The E series was a collection of successive humanoid robots created by the Honda Motor Company between the years of 1986 and 1993.
[1] These robots were only experimental, but later evolved into the Honda P series, with Honda eventually amassing the knowledge and experience necessary to create Honda's advanced humanoid robot: ASIMO.
It walked in a straight line on two feet, in a manner resembling human locomotion, taking around 5 seconds to complete a single step.
Quickly engineers realised that in order to walk up slopes, the robot would need to travel faster.
[2] The model has 6 degrees of freedom: one in each groin, one in each knee and one in each ankle.