When we move our bodies, we begin by thinking about the movement.
By thinking, “I want to walk,” the brain sends the necessary signals through the nerves to the muscles needed for that movement.

In the body of a healthy person, each muscle receives signals sent from the brain, allowing the muscles to move only the amount of force necessary to match the intention.

As the signals travel towards the muscles, they leak on the skin surface as very faint signals, so-called “bio-electric signals [BES]”. HAL can read the BES with its originally developed electrodes attached to the wearer‘s skin surface. Based on various other information obtained as well, HAL determines the wearer's desired movements.

HAL controls the power unit according to the movements it recognizes to assist the wearer in moving according to his or her intentions or even exerting more force than usual.

HAL has two types of control systems that can be used together according to the conditions of the wearer. The “Cybernics Voluntary Control System” uses BES to perform the wearer‘s desired movements. The other is the “Cybernics Autonomous Control System” to realize human-like movements even if the BES cannot be detected. These two control methods are the reason why HAL is such advanced technology.

Once the movement is complete, the brain checks how the body moved according to the signals sent. When HAL realizes the wearer‘s intended motion, the body feeds back information of the successful movement. This allows the brain to gradually learn how to send out the signals necessary for good movements. Repeating this process could help a person with a disability improve their physical function after taking off HAL.