This research effort aims to develop a series of full-sized humanoid robots, and to
research a simple but reliable bipedal walking method.
Since the debut of Wabot from Waseda University in 1973, several full-sized humanoid
robots have been developed around the world that can walk, and run. Although various
humanoid robots have successfully demonstrated their capabilities, bipedal walking
methods are still one of the main technical challenges that robotics researchers are
attempting to solve. It is still challenging because most bipedal walking methods,
including ZMP (Zero Moment Point) require not only fast sensor feedback, but also fast
and precise control of actuators. For this reason, only a small number of research groups
have the ability to create full-sized humanoid robots that can walk and run.
However, if we consider this problem from a different standpoint, the development of a
full-sized humanoid robot can be simplified as long as the bipedal walking method is
easily formulated. Therefore, this research focuses on developing a simple but reliable
bipedal walking method. It then presents the designs of two versions of a new class of
super lightweight (less than 13 kg), full-sized (taller than 1.4 m) humanoid robots called
CHARLI-L (Cognitive Humanoid Autonomous Robot with Learning Intelligence –
Lightweight) and CHARLI-
2. These robots have unique designs compared to other fullsized humanoid robots.
CHARLI-L utilizes spring assisted parallel four-bar linkages with
synchronized actuation to achieve the goals of lightweight and low cost. Based on the
experience and lesions learned from CHARLI-L, CHARLI-2 uses gear train reduction
mechanisms, instead of parallel four-bar linkages, to increase actuation torque at the
joints while further reducing weight.
Both robots successfully demonstrated untethered bipedal locomotion using an intuitive
walking method with sinusoidal foot movement. This walking method is based on the
ZMP method. Motion capture tests using six high speed infrared cameras validate the
proposed bipedal walking method. Additionally, the total power and energy
consumptions during walking are calculated from measured actuator currents.
