This paper deals with reflexes against sudden obstacles for humanoid robots, which are combined with a proposed piecewise-linear pattern generator. The reflex action consists of modulating the motorspsila commands by the outputs of the force sensors located under the robot legs, and through a given primitive neural network previously proposed. Eventually, the primitive reflex is modified by the afferent signals to be more adaptable and robust against sudden obstacles. The final reflex structure enables the response of the sensory signals to be coordinated and modulated with locomotion controllerpsilas outputs to achieve an intended stabilizing behavior of the robot. The effectiveness of the proposed reflex is demonstrated by experiment using Fujitsupsilas humanoid robot HOAP-3. It is shown that the primitive reflex movement previously proposed becomes robust against sudden obstacle that hits the robot sole plate at different locations. The proposed reflex system, therefore, contributes towards the safer interaction of the humanoid robot with the environment.

Reflexes have been viewed as integrated motions with the centrally generated motors commands to produce adaptive movement. In this paper, a walking pattern generator for humanoid robots based on piecewise linear functions and inspired by passive walking is considered. To deal with lateral and frontal disturbances, sensory feedback is realized based on the inverse pendulum model. The reflex system that highly adapts and controls the movement of the humanoid robot, when a large disturbance occurs, is combined with the motion pattern generator and proposed in a unified form with regards to three types of sudden events. Experiments using Fujitsu's humanoid robot HOAP-3 demonstrate that a reflex movement is successfully integrated with the rhythmic motion when there are sudden changes in floor level, when obstacles suddenly appear, and in the presence of a large disturbance. The proposed reflex system therefore contributes toward the safe interaction of humanoid robots with the environment.

Reflexes have been viewed as an integrated motion with the centrally generated motors commands to produce adaptive movement. In this paper, the reflexes that highly adapt and control the movement of the humanoid robot when a large disturbance occurs is considered. The structure of the reflex system is proposed combined with the walking motion generator. Our approach to generate a rhythmic motion does not require complex dynamics models. It is based on linear oscillators and provides flexibility in introducing reflexes. In order to demonstrate the effectiveness of the proposed system, the humanoid robot HOAP-3 of Fujitsu is used. It is shown that a reflex movement is successfully integrated with the rhythmic motion in the following case; sudden change in the floor level, sudden change in load, and presence of a large disturbance. As a result, the proposed reflex system contributes toward the safe interaction of the humanoid robots with the environment