Driving-unit operation method and controller

A driving-unit operation method of operating a driving unit for driving a passive element relative to an active element,

• the active element including a resonator and at least one excitation section configured to excite a vibration of the resonator,
• the resonator including at least one arm extending from a coupling portion of the resonator,
• the at least one arm including a contact portion at an outer end of the at least one arm,
• the contact portion being movable by vibrational motion of the at least one arm,
• the passive element being disposed to be driven by the vibrational motion to move relative to the active element,
• the passive element including a first contact region and being disposed such that the first contact region and the first contact portion make contact with each other by a prestressing force when the active element is not excited,
• the driving-unit operation method comprising:
• driving the at least one excitation section by a drive signal that is a periodic signal including a drive pulse repeated at an excitation frequency, while repeatedly omitting the drive pulse, thereby generating a periodically repeated pulse block with a pulse block duty cycle expressed by a relation Ton/Tb between a pulse block on time (Ton) and a pulse block cycle (Tb);
• and
• modifying the drive signal depending on the position error signal, wherein
• in the modifying the drive signal:
• in case that a position error signal is within a first range, a shape of the drive pulse is modified into a first driving pulse shape or the excitation frequency is modified by a first excitation frequency detuning value, and the pulse block duty cycle is set to a first pulse block duty cycle value, and
• in case that the position error signal is within a second range, the shape of the drive pulse is modified into a second drive pulse shape or the excitation frequency is modified by a second excitation frequency detuning value, and the pulse block duty cycle is set to a second pulse block duty cycle value.