Yes, this is just the power for the joint, not the hinge.
How to do this in a tight space is a tough mechanical engineering problem. Tesla's Optimus uses a 4-bar linkage as the hinge, and some kind of cylindrical linear
actuator as the power drive. Can't tell much about the actuator from the patent for the hinge.
Boston Dynamics used to use hydraulic pistons in their legs, but that did not scale down well from their Big Dog mule-sized machine. They finally went electric, and their machines became far less clunky. Motor power/weight ratios have improved a lot since the early BD days.
Electrical linear motors would be a nice solution. They're rarely used, because they tend to have to be custom for each application. But we might see more of that as humanoid robots approach volume production. The technology has reached 15:1 power/weight ratio.[1] With cooling.
alt Hacker News
Yes, this is just the power for the joint, not the hinge.
How to do this in a tight space is a tough mechanical engineering problem. Tesla's Optimus uses a 4-bar linkage as the hinge, and some kind of cylindrical linear actuator as the power drive. Can't tell much about the actuator from the patent for the hinge.
Boston Dynamics used to use hydraulic pistons in their legs, but that did not scale down well from their Big Dog mule-sized machine. They finally went electric, and their machines became far less clunky. Motor power/weight ratios have improved a lot since the early BD days.
Electrical linear motors would be a nice solution. They're rarely used, because they tend to have to be custom for each application. But we might see more of that as humanoid robots approach volume production. The technology has reached 15:1 power/weight ratio.[1] With cooling.
[1] https://irisdynamics.com/