# How fast could a humanoid robot run?

Speedsters like Quicksilver and the Flash run far faster than a real human ever could. A human body could not withstand the force of friction, survive the rapid acceleration, or process stimuli fast enough.

An Android, however, could have far faster reaction times than a human, as well as survive far greater stress than us meatbags. With our current knowledge of materials and engineering, how fast could a robotic flash run?

• By “run” you mean propelled only by temporary contact with the ground by X number of limbs, right? So cars and jets aren’t considered “running”? Cool question. Sep 26 '19 at 21:55
• You should look at Boston Dynamics' Atlas robot. It seems it isn't as fast as a human yet, but it shows where the state of the art is going. Sep 26 '19 at 22:41
• @Dubukay What if we replaced the wheels with a giant wheel of Legs (spokes) so densely packed together they appear as a wheel? Sep 27 '19 at 0:03
• I don't know,but I would hate to be chased by one. Sep 27 '19 at 18:57

Your principal problem is the aerodynamic profile, center of balance and grip.

We run inclining our torsos and waving our arms, forearms and hands to and fro. That creates turbulence. To say nothing of our frontal profile, created by Face + Torso.

Center of balance. The head of a cheetah is at our hip. To maneuver around an obstacle we would need a gentle course correction, instead of turning on a dime.

Grip. When a pneumatic hammer strikers the asphalt, it tears it apart. There is only so much force you can apply before tearing the surface you are using. The alternatives are: increase the surface or increase the time of contact. In order to "run", the maximum time the soles of the robot are touching the ground is going to be finite given a certain speed and leg length.

Boston Dynamics got a mechanical cheetah to clock below 50 km/h. Boston Dynamics Robotic Cheetah Clocked At 28.3 MPH

That gives us a nice baseline for real and proven data.

Even if we indeed could reach the same speed as a F1 300 Km/h, there are inherent limits to the ROBO-FLASH body if it needs to be humanoid.

Unlike the F1 car, you don't have spoilers to generate down force in order to squeeze out more traction. Human body shape lacks spoilers. Unless you twist the Robo Flash ears :-P Seriously, this is IMHO the main limit. The F1 cars generate extra downforce in function of speed. In excess of 2000 kgs. Some even generate so much force that it makes the asphalt ripple. Without it, the tires would rotate in place, overcoming the ground friction limit.

2 legs. The feet size is finite so you could theoretically make it run on all fours, giving you extra 2 points of contact with the aid of hands.

No tail provides fewer means to control the sharp turns. Soo good luck if there is a single obstacle in front. We are already hammering the floor with RoboFlash powerfull servo legs. A jump means extra force -> pneumatic hammer effect.

All of this without even a single mention of energy considerations, heat, etc. I have no clue on how to determine the maximum speed for RoboFlash.

I would start with the maximum mechanical force a shoe sized piece of asphalt can take and go from there.

• You could probably ignore heating issues under the assumption that while running, the airflow you generate would be great enough to remove all excess heat. You would basically be making our own fan. However, the cooling process will create a lot of extra drag (since you need it to flow over hot surfaces). You can also ignore the tail, because you can place Gyros long the robot body to generate the same effect. Sep 27 '19 at 0:17
• @Shadowzee, totally forgot the Gyros! Sep 27 '19 at 13:09