Described as a “human symbiotic robot” Twendy-One is designed to co-exist with humans and assist with nursing care and housekeeping. To this end its developers focused on safety, dependability and dexterity in constructing their robot. For collision safety the robot’s outer shell is overlaid with soft silicone skins and force sensors that detect physical contact with a person on any part of its body. This is a key component of a “passive impedance mechanism” that enables the robot to adapt to unexpected external forces on the fly.
Twendy-One’s size and range of movement are designed to reflect those of the average adult female. It measures 1.46m (4.8 feet) high and 73.4cm (2 feet) wide. To overcome the limitations and difficulties of a bipedal design the developers of Twendy-One gave it an omni-directional wheel-based mechanism for mobility that allows the robot to move around efficiently even if the robot is in a narrow space. This mobile mechanism equips twelve ultrasonic sensors and a six-axis force sensor to detect objects and humans near the robot and avoid collisions.