A Collaborative Robot (Co-robot or Cobot) is defined as "a robot designed to operate in a shared workspace and interact directly and physically with humans in close proximity." Unlike traditional industrial robots, cobots prioritize safety and flexibility, allowing them to work alongside humans while boosting production efficiency. With the continuous evolution of Artificial Intelligence (AI) and smart machinery technology, the application scope of collaborative robots is gradually expanding from manufacturing to broader areas, including industrial production, logistics, medical care, and retail services, demonstrating strong development momentum.

TESLA’s humanoid robot, Optimus, has continuously seen technical innovation since its public debut in August 2021, especially in its walking and object manipulation capabilities. By May 2023, the official website showed Optimus walking smoothly and grasping objects. By September, it was using machine vision technology to classify moving and non-moving objects and was fully trained end-to-end by neural networks, even performing actions like single-leg yoga poses. The Optimus Gen2, showcased in early December 2024, appeared capable of simulating the tactile pressure of human fingers, easily picking up fragile items like eggs. Optimus Gen2's hands have 11 degrees of freedom, and its walking speed is 30% faster than the previous generation, with its overall weight reduced by 10 kg. Its movement and manipulation capabilities are closer to human actions. It is expected that mass production of the Optimus robot is not far off, but reaching the stated goal of 100,000 units may require validated, real-world applications with actual performance. With continuous technological progress and gradual production capacity increases, the upgrades and validation progress of the Optimus humanoid robot will remain a global focus, serving as a key indicator of success or failure for humanoid robots in this wave of development.

In recent years, the rapid advancement of artificial intelligence technology has led to the emergence of many legged walking robots. Based on current robot products in Europe, America, and China, we have summarized the constituent elements of the new generation of robots (AI Robots), particularly humanoid robots, as shown in Figure 1. Compared to industrial robots, humanoid robots possess a more advanced and complex perception and interaction system, including sensing modules and related software (navigation technology, intelligent decision-making, etc.). They also require greater focus on balance compared to common service robots. Regular service robots have a chassis and use wheeled drives, so falling is less of an issue. Flexible and agile humanoid robots walk on two legs, need to adapt to different surfaces, experience more complex forces at each joint, and require faster response speeds from reducers and motors.