Musk said on Wednesday evening that Tesla’s humanoid robot, Optimus, was still in the R&D phase. Still, the company plans to unveil the third generation of its robot in the first quarter. Tesla also plans to convert its Model S and X assembly capacity in California to a robot assembly line.

Tesla (TSLA.O) plans to more than double capital spending to a record high of more than $20 billion this year - but little of it will go to its traditional business of selling electric vehicles to hum...