Patent ID: 8725431

Claim:
A tactile sensor unit, comprising: a substrate; a coat formed on the substrate; and a cantilever beam structure having one end fixed to the substrate and curved to rise in such a direction that the other end of the cantilever beam structure is farther from the substrate than the one end; the tactile sensor unit detecting a load applied to the coat; wherein: the cantilever beam structure is capable of resonating at a first resonant frequency and a second resonant frequency which is different from the first resonant frequency; and the tactile sensor unit further comprising a computation section for calculating a directional component of the load based on a change ratio of the first resonant frequency obtained in accordance with a change in the load and a change ratio of the second resonant frequency obtained in accordance with the change in the load; the first resonant frequency is a frequency in a first resonance mode; the second resonant frequency is a frequency in a second resonance mode which is different from the first resonance mode; and the computation means includes: voltage application means for applying AC voltages of a plurality of different frequencies to a piezoelectric layer included in the cantilever beam structure to resonate the cantilever beam structure in the first resonance mode and the second resonance mode; resonant frequency detection means for detecting the first resonant frequency and the second resonant frequency; and load calculation means for, where a load-free state is a state in which no load is applied to the coat, calculating a directional component of the load in a direction normal to the coat and another directional component of the load in a shear direction based on a first change ratio with respect to the load-free state, which is a change ratio of the first resonant frequency obtained in accordance with the change in the load, and also based on a second change ratio with respect to the load-free state, which is a change ratio of the second resonant frequency obtained in accordance with the change in the load.