Tang, founder of computer vision startup SenseTime, which last year raised $1.2 billion in venture capital at a valuation of more than $4.5 billion; and Eric Schmidt, former executive chairman of Google.