Calibration method for inertial drive actuator, and inertial drive actuator device

A calibration method for inertial drive actuator of driving a target moving body among a plurality of moving bodies to move by inertia between a first movement limit position and a second movement limit position in relation to an oscillating plate that is moved to reciprocate by a moving member, and detecting positions of the moving bodies based on electrostatic capacitances includes detecting electrostatic capacitances of opposing parts of a moving body side electrode provided in a target moving body and an oscillating plate electrode provided in the oscillating plate is detected at the first movement limit position and the second movement limit position, respectively; and calculating a ratio of a difference between the electrostatic capacitances at the first movement limit position and the second movement limit position to a movement limit distance that is a distance between the first movement limit position and the second movement limit position. At least one of the first movement limit position and the second movement limit position is a position where the target moving body abuts against a non-target moving body.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2009-064046 filed on Mar. 17, 2009; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a calibration method for inertial drive actuator and an inertial drive actuator device.

2. Description of the Related Art

FIG. 20is a side-view depicting the structure of a conventional actuator920. As shown inFIG. 20, the actuator920includes a piezoelectric element911, which is a type of electromechanical converting element, a drive shaft912, a moving body913that is friction-coupled to the drive shaft912, and a frame914of the actuator920. One end of the piezoelectric element911is fixed to the frame914while the other end of the piezoelectric element911is fixed to the drive shaft912. A detecting member921that is fixed to the frame914constitutes a fixed electrode for detecting a position of the moving body913based on an electrostatic capacitance. The detecting member921is disposed parallel to a direction of movement of the moving body913in a contactless manner. The drive shaft912, the moving body913, and the detecting member (fixed electrode)921are made of a conductive material. The surface of the detecting member921that opposes the moving body913constitutes an electrode921. The electrode921and the moving body913are arranged with a gap D therebetween and they constitute a capacitor having an electrostatic capacitance C.

FIG. 21is a plan-view depicting the structure of the detecting member921and the relationship between the detecting member921and the moving body913. As shown inFIG. 21, the detecting member921includes a first electrode921aand a second electrode921barranged on an insulation member921p. Each of the first electrode921aand the second electrode921bhas a shape of a right-angled triangle. The first electrode921aand the second electrode921bare arranged in such a way that their oblique sides are adjacent to each other. A driving pulse output from a driving circuit918(seeFIG. 20) is applied to the piezoelectric element911and also to the moving body913via the drive shaft912.

As in an exemplary state shown inFIG. 21, the moving body913and the first electrode921aface each other and are coupled by electrostatic-capacitive coupling. Similarly, the moving body913and the second electrode921bface each other and they are coupled by an electrostatic-capacitive coupling. As a result, the driving pulse applied to the moving body913flows toward the first electrode921aand the second electrode921b. A current i flowing toward the first electrode921aand the second electrode921bis detected by a detecting circuit919the value of the current i is input into a control circuit917.

As an example, a case is explained here in which the moving body913moves in the direction of an arrow a (seeFIG. 21) from the first electrode921atoward the second electrode921b. Because of the movement of the moving body913, while on one hand an opposing electrode surface area between the moving body913and the first electrode921adecreases gradually leading to a gradual decrease in an electrostatic capacitance Ca between the two, on the other hand an opposing electrode surface area between the moving body913and the second electrode921bincreases gradually leading to a gradual increase in an electrostatic capacitance Cb between the two. Consequently, as the moving body913moves, a current is flowing from the moving body913to the first electrode921adecreases gradually, and a current ib flowing from the moving body913to the second electrode921bincreases gradually.

On the other hand, when the moving body913moves in the opposite direction of the arrow a, from the second electrode921btoward the first electrode921a, while on one hand the opposing electrode surface area between the moving body913and the first electrode921aincreases gradually leading to a gradual increase in the electrostatic capacitance Ca between the two, on the other hand the opposing electrode surface area between the moving body913and the second electrode921bdecreases gradually leading to a gradual decrease in the electrostatic capacitance Cb between the two. Consequently, as the moving body913moves, the current ia flowing from the moving body913to the first electrode921aincreases gradually, and the current ib flowing from the moving body913to the second electrode921bdecreases gradually.

Thus, the position of the moving body913in relation to the detecting member921can be determined by comparing the amounts of the currents ia and ib that increase and decrease with the movement of the moving body913. In addition, the direction of movement of the moving body913can be determined based on whether the currents ia and ib increase or decrease.

Such an actuator is disclosed, for example, in Japanese Patent Application Laid-open No. 2003-185406.

However, due to factors such as humidity, temperature (minute deformation of an electrode), gravitation, and aging, the detected value of the electrostatic capacitance sometimes varies from the value detected at the time of assembly of an actuator. Due to this, a relationship between the electrostatic capacitance at the time of assembly and position data is likely to break, thereby causing deterioration of accuracy in position detection.

Thus, a calibration needs to be performed to eliminate deterioration of accuracy in position detection. When a plurality of moving bodies exists, the respective moving body cannot be individually controlled in the conventional technology, thus resulting in incorrect calibration.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above discussion. It is an object of the present invention to provide an inertial-drive actuator calibration method and an inertial drive actuator device that can perform accurate calibration when there are a plurality of moving bodies.

The present invention has another object to provide a technique for correcting, even if electrostatic capacitance between moving bodies and an electrode differs at a later stage after the assembly of the actuator, the electrostatic capacitances to appropriate values to allow absolute positions of plural moving bodies to be reliably and accurately calculated.

To solve the above problems and to achieve the above object, according to an aspect of the present invention, a calibration method for inertial drive actuator of driving a target moving body among a plurality of moving bodies to move by inertia between a first movement limit position and a second movement limit position in relation to an oscillating plate that is moved to reciprocate by a moving member, and detecting positions of the moving bodies based on electrostatic capacitances includes steps of detecting in which, electrostatic capacitances of opposing parts of a moving body side electrode provided in a target moving body and an oscillating plate electrode provided in the oscillating plate is detected at the first movement limit position and the second movement limit position, respectively; storing in which, the electrostatic capacitances at the first movement limit position and the second movement limit position detected at the detecting step are stored; and calculating in which, a ratio of a difference between the electrostatic capacitances at the first movement limit position and the second movement limit position stored at the storing step to a movement limit distance that is a distance between the first movement limit position and the second movement limit position is calculated, wherein it is made possible to calculate an absolute position of the target moving body between the first movement limit position and the second movement limit position by using the ratio calculated at the calculating step, and at least one of the first movement limit position and the second movement limit position is a position where the target moving body abuts against a non-target moving body.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that positions of the target moving bodies in a movement range from the first movement limit position to the second movement limit position, and the electrostatic capacitances have a proportional relationship.

The calibration method for inertial drive actuator according to another aspect of the present invention includes a step of comparing in which, the electrostatic capacitances stored at the storing step are compared.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that there are a plurality of target moving bodies and a calibration thereof is mutually and simultaneously performed.

It is preferable that the calibration method for inertial drive actuator according to another aspect of the present invention includes a step of locking in which, the non-target moving body is locked to the oscillating plate.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that a movement amount per driving waveform is simultaneously calculated for each of the moving bodies.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that a movement amount per driving waveform is individually calculated for each of the moving bodies.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that recalibration is induced when the electrostatic capacitance varies and an error is detected in a relationship between position data and the electrostatic capacitance even if the moving body is idle in absence of an input signal.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that a movement amount per driving waveform when the target moving body is moved from the first movement limit position toward the second movement limit position and a movement amount per driving waveform when the target moving body is moved from the second movement limit position toward the first movement limit position is measured or calculated, and one of the movement amount per driving waveforms is stored or both the movement amount per driving waveforms are stored separately.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that when calculating the movement amount per driving waveform, the target moving body is moved at least once near a center in a movement range from the first movement limit position to the second movement limit position.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that the oscillating plate electrode is provided in a plurality, and the position of the target moving body is calculated by comparing or calculating electrostatic capacitances between the moving body side electrode and the respective oscillating plate electrodes.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that the oscillating plate electrode includes any one of a driving electrode and a position detecting electrode or both.

It is preferable that the calibration method for inertial drive actuator according to another aspect of the present invention further includes a step of confirming in which, a calibration result is confirmed.

In the calibration method for inertial drive actuator according to another aspect of the present invention, it is preferable that recalibration is performed if it is confirmed at the confirming step that calibration is not performed correctly.

An inertial drive actuator device according to another aspect of the present invention includes an oscillating plate that is moved to reciprocate by a moving member; a driving circuit that applies a drive signal to the moving member; a plurality of moving bodies that move by inertia in relation to the oscillating plate, wherein a target moving body among the moving bodies moves by inertia between a first movement limit position and a second movement limit position, and at least one of the first movement limit position and the second movement limit position is a position where the target moving body abuts against a non-target moving body; an electrostatic capacitance detecting circuit that detects an electrostatic capacitance of opposing parts of a moving body electrode provided in the moving bodies and an oscillating plate electrode provided in the oscillating plate; an electrostatic capacitance storage unit that stores therein the electrostatic capacitance detected by the electrostatic capacitance detecting circuit; a ratio calculating unit that calculates a ratio of the electrostatic capacitance stored in the electrostatic capacitance storage unit to the movement limit distance; a ratio storage unit that stores therein the ratio calculated by the ratio calculating unit; a current-position calculating unit that calculates current positions of the moving bodies based on the electrostatic capacitances detected by the electrostatic capacitance detecting circuit and the ratio stored in the ratio storage unit; and a drive-signal calculating unit that calculates drive signals with respect to the moving bodies based on differences between the current positions calculated by the current-position calculating unit and target positions.

In the inertial drive actuator device according to another aspect of the present invention, it is preferable that the moving bodies include a conductive material.

In the inertial drive actuator device according to another aspect of the present invention, it is preferable that a permanent magnet is disposed on a side of the oscillating plate facing the moving bodies, and the moving bodies include a magnetic material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of an inertial drive actuator and an inertial drive actuator device according to the present invention are explained below with reference to the accompanying drawings. However, the invention is not limited to the embodiments explained below.

The structure of an inertial drive actuator100according to a first embodiment is explained with reference toFIGS. 1 and 2.FIG. 1is a plan-view depicting the structure of an inertial drive actuator device that includes the inertial drive actuator100according to the first embodiment.FIG. 2is a side-view depicting the structure of the inertial drive actuator100. Attention is drawn to the fact that projecting sections105and106are not shown inFIG. 1. In the following explanation, the inertial drive actuator device includes the inertial drive actuator100, an electrostatic capacitance detecting circuit131and a driving circuit133that are connected to the inertial drive actuator100, and a control circuit132.

The inertial drive actuator100includes a fixed member101, a piezoelectric element102, an oscillating plate103displaceably mounted on the fixed member101, a spring104, the projecting sections105and106formed on the fixed member101, oscillating plate electrodes111and112disposed on the oscillating plate103, and moving bodies121and122. A permanent magnet107is disposed below the fixed member101.

One end of the piezoelectric element102is disposed adjacent to an inner surface101aof the fixed member101. The other end of the piezoelectric element102is disposed adjacent to a right hand side surface103aof the oscillating plate103.

The spring104is disposed so as to face the piezoelectric element102via the oscillating plate103. In other words, one end of the spring104is disposed adjacent to an inner surface101dof the fixed member101while the other end is disposed adjacent to a left hand side surface103dof the oscillating plate103.

In the inertial drive actuator100, when the piezoelectric element102expands and because of which the oscillating plate103is displaced, the spring104supports the oscillating plate103. On the contrary, when the piezoelectric element102contracts, the elastic force of the spring104causes the oscillating plate103to revert to its original position. In other words, the spring104assists to convey the expansion and contraction of the piezoelectric element102to the oscillating plate103. A structure is allowable in which both ends of the piezoelectric element102and both ends of the spring104are fixed to any one of the fixed member101and the oscillating plate103or both.

The oscillating plate electrodes111and112are formed on the upper surface of the oscillating plate103. Moreover, an insulation layer115is formed on the upper surface of the oscillating plate electrodes111and112(seeFIG. 2).

The oscillating plate electrodes111and112are formed in a planar shape of right-angled triangles and they are disposed in such a way that the oblique sides thereof are adjacent to each other. In other words, a width of the oscillating plate electrode111narrows as one goes from the spring104toward the piezoelectric element102in a longitudinal direction (right and left directions inFIGS. 1and2) of the oscillating plate103and a width of the oscillating plate electrode112narrows as one goes from the piezoelectric element102toward the spring104in the longitudinal direction of the oscillating plate103.

The oscillating plate electrodes111and112should preferably be configured in such a way that, due to their planar shape, the electrostatic capacitances between the oscillating plate electrodes111and112, and a moving body side electrode121aof the moving body121vary proportionally with a movement amount as the moving body121moves from one movement limiting position to the other movement limiting position.

Two moving bodies121are mounted on the oscillating plate electrodes111and112, with the insulation layer115disposed therebetween. A moving body side electrode121ais formed on the lower surface of the moving body121, that is, on the surface that is in contact with the oscillating plate electrodes111and112, and a moving body side electrode122ais formed on the lower surface of the moving body122, that is, on the surface that is in contact with the oscillating plate electrodes111and112.

With the displacement of the oscillating plate103, the moving bodies121and122are capable of moving slidingly in relation to the insulation layer115in a longitudinal direction of the oscillating plate103having a rectangular shape. The moving bodies121and122should preferably be made of a magnetic material or a conductive material.

The driving circuit133is connected to each of the piezoelectric element102, the oscillating plate electrodes111and112, and the moving body side electrodes121aand122aof the moving bodies121and122. The driving circuit133applies a driving voltage to drive each of the piezoelectric element102, the oscillating plate electrodes111and112, and the moving body side electrodes121aand122b. Furthermore, the electrostatic capacitance detecting circuit131is connected to each of the oscillating plate electrodes111and112. The electrostatic capacitance detecting circuit131detects electrostatic capacitances between the moving body side electrodes121aand122aof the moving bodies121and122and each of the oscillating plate electrodes111and112. Signals output from the electrostatic capacitance detecting circuit131are input into the control circuit132.

An outline of the processes performed by the control circuit132is explained with reference toFIG. 3.FIG. 3is a block diagram depicting the detailed structure of the control circuit132. The control circuit132includes an electrostatic capacitance storage unit132a, a ratio calculating unit132b, a ratio storage unit132c, a current position calculating unit132d, and a drive signal calculating unit132e.

To begin with, the electrostatic capacitances input as detection results from the electrostatic capacitance detecting circuit131into the control circuit132are stored into the electrostatic capacitance storage unit132a. That is, the electrostatic capacitances between the moving body side electrodes121aand122aof the moving bodies121and122and the oscillating plate electrode111, and the electrostatic capacitances between the moving body side electrodes121aand122aand the oscillating plate electrode112are stored in the electrostatic capacitance storage unit132a. The ratio calculating unit132bcalculates a ratio of movement distances and the electrostatic capacitances of the moving bodies121and122based on these detected electrostatic capacitances. The calculation result is stored in the ratio storage unit132c.

The calculation result obtained at the ratio calculating unit132bis output to the current position calculating unit132d. The current position calculating unit132dcalculates an absolute position (current position) of each of the moving bodies121and122on the oscillating plate103. Subsequently, the drive signal calculating unit132egenerates drive signals for driving the oscillating plate electrodes111and112, and the piezoelectric element102based on the calculation result obtained by the ratio calculating unit132band a calculation result obtained by the current position calculating unit132d.

The generated drive signals are output to the driving circuit133. The driving circuit133drives each of the oscillating plate electrodes111and112, the moving body side electrodes121aand122b, and the piezoelectric element102based on the drive signals input from the control circuit.

The projecting section105is formed on the upper surface at the end of the fixed member101on the side of the spring104. The projecting section105is formed in such a way that it covers from above the spring104and the end of the insulation layer115on the side of the spring104. On the other hand, the projecting section106is formed on the upper surface at the end of the fixed member101on the side of the piezoelectric element102. The projecting section106is formed in such a way that it covers from above the piezoelectric element102and the end of the insulation layer115on the side of the piezoelectric element102.

The projecting sections105and106limit or regulate the range of movement of each of the moving bodies121and122.

In other words, a position where the moving body121abuts against the projection section105on the spring104side marks a first movement limit position of the moving body121and a position where the moving body121abuts against the moving body122on the piezoelectric element102side marks a second movement limit position of the moving body121. On the other hand, a position where the moving body122abuts against the moving body121on the spring104side marks a first movement limit position of the moving body122and a position where the moving body122abuts against the projection section106on the piezoelectric element102side marks a second movement limit position of the moving body122.

The maximum distance (movement limit distance) that the moving body121can move is to the position where the moving body122abuts against the projection section106. On the other hand, the maximum distance (movement limit distance) that the moving body122can move is to the position where the moving body121abuts against the projection section105.

Principles of Position Detection

A detection method for detecting the positions of each of the moving bodies121and122is explained next. The positions of the moving bodies121and122are detected by using the same components that are used for driving the inertial drive actuator100. That is, the positions of the moving bodies121and122are detected by using the moving body side electrodes121aand122aprovided on the moving bodies121and122and the oscillating plate electrodes111and112provided on the oscillating plate103. Opposing portions of the moving body side electrodes121aand122aand the oscillating plate electrodes111and112can be considered as capacitors.

The positions of the moving bodies121and122relative to the oscillating plate103can be detected by comparing, or detecting, the difference between the electrostatic capacitances equivalent to opposing surface areas between the moving body side electrodes121aand122aand the oscillating plate electrode111, and comparing, or detecting, the difference between the electrostatic capacitances equivalent to opposing surface areas between the moving body side electrodes121aand122aand the oscillating plate electrode112.

For example, when the moving bodies121and122are moved toward the right on the paper surface inFIG. 1or2, the opposing surface areas between the moving body side electrodes121aand122aand the oscillating plate electrode112increase, and hence the electrostatic capacitances between the oscillating plate electrode112and the moving body side electrodes121aand122aincrease. On the other hand, the opposing surface areas between the moving body side electrodes121aand122aand the oscillating plate electrode111decrease, and hence the electrostatic capacitances between the oscillating plate electrode111and the moving body side electrodes121aand122adecrease. By determining the difference between the corresponding electrostatic capacitances, the positions of the moving bodies121and122can be determined with a high degree of precision based on a magnitude relationship of the electrostatic capacitances.

Any one of the projection sections105and106, and the contacting moving body can be set as the first movement limit position. The positions of the moving bodies and the electrostatic capacitance need not have a proportional relationship as long as the electrostatic capacitance varies as the positions of the moving body shifts.

In the above-described structure, when a driving voltage is applied to each of the oscillating plate electrodes111and112, and the piezoelectric element102, the oscillating plate103is displaced in a direction of displacement of the piezoelectric element102. The displacement of the oscillating plate103enables the moving bodies121and122disposed on the oscillating plate103to move by inertia within a movement range between the first movement limit position and the second movement limit position defined, respectively, by the projection sections105and106.

The movement and locking of the moving body121is explained with reference toFIGS. 4A to 4C,5A to5C, and6A to6C. Only the moving body121is explained below. However, the same explanation is applicable to the moving body122.

FIGS. 4A to 4Cdepict graphs of a driving waveform by which the moving body121is caused to move to the right inFIG. 1, and a driving voltage applied to each of the piezoelectric element102inFIG. 4A, the oscillating plate electrodes111and112inFIG. 4B, and the moving body side electrode121ainFIG. 4C.

When a steep rising driving voltage (seeFIG. 4A) is applied to the piezoelectric element102by the driving circuit133(in a time period from a time I to a time II shown in FIGS.4A to4C), the piezoelectric element102rapidly expands and is displaced toward the left (to the spring104side). With the displacement of the piezoelectric element102toward the left, the oscillating plate103is also rapidly displaced toward the left.

If the voltage of the oscillating plate electrodes111and112formed on the oscillating plate103(seeFIG. 4B) and the voltage of the moving body side electrode121aof the moving body121(seeFIG. 4C) have the same potential, no electrostatic attraction is produced between the oscillating plate electrodes111and112, and the moving body side electrode121a. Consequently, the moving body121remains stationary due to inertia.

When there is a steep fall in the voltage applied to the piezoelectric element102(in a time period from the time II to the time III shown inFIGS. 4A to 4C), the piezoelectric element102rapidly contracts. Due to the elastic force of the spring104that presses against the piezoelectric element102and the oscillating plate103, the piezoelectric element102is rapidly displaced toward the right. With the displacement of the piezoelectric element102toward the right, the oscillating plate103is also rapidly displaced toward the right.

If electrostatic attraction is produced by creating a potential difference between the oscillating plate electrodes111and112of the oscillating plate103, and the moving body side electrode121aof the moving body121, frictional forces between the oscillating plate electrodes111and112and the moving body side electrode121aof the moving body121increase. Consequently, the moving body121is also displaced toward the right with the displacement of the oscillating plate103.

The moving body121can be moved toward the right in relation to the oscillating plate103by repeating the above-explained operation.

FIGS. 5A to 5Cdepict graphs of a driving waveform by which the moving body121is caused to move to the left inFIG. 1, and a driving voltage applied to each of the piezoelectric element102inFIG. 5A, the oscillating plate electrodes111and112inFIG. 5B, and the moving body side electrode121ainFIG. 5C.

When there is a steep fall in the driving voltage (seeFIG. 5A) applied to the piezoelectric element102by the driving circuit133(in a time period from a time I to a time II shown inFIGS. 5A to 5C), the piezoelectric element102rapidly contracts and is displaced toward the right (in a direction away from the spring104). With the displacement of the piezoelectric element102toward the right, due to the elastic force of the spring104, the oscillating plate103is also rapidly displaced toward the right.

If the voltage of the oscillating plate electrodes111and112formed on the oscillating plate103(seeFIG. 5B) and the voltage of the moving body side electrode121aof the moving body121(seeFIG. 5C) have the same potential, no electrostatic attraction is produced between the oscillating plate electrodes111and112, and the moving body side electrode121a. Consequently, the moving body121remains stationary due to inertia.

When there is a steep rise in the voltage applied to the piezoelectric element102(in a time period from the time II to the time III shown inFIGS. 5A to 5C), the piezoelectric element102rapidly expands and is rapidly displaced toward the left. With the displacement of the piezoelectric element102toward the left, the oscillating plate103is also rapidly displaced toward the left.

If electrostatic attraction is produced by creating the potential difference between the oscillating plate electrodes111and112of the oscillating plate103, and the moving body side electrode121aof the moving body121, frictional forces between the oscillating plate electrodes111and112, and the moving body side electrode121aof the moving body121increase. Consequently, the moving body121is displaced toward the left with the displacement of the oscillating plate103.

The moving body121can be moved toward the left in relation to the oscillating plate103by repeating the above-explained operation.

FIGS. 6A to 6Cdepict graphs of a driving waveform by which the moving body121is caused to remain stationary at a fixed position on the oscillating plate electrodes111and112, in other words, by which the moving body121is locked to the oscillating plate electrodes111and112, and a driving voltage applied to the piezoelectric element102inFIG. 6A, the oscillating plate electrodes111and112inFIG. 6B, and the moving body side electrode121ainFIG. 6C.

Electrostatic attraction is produced by constantly maintaining a potential difference between the oscillating plate electrodes111and112of the oscillating plate103, and the moving body side electrode121aof the moving body121. Due to this, a certain frictional force is maintained between the oscillating plate electrodes111and112, and the moving body side electrode121aof the moving body121. Although there is a displacement of the oscillating plate103, the moving body121remains stationary at a fixed position on the oscillating plate103. In other words, the moving body121is locked to the oscillating plate electrodes111and112.

A calibration method is explained next with reference toFIG. 7.FIG. 7is a flowchart of the calibration method of the inertial drive actuator100according to the first embodiment of the present invention.

In the following explanation, the moving body121is caused to move after the moving body122is locked to the oscillating plate electrodes111and112. In other words, the moving body121is a target moving body for calculating an absolute position while the moving body122is a non-target moving body.

The calibration of the inertial drive actuator100is performed by first performing the process for the moving body121as the target moving body while the moving body122is locked, and then performing the process for the moving body122as the target moving body while the moving body121is locked. Any of these processes can be performed in the same sequence that is explained below.

In the calibration method explained inFIG. 7, the first movement limit position is the position where the moving body121abuts against the projection section105of the inertial drive actuator100, and the second movement limit position is the position where the moving body121abuts against the moving body122that has been locked due to abutment with the projection section106of the inertial drive actuator100.

The electrostatic capacitances between the moving body side electrode121aof the moving body121and the oscillating plate electrodes111and112increase as the moving body121moves from the side of the projection section105toward the side of the projection section106(the moving body122side).

After the calibration starts, the driving voltages shown inFIGS. 4A to 4Care applied to the piezoelectric element102, the oscillating plate electrodes111and112, and the moving body side electrode122a, and the moving body122is caused to move to the projection section106. The moving body122is then locked to the oscillating plate electrodes111and112by applying the driving voltages shown inFIGS. 6A to 6Cto the oscillating plate electrodes111and112, and the moving body side electrode122a, thus marking the movement limit position (the second movement limit position) of the moving body121(locking step, Step S101).

Subsequently, a voltage is applied to each of the oscillating plate electrodes111and112, the moving body side electrode121a, and the piezoelectric element102, and the moving body121is caused to move to the first movement limit position (Step S102).

An electrostatic capacitance Bn at the first movement limit position is detected (electrostatic capacitance detection step, Step S103). The detected electrostatic capacitance Bn is stored in the electrostatic capacitance storage unit132a(electrostatic capacitance storage step, Step S104).

Subsequently, a voltage is applied to each of the oscillating plate electrodes111and112, the moving body side electrode121a, and the piezoelectric element102, and the moving body121is caused to move to the second movement limit position (Step S105). An electrostatic capacitance An at the second movement limit position is detected (electrostatic capacitance detection step, Step S106). The detected electrostatic capacitance An is stored in the electrostatic capacitance storage unit132a(electrostatic capacitance storage step, Step S107).

The electrostatic capacitances An and Bn stored in the electrostatic capacitance storage unit132aare substituted in Equation (I) given below to calculate a ratio X1of a difference between the electrostatic capacitances at the first movement limit position and the second movement limit position, and a movement limit distance l between the first movement limit position and the second movement limit position (ratio calculation step, Step S108).
X1=l/(An−Bn)  (I)

The ratio X1represent a relation between the current electrostatic capacitances (that is, electrostatic capacitances when the calibration is being performed) and the movement limit distance (l) set at the time of assembly of the actuator. The calculated ratio X1is stored in the ratio storage unit132c, or in a central processing unit (CPU), after which the calibration ends. The distance l of the inertial drive actuator100can be a value set at the time of assembly of the actuator or can be regulated by the projection sections105and106.

By using the ratio X1calculated at the ratio calculation step as described above, the absolute position (current position) of the moving body121between the first movement limit position and the second movement limit position can be calculated by using Equation (II) given below.
absolute position=electrostatic capacitance at the current position of the moving body 121×X1  (II)

Next, Steps S101to S108shown inFIG. 7are performed by taking the moving body122as the target moving body and locking the moving body121. Thus, the absolute position (current position) of the moving body121between the first movement limit position and the second movement limit position can be calculated.

The structure of an inertial drive actuator200according to a second embodiment is explained with reference toFIGS. 8 and 9.FIG. 8is a plan-view of the structure of an inertial drive actuator device that includes the inertial drive actuator200according to the second embodiment of the present invention.FIG. 9is a side-view of the structure of the inertial drive actuator200. Attention is drawn to the fact that projection sections205and206are not shown inFIG. 8.

The inertial drive actuator200according to the second embodiment differs from the inertial drive actuator100according to the first embodiment in that it includes three oscillating plate electrodes211,212, and213each having identical rectangular shape. The oscillating plate electrodes211,212, and213are sequentially arranged in a longitudinal direction of an oscillating plate203. The rest of the structure of the inertial drive actuator200is identical to that of the inertial drive actuator100according to the first embodiment.

The oscillating plate electrodes211,212, and213should preferably be configured in such a way that the electrostatic capacitances between moving body side electrodes221aand222aand the oscillating plate electrodes211,212, and213vary, for example, increase, as moving bodies221and222move from one movement limiting position to the other movement limiting position. Furthermore, the positions of the moving bodies and the electrostatic capacitances should preferably have a proportional relationship in the movement range from one movement limiting position to the other movement limiting position. To achieve this, a slant can be given to the thickness of the oscillating plate electrodes211,212, and213so that the distance between each of the moving bodies221and222and each of the oscillating plate electrodes211,212, and213reduces as the moving bodies221and222move from one movement limiting position to the other movement limiting position.

A fixed member201, a piezoelectric element202, a spring204, the projection sections205and206, a permanent magnet207, and the moving bodies221and222of the inertial drive actuator200are identical, respectively, to the fixed member101, the piezoelectric element102, the spring104, the projection sections105and106, the permanent magnet107, and the moving bodies121and122of the inertial drive actuator100according to the first embodiment, and hence the explanation thereof is omitted.

The oscillating plate electrodes211,212, and213are formed on the upper surface of the oscillating plate203. An insulation layer215is formed on the upper surface of the oscillating plate electrodes211,212, and213. The moving bodies221and222are mounted on the oscillating plate electrodes211,212, and213with the insulation layer215disposed therebetween. The moving body side electrodes221aand222aare respectively formed on the lower surface of the moving bodies221and222, that is, on the surface that is in contact with the oscillating plate electrodes211,212, and213. With the displacement of the oscillating plate203, the moving bodies221and222are capable of moving slidingly in relation to the insulation layer215in a longitudinal direction (right and left directions inFIGS. 8 and 9) of the oscillating plate203having a rectangular shape. The moving bodies221and222should preferably be made of a magnetic material or a conductive material.

A driving circuit233is connected to each of the piezoelectric element202, the oscillating plate electrodes211,212, and213, and the moving body side electrodes221aand222a. The driving circuit233applies a driving voltage to drive the piezoelectric element202, the oscillating plate electrodes211,212, and213, and the moving body side electrodes221aand222a. Furthermore, an electrostatic capacitance detecting circuit231is connected to each of the oscillating plate electrodes211,212. The electrostatic capacitance detecting circuit231detects electrostatic capacitances between the moving body side electrodes221aand222a, and the oscillating plate electrodes211,212, and213. Signals output from the electrostatic capacitance detecting circuit231are input into a control circuit232.

The structure of the control circuit232is identical to that of the control circuit132of the inertial drive actuator100, and hence the explanation thereof is omitted. The inertial drive actuator device according to the second embodiment includes the inertial drive actuator200, the electrostatic capacitance detecting circuit231and the driving circuit233that are connected to the inertial drive actuator200, and the control circuit232.

By virtue of the above-described structure, a calibration identical to that of the inertial drive actuator100can be executed even in the inertial drive actuator200, and consequently, even if the electrostatic capacitances between the moving bodies221and222, and the oscillating plate electrodes211,212, and213differ at a later stage after the assembly of the actuator, they can be corrected to appropriate values. As a result, absolute positions of the moving bodies221and222can be reliably and accurately calculated.

The structure of an inertial drive actuator300according to a third embodiment is explained with reference toFIGS. 10 and 11.FIG. 10is a plan-view depicting the structure of an inertial drive actuator device that includes the inertial drive actuator300according to the third embodiment of the present invention.FIG. 11is a side-view depicting the structure of the inertial drive actuator300. Attention is drawn to the fact that projecting sections305and306are not shown inFIG. 10.

The inertial drive actuator300according to the third embodiment differs from the inertial drive actuator100according to the first embodiment in that it includes only one oscillating plate electrode311. Moreover, a width of the oscillating plate electrode311narrows as one goes from a spring304toward a piezoelectric element302in a longitudinal direction of an oscillating plate303. The rest of the structure of the inertial drive actuator300is identical to that of the inertial drive actuator100according to the first embodiment.

Because of the change in the width of the oscillating plate electrode311in the longitudinal direction of the oscillating plate303, as moving bodies321and322move from one movement limit position to the other movement limit position, the electrostatic capacitances between moving body side electrodes321aand322aof the moving bodies321and322and the oscillating plate electrode311varies, for example, increase. Furthermore, as a planar shape of the oscillating plate electrode311is made into a triangular shape, there is a proportional relationship between the positions of the moving bodies321and322and the electrostatic capacitances in the movement range from one movement limit position to the other movement limit position.

A fixed member301, the piezoelectric element302, the spring304, the projecting sections305and306, a permanent magnet307, and the moving bodies321and322of the inertial drive actuator300are identical, respectively, to the fixed member101, the piezoelectric element102, the spring104, the projecting sections105and106, the permanent magnet107, and the moving bodies121and122of the inertial drive actuator100according to the first embodiment, and hence the explanation thereof is omitted.

The oscillating plate electrode311is formed on the upper surface of the oscillating plate303. Moreover, an insulation layer315is formed on the upper surface of the oscillating plate electrode311. The moving bodies321and322are mounted on the oscillating plate electrode311, with the insulation layer315disposed therebetween. A moving body side electrode321ais formed on the lower surface of the moving body321, that is, on the surface that is in contact with the oscillating plate electrode311and a moving body side electrode322ais formed on the lower surface of the moving body322, that is, on the surface that is in contact with the oscillating plate electrode311. With the displacement of the oscillating plate303, the moving bodies321and322are capable of moving slidingly in relation to the insulation layer315in a longitudinal direction (right and left directions inFIGS. 10 and 11) of the oscillating plate303having a rectangular shape. The moving bodies321and322should preferably be made of a magnetic material or a conductive material.

A driving circuit333is connected to each of the piezoelectric element302, the oscillating plate electrode311, and the moving body side electrodes321aand322aof the moving bodies321and322. The driving circuit333applies a driving voltage to drive each of the piezoelectric element302, the oscillating plate electrode311, and the moving body side electrodes321aand322a. Furthermore, an electrostatic capacitance detecting circuit331is connected to the oscillating plate electrode311. The electrostatic capacitance detecting circuit331detects electrostatic capacitances between the moving body side electrodes321aand322aof the moving bodies321and322and the oscillating plate electrode311. Signals output from the electrostatic capacitance detecting circuit331are input into a control circuit332.

The structure of the control circuit332is identical to the control circuit132of the inertial drive actuator100, and hence the explanation thereof is omitted. The inertial drive actuator device according to the second embodiment includes the inertial drive actuator300, the electrostatic capacitance detecting circuit331and the driving circuit333that are connected to the inertial drive actuator300, and the control circuit332.

By virtue of the above-described structure, a calibration identical to that of the inertial drive actuator100can be executed even in the inertial drive actuator300, and consequently, even if the electrostatic capacitances between the moving bodies321and322and the oscillating plate electrode311differ at a later stage after the assembly of the actuator, they can be corrected to an appropriate value. As a result, the absolute positions of the moving bodies321and322can be reliably and accurately calculated.

The structure of an inertial drive actuator400according to a fourth embodiment is explained with reference toFIGS. 12 and 13.FIG. 12is a plan-view depicting the structure of an inertial drive actuator device that includes the inertial drive actuator400according to the fourth embodiment of the present invention.FIG. 13is a side-view depicting the structure of the inertial drive actuator400. Attention is drawn to the fact that projecting sections405and406are not shown inFIG. 12.

The inertial drive actuator400according to the fourth embodiment differs from the inertial drive actuator100according to the first embodiment in that it includes two oscillating plate electrodes411and412of trapezoidal shape and disposed in such a way that the oblique sides thereof are adjacent to each other. In other words, a width of the oscillating plate electrode411facing toward the oscillating plate electrode412narrows as one goes from a spring404toward a piezoelectric element402, and a width of the oscillating plate electrode412facing toward the oscillating plate electrode411narrows as one goes from the piezoelectric element402to the spring404. The rest of the structure of the inertial drive actuator400is identical to that of the inertial drive actuator100according to the first embodiment.

The oscillating plate electrodes411and412should preferably be configured in such a way that the electrostatic capacitance between moving body side electrodes421aand422aof moving bodies421and422, and the oscillating plate electrodes411and412varies, for example, increases, as the moving bodies421and422move from one movement limiting position to the other movement limiting position. Furthermore, the positions of the moving bodies and the electrostatic capacitances should preferably have a proportional relationship in the movement range from one movement limiting position to the other movement limiting position. To achieve this, a slant can be given to the thickness of the oscillating plate electrodes411and412so that the distance between the moving body421and each of the oscillating plate electrodes411and412reduces as the moving body421moves from one movement limiting position to the other movement limiting position.

A fixed member401, the piezoelectric element402, the spring404, the projecting sections405and406, a permanent magnet407, and the moving bodies421and422of the inertial drive actuator400are identical, respectively, to the fixed member101, the piezoelectric element102, the spring104, the projecting sections105and106, the permanent magnet107, and the moving bodies121and122of the inertial drive actuator100according to the first embodiment, and hence the explanation thereof is omitted.

The oscillating plate electrodes411and412are formed on the upper surface of the oscillating plate403. Moreover, an insulation layer415is formed on the upper surface of the oscillating plate electrodes411and412. The moving bodies421and422are mounted on the oscillating plate electrodes411and412, with the insulation layer415disposed therebetween. A moving body side electrode421ais formed on the lower surface of the moving body421, that is, on the surface that is in contact with the oscillating plate electrodes411and412, and a moving body side electrode422ais formed on the lower surface of the moving body422, that is, on the surface that is in contact with the oscillating plate electrodes411and412.

With the displacement of the oscillating plate403, the moving bodies421and422are capable of moving slidingly in relation to the insulation layer415in a longitudinal direction (right and left directions inFIGS. 12 and 13) of the oscillating plate403having a rectangular shape. The moving bodies421and422should preferably be made of a magnetic material or a conductive material.

A driving circuit433is connected to each of the piezoelectric element402, the oscillating plate electrodes411and412, and the moving body side electrodes421aand422aof the moving bodies421and422. The driving circuit433applies a driving voltage to drive each of the piezoelectric element402, the oscillating plate electrodes411and412, and the moving body side electrodes421aand422a. Furthermore, an electrostatic capacitance detecting circuit431is connected to each of the oscillating plate electrodes411and412. The electrostatic capacitance detecting circuit431detects electrostatic capacitances between the moving body side electrode electrodes421aand422aof the moving bodies421and422and each of the oscillating plate electrodes411and412.

Signals output from the electrostatic capacitance detecting circuit431are input into the control circuit432. The structure of the control circuit432is identical to that of the control circuit132of the inertial drive actuator100, and hence the explanation thereof is omitted. The inertial drive actuator device includes the inertial drive actuator400, the electrostatic capacitance detecting circuit431and the driving circuit433that are connected to the inertial drive actuator400, and the control circuit432.

The electrostatic capacitance detecting circuit431detects the electrostatic capacitances between the oscillating plate electrode411and the moving body side electrode421aand422aas well as the electrostatic capacitances between the oscillating plate electrode412and the moving body side electrodes421aand422a. These electrostatic capacitances vary as the moving bodies421and422move from one movement limit position to the other movement limit position. The electrostatic capacitances between the moving body side electrode421aand422aand either of the oscillating plate electrodes411and312can be used for detecting the positions of the moving bodies421and422.

By virtue of the above-described structure, a calibration identical to that of the inertial drive actuator100can be executed even in the inertial drive actuator400, and consequently, even if the electrostatic capacitances between the moving bodies421and422and the oscillating plate electrodes311and312differ at a later stage after the assembly of the actuator, they can be corrected to appropriate values. As a result, the absolute position of the moving body421can be reliably and accurately calculated.

The structure of an inertial drive actuator500according to a fifth embodiment is explained with reference toFIGS. 14 and 15.FIG. 14is a plan-view depicting the structure of an inertial drive actuator device that includes the inertial drive actuator500according to the fifth embodiment of the present invention.FIG. 15is a side-view depicting the structure of the inertial drive actuator500. Attention is drawn to the fact that projecting sections505and506are not shown inFIG. 14.

The inertial drive actuator500according to the fifth embodiment differs from the inertial drive actuator100according to the first embodiment in that it includes an oscillating plate503on which are formed two oscillating plate position detecting electrodes516and517, with an oscillating plate driving electrode511disposed therebetween, instead of the oscillating plate electrodes111and112. The rest of the structure of the inertial drive actuator500is identical to that of the inertial drive actuator100according to the first embodiment.

Specifically, the oscillating plate position detecting electrodes516and517have a planar shape of right-angled triangles and are disposed in such a way that the oblique sides thereof are adjacent to each other. Furthermore, the oscillating plate driving electrode511has a planar shape of a parallelogram whose long sides are arranged adjacent to the oblique sides of the oscillating plate position detecting electrodes516and517.

Because the oscillating plate position detecting electrodes516and517have the planer shape described above, the electrostatic capacitances between the oscillating plate position detecting electrodes516and517, and moving body side electrodes521aand522aof moving bodies521and522vary proportionally with the movement amounts as the moving bodies521and522move from one movement limit position to the other movement limit position.

A fixed member501, a piezoelectric element502, a spring504, the projecting sections505and506, a permanent magnet507, and the moving bodies521and522of the inertial drive actuator500are identical, respectively, to the fixed member101, the piezoelectric element102, the spring104, the projecting sections105and106, the permanent magnet107, and the moving bodies121and122of the inertial drive actuator100according to the first embodiment, and hence the explanation thereof is omitted.

The oscillating plate driving electrode511, and the oscillating plate position detecting electrodes516and517are formed on the upper surface of the oscillating plate503, and an insulation layer515is formed on the upper surface of the oscillating plate driving electrode511. The moving bodies521and522are mounted on the oscillating plate driving electrode511, and the oscillating plate position detecting electrodes516and517with the insulation layer515disposed therebetween. The moving body side electrode521ais formed on the lower surface of the moving body521, that is, on the surface that is in contact with the oscillating plate driving electrode511, and the oscillating plate position detecting electrodes516and517, and the moving body side electrode522ais formed on the lower surface of the moving body522, that is, on the surface that is in contact with the oscillating plate driving electrode511, and the oscillating plate position detecting electrodes516and517. With the displacement of the oscillating plate503, the moving bodies521and522are capable of moving slidingly in relation to the insulation layer515in a longitudinal direction (left and right directions inFIGS. 14 and 15) of the oscillating plate503having a rectangular shape. The moving bodies521and522should preferably be made of a magnetic material or a conductive material.

A driving circuit533is connected to each of the piezoelectric element502, the oscillating plate driving electrode511, and the moving body side electrodes521aand522aof the moving bodies521and522and applies the driving voltage to drive the piezoelectric element502, the oscillating plate driving electrode511, and the moving body side electrodes521aand522a. Furthermore, an electrostatic capacitance detecting circuit531is connected to each of the oscillating plate position detecting electrodes516and517. The electrostatic capacitance detecting circuit531detects the electrostatic capacitances between the moving body side electrodes521aand522aof the moving bodies521and522and the oscillating plate position detecting electrodes516and517.

Signals output from the electrostatic capacitance detecting circuit531are input into the control circuit532. The structure of the control circuit532is identical to that of the control circuit132of the inertial drive actuator100, and hence the explanation thereof is omitted. The inertial drive actuator device includes the inertial drive actuator500, the electrostatic capacitance detecting circuit531and the driving circuit533that are connected to the inertial drive actuator500, and the control circuit532.

The electrostatic capacitance detecting circuit531detects the electrostatic capacitances between the oscillating plate position detecting electrode516and the moving body side electrodes521aand522aas well as the electrostatic capacitances between the oscillating plate position detecting electrode517and the moving body side electrodes521aand522a. These electrostatic capacitances vary as the moving bodies521and522move from one movement limit position to the other movement limit position. The electrostatic capacitances between the moving body side electrodes521aand522aand either of the oscillating plate position detecting electrodes516and517can be used for detecting the positions of the moving bodies521and522.

By virtue of the above-described structure, a calibration identical to that of the inertial drive actuator100can be executed even in the inertial drive actuator500, and consequently, even if the electrostatic capacitances between the moving bodies521and522and the oscillating plate position detecting electrodes516and517differs at a later stage after the assembly of the actuator, they can be corrected to appropriate values. As a result, the absolute position of the moving bodies521and522can be reliably and accurately calculated.

The structure of an inertial drive actuator600according to a sixth embodiment is explained with reference toFIGS. 16 and 17.FIG. 16is a plan-view depicting the structure of an inertial drive actuator device that includes the inertial drive actuator600according to the sixth embodiment of the present invention.FIG. 17is a side-view depicting the structure of the inertial drive actuator600. Attention is drawn to the fact that projecting sections605and606are not shown inFIG. 16.

The inertial drive actuator600according to the sixth embodiment differs from the inertial drive actuator100according to the first embodiment in that it includes moving bodies621,622, and623. The rest of the structure of the inertial drive actuator600is identical to that of the inertial drive actuator100according to the first embodiment.

The moving bodies621,622, and623are mounted on oscillating plate electrodes611and612, with an insulation layer615disposed therebetween. Moreover, moving body side electrodes621a,622a, and623aare respectively formed on the lower surface of the moving bodies621,622, and623. With the displacement of an oscillating plate603, the moving bodies621,622, and623are capable of moving slidingly in relation to the insulation layer615in a longitudinal direction (right and left direction inFIGS. 16 and 17) of the oscillating plate603having a rectangular shape. The moving bodies621,622, and623should preferably be made of a magnetic material or a conductive material.

Calibration of the inertial drive actuator600can be performed in a similar manner to that of the inertial drive actuator100by selecting one moving body as the target moving body while locking the other non-target moving bodies to the oscillating plate electrodes611and612.

The calibration can also be performed simultaneously for a plurality of moving bodies (two or more moving bodies).

In performing calibration of a plurality of moving bodies simultaneously, all the moving bodies are first caused to move to the one movement limiting position. Subsequently, all the moving bodies are caused to move to the other movement limit position. The movement limiting position of each moving body is marked in the same manner as explained with reference toFIG. 7, that is, by the projection sections or by the other moving bodies sequentially butting against the projection section.

When the speed of all the moving bodies moving toward one movement limiting position and the other movement limiting position is the same, a movement amount per driving waveform can be simultaneously measured for the multiple moving bodies in the same manner as for two moving bodies explained with reference toFIG. 7.

On the other hand, when there is an incorrectly calibrated moving body, the positions of the moving bodies and the electrostatic capacitances are simultaneously associated and a calibration is performed, and the movement amount per driving waveform of each moving body is individually measured. When there is an incorrectly calibrated moving body, the incorrectly calibrated moving body is regarded as the target moving body and the rest of the moving bodies are locked, and the movement amount per driving waveform is measured separately.

Positions and electrostatic capacitances of moving bodies of multiple groups are simultaneously associated and the calibration is performed, and a movement amount per driving waveform is measured separately.

There is a low likelihood that all the moving bodies will have identical frictional state. Therefore, while no problem is encountered when moving the moving bodies to the movement limiting position and associating the position and the electrostatic capacitance, measuring the movement amount per driving waveform simultaneously would pose a problem because of the difference in the speed and the resulting collision of the moving bodies with each other. In such a case, all the moving bodies except the moving body for which the movement amount per driving waveform is to be measured should be moved completely in the direction opposite to that of the moving body for which the movement amount per driving waveform is to be measured. The clearing that results from this action serves as the movement limit distance of the moving body for which the movement amount per driving waveform is to be measured. The non-target moving body is immovably locked at a locking step. The movement amount per driving waveform is measured by the same method as for a single group.

The structure of an inertial drive actuator700according to a seventh embodiment is explained with reference toFIGS. 18 and 19.FIG. 18is a plan-view depicting the structure of an inertial drive actuator device that includes the inertial drive actuator700according to the sixth embodiment of the present invention.FIG. 19is a side-view depicting the structure of the inertial drive actuator700. Attention is drawn to the fact that projecting sections705and706are not shown inFIG. 18.

The inertial drive actuator700according to the seventh embodiment differs from the inertial drive actuator600according to the sixth embodiment in that it includes a third projection section708that is provided between moving bodies722and723among three moving bodies721,722, and723. The rest of the structure is identical to that of the inertial drive actuator600according to the sixth embodiment. In other words, a fixed member701, a piezoelectric element702, an oscillating plate703, a spring704, the projection sections705and706, a permanent magnet707, oscillating plate electrodes711and712, the moving bodies721,722, and723, an electrostatic capacitance detecting circuit731, a control circuit732, and a driving circuit733of the inertial drive actuator700according to the seventh embodiment are identical, respectively, to a fixed member601, a piezoelectric element602, the oscillating plate603, a spring604, the projection sections605and606, a permanent magnet607, the oscillating plate electrodes611and612, the moving bodies621,622, and623, an electrostatic capacitance detecting circuit631, a control circuit632, and a driving circuit633of the inertial drive actuator600according to the sixth embodiment, and hence the explanation thereof is omitted.

The projection section708is fixed to the oscillating plate703by adhesion or any other method. A configuration is allowable in which the projection section708is placed between the moving bodies721and722.

By virtue of the above-described structure, calibration of the moving bodies721and722can be performed in the same manner as for the inertial drive actuator100according to the first embodiment. Further, for the calibration of the moving body723, the position where the moving body723abuts against the projection section708can be regarded as the first movement limit position and the position where the moving body723abuts against the projection section706can be regarded as the second movement limit position.

An inertial drive actuator according to the present invention can be used in gadgets that require minute displacement of moving bodies.

When a plurality of moving bodies exist, an inertial-drive actuator calibration method and an inertial drive actuator device according to an embodiment of the present invention can perform a calibration accurately.