A lens driving device according to an embodiment includes a moving part including a lens; a driving part for driving the moving part in an optical axis direction; and a sensing part for sensing a position of the moving part; wherein the moving part includes: a magnet scaler in which a first pole and a second pole are alternately arranged in a first direction; and a reference magnet corresponding to the magnet scaler and having a first pole and a second pole disposed in a second direction perpendicular to the first direction.

A vibration type actuator includes a vibrating body including an elastic body and an electro-mechanical energy conversion element, a contact body contacting the vibrating body, a flexible printed board provided with a concave portion on a surface opposite to a surface contacting the electro-mechanical energy conversion element and configured to supply electric power to the electro-mechanical energy conversion element, and a holding member provided with a projection portion engaging with the concave portion.

A vibration actuator capable of reducing variations of pressure force and reaction force acting on a vibrator and a contact member has a specific construction. Vibrator devices respectively have vibrators, each of which includes an elastic member and an electro-mechanical energy conversion element. A contact member contacts the vibrators and is movable in a predetermined direction relatively to the vibrators. A restraint member fixes a first vibrator device among the vibrator devices to restrict a degree of freedom in the predetermined direction. A flexible member connects a second vibrator device among the vibrator devices to the first vibrator device. The flexible member has predetermined rigidity in the predetermined direction and has rigidity, which is lower than the predetermined rigidity, in directions other than the predetermined direction.

A vibration-wave motor includes a vibrator having two protruding parts, a holding member configured to hold the vibrator, a movable member configured to translationally move together with the holding member, a rotating unit configured to allow the holding member to rotate around each of three axes relative to the movable member and to restrict the holding member from translating in each of the three axes relative to the movable member, a urging member configured to urge the holding member and the movable member so that the holding member and the movable member translationally move together, and a restricting unit configured to restrict the holding member from rotating around the rotating unit as a center by the urging member.

A vibration-type actuator includes a vibrator, a contact member, a ball, and a base table having a third guide. The vibrator has an elastic member and an energy conversion element. The contact member is fixed to the base table, contacts the elastic member, and extends in a predetermined direction. The vibrator and the contact member are driven along the predetermined direction due to a vibration generated by a voltage applied to the energy conversion element. A first guide provided on the contact member extends in the predetermined direction and a second guide that is connected with the vibrator faces the first guide and moves integrally with the vibrator. The ball is held between the first guide and the second guide rollably in the predetermined direction. The second guide extends in the predetermined direction and includes a fitting projection portion loosely fitted to a groove portion provided on the third guide.

A control apparatus for a vibration actuator configured to relatively move a contact body in contact with a vibrator with respect to the vibrator using vibration occurring on the vibrator includes a control amount output unit including a trained model trained to, if an instruction about a first speed to relatively move the contact body with respect to the vibrator at is issued, output a first control amount to relatively move the contact body with respect to the vibrator.

A piezoelectric drive unit is configured for driving a passive element relative to an active element, wherein the active element includes a resonator with two arms, each extending in parallel to a reference plane and ending in a contact element, which is movable by oscillating movements of the arms and thereby drives the passive element. Each of the arms has, at the outer end of the arm, a protrusion extending inward, toward the other arm, and on at least one of the arms, the respective contact element, arranged at the arm's outer end, extends outward, away from the other arm.

A method of controlling a piezoelectric driving apparatus including a vibration section that has a piezoelectric element and a transmission section that transmits vibration of the vibration section to a driven body, and, by energization of the piezoelectric element, vibrates the vibration section in a combination of longitudinal vibration and bending vibration to cause the transmission section to perform an elliptical motion and to move the driven body by the elliptical motion, the method of controlling the piezoelectric driving apparatus including switching, according to an external force received by the driven body, a drive algorithm of the piezoelectric driving apparatus between a first drive mode in which a separation amplitude, which is an amplitude of the longitudinal vibration, is changed while a feed amplitude, which is an amplitude of the bending vibration, is constant and a second drive mode in which both the feed amplitude and the separation amplitude are changed.

A controller is capable of reducing time required to stop a control target at a target stop position as a final stop position. The controller drives a vibration element including a piezoelectric element by an AC signal to thereby move a contact body, in contact with the vibration element, relative to the vibration element. The controller controls a pulse duty cycle of a signal converted to the AC signal based on a difference between a target stop position, which is a final stop position of the contact body, and a current position of the contact body, and an actual speed of the contact body.

A control device for a vibration-type actuator includes a control unit including first and second output units. The first output unit includes a first learned model subjected to machine learning in such a way as to output a first control amount for causing the contact body to relatively move with respect to the vibrator. The second output unit includes a second learned model subjected to machine learning in such a way as to output a second control amount, which is data of the same data format as that of the first control amount. The control unit updates parameters of the first learned model and parameters of the second learned model based on a control deviation, which is a difference between the first control amount and the second control amount output within the same sampling period as that of the first control amount.