JPS5865366A - Anti-backlash driving device of rotor - Google Patents

Abstract

PURPOSE:To prevent a hunting phenomenon by connecting output shafts of two motors for driving a load in the opposite direction by torque transmitting means adapted to slide when receives torque more than the statical friction torque of the motors. CONSTITUTION:Output shafts 5a, 6a of both motors 5, 6 are connected to each other by a belt 19 adapted to transmit force of one side to the other side when receives torque less than the statical friction torque of the motors and slide when receives torque more than the statical friction torque of the motors. Therefore, if input is a speed command for rotating the first motor 5 counter-clockwise, an increase in torque of the first motor 5 is immediately transmitted to the second motor 6, resulting in that the first and second pinion gears 3, 4 are rotated counter-clockwise, not influenced by the statical friction of the motors, which causes a load 2 to rotate clockwise. Therefore, there is no hunting phenomenon so as to accomplish a low-speed drive smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-backlash drive device for a rotating body.

Conventionally, when an antenna is driven to rotate, an anti-backlash drive method is generally adopted so that the antenna can be driven without backlash. First, this anti-backlash drive system will be explained.

Figure 1 shows the schematic configuration of a conventional anti-backlash drive device, and Figure 2 shows its speed error signal and output torque characteristics.
FIG. 3 shows the block configuration of the control system. In FIG. 1, (1) is a rotating shaft of an antenna (not shown), and (2) is a gear attached to this rotating shaft (1), and this gear can be seen as a load of the main drive system. 131 (41 is the first and second pinion gears that mesh with the gear (2), (5
1f6+ are first and second motors that rotate the pinion gear f31+4+ counterclockwise and clockwise, respectively; 2nd motor +5>
161 rotation is geared down and the above pinion gear (3
) (4).

Further, in FIG. 3, a is a speed command signal, ('?) is the speed command signal a and a tacho generator α51 (described later).
Speed feedback signal from 1G+11. "Ill" is an amplifier that amplifies the speed error signal C which is the output of the adder (9), and "unua" is an amplifier that amplifies the speed error signal C which is the output of the adder (9). The adders (13) and (14) amplify the output of the adder Uυ412 and add it to the motor II +51 (61) as (161 is the first and second motor (5) f6
The tacho generator attached to +, dηa~, multiplies the speed signal detected by tacho generator a9αe by 1/2,
This is a multiplier that outputs speed feedback signals tl and f++.

This drive method drives the load without backlash, so
The load is driven by applying a reverse bias to the two motors (51(6)).In other words, when the load (2) is not rotating and the speed command signal λ is at 0°, the speed is The error signal C is also '0''', and the DC bias +v, -
VB remains as it is 1. Since the second motor (51 (61) is , positive reference signal &
is input, the first . Second tachometer generator t1!9
Since the speed feedback signals is and is from ns are O, the speed feedback signal becomes the speed error signal C as it is, and is amplified by the amplifier αG to become n.

In the adder α, 1 (12), a signal of +V B + a O is applied to the bias component, and a signal of +V B + a O is applied to the second motor (
6), a signal of -(VB-ao) is applied to each of them. Therefore, as shown in Fig. 2, the first motor (
The output torque of 5) is Tp+Tao, the second motor (6)
The output torque of is -(Tp-Tao), and the counterclockwise rotational torque of the first motor (5) is greater than the output torque of the second motor (6).
) The load (2) is larger than the clockwise rotational torque of
will rotate clockwise. Then, when the rotational speed of load (2) increases and reaches the above command value go K, the first
゜Since the rotation speed of M2 motor (51161 is also λ,
The speed feedback signals ft and fg from the tacho generator (I51 (161) are each 172 mm, and as a result, the speed error signal e is equal to the friction silk required for rotation, and the first and second motors t5) +61 The rotational torque of is TP+rt;-(T p −T (), and the load (2
) will continue to rotate at the above speed io. Note that A in FIG. 2 indicates an anti-backlash area.

However, in such a conventional anti-pack rack drive system, due to the so-called ringing determined by the motor (51+61 and gearbox (here JM is the moment of inertia of the motor and KG/2 is the spring constant between the two motors). Force exchange occurs between the motors (51+61), causing a hunting phenomenon in which both motors (51+61 are driven alternately at twice the commanded speed), resulting in a deterioration of low speed characteristics.

That is, if there is no static friction in the system and the rigidity f between the two motors is high, the movement of the first motor (5) is immediately transmitted to the second motor (6), and each tachogenerator (Is (161
Two speed signals are fed back via nl resulting in a speed command signal & and two speed feedback signals fl.

However, if the static friction of the motors is large and the rigidity between the two motors is low, the first motor (5)
Even if it rotates, the movement is not immediately transmitted to the second motor (6), and the second motor (6) is not immediately transmitted to the second motor (6) until the static friction force of the second motor is accumulated in the two Tanabata threshold springs. Since the speed signal is not fed back from the first motor and only the first motor generates a speed feedback signal that can cancel out the speed command signal, the first motor (5) rotates at twice the speed of the command speed. Become.

Then, when the force equivalent to two static friction torques of the second motor is accumulated in the spring between the two motors and the force is transmitted to the 5g2 motor (61), especially in a system where the motor's stillness is large, the second motor ( 6) rotates, and thereafter both motors are driven alternately at twice the speed, and in this way a hunting phenomenon occurs.This hunting phenomenon is distinguished by a so-called ringing frequency overfilter), and anti-backlash. 1st without any control. It can be improved by controlling the speed of each second motor independently, but in systems where the static friction of the motors is large and the spring constant between the two motors is small, the frequency range in which anti-backlash control is performed is extremely narrow. Therefore, depending on the required dynamic 1m4 degree, there was a drawback that anti-trash control was meaningless.

This invention was made to solve the above-mentioned conventional problems. When a torque of 1 static friction or less is applied between two motors, that force is transmitted to the other motor, and if further force is applied. By providing a torque transmitting means that does not transmit the force to the other when the rotational speed is exceeded, it is possible to prevent the two motors from rotating alternately at twice the command speed, and to improve the low speed characteristics of the rotating body. The purpose is to provide a backlash drive device.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows l! according to an embodiment of the present invention. ! A single-turn anti-backlash drive device is shown. In the figure, the same reference numerals as in Fig. 1 indicate the same parts as in Fig. 1, and the symbols ( ) indicate the cylindrical bodies attached to the output shafts (551) (6 m) of the motors (5) and (6), respectively. is a belt attached between the 100 cylindrical bodies deca, and when a torque less than the static friction torque of the system is applied to one side of the motor output shaft (51) (6 m), this belt transmits it to the other, When a torque greater than the static friction torque is applied, the cylinder slides between the supports and prevents the torque from being transmitted.

Next, the operation will be explained.

In this embodiment, the belt is connected between the output shafts (5 m) and (6 m) of both motors f51 +6+ to transmit the force of one to the other when the motor's torque is less than 1 m), and to cause the belt to slip when more force is applied. For example, if a speed command is input to rotate the first motor (5) counterclockwise, the increased torque of the first motor (5) is immediately transferred to the second motor (6). As a result, 1. Second
The pinion gear 131+4+ rotates counterclockwise without being affected by the static friction of the motor, thereby causing the load (2) to rotate clockwise.

Therefore, the hunting phenomenon unlike the conventional one does not occur, and low-speed driving can be performed smoothly. Further, conventional high-pass filters or low-pass filters are no longer necessary.

In the above embodiment, a belt is used as a torque transmission means to connect both motors so that force is transmitted below the static friction torque of the motors, but not when the torque is greater than that. They may be connected by

As described above, according to the present invention, in the anti-backlash drive device for a rotating body, when a torque equal to or less than the motor torque is applied between the output shafts of two motors that drive a load in opposite directions, transmits that torque,
When more torque is applied, the connection is made by a torque transmission means such as a belt or clutch in a sliding manner, which prevents the hunting phenomenon caused by the static friction of the motor and reduces the effect of ringing, thereby reducing the risk of low-speed driving. Since the control characteristics of the control system can be improved and the hunting phenomenon described above can be prevented, there is an effect that the high-pass filter or low-pass filter conventionally used in the control system is unnecessary.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional anti-backlash drive device, and Figure 2 shows its speed! FIG. 3 is a block diagram of its control system, and FIG. 4 is a schematic diagram of an anti-backlash drive device according to an embodiment of the present invention. (2)... Gear, (31 (41... Pinion gear (
drive gear), (5)...first motor, (6)...second motor, (71(81...gear box, ul...
- Belt (torque transmission means).

Claims (1)

[Claims] (1) A gear attached to a rotating body, and a first gear that meshes with this gear. a second drive gear; The second drive gear is moved counterclockwise and clockwise KJ through the gearbox, respectively. a second motor;
The first motor is mounted between the output shafts of the second motor. and a torque transmitting means that transmits a torque equal to or less than the static friction torque of the second motor from one output shaft to the other, and does not transmit a torque equal to or greater than the static friction torque. Rush drive.