How Human can Humanoid Robots get?

The dream to create skilled and intelligent machines has been part of
humanity from the beginning of time. This dream has now become a part of our world’s reality. The last century brought the first explorations of the connection between human intelligence and machines, marking the beginning of an era of research in the field of artificial intelligence (AI). Around the mid-twentieth century time, the first robots were created. They grew more advanced over time, and thus humanoid robots were born.

Humanoid robotics focuses on the creation of robots that imitate aspects of human form and behavior. Humanoids come in various shapes and sizes, from complete human-size legged robots to isolated
robotic heads with human-like sensing and expression. A challenge for humanoid robots is to convey and interpret human intent through subtle natural movements and gestures such as eye gaze, facial expressions, and body language.

With this, the question arises that how human can a humanoid robot get?
Most humanoid robots can imitate human body structure to some extent. They have two arms and two legs, and each leg typically consists of a three degrees-of-freedom (DOF) hip, a one-DOF knee, and two- or three-DOF ankle joints, similar to the human leg structure. Many humanoid robots have been successful in emulating the human body, at least at a higher level. Robots use actuators for movements of limbs, but none of the existing human-made actuators can match the power density of human muscles. They have a significantly fewer number of joints too, and this hampers the ability of humanoids to have the same range of motion as humans. For example, even after many advances in the design of robotic hands, we are unable to achieve the same seamless movement that even a toddler can easily accomplish.

Modeling the entire human motor control system is virtually impossible because the brain's network details are largely unknown. However, researchers have developed controllers for humanoid robots inspired by the work in biomechanics and neuroscience. The simplest element in human motor control is the somatosensory reflex. Sensory information such as muscle length and tension is fed back to muscles through the spinal cord without going through the brain. The reflex loop is similar
to simple output or state feedback often used in robot control, but the typical delay is much longer in humans (at least 25 ms). This has proved to be of great use, especially in the control of leg prostheses. Robotic limbs have been designed to restore natural human locomotion and behavior.

Communication between people is based not only on speech but also on spoken language with various nonverbal behaviors such as eye gaze, gestures, and emotional cues. Humanoid robots' fundamental behavioral and cognitive capability is speech, as spoken language is the primary means of communication between humans. With time, humanoid robots have been able to develop these tendencies. A study was conducted in which participants with gestures were being acted out by a human and a robot. Among the 15 gestures that the human demonstrator performed, the participants recognized eight gestures: nodding, clapping, walking, hugging, flying, expressing anger, shaking hands, and showing directions. Among the eight gestures that the participants recognized, the participants recognized six of the gestures when the robot performs those gestures.

While humanoids have started to become a lot like us, they do not yet have good emotional capabilities. To manifest this emotional capability requires the humanoid to be capable of both recognizing human emotions as well as expressing human-like emotions. However, it seems like this barrier too will soon be crossed keeping in mind the advancement of technology.

-Devanshi Garg, Techniche Media