A New Type of Electromagnetic Vibration Actuator Capable of Combined Linear and Rotational Motions

Abstract

The deterioration of large steel structures, such as bridges and power generation facilities built in the 1960s, has become a problem. Such infrastructure requires regular inspections every few years, and many robots have been proposed for structural inspection. However, inspection technology for large steel structures by robots has not yet been established. The establishment of inspection technology in bridges is one of the most important issues in the maintenance of social infrastructure. This paper proposes a novel vibration actuator as a new robot drive source, which combines mechanical resonance and electromagnetic force and enables reciprocating movement by orthogonally arranging multiple vibration components. By controlling the phase difference of these vibration components with only a simple signal generator and amplifier, machine tests showed that reciprocating and rotating reciprocating motions with almost the same characteristics are possible. Experimental results reveal that the vibration actuator is able to pull a load mass of 150 g. In addition, motion analysis is conducted by applying the energy method and considering the effects of phase control on the linear and rotational motions of the vibration actuator. The results obtained in the machine test and the analysis results are mostly in agreement. This confirms that even if the parameters for the vibration actuator are varied, the linear and rotational characteristics of the actuator can be predicted by theoretical calculations. A new drive source for robots and the operation of electromagnetic motors capable of linear and rotational motion are established in this paper. For this reason, the possibility of realizing social infrastructure improvement for large steel structures such as bridges is demonstrated.