Electric actuator

An electric actuator configured to rotationally drive a first portion having a plate shape, the plate shape including a plate surface and an outer peripheral edge, around a central axis orthogonal or substantially orthogonal to the plate surface to change a contact position of a second portion including a contact portion, the contact portion being in contact with the outer peripheral edge, the electric actuator comprising:

• an output shaft coupled to the first portion;
• a motor to rotate the output shaft around the central axis;
• a rotation sensor to detect a rotation angle of the output shaft;
• and
• a controller configured or programmed to control the motor;
• wherein
• the outer peripheral edge includes a valley portion;
• the valley portion includes:
• a first inclined surface;
• a second inclined surface located on one side of the first inclined surface in a circumferential direction around the central axis;
• and
• a bottom portion to connect the first inclined surface and the second inclined surface;
• the controller is configured or programmed to execute obtaining control to obtain, as a bottom position rotation angle, a rotation angle of the output shaft at a time when the contact position corresponds to the bottom portion;
• and
• the obtaining control includes:
• from a state where a rotation angle of the output shaft is a start angle at which the contact position corresponds to the valley portion, alternately repeating first rotational driving to rotate the output shaft to one side in the circumferential direction around the central axis and second rotational driving to rotate the output shaft to another side in the circumferential direction around the central axis;
• setting an output torque of the motor in the first rotational driving to be smaller than an output torque that allows the contact portion to climb over the first inclined surface;
• switching from the first rotational driving to the second rotational driving when the output shaft is determined to be stopped in the first rotational driving;
• and
• reducing the output torque of the motor in the first rotational driving each time the first rotational driving is performed.