Factory arms have next to no sensing. They blindly wave around on preprogrammed trajectories. They are much stronger than humanoids and they are bolted to the f

Factory arms have next to no sensing. They blindly wave around on preprogrammed trajectories. They are much stronger than humanoids and they are bolted to the floor. They will crush you without noticing at all and continue about their work. They use high gear ratios on their motors, which means they are extremely stiff and they have much more inertia in motion than you would expect even from their large size and weight. The rotor in the motor is rotating at tremendous speed and its kinetic energy goes with the speed squared. If the arm hits you it will keep going, and if it pins you against something you will not be able to push it even a centimeter. Humanoids use lower gear ratios and, of course, are not bolted to the floor. I would much rather be bumped by a humanoid than a factory arm.