JP2009296681A - Drive unit and its controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive unit which keeps a driven body stopped at a desired position for a long time and safely drives the driven body with an oscillating-wave motor. <P>SOLUTION: The driving force of the oscillating-wave motor 44 is transmitted to a tilting rotation shaft (not shown) to which a camera head 50 is attached through a tilting rotation pinion gear 43 and a tilting rotation gear 42, to cause the tilting rotation shaft to rotate. A play CL is provided between the tilting rotation gear 42 and the tilting rotation pinion gear 43. The oscillating-wave motor 44 is so controlled as to make the tilting rotation pinion gear 43 perform a particular action for rotation while alternately repeating normal rotation and reverse rotation within a range of the play CL. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device using a vibration wave motor as a drive source and a control method thereof.

  In recent years, surveillance camera devices have been installed in public places, offices, stores, parking lots and the like from the viewpoints of ensuring safety in social life and crime prevention. Furthermore, the installation of surveillance camera devices is becoming popular in ordinary households.

  The monitoring camera device generally includes a camera platform that can move the camera head (or lens) in the pan or tilt direction. The camera platform is required to have acceleration characteristics such as accelerating or decelerating the speed for moving the camera head to a target speed in a short time in order to track a fast-moving subject. Electromagnetic motors such as DC motors and pulse motors are widely used as pan head drive sources that satisfy the required acceleration characteristics because of their relatively low cost and easy control. Yes. In addition, many surveillance camera devices including a pan head are configured to be remotely operable via a network.

  However, when the above-described electromagnetic motor is used as a driving source for the pan head, the electromagnetic motor needs to generate a holding torque for holding the pan head at the stop position when the pan head is stopped. Even when the table is stopped, power is consumed.

  Therefore, there is a vibration wave motor (so-called ultrasonic motor) as a drive source for enabling power saving when the head is stopped instead of the electromagnetic motor. This vibration wave motor excites a progressive vibration wave to a vibrating body to which an electromechanical energy conversion element is fixed, and relatively moves a mover that is in pressure contact with the vibrating body.

  Even if the vibration wave motor is small, the generated torque is large and the acceleration characteristics are good. In addition, since the vibration wave motor is in a frictional state, the vibration wave motor generates a holding force (self-holding torque) when stopped, and does not require electric power for generating the holding torque unlike an electromagnetic motor.

  When the vibration wave motor is used as a pan head drive source, it is possible to obtain good acceleration characteristics and to perform good speed control. In addition, at the time of stopping, it is possible to achieve power saving when holding the pan head in a stopped state with a self-holding torque due to friction.

  As a usage form of the monitoring camera device provided with a pan head, for example, a form in which an object is photographed while tracking at a high speed, or a form in which a predetermined position is continuously focused for a long time (fixed point monitoring). There is.

  Here, when the fixed point monitoring is performed, the vibration wave motor is stopped for a long time, that is, the pan head is stopped at a predetermined position. In this case, the frictional state of the contact portion between the vibrating body and the moving member that is in pressure contact with the vibrating body may change to a low frictional state due to the influence of moisture or the like contained in the surrounding environment, and the self-holding torque may decrease. When the vibration wave motor is driven after being stopped for a long time in this way, the contact portion between the vibrating body and the moving element is in a friction state different from the steady friction state during a period until a certain amount of time has elapsed from the start of driving. is there. As a result, immediately after the start of driving, speed control or positioning control that accurately follows the speed control profile cannot be performed, and the control accuracy may temporarily deteriorate.

  The speed control profile represents the relationship between the target rotation speed and time set for controlling the drive of the motor. Here, for example, it is assumed that a speed control profile P as shown in FIG. 13 is set. In accordance with this speed control profile P, when the rotational speed of the motor is increased and reaches the target rotational speed, the rotational speed of the motor is held at the target rotational speed for a predetermined time, and deceleration is started after the lapse of the predetermined time. The drive of the motor is controlled. When the actual rotational speed of the motor is controlled along the speed control profile P, it can be said that the control of the motor is a control with good followability to the speed control profile. On the other hand, when the actual motor rotation speed draws a locus P ′ as indicated by a dotted line with respect to the speed control profile P, the motor control can be said to be a control with poor followability to the speed control profile. .

  Therefore, a method for stably controlling the driving of the vibration wave motor without deteriorating the followability with respect to the speed profile with respect to the change in the frictional state of the contact portion between the vibrating body and the moving member at the time of stopping and driving described above Has been proposed.

  For example, a method has been proposed in which a drive signal having a phase difference of π / 2 (rad) is applied to an electrode of a vibration wave motor when driving, and a drive signal having the same phase is applied when stopped (Patent Document 1). . In the case of this method, an in-phase drive signal is applied even when stopped, and a vibration wave is generated, and the vibration wave motor is in a heat generation state similar to that during driving. As a result, the temperature of the vibration wave motor is made constant and stable driving can be performed.

In addition, in order to avoid the sticking of the vibrating body and the moving element that occurs when the vibration wave motor is left for a long period of time, the vibration wave motor is timed continuously, and the vibration wave motor temporarily depends on the continuous stop time. There is a way to make it work.
Japanese Patent Laid-Open No. 2-114869 (Patent Registration No. 2509310) Japanese Patent Application Laid-Open No. 10-191662

  When an in-phase drive signal is applied to the electrodes when the vibration wave motor is stopped, a holding force can be obtained due to the frictional force between the vibrating body and the moving element, but a holding force for holding the driven body in a stopped state can be obtained. May not be possible.

  For example, in a tilt mechanism that uses a vibration wave motor as a drive source and moves the camera head in the tilt direction, the center of gravity of the tilt mechanism including the camera head may not be on the tilt rotation axis. In this case, moment force acts on the tilt rotation axis when the camera head is stopped at a desired position. Here, if the moment force acting on the tilt rotation axis is increased by the holding torque of the vibration wave motor, the camera head may not be held in the desired position.

  In the case of a method of measuring the continuous stop time of the vibration wave motor and temporarily operating the vibration wave motor according to the continuous stop time, the camera head is moved along with the operation of the vibration wave motor. Therefore, in the case of fixed-point monitoring, monitoring for a predetermined position, that is, fixed-point monitoring is temporarily interrupted.

  An object of the present invention is to provide a driving device capable of holding a driven body in a stopped state at a desired position for a long time by a vibration wave motor and capable of stably driving the driven body It is to provide a control method.

  In order to achieve the above object, the present invention provides a vibration wave motor, a driven body driven by the vibration wave motor, and at least a first transmission for transmitting an output of the vibration wave motor to the driven body. A transmission means having a member and a second transmission member, wherein play is provided between the first transmission member and the second transmission member; and a control means for controlling the vibration wave motor. And the control means controls the vibration wave motor so that the vibration wave motor performs a specific operation for reciprocating the first transmission member within the range of play. A driving device is provided.

  In order to achieve the above object, the present invention provides a vibration wave motor, a driven body driven by the vibration wave motor, a first transmission member to which a driving force output from the vibration wave motor is transmitted, and the A second transmission member configured to transmit the driving force transmitted to the first transmission member to the driven body, and play between the second transmission member and the first transmission member; And a transmission means provided with a transmission means, wherein the vibration wave motor performs a specific operation for reciprocating the first transmission member within the range of play. A control method for a driving apparatus is provided, wherein the vibration wave motor is controlled.

  According to the present invention, the driven wave body can be held in a state of being stopped at a desired position for a long time by the vibration wave motor, and the driven body can be driven stably.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view of a surveillance camera device in which the drive device according to the first embodiment of the present invention is used as a tilt mechanism as seen from the front. FIG. 2 is a perspective view showing a main part configuration of a tilt mechanism used in the monitoring camera apparatus of FIG. FIG. 3 is a plan view schematically showing the meshing state of the tilt rotation gear 42 and the tilt rotation pinion gear 43 of FIG.

  As shown in FIG. 1, the surveillance camera device includes a camera head 50 and a camera platform 40 on which the camera head 50 is mounted. The pan / tilt head 40 has a pan mechanism for rotating the camera head 50 in the pan direction and a tilt mechanism for rotating the camera head 50 in the tilt direction.

  The pan mechanism includes a table 47, a motor 48 that generates a driving force for rotating the table 47 around a pan rotation axis (not shown; an axis extending coaxially with the Y axis in the drawing), and the motor 48. Has a transmission mechanism (not shown) for transmitting the driving force to the table 47. As the motor 48, arbitrary types, such as a vibration wave motor and a DC motor, can be used, for example. Further, a control unit (not shown) for controlling the operation of the motor 48 is provided. Further, a sensor (not shown) for detecting a rotation angle of the table 47 around the pan rotation axis (that is, a pan angle of the camera head 50) is provided.

  The tilt mechanism has a pair of support portions 41 provided on the table 47, and each of the support members 41 is coaxial with a tilt rotation axis (not shown; X axis orthogonal to the Y axis in the figure). The corresponding end of the extending shaft) is rotatably supported. A camera head 50 is fixed to the tilt rotation shaft, and a vibration wave motor 44 is used as a drive source for rotating the tilt rotation shaft about its axis.

  As shown in FIG. 2, an encoder scale 45 and a tilt rotation gear 42 (second gear) are fixed to the end of the tilt rotation shaft on the one support member 41 side. The encoder scale 45 is provided with a plurality of slits (not shown). Each slit of the encoder scale 45 is read by the encoder sensor 46, and a signal output from the encoder 46 is used to detect the rotation angle of the tilt rotation axis, that is, (tilt angle of the camera head 50), as will be described later.

  The tilt rotation gear 42 meshes with a tilt rotation pinion gear 43 (first gear). The tilt rotation pinion gear 43 is fixed to an output shaft (not shown) of the vibration wave motor 44. When the vibration wave motor 44 is rotated, the tilt rotation pinion gear 43 is rotated, and the tilt rotation gear 42 meshed with the tilt rotation pinion gear 43 is rotated. Here, the gear ratio between the tilt rotation pinion gear 43 and the tilt rotation gear 42 is set to be a predetermined reduction ratio. The tilt rotation gear 42 and the tilt rotation pinion gear 43 constitute transmission means having a first transmission member and a second transmission member for cooperating with each other and transmitting the driving force of the vibration wave motor 44 to the tilt rotation shaft. To do. The driving force of the vibration wave motor 44 is transmitted to the tilt rotation shaft through the tilt rotation pinion gear 43 and the tilt rotation gear 42, and the tilt rotation shaft is rotated around the axis. Thereby, the camera head 50 is rotated around the tilt rotation axis, that is, in the tilt direction.

  Here, a play CL is provided between the tilt rotation gear 42 and the tilt rotation pinion gear 43 as shown in FIG. The size of the play CL is set such that the tilt rotation pinion gear 43 can rotate forward and reverse alternately alternately without contacting the tilt rotation gear 42. Then, the vibration wave motor 44 is controlled such that the vibration wave motor 44 performs a specific operation for rotating the tilt rotation pinion gear 43 while alternately repeating forward rotation and reverse rotation within the range of the play CL. That is, the output shaft of the vibration wave motor 44 rotates so as to alternately repeat forward rotation and reverse rotation within a rotation angle range corresponding to the play CL range (reciprocating motion). Hereinafter, the specific operation of the vibration wave motor 44 is referred to as recovery wave processing, and details of the recovery wave processing will be described later.

  Next, the configuration of the vibration wave motor 44 will be described with reference to FIGS. 4 and 5. FIG. 4A is a longitudinal sectional view showing a main part configuration of a vibration wave motor 44 used as a drive source of the tilt mechanism of the pan head 40 of FIG. 4B is an enlarged longitudinal sectional view showing a contact portion between the vibrating body 92 and the slider member 93 of the vibration wave motor 44 shown in FIG. FIG. 5 is a diagram showing a waveform diagram of a drive signal applied to the vibration wave motor 44 of FIG.

  As shown in FIG. 4A, the vibration wave motor 44 includes a laminated piezoelectric element (electromechanical energy conversion element) 91. The laminated piezoelectric element 91 is composed of a laminated body of thin annular ceramic piezoelectric elements polarized in two poles, and has an A phase and a B phase. A vibration body 92 made of a cylindrical elastic body is fixed to the laminated piezoelectric element 91. An annular slider member 93 is brought into pressure contact with the vibrating body 92, and the slider member 93 is integrally fixed to a cylindrical moving element 94 (see FIG. 4B). An output shaft 95 (output member) is connected to the movable element 94 so that the movable element 94 can rotate (movement) in conjunction with the rotation of the movable element 94, and the output shaft 95 can rotate around its axis. It is supported by. The tilt rotation pinion gear 43 described above is fixed (connected) to one end of the output shaft 95.

  Here, it is assumed that the drive signal SA and the drive signal SB are applied to the A phase and the B phase of the piezoelectric element 91, respectively. The drive signals SA and SB are made of signals having the same frequency and have a phase difference φ.

  For example, when drive signals SA and SB having a phase difference φ of + π / 2 (rad) as shown in FIG. 5A are applied to the A phase and the B phase of the piezoelectric element 91, the piezoelectric element 91 vibrates. A progressive vibration wave is excited in the body 92. The progressive vibration wave causes a frictional force at the contact portion C between the vibrating body 92 and the slider member 93 (see FIG. 4B), and the sliding force causes the slider member 93 to move against the vibrating body 92. Relative movement or relative rotation. That is, the mover 94 is rotated. The output shaft 95 is rotated about its axis by the rotation of the moving element 94. As described above, when the drive signals SA and SB having the phase difference φ of + π / 2 (rad) are applied to the A phase and the B phase of the piezoelectric element 91, respectively, the output shaft 95 rotates in the rotation direction CW (forward rotation direction). Is rotated.

  In contrast, when drive signals SA and SB having a phase difference φ of −π / 2 (rad) as shown in FIG. 5B are applied to the A phase and the B phase of the piezoelectric element 91, respectively, the same applies. Further, although the output shaft 95 is rotated, the rotation direction is a rotation direction CCW (reverse rotation direction) opposite to the rotation direction CW.

  Further, as shown in FIG. 5C, when the phase difference φ is 0 (rad), that is, the drive signals SA and SB having no phase difference are applied to the A phase and the B phase of the piezoelectric element 91, respectively, the vibrating body 92 In this case, a standing wave is generated without exciting a progressive vibration wave. In the state where the standing wave is generated, no frictional force is generated between the vibrating body 92 and the slider member 93, and the output shaft 95 does not rotate. Further, in the contact portion C (FIG. 4B) between the slider member 93 and the vibrating body 92, the slider member 93 and the vibrating member 92 are separated from each other at a minute interval, and the value of the self-holding torque becomes very small.

  Next, when the vibration wave motor 44 is left in a state of being stopped for a long time without applying the drive signals SA and SB to the vibration wave motor 44, the value of the self-holding torque of the vibration wave motor 44 becomes very small. Will be described.

  During normal rotation of the vibration wave motor 44, the contact portion C between the slider member 93 and the vibrating body 92 is in a frictional state due to rotation and is in a dry state. However, when the vibration wave motor 44 is left for a long time without applying the drive signals SA and SB to the vibration wave motor 44, water molecules in the surrounding atmosphere cause contact between the slider member 93 and the vibration body 92. C (FIG. 4B) enters, and the slider member 93 and the vibrating body 92 become slippery. For this reason, when starting the operation of the vibration wave motor 44 that has been left stopped for a long time, the contact portion C between the slider member 93 and the vibrating body 92 is initially in a low friction state. When a certain amount of time has elapsed from the start of the operation of the vibration wave motor 44, the contact portion C between the slider member 93 and the vibrating body 92 changes from the low friction state to the steady friction state. Therefore, during a period from when the operation of the vibration wave motor 44 starts until a certain time elapses, the generated torque decreases, and the rotational speed of the vibration wave motor 44 cannot be accurately controlled to follow the speed profile. .

  Next, a configuration of a control unit for controlling the vibration wave motor 44 in the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of a control unit for controlling the vibration wave motor 44 of FIG.

  The control unit 100 for controlling the vibration wave motor 44 includes a CPU 1 as shown in FIG. The CPU 1 outputs a drive signal for operating and stopping the vibration wave motor 44 based on an instruction signal from the host computer 2 (for example, an instruction signal indicating drive start, target speed, stop, etc.). Further, the CPU 1 outputs a rotation direction switching signal for switching the rotation direction of the vibration wave motor 44 to the phase conversion unit 6 based on the instruction signal from the host computer 2.

  The drive signal from the CPU 1 is converted into an analog signal by a D / A converter (digital / analog converter) 4 and then input to a VCO (Voltage Controlled Oscillator) 5. The VCO 5 generates an alternating voltage having a frequency corresponding to the voltage of the drive signal input from the D / A converter 4. The AC voltage generated by the VCO 5 is input to the phase converter 6.

  Based on the rotation direction switching signal from the CPU 1, the phase conversion unit 6 converts the AC voltage input from the VCO 5 into a phase difference φ (+ π / 2 or −π / 2 () that defines the rotation direction of the vibration wave motor 44. rad)) are converted into two alternating voltages, and each alternating voltage is output. Here, the two alternating voltages after conversion have the same frequency and voltage, respectively.

  One of the AC voltages output from the phase converter 6 is output to the vibration wave motor 44 as a drive signal SA through a power amplifier (hereinafter referred to as an amplifier) 7 and a matching coil 9. The drive signal SA is applied to the A phase of the laminated piezoelectric element 91 of the vibration wave motor 44. The other of the AC voltages output from the phase converter 6 is output to the vibration wave motor 44 as a drive signal SB via the amplifier 8 and the matching coil 10, and the drive signal SB is applied to the B phase of the laminated piezoelectric element 91. Is done.

  The CPU 1 receives an output signal from the encoder sensor 46 and detects the rotational speed and direction of the vibration wave motor 44 based on the output signal. Then, the CPU 1 performs feedback control so that the detected rotation speed and rotation direction of the vibration wave motor 44 coincide with the target rotation speed and rotation direction.

  Further, the CPU 1 individually operates the continuation stop timer 3a, the recovery wave processing timer 3b, and the drive control timer 3c included in the timer circuit 3, and performs control, operation time, and the like based on the time measured by each timer 3a to 3c. Control. Here, the continuous stop timer 3a is a timer that measures a time (continuous stop time) t1 during which the vibration wave motor 44 is continuously stopped without applying the drive signals SA and SB to the vibration wave motor 44. The recovery wave processing timer 3b is a timer that times an execution time t2 of recovery wave processing described later. The drive control timer 3c is a timer that measures a time t3 for controlling the application time of the drive signals SA and SB.

  In the present embodiment, when the vibration wave motor 44 is stopped, the continuous stop time t1 is measured by the continuous stop timer 3a. When the continuous stop time t1 counted by the continuous stop timer 3a reaches a preset threshold value ta, the recovery wave process is started. When the recovery wave process is started, the recovery wave process timer 3b starts measuring the recovery wave process execution time t2. When the time of the recovery wave processing execution time t2 timed by the recovery wave processing timer 3b reaches a predetermined time tp, the recovery wave processing is terminated. During execution of the recovery wave process, the application times of the drive signals SA and SB are controlled based on the time t3 counted by the drive control timer 3c.

  Next, the recovery wave process will be described with reference to FIGS. FIG. 7 is a diagram showing a switching state of the rotation direction of the output shaft 95 of the vibration wave motor 44 by the recovery wave process of the control unit 100 of FIG. FIG. 8 is a diagram schematically illustrating the execution timing of the recovery wave process by the control unit 100.

  As described above, the recovery wave process operates the vibration wave motor 44 so that the output shaft 95 alternately repeats forward rotation and reverse rotation within a rotation angle range corresponding to the range of the play CL (see FIG. 3). The control process is executed for a predetermined time.

  In the recovery wave process, as shown in FIG. 7, first, based on the time t3 of the drive control timer 3c, the vibration wave motor 44 is rotated so that the output shaft 95 rotates, for example, in the forward rotation direction CW for a minute time ts. Is controlled. That is, the drive signal SA is applied to the A phase for a minute time ts, and the drive signal SB having a phase difference φ of + π / 2 (rad) from the drive signal SA is applied to the B phase (FIG. 5). (See (a)). Here, the time ts indicates that the output shaft 95 of the vibration wave motor 44 is rotated in the forward rotation direction CW by the rotation angle within the range of the play CL (FIG. 3) between the tilt rotation gear 42 and the tilt rotation pinion gear 43. This is the time required to rotate in the reverse rotation direction CCW. For example, 0.003 seconds is set as the time ts.

  After the forward rotation of the vibration wave motor 44, a rotation direction switching signal is input from the CPU 1 to the phase converter 6 so as to switch the rotation direction of the vibration wave motor 44. Then, for the minute time ts, the drive signal SA and the drive signal SB having a phase difference φ of −π / 2 (rad) from the drive signal SA are applied to the A phase and the B phase of the vibration wave motor 44, respectively (FIG. 5 (b)). As a result, the output shaft 95 of the vibration wave motor 44 is rotated in the reverse direction CCW. The rotation in the reverse direction CCW is executed for the time ts. Next, the rotation direction of the vibration wave motor 44 is switched again.

  As described above, by the recovery wave process, the forward rotation and the reverse rotation of the vibration wave motor 44 (the output shaft 95) are alternately repeated within a rotation angle range corresponding to the play CL range. Simultaneously with the start of the recovery wave processing, the recovery wave processing timer 3b starts an operation for measuring the execution time t2 of the recovery wave processing, and when the execution time t2 of the recovery wave processing reaches a predetermined time tp, the recovery wave processing Ends. The predetermined time tp is the number of repetitive forward and reverse rotations necessary to bring the state of the contact portion C between the slider member 93 and the vibrating body 92 into a steady friction state (a friction state in which the influence of water molecules has been eliminated). It is time that can be decided from. For example, the predetermined time tp is determined to be 3 seconds.

  The threshold ta is the maximum value of the continuous stop time during which the vibration wave motor 44 can normally start operation without causing a decrease in the self-holding torque. If the time is within the threshold ta, the vibration wave motor 44 left in a stopped state can be driven while accurately following the speed control profile. In the present embodiment, the threshold value ta is set to 3 minutes.

  Thus, when the continuous stop time t1 reaches the threshold value ta, the recovery wave process is started as shown in FIG. 8, and the state at the contact portion C between the slider member 93 and the vibrating body 92 is changed by the recovery wave process. A steady friction state. Therefore, when the vibration wave motor 44 is left in a stopped state for a long time without applying the drive signals SA and SB to the vibration wave motor 44, it is possible to prevent a decrease in the self-holding torque of the vibration wave motor 44. . As a result, for example, even if the position where the load of the camera head 50 is applied is not on the tilt rotation axis, if the moment force applied by the load is within the range of the self-holding torque, the camera in the stopped state of the vibration wave motor 44 The head 50 does not move from the target position. That is, even when the vibration wave motor 44 is left in a stopped state for a long time without applying the drive signals SA and SB to the vibration wave motor 44, the camera head 50 can be held in a stopped state at the target position. it can.

  Further, after the recovery wave process is completed, when there is no drive instruction signal from the host computer 2 and the continuous stop time t1 reaches the threshold value ta again, the recovery wave process is started. At this time, if the last rotation direction in the previous recovery wave process is the forward rotation direction CW, the first rotation direction of the current recovery wave process is controlled to be the reverse rotation direction CCW.

  Next, a procedure when the control unit 100 executes the recovery wave process will be described with reference to FIG. FIG. 9 is a flowchart showing a procedure when the control unit 100 of FIG. 6 executes the recovery wave process. The procedure shown in the flowchart of FIG. 9 is executed by the CPU 1.

  When the CPU 1 of the control unit 100 stops the vibration wave motor 44 based on the stop instruction signal from the host computer 2, the CPU 1 operates the continuous stop timer 3a as shown in FIG. Timing is started (step S1). Then, the CPU 1 determines whether or not a drive start instruction signal from the host computer 2 has been received (step S2).

  When the drive start instruction signal from the host computer 2 is not received in the step S2, the CPU 1 determines whether or not the time t1 counted by the continuous stop timer 3a has reached the threshold value ta (step S3). ). Here, when the time t1 has not reached the threshold value ta, the CPU 1 returns to step S2.

  When it is determined in step S3 that the time t1 has reached the threshold value ta, the CPU 1 starts the recovery wave process described above (step S4). At this time, the CPU 1 starts measuring the recovery wave processing execution time t2 by the recovery wave processing timer 3b. Then, the CPU 1 determines whether or not the recovery wave processing execution time t2 timed by the recovery wave processing timer 3b has reached a predetermined time tp (step S5).

  When it is determined in step S5 that the recovery wave process execution time t2 has reached the predetermined time tp, the CPU 1 ends the recovery wave process (step S6). As the recovery wave process ends, the recovery wave process timer 3b is reset. Then, the CPU 1 resets the continuous stop timer 3a (step S7), and returns to step S1.

  On the other hand, when it is determined in step S5 that the recovery wave processing execution time t2 has not reached the predetermined time tp, the CPU 1 determines whether or not a drive start instruction signal from the host computer 2 has been received ( Step S8). If the drive start instruction signal has not been received, the CPU 1 returns to step S5.

  When it is determined in step S8 that the drive start instruction signal is received from the host computer 2, the CPU 1 stops the recovery wave process (step S9) and resets the continuous stop timer 3a (step S10). Then, the CPU 1 shifts to control for starting the operation of the vibration wave motor 44 based on the received drive start signal (step S11).

  If it is determined in step S2 that the drive start instruction signal has been received from the host computer 2, the CPU 1 resets the continuous stop timer 3a (step S10). Then, the CPU 1 shifts to control for starting the operation of the vibration wave motor 44 based on the received drive start signal (step S11).

  Thus, according to the present embodiment, the tilt rotation shaft (camera head 50) can be held at a desired position for a long time by the vibration wave motor 44, and the tilt rotation shaft can be held. The (camera head 50) can be driven stably.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a flowchart showing a procedure for executing the recovery wave process of the driving apparatus according to the second embodiment of the present invention.

  The present embodiment has the same configuration as that of the first embodiment, but the first embodiment is different in that a drive start instruction signal from the host computer 2 is not accepted during execution of the recovery wave process. The form is different. In the following description, the same reference numerals are used for the same members and the same blocks in the first embodiment.

  When the CPU 1 of the control unit 100 stops the vibration wave motor 44 based on the stop instruction signal from the host computer 2, as shown in FIG. 10, the CPU 1 operates the continuous stop timer 3a and sets the continuous stop time t1. Timekeeping is started (step S21). Then, the CPU 1 determines whether or not a drive start instruction signal from the host computer 2 has been received (step S22).

  When the drive start instruction signal is not received from the host computer 2 in step S22, the CPU 1 determines whether or not the time t1 counted by the continuous stop timer 3a has reached the threshold value ta (step S23). ). Here, when the time t1 has not reached the threshold value ta, the CPU 1 returns to step S22.

  When it is determined in step S23 that the time t1 has reached the threshold value ta, the CPU 1 starts the recovery wave process described above (step S24). At this time, the CPU 1 starts measuring the recovery wave processing execution time t2 by the recovery wave processing timer 3b. Then, the CPU 1 determines whether or not the recovery wave processing execution time t2 timed by the recovery wave processing timer 3b has reached a predetermined time tp (step S25).

  When it is determined in step S25 that the recovery wave process execution time t2 has reached the predetermined time tp, the CPU 1 ends the recovery wave process (step S26). As the recovery wave process ends, the recovery wave process timer 3b is reset. Then, the CPU 1 resets the continuous stop timer 3a (step S27), and returns to step S21.

  If it is determined in step S22 that the drive start instruction signal has been received from the host computer 2, the CPU 1 resets the continuous stop timer 3a (step S28). Then, the CPU 1 shifts to control for starting the operation of the vibration wave motor 44 based on the received drive start signal (step S29).

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a diagram showing the execution timing of the recovery wave processing by the vibration wave motor driving apparatus according to the third embodiment of the present invention. FIG. 12 is a flowchart showing a procedure for executing the recovery wave process of the driving apparatus according to the third embodiment of the present invention.

  The present embodiment has the same configuration as that of the first embodiment, but when an initialization instruction that requires an initialization operation of the pan head 40, such as a power-on or reset instruction, is input, The difference is that recovery wave processing is executed before execution of the digitizing operation. In the following description, the same reference numerals are used for the same members and the same blocks in the first embodiment.

  In the present embodiment, when the initialization instruction is input, the panning mechanism and the tilting mechanism of the pan head 40 perform initialization operations such as positioning with respect to the initial position. For example, in the tilt mechanism, an initialization operation for operating the vibration wave motor 44 and stopping the camera head 50 at the initial position is performed.

  Here, regarding the tilt mechanism, as shown in FIG. 11, when an initialization instruction is input, recovery wave processing is first executed. Then, after the recovery wave process is completed, drive signals SA and SB corresponding to the initialization operation are output to the vibration wave motor 44.

  As shown in FIG. 12, the CPU 1 of the control unit 100 determines whether or not an initialization instruction has been input (step S31). Here, when an initialization instruction is input, the CPU 1 executes a recovery wave process (step S32). The execution time of this recovery wave process is 10 seconds unlike the first and second embodiments. Next, the CPU 1 outputs drive signals SA and SB corresponding to the initialization operation to the vibration wave motor 44, and controls the operation of the vibration wave motor 44 (step S33). And CPU1 complete | finishes this process.

  As described above, in this embodiment, when the initialization instruction is input, the vibration wave motor 44 is operated after the recovery wave process is executed, and the camera head 50 is stopped at the initial position in the tilt direction. The initialization operation is performed. Thereby, it is possible to prevent the self-holding torque of the vibration wave motor 44 from being lowered at the start of the initialization operation.

It is the perspective view which looked at the surveillance camera device from which the drive device concerning a 1st embodiment of the present invention is used as a tilt mechanism from the front. It is a perspective view which shows the principal part structure of the tilt mechanism used for the surveillance camera apparatus of FIG. FIG. 3 is a plan view schematically showing an engagement state of a tilt rotation gear 42 and a tilt rotation pinion gear 43 in FIG. 2. (A) is a longitudinal cross-sectional view showing a main part configuration of a vibration wave motor 44 used as a drive source of the tilt mechanism of the pan head 40 of FIG. FIG. 4B is an enlarged longitudinal sectional view showing a contact portion between the vibrating body 92 and the slider member 93 of the vibration wave motor 44 of FIG. It is a figure which shows the wave form diagram of the drive signal applied to the vibration wave motor 44 of Fig.4 (a). FIG. 5 is a block diagram illustrating a configuration of a control unit for driving the vibration wave motor 44 of FIG. 4. It is a figure which shows the switching state of the rotation direction of the output shaft 95 of the vibration wave motor 44 by the recovery wave process of the control part 100 of FIG. It is a figure which shows typically the execution timing of the recovery wave process by the control part. It is a flowchart which shows the procedure at the time of the control part 100 of FIG. 6 performing a recovery wave process. It is a flowchart which shows the procedure at the time of performing the recovery wave process of the drive device which concerns on the 2nd Embodiment of this invention. It is a figure which shows the implementation timing of the recovery wave process by the drive device of the vibration wave motor which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the procedure at the time of performing the recovery wave process of the drive device which concerns on the 3rd Embodiment of this invention. It is a figure which shows an example of a speed control profile.

Explanation of symbols

1 CPU
3a Continuous stop timer 6 Phase conversion unit 40 Pan head 42 Tilt rotation gear 43 Tilt rotation pinion gear 44 Vibration wave motor 45 Encoder scale 46 Encoder sensor 50 Camera head 91 Multilayer piezoelectric element 92 Vibrating body 93 Slider member 94 Mover 95 Output shaft 100 Control unit

Claims (8)

A vibration wave motor;
A driven body driven by the vibration wave motor;
It has at least a first transmission member and a second transmission member for transmitting the output of the vibration wave motor to the driven body, and between the first transmission member and the second transmission member A transmission means provided with play;
Control means for controlling the vibration wave motor,
The control means controls the vibration wave motor so that the vibration wave motor performs a specific operation for repeatedly reciprocating the first transmission member within the play range. apparatus. Comprising time measuring means for measuring a continuous stop time in which the vibration wave motor is continuously stopped;
The control means controls the vibration wave motor so that the vibration wave motor performs the specific operation when the continuous stop time measured by the time measurement means reaches a predetermined time set in advance. The drive device according to claim 1.   The drive unit according to claim 2, wherein the control unit controls the vibration wave motor so that the vibration wave motor performs the specific operation for a predetermined execution time.   The control means receives the specific instruction of the vibration wave motor when an instruction to start driving the vibration wave motor is input before a predetermined execution time elapses from the start of the specific operation of the vibration wave motor. 3. The drive device according to claim 2, wherein the vibration wave motor is controlled such that the operation of the vibration wave motor is stopped and the vibration wave motor starts an operation based on the drive start instruction.   When the initialization instruction is input, the control means causes the vibration wave motor to perform the specific operation before the vibration wave motor starts an operation based on the initialization instruction. The drive device according to claim 1, wherein the motor is controlled. The vibration wave motor includes a vibration body, an electromechanical energy conversion element fixed to the vibration body and exciting the vibration body to the vibration body, and a vibration wave that is in contact with the vibration body and excited by the vibration body. A mover that relatively moves, and an output member that moves by relative movement of the mover,
The drive device according to claim 1, wherein the output member is connected to the first transmission member. The first transmission member includes a first gear fixed to the output member,
The second transmission member comprises a second gear meshed with the first gear and provided with play between the first gear,
The control means controls the vibration wave motor as the specific operation so that the vibration wave motor rotates the first gear while repeating normal rotation and reverse rotation within the range of play. The drive device according to claim 6. A vibration wave motor, a driven body driven by the vibration wave motor, a first transmission member to which a driving force output from the vibration wave motor is transmitted, and a driving force transmitted to the first transmission member And a second transmission member for transmitting a drive signal to the driven body, and a transmission means provided with play between the first transmission member and the second transmission member. An apparatus control method comprising:
A control method for a driving apparatus, comprising: controlling the vibration wave motor so that the vibration wave motor performs a specific operation for reciprocating the first transmission member within the range of play.

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