Since Tesla introduced the first-generation humanoid robot Optimus at the 2022 AI Day, it has drawn global attention and energized the robotics field. In December 2023, Tesla CEO Elon Musk launched Optimus-Gen 2. Its enhanced performance is pushing humanoid robots towards wider use, opening vast market potential for planetary roller screws, a crucial component.
I. Robot Structure and Roller Screw Application
Tesla's humanoid robots demand high-precision motion control. In Optimus-Gen 2, each of the 14 linear actuators needs 1 planetary roller screw for straight-line movement. The 12 brushless cup joints in its dexterous hands each require 1 miniature planetary roller screw to ensure hand movement precision and flexibility.
II. Technical Advantages of Planetary Roller Screws
Unlike ball screws (point contact), planetary roller screws use threaded rollers for line contact. This gives them 3-times the static load-bearing capacity of ball screws and a lifespan 10-15 times longer. They also offer high precision, high speed, impact resistance, and low noise. With lead accuracy from KL5 (standard) to KL10 (G3), they can reach a max speed of 2000mm/s, an input rotation speed of 5000 rpm or more, and an acceleration of 3g.
III. Market Scale Driven by Tesla's Robots
Early in humanoid robot development, customized planetary roller screws were expensive. But as Tesla ramps up robot production, prices are falling. Estimates show that when production hits 1 million units, an ordinary linear screw may cost about 907 yuan and a miniature one around 302 yuan. Beyond that, prices will likely stabilize. At 1 million and 2 million units, the market for these linear screw drives could reach 16.3 billion and 32.7 billion yuan respectively. If production reaches 5 million units, the market may expand to 44.5 billion yuan, fully unlocking demand.
IV. Ball Screws in the Robot Market and Comparison with Roller Screws
Ball screws are used in industrial and mobile robots. In SCARA robots, axes 1 and 2 use servo-motor-harmonic-reducer setups, while axes 3 and 4 use 1 ball screw (for linear motion) and 1 spline, or a ball-screw-spline. They're also found in multi-joint robot end-effectors.
