A NEW OPERATION PRINCIPLE OF SYSTEM THAT COMBINES PHASE-CONTROLLED ACTUATOR WITH DIFFERENT DRIVE FREQUENCIES

Abstract

In Japan, the shortage of construction workers and inspectors has become a social problem due to the declining birthrate and aging population. In addition, the slow progress of automation in challenging environments, such as construction sites and bridges, has been pointed out. Although various types of inspection robot have been developed, bridge inspection technology has not been fully established. In this study, the operation of a phase-controlled actuator equipped with vibration components with different drive frequencies is investigated. The phase-controlled actuator, in which a second-harmonic vibration component is coupled to a fundamental-wave vibration component to avoid vibration interference, exhibits excellent propulsive characteristics. To further improve the propulsion characteristics, a prototype actuator system, in which two phase-controlled actuators with different drive frequencies are coupled, is developed. Tests on prototypes show that this system can simultaneously achieve high-speed movement and good traction characteristics. Furthermore, the operation principle of this actuator system is established based on test results. The potential of an inspection device with the proposed actuator for the internal inspection of bridges with a small automatic tapping device is demonstrated.