JPS5888202A - Driving apparatus - Google Patents

Abstract

PURPOSE:To obtain a driving apparatus with high thrust, high torque, and high accuracty by controlling a load driving servomotor so that the deviation between the detection signal for transfer of a load and the command signal becomes zero and controlling feeding of pressurized fluid to a load driving actuator according to the magnitude of said deviation. CONSTITUTION:As for an arm 4 which suspends a load 5 at the edge, the center part close to the rear edge is pivotally supported on a supporting base, and a cylinder 14 is installed between the supporting base and the part close to the top edge of the arm, and a screw rod 9 and a nut 10 are arranged between the supporting base and the rear edge part of the arm. The command pulse for positioning through turning of a screw rod 9 by a servomotor 10, is input into one input terminal 19 of a deviation counter 18, and the signal having the polarity corresponding to the normal and reverse revolution of the screw rod 9 is input into the other input terminal 20. The output signal of the deviation counter 18 drives the servomotor 10, and at the same time, drives the cylinder 14 by controlling valves 45 and 46 through an amplifier 30 and a zero-voltage relay 42.

Description

[Detailed description of the invention] The present invention relates to a device for driving a load.

Conventionally, in order to position and control the load,
Fluid pressure actuators such as servo motors or hydraulic cylinders are used. Although highly accurate control can be performed using a servo motor, there is a limit to its output capacity, and there is a problem in that as the capacity increases, responsiveness decreases. This is particularly noticeable when the servo motor is placed under a high negative load due to vertical rotation of the arm. However, fluid pressure actuators. Although it is possible to obtain a large thrust or torque by using a cylinder, there is a limit to the accuracy depending on machining accuracy and temperature characteristics of fluid pressure.

An object of the present invention is to provide a drive device that can drive a load with high thrust or high torque, and achieves highly accurate positioning and excellent responsiveness.

FIG. 1 is a front view of one implementation of the invention. A support stand 2 is erected on the fixed fsl, and an arm 4 is rotatably supported on the upper part of the support stand 2 by a pin 3 having a horizontal axis. A load 5 is connected to one end of the arm 4. At the other end of the arm 4, an end of a cylinder 7 is pivotally supported by a pin 6 having a horizontal axis parallel to the pin 3.

A nut 8 is fixed to the other end of the cylindrical body 7, and a screw stud 9 of a pole screw is screwed into the nut 8. This screw stud 9ii' can be inserted into the cylindrical body 7. It has nine screws and is rotationally driven by a servo motor.

It is supported by a trunnion shaft 11 with a servo motor and a horizontal axis parallel to the pin 3 on a plaque 12 fixed to the support base 2. On the opposite side of the pin 3 from the pin 6 is another one having a horizontal axis parallel to the pin 3.
Hydraulic sillage-4 piston rod 1 by two pins 13
5 is pivoted. Schilling-4#-t, clevis bottle 1
6, it is pivotally supported by a bracket 17 fixed to the support base 2.

FIG. 2 is a circuit diagram related to servo motor 0 and Schilling-4. One input 19 of the deviation force 2 terminal 18
A command pulse representing the amount of displacement for positioning by the servo motor 0 is input to the servo motor 0 . Another input 20 of the deviation counter 18 is supplied with a signal having a polarity corresponding to the forward rotation and reverse rotation of the payload 9. Yet another input 21 of this deviation counter 18 is
A pulse is provided from an ejector 22 that detects the amount of displacement of the servo motor 10. A deviation pulse representing the difference of the pulses from λ 19.21 is applied from line 23 to a digital/analog converter 24 where it is converted into a voltage value and applied to one side of a subtractor 25. At the input of the subtracter 25, a digital p/L74g signal representing the speed detected by the detector 22 is provided from the frequency/voltage converter 26.

The deviation voltage from the subtractor 25 is transferred from the line 28 to the amplifier 2.
9 to the servo motor 1o.

Detection JJ22,1. The signal applied to input 21 and the output from frequency/voltage converter 426 are negatively fed back to the servo console so that the deviation voltage in line 28 maintains a speed change corresponding to the number of command pulses applied from input 19. - Drive the screw 9 on the 1st floor.

The deviation voltage from line 28 is also amplified by amplifier 30 and provided to zero voltage relay 32 from line 31. This zero voltage relay 32 has a function of conducting when the output from the line 31 is less than a predetermined value and cutting off when the output is equal to or greater than the predetermined value. The output from zero voltage relay 32 is given to absolute value circuit 33.

The absolute value circuit 33 derives an output corresponding to the absolute value of the input voltage ranging from positive to negative as shown in FIG. The output from the absolute value circuit 33 is converted into a frequency by the voltage/same wave number converter 34 and is input to one input 3 of the deviation counter 35.
given to 6. The other input 37 of the deviation counter 3'5
is provided with an output from zero voltage relay 32. Deviation counter 35 outputs and holds on line 38 J0 a pulse from input 36 having the polarity given to input 37. The digital/analog converter 39 converts the deviation counter 3
Convert the output from 5 to a voltage value. This voltage value is amplified by an amplifier 40 and applied to one input of an adder 41. Another input to adder 41 is line 3.
1 is applied via zero voltage relay 42.

The zero voltage relay 42 has a function of cutting off when the voltage of the line 31 is less than a predetermined value and turning on when it is equal to or higher than the predetermined value. The output from the summing@41 is provided from the amplifier 43 via line 44 to the pressure valve 45.46. When the voltage of the pressure valve 45 and the line 44 is negative, pressure oil is supplied through the line 47 to the cylinder chamber 48 on the head side of the cylinder 14 . Another pressure valve 46
supplies pressure oil from line 47 to cylinder chamber 49 on the piston rod 15 side when the voltage on line 44 is positive.

The liquid from the cylinder chambers 48, 49 is discharged via line 50. Pressure valves 45 , 46 direct pressure oil having a pressure proportional to the voltage from line 44 to cylinder chamber 48 .
49 respectively.

The operation of the embodiment shown in FIGS. 1 and 2 is explained in step A9. When the load 5 is stationary, the arm 4 has:
The weight of the load 5 acts around the axis of the pin 3 in a counterclockwise direction as shown in FIG. Therefore, the cylinder 7
and the nut 8 is pulled upwards in FIG. This causes a rotational force to act on the threaded rod 9 of the ball screw. Therefore, the output shaft of the servo motor 10 rotates slightly. Detector 22 thus generates a pulse, which generates a negative deviation pulse in line 23.

This deviation pulse causes 10 servo motors and 5 loads.
generates a torque in a direction that opposes the torque of the threaded rod 9 due to its own weight. The deviation voltage on line 28 is also amplified by amplifier 30.

Since the voltage on this amplified line 31 is less than the predetermined value, the voltage on the amplified line 31 is
A positive voltage is applied to the counter value circuit 33, and this voltage is converted into a frequency and held in the deviation counter 35. The deviation voltage on line 28 is negative and therefore input 37 of deviation capunta 35 is provided with a signal of negative polarity.

The negative pulse on line 38 is therefore
The analog converter 39 converts it into a negative analog signal. Thus, amplifier 40, adder 41 and amplifier 4
3 to line 44 will be of negative conductivity. Therefore, the pressure valve 45 is opened and pressure oil is supplied to the cylinder chamber 48 on the head side. Therefore, the piston rod 15
A force +p is generated in the direction of extension of the arm 4,
ll1hlv! ! A slight angular displacement in a clockwise direction. This changes the output of the detector 22, causing the line 2
The deviation voltage at 8 approaches zero and static balance is maintained.

In this manner, when the load 5 is in a stationary state, the force caused by the load 5's own weight is overcome by the action of the cylinder 14, and the arm 4 can be kept stationary. Therefore, the servo motor 10/4 furnace can be made smaller. Further, since the output from the detector 22 which detects the upper and lower positions of the load 5 and the amount of displacement by the servo motor 10 is fed back negative feedback, positioning and tracking a1 can be performed with high precision.

The operation of lifting the arm 4 clockwise around the axis of the pin 3 and rotating it up and down will be explained. In this case, a command pulse representing the amount of displacement is applied to the input 19 of the deviation capacitor 18, and a negative signal is applied to the input 20. As a result, negative deviation electrons are generated in the line 28. In this way, the servo motor 10 rotates the threaded rod 9 to rotate the threaded rod 9 so as to displace the cylinder 7 and the NAND 8 downward.

At the same time, the deviation voltage in line 28 is amplified by amplifier 30 so that the voltage in line 31 exceeds the predetermined value of zero voltage relay 42. Therefore, zero voltage relay 42 becomes conductive.

Therefore, the output of the amplifier 43 is transferred from the line 44 to the power valve 45.
This supplies pressure oil to the cylinder chamber 48 on the head side. Therefore, the piston rod 15 is
exerts upward acceleration force.

In order to angularly displace the arm 4 in a counterclockwise direction around the axis of the pin 3 in order to displace the load 5 downward in FIG. , the input 20 is of positive polarity. This generates a positive deviation voltage in line 28,
The servo motor 10 rotates the threaded rod 9 so as to displace the cylinder 7 and the nut 8 upward, and also outputs a voltage from the amplifier 30 via the line 31 to a zero voltage relay 42.
from summing@41, amplifier 43 and via line 44 to pressure valve 46. Therefore, pressure oil is supplied to the cylinder chamber 49 on the piston rod 15 side, and the piston rod 15 is reduced. The detector 22 is driven by the servo motor 10.
output is generated, and the servo motor 10 and cylinder 14 are moved one time until the deviation electron in line 28 becomes zero.

FIG. 4 is a cross-sectional view of a portion of an elongated embodiment of the present invention.

It is connected to the servo motor 10 by a screw*9u'-gear 51.52 and is supported by a bracket 55 fixed to the support 2 by a thrust bearing 53.54 of this threaded rod. This bracket 55 is provided with a radial bearing 56. Thrust bearing 53.5
Pressure detectors 57 and 58 for detecting the thrust load acting on the threaded rod 9 are interposed between the screw rod 4 and the bracket 55, respectively. According to the idea of the invention, the output from pressure detectors 57,58 may be provided on line 59. At this time, the zero voltage relay 32 interposed between the lines 31 and 59 is omitted.

As another practical example of the present invention, the cylinder 14 may be replaced with a rotary actuator operated by fluid pressure. Although the servo motor 10#-j drives the locking screw 9 in the above-described embodiment, in another embodiment of the present invention, the force from the servo motor 10 is transmitted to a reduction gear, and the load 5 is transmitted to the reduction gear by this reduction gear. You may also try to force yourself to do so.

As described above, according to the present invention, load positioning and follow-up control are performed by a servo motor in a negative feedback loop, making it possible to perform highly accurate positioning and follow-up control. Further, a fluid pressure actuator is also used when the load is stationary and for moving the load, which allows the load to be moved with a large thrust or torque, and also allows the servo motor to be downsized. By downsizing the servo motor, it is possible to prevent a decrease in responsiveness.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a circuit diagram of the embodiment shown in FIG. 1, FIG. 3 is a graph showing the characteristics of the absolute value circuit 33, and FIG. This is a cross-sectional view of a part of an embodiment of the invention. 2... Support stand, 3, 6, 11, 13. 16... Pin, 4... Arm, 5... Load, 7... Cylindrical body, 8...
... Nut, 9 ... Screw head, 10 ... Servo motor, 14 ... Schilling, 18.35 ... Deviation kakunta, 22 ... Detector, 24.39 ... Digital/analog conversion Container, 25... Subtractor, 29, 30, 40.4
3...Amplification type, 32゜42...Zero voltage relay, 33
... Absolute value circuit, 34 ... Voltage/frequency converter, 4
5.46...Pressure valve agent Patent attorney Kei Nishikyo part l pekku stay Z◇Zkuku St'/AX begging l pet heart Figure 3 Figure 4

Claims (1)

[Claims] A servo motor that drives a load, a detector that detects movement of the load, and a deviation between a command signal and a detection output from an injector,
A circuit constituting a negative feedback loop that controls a servo motor so that the deviation becomes zero, a fluid pressure actuator that drives a load, a means for supplying pressure fluid to the fluid pressure actuator, and a circuit that controls a servo motor so that the deviation becomes zero. a circuit for controlling a pressure fluid supply means such that the fluid pressure actuator generates a force corresponding to the deviation; and when the deviation is less than a predetermined value, the fluid pressure actuator acts on the servo motor. A drive device comprising: a circuit for controlling a pressure fluid supply means to generate a force corresponding to a deviation resisting the force.