Estimation Technique of Friction Caused by Robot Walking Motion

We develop a new sensing technique to estimate the friction produced between the foot of a biped walking robot and the floor. This technique is based on the criteria of effective non-contact and non-attachment, which are considered when studying a robot's walking motion. Our technique involves measuring the electrostatic induction current generated from triboelectricity that results from a change in the electric potential of a walking robot. The waveform of the induced current contains cadence components of both feet. The walking motion of a commercially available biped robot is detected by measuring the current generated in the robot walking under non-contact and non-attached conditions. A theoretical model is proposed for the electrostatic induction current generated as a result of the change in the electric potential of the robot. The waveforms of the electrostatic induction current generated by the biped robot's walking motion on a wood are observed. It is evident that the differences in the floor materials are reflected in the waveform and in the amplitude of the observed peaks. It is considered that friction conditions affect the waveform of the electrostatic induction current since the obtained waveform strongly depends on the floor material.