JP3195820B2 - Apparatus with vibratory motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus provided with a vibration type motor for driving a movable member by using a vibration type motor as a driving source, and when driving a predetermined driving amount, faithful to an algorithm at the time of deceleration. The purpose is to perform speed control, thereby alleviating the time delay between the speed of the movable member and the control speed of the control unit, and stabilizing the drive amount of the movable member by performing stable deceleration control. The present invention relates to an apparatus provided with a vibration type motor that can perform the above-described operations.

[0002]

2. Description of the Related Art Conventionally, many products have been put into practical use with respect to a device using a DC motor or the like, but when driving a predetermined drive amount, a pattern of acceleration, constant speed, and deceleration is used. Is a factor that always follows, and among them, a factor that is absolutely related to securing a stable drive amount with respect to deceleration.

In the case of a DC motor, a voltage is generally raised as a factor for determining the rotation speed of the motor. The relationship between the voltage V and the rotation speed N is as shown in FIG.

[0004] From FIG. 3, a relationship of △ N / △ V = △ n / △ v is almost established. That is, the voltage and the rotational speed are in a substantially proportional relationship.

When controlling the speed of a DC motor,
Regardless of which speed is used as long as the determined algorithm is a straight line, the voltage is calculated by calculating the difference or ratio between the current speed of the movable member and the speed of the algorithm, and calculating the amount of change △ V from the calculated value. When the time is delayed in consideration of the control and the delay of the movable member, the predetermined algorithm can be applied to some extent, and the movable member can be stably controlled.

On the other hand, a vibration type motor utilizing vibration has been developed in recent years. This vibration type motor has an annular vibrator or a rod-like vibrator using a piezoelectric element as an electromechanical energy conversion element as a vibration source. Although a method having a vibrating body has been proposed, basically, an alternating voltage having different phases is applied to a two-phase driving piezoelectric element to excite two standing waves having different phases into an elastic body. By the combination, a circular or elliptical motion is formed on the surface particles of the driving surface, and the moving body that comes into pressure contact with the driving surface is moved by friction driving.

[0007] The vibration type motor has an excellent effect that the overshoot amount is much smaller than that of the DC motor, and high-accuracy position control can be realized because the moving body is always in pressure contact with the vibration body. Have.

In the above example, the speed control method for a DC motor is used. When a vibration type motor is used for the driving unit, it is necessary to determine the number of revolutions of the vibration type motor because the frequency of the input sine wave is important. f is generally put to practical use.

[0009]

FIG. 4 shows the relationship between the number of revolutions f and the number of revolutions N of a vibration type motor. This is shown in FIG.
When compared with the VN characteristic of the C motor, the DC motor has a proportional relationship, whereas the vibration type motor is non-linear, so the rotation speed control is the same as the above-described DC motor voltage. In the case where control is performed by replacing the frequency of the vibration type motor, it is difficult to apply the speed of the movable member to a linear algorithm.

From FIG. 4, since ΔN> Δn with respect to ΔF = Δf, when the speed of the movable member is around the frequency F, the frequency is changed only slightly. The speed changes abruptly, and when the frequency f is used, the speed does not change unless the frequency is changed much.

[0011]

The present invention SUMMARY OF] is a frequency signal electrical - with a vibration type motor to obtain a driving force is applied to the mechanical energy conversion element, the apparatus having a vibration motor for driving the movable member, When decelerating the driving speed for the movable member, a target driving speed from deceleration start to stop is set.
And comparing the speed of the movable member with the target drive speed.
Frequency signal so that the speed of the movable member becomes the target drive speed.
Speed control means for changing the frequency of
The frequency range is divided into a plurality of ranges,
Change amount per change of frequency
To different values according to each range, and start deceleration
One change for each range from the position to the stop position
Frequency change amount setting means for increasing the amount stepwise;
It is determined in which of the above ranges the movable member is located.
Determining means for determining the range determined by the determining means.
The amount of change in the frequency corresponding to each time
Set by the change amount setting means and change the frequency.
Features .

[0012]

According to the present invention, a frequency signal electrical - with a vibration type motor to obtain a driving force is applied to the mechanical energy conversion element, the apparatus having a vibration motor for driving the movable member,
When the driving speed is decelerated with respect to the movable member, deceleration Open
Set the target drive speed from start to stop, and set the movable member
Comparing the speed of the movable member with the target drive speed.
Change the frequency of the frequency signal to achieve the target drive speed
The speed control means and the area up to the stop position are divided into multiple ranges.
Change when the frequency is changed by the speed control means.
The change amount of each frequency to be changed at one time
Set a different value for each of them, from the deceleration start position to the stop position.
The amount of change per step for each range in
Frequency changing amount setting means to be adjusted, and the movable member
Determining means for determining in which range of the surrounding area is provided,
Of the frequency corresponding to the range determined by the determination means.
The change amount per operation is set by the frequency change amount setting means.
Since the frequency is changed and the frequency is changed , the deceleration control of the vibration type motor can be stabilized, and the stop position accuracy can be improved.

[0013]

FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, reference numeral 0 denotes a microcomputer having a timer and a counter for controlling the system (hereinafter abbreviated as a microcomputer), and 1 denotes a VF conversion for generating a frequency for controlling the number of revolutions of a vibration type motor. , 2 is a drive circuit for driving the vibration type motor,
З is a vibration type motor, 4 is an encoder unit for detecting the driving amount and speed of the movable member 6, and 5 is a speed reducer for reducing the rotation speed of the vibration type motor (not for securing torque, but for And 6 is a movable member movable by the vibration type motor 1.

When the driving of the vibration type motor is started, the microcomputer 0 also operates the counter and the timer, and counts the pulses from the encoder 4 by the counter. Calculate the speed. In addition, the increase or decrease of the frequency is adjusted so that the predetermined frequency can be adjusted over a plurality of stages.

On the other hand, the frequency range used for speed control is
As shown in FIG. 4, on the side where the frequency is lower than the resonance frequency f0, since the change is sharp, an area where the frequency is higher than the resonance frequency f0 is used. Therefore, as the frequency increases, the number of rotations decreases.

The position control of the movable member 6 in this embodiment shows a case where the movable member 6 is intermittently driven by a fixed amount.
The microcomputer 0 divides a corresponding section from a deceleration start position to a deceleration position into four regions so that the deceleration acceleration in each region is constant, that is, as shown in FIG. V and the movement position (pulse P) are controlled to be linear.

FIG. 2 shows the speed algorithm of the movable member in the present embodiment, and further shows the relationship between the frequency changes Δf to Δf4 when the driving amount is divided into each zone.

In FIG. 2, when the deceleration section is divided into four and each zone is set to L1 to L4, the relation of the speed of the movable member is L1>L2>LЗ> L4.

That is, as shown in FIG. 4, in the vibration type motor, the amount of change in the number of revolutions with respect to the frequency increases as the number of revolutions increases, so that the driving amount of the movable member 6 (movable member 6 is located in the L1 zone), the frequency change amount Δf1 must be reduced.

Similarly, the relationship of the frequency variation when the driving amount is in another zone is △ f1 <△ f2 <△ f3 <△ f4.

FIG. 5 is a flowchart showing the operation of this embodiment in consideration of the function of each unit shown in the block diagram of FIG.

In FIG. 5, it is determined whether or not a driving command for deceleration to vibration type motor 3 has been input from outside (# 1).
00). If it is input, the drive amount (all drive pulses) is input at the same time, the voltage is sent to the VF converter 1 and converted to a frequency to drive the vibration type motor 3 for deceleration (# 10).
1).

Next, counting of the driving amount (current driving pulse) is started based on the output from the encoder 4 (# 102),
At the same time, the timer data (timer DATA) is read to calculate the drive speed of the movable member (# 103).

Based on the speed algorithm of FIG.
3 (# 104), and if it is within the determined range, the counter data (counter DAT)
A) is taken in (# 105) and compared with the drive amount input in # 101 (# 106). If they are equal, the energization of the vibration motor 3 is stopped and the process is terminated (# 107).

On the other hand, if the speed of the movable member 6 is low in # 104, the input is made in # 101 (all drive pulses).
-(Current drive pulse) = (A) is calculated (# 10
8) When the range of A is larger than L1 (# 109)
Lowers the driving frequency f of the vibration motor 3 by one step (one-step D
OWN, # 114), increase the speed of the movable member.

When the range of A is smaller than L1 and larger than L2 (# 110), the frequency f is lowered by two steps (2
Stage DOWN, # 115).

Similarly, when the range of A is smaller than L2 and larger than L3 (# 111), the frequency f is lowered by З (3 steps DOWN, # 116), and the range of A is smaller than L3 and L4
If larger (# 112), the frequency f is lowered by four steps (4
(Step DOWN, # 117) When A is smaller than L4 (#
11З), lower the frequency f by 5 steps (5 steps DOWN, # 1)
18).

If the speed of the movable member is high in step # 104, (all drive pulses)-(current drive pulse) = (A) input in step # 101 is calculated (# 108).
When the range of A is larger than L1 (# 109), the drive frequency f of the vibration motor 3 is increased by one step (# 119), and the speed of the movable member is reduced.

When the range of A is smaller than L1 and larger than L2 (# 110), the frequency f is increased by two stages (# 120).

Similarly, when the range of A is smaller than L2 and larger than L3 (# 111), the frequency f is increased by З steps (#
121), when the range of A is smaller than L3 and larger than L4 (# 112), the frequency f is increased by four steps (# 122),
If A is smaller than L4 (# 113), the frequency f is increased by five steps (# 123).

The above # 114 to # 118 and # 11
When the processes from # 9 to # 123 are completed, the process returns to # 103, takes in the timer DATA again, and performs a normal routine process.

The counters and timers described above are incorporated in the microcomputer 0. In this embodiment, the deceleration section is divided into four sections.
Depending on the ROM capacity, a certain degree of control is possible even with multiple divisions or two divisions.

[0034]

As described above, according to the present invention, when the movable member is driven by controlling the rotation speed by the frequency using the vibration type motor, the FN characteristic of the vibration type motor is not improved. The purpose is to remove the unstable element of speed during deceleration due to linearity, and to stabilize the stop position of the movable member even in the case of any drive amount from minute drive to large drive.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 shows a speed algorithm during deceleration and a frequency change in speed control in the movable member of the embodiment of FIG.

FIG. 3 is a VN characteristic diagram of a DC motor.

FIG. 4 is an FN characteristic diagram of a vibration type motor.

FIG. 5 is a flowchart for explaining the operation of the embodiment of FIG. 1;

[Explanation of symbols]

0: Microcomputer 1: VF converter 2: Drive circuit 3: Vibration motor 4: Encoder 5: Reducer 6: Movable member L, L2, L3, L4: Pulse amount when the deceleration section is divided △ f, △ f2, △ f3,… f4... L-L4 frequency change amount at each division

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-118776 (JP, A) JP-A-4-79777 (JP, A) JP-A-1-227767 (JP, A) JP-A-4- 75478 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02N 2/00

Claims (2)

(57) [Claims] 1. A electricity frequency signals - reduced by the vibration type motor to obtain a driving force is applied to the mechanical energy conversion element, the apparatus having a vibration motor for driving the movable member, the driving speed for said movable member When opening,
Set the target drive speed from start to stop, and set the movable member
Comparing the speed of the movable member with the target drive speed.
Change the frequency of the frequency signal to achieve the target drive speed
The speed control means and the area up to the stop position are divided into multiple ranges.
Change when the frequency is changed by the speed control means.
The change amount of each frequency to be changed at one time
Set a different value for each of them, from the deceleration start position to the stop position.
The amount of change per step for each range in
Frequency changing amount setting means to be adjusted, and the movable member
Determining means for determining in which range of the surrounding area is provided,
Of the frequency corresponding to the range determined by the determination means.
The change amount per operation is set by the frequency change amount setting means.
And the frequency is changed . 2. The method according to claim 1, wherein the target drive speed is stopped from the start of deceleration.
The drive speed is linear within a predetermined range of
2. The vibration according to claim 1, wherein the vibration is set to change to
A device equipped with a model drive motor .