JP2013174262A - Active damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active damper that can prevent vibration transmission from an unsprung part (supporting frame) to a sprung part (damping object) in a high frequency range where a response of a pump motor cannot be followed, without increasing extra control or unnecessary loss in a conventional manner.SOLUTION: An active damper includes a hydraulic cylinder interposed between a damping object and a supporting frame; a hydraulic pump discharging hydraulic fluid to the hydraulic cylinder; a pump motor driving the hydraulic pump; and an accumulator connected to a hydraulic-oil supply channel in communication between the hydraulic cylinder and the hydraulic pump.

Description

 The present invention relates to an active damper.

  As is well known, an active damper is used to mitigate impact and suppress vibration (vibration suppression) by dynamically controlling an actuator, such as a suspension provided in a vehicle, a die cushion device provided in a press machine, etc. It is applied to various devices. A general active damper includes a hydraulic cylinder interposed between an object to be controlled and a support frame, a hydraulic pump that discharges hydraulic oil to the hydraulic cylinder, a pump motor that drives the hydraulic pump, and a pump motor. And a controller for controlling (see Patent Documents 1 and 2 below).

JP 2000-264033 A JP 2009-196597 A

  The technique of Patent Document 1 is a system in which a motor torque is generated as a hydraulic cylinder thrust through a hydraulic pump to generate a control force by an actuator, but a relatively low frequency region in which the response of the pump motor follows. However, there is a problem that an effective control force cannot be generated in a high frequency region where the response of the pump motor cannot follow.

  The ideal function of the actuator is to allow effective control force to act on the sprung mass, but not to transmit the vibration of the unsprung mass to the upper part. Then, it acts as a vibration transmission element from the unsprung to the unsprung, and may increase the vibration on the unsprung mass side.

  In order to compensate for the drawbacks of the technique of Patent Document 1, the technique of Patent Document 2 can be cited. However, in addition to the rotation control of the pump motor, control of the variable throttle is necessary, and all the control force generated by the variable throttle is all. It will be a loss.

 The present invention has been made in view of the above-described circumstances, and does not increase unnecessary control and useless loss as in the prior art. In a high-frequency region where the response of the pump motor cannot follow, the spring from the unsprung (support frame) is used. An object of the present invention is to provide an active damper capable of suppressing vibration transmission to the top (an object to be controlled).

 In order to achieve the above object, according to the present invention, as a first solving means related to an active damper, a hydraulic cylinder interposed between an object to be controlled and a support frame, and hydraulic oil is discharged to the hydraulic cylinder. And a hydraulic motor that drives the hydraulic pump, and an accumulator connected to a hydraulic oil supply passage that connects the hydraulic cylinder and the hydraulic pump.

 Further, in the present invention, as a second solving means related to the active damper, in the first solving means, a pressure sensor that detects the pressure of the hydraulic oil supply flow path and outputs a pressure detection signal indicating the detection result. And a control device that controls the pump motor based on a pressure detection signal input from the pressure sensor and a damping force command signal input from the host control device.

 According to the present invention, by using an accumulator, without increasing unnecessary control and useless loss as in the prior art, in the high frequency region where the response of the pump motor cannot follow, the sprung from the unsprung (supporting stand) (suppressed). It is possible to suppress vibration transmission to the (vibration object).

It is a schematic structure figure of active damper 1 concerning this embodiment. It is a figure which shows the 1st modification of this embodiment. It is a figure which shows the 2nd modification of this embodiment. It is a figure which shows the 3rd modification of this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an active damper 1 according to the present embodiment. As shown in FIG. 1, the active damper 1 according to the present embodiment dynamically controls thrust generated in a hydraulic cylinder 11 interposed between the vibration control object 2 and the support frame 3. Thus, vibration suppression (vibration suppression) of the vibration suppression object 2 is realized. From the hydraulic cylinder 11, the hydraulic pump 12, the oil storage tank 13, the pump motor 14, the accumulator 15, the pressure sensor 16, the pulse generator 17, and the controller 18. It is configured.

 Assuming that the application of the active damper 1 is, for example, a vehicle suspension, the vibration damping object 2 is a vehicle body (sprung mass M), and the support frame 3 is a tire support arm (unsprung mass m). Further, the vibration source in the figure is a road surface, and the spring element 4 interposed between the road surface and the support frame 3 is a tire. Furthermore, the spring element 5 interposed between the damping object 2 (vehicle body) and the support frame 3 (support arm) is a spring coil, and the damping element 6 is a gas-filled damper, for example.

 The hydraulic cylinder 11 is interposed between the vibration control object 2 and the support base 3 and generates thrust necessary for vibration control of the vibration control object 2 by oil pressure. The cylinder 11a, the piston 11b, A rod 11c is provided. The cylinder 11a is a cylindrical part that accommodates hydraulic oil therein. The piston 11b is a disk-shaped component that divides the internal space of the cylinder 11a into two chambers (first chamber R1 and second chamber R2) and is reciprocally moved along the inner wall of the cylinder 11a. The hydraulic oil is accommodated in the second chamber R2.

 The rod 11c is a rod-like component having one end fixed to the piston 11b so that its own central axis coincides with the central axis of the piston 11b. The other end of the rod 11c penetrates from the second chamber R2 side of the cylinder 11a to the outside and is connected to the vibration control object 2 to which the thrust generated in the hydraulic cylinder 11 is to be applied.

 The hydraulic pump 12 is, for example, a two-way discharge type displacement pump, and has an input shaft connected to the rotating shaft of the pump motor 14 and one discharge port of the hydraulic cylinder 11 via the hydraulic oil supply passage L1. Connected to the second chamber R2, the other discharge port is connected to the oil storage tank 13 via the hydraulic oil discharge passage L2. The hydraulic pump 12 determines the discharge direction of hydraulic oil (in other words, from which discharge port the hydraulic oil is discharged) according to the rotation direction of the input shaft, and determines the discharge flow rate according to the rotation speed of the input shaft. . The oil storage tank 13 is a container for storing hydraulic oil discharged from the hydraulic pump 12.

 The pump motor 14 is an AC servo motor, for example, and has a rotating shaft that rotates in accordance with a motor drive signal supplied from the controller 18. As described above, since the rotary shaft of the pump motor 14 is connected to the input shaft of the hydraulic pump 12, the hydraulic oil generated by the hydraulic pump 12 is controlled by controlling the rotational direction and the rotational speed (rotational speed) of the pump motor 14. The discharge direction and discharge flow rate can be controlled arbitrarily. That is, by controlling the rotation direction and the number of rotations of the pump motor 14, an arbitrary pressure difference can be generated between the first chamber R1 and the second chamber R2 of the hydraulic cylinder 11, and as a result, the hydraulic cylinder 11 It is possible to arbitrarily control the thrust (force acting on the vibration control object 2) generated by

 The accumulator 15 is a pressure accumulator connected in the middle of the hydraulic oil supply flow path L1 connecting the hydraulic cylinder 11 and the hydraulic pump 12 (a position close to the hydraulic cylinder 11 is preferable). This accumulator 15 includes a rubber film filled with nitrogen gas inside the main body, and when the pressure of the hydraulic oil supply flow path L1 becomes higher than the nitrogen gas filled pressure, the rubber film is compressed and accumulates the hydraulic oil inside. When the pressure of the hydraulic oil supply flow path L1 becomes lower than the nitrogen gas charging pressure, the hydraulic oil is released by the expansion of the rubber film.

 The pressure sensor 16 detects the pressure in the hydraulic oil supply flow path L1 and outputs a pressure detection signal indicating the detection result to the controller 18. The pulse generator 17 is, for example, a rotary encoder, and generates a pulse signal corresponding to the rotation of the pump motor 14 (specifically, a pulse signal having a period required for the pump motor 14 to rotate at a certain angle). And a pulse generator to be output to the controller 18.

 The controller 18 controls the rotation of the pump motor 14 based on the pressure detection signal input from the pressure sensor 16, the pulse signal input from the pulse generator 17, and the damping force command signal input from the host controller 19. The apparatus includes a pressure / thrust conversion unit 18a, an addition unit 18b, a subtraction unit 18c, a PID calculation unit 18d, and a motor driver 18e. The pressure / thrust conversion unit 18a, the addition unit 18b, the subtraction unit 18c, and the PID calculation unit 18d are software functions that are realized by a microcomputer built in the controller 18 executing a program.

 Here, the damping force command signal input from the host controller 19 is, for example, an attenuation corresponding to the resistance force to the relative speed calculated based on the relative speed between the control object 2 and the support base 3. It is a signal indicating a force command value (in other words, an attenuation coefficient). That is, the host controller 19 calculates a damping force command value corresponding to a resistance force to the relative speed based on the output signal of the relative speed detection unit 20 that detects the relative speed between the control object 2 and the support base 3. Then, a damping force command signal indicating the calculation result is output to the controller 18.

 The pressure / thrust conversion unit 18a recognizes the pressure of the hydraulic oil supply flow path L1 (hereinafter referred to as hydraulic oil pressure) based on the pressure detection signal input from the pressure sensor 16, and performs predetermined conversion to this hydraulic oil pressure. By multiplying the coefficient, the thrust currently generated in the hydraulic cylinder 11 (hereinafter referred to as a cylinder thrust current value) is calculated. The adder 18b calculates the cylinder thrust target value by adding the damping force command value indicated by the damping force command signal input from the host controller 19 and the weight support load (constant load) of the hydraulic cylinder 11. .

 The dead weight of the damping object 2 is expressed by M × g using the mass M and the gravitational acceleration g. For example, the spring element 5 and the damping element interposed between the damping object 2 and the support frame 3. If the self-weight support burden of 6 is 90%, the self-weight support burden of the hydraulic cylinder 11 is expressed by M × g × (1-0.9). The subtraction unit 18c is calculated by the pressure / thrust conversion unit 18a from the cylinder thrust target value calculated by the addition unit 18b as described above (= damping force command value + self weight support load of the hydraulic cylinder 11). The cylinder thrust deviation value is calculated by subtracting the cylinder thrust current value.

  The PID calculation unit 18d performs PID calculation based on the cylinder thrust deviation value (= cylinder thrust target value−cylinder thrust current value) calculated by the subtraction unit 18c (multiplies the cylinder thrust deviation value by a control gain). Thus, an operation signal for making the cylinder thrust deviation value zero, in other words, for making the cylinder thrust target value coincide with the cylinder thrust current value is generated and output to the motor driver 18e.

  The motor driver 18e generates a motor drive signal (drive current) for driving the pump motor 14 according to an operation signal input from the PID calculation unit 18d (that is, a microcomputer) and outputs the motor drive signal (drive current) to the pump motor 14. Note that the pulse signal output from the pulse generator 17 is fed back to the motor driver 18e, and feedback control is performed so that the rotation speed indicated by the operation signal matches the actual rotation speed of the pump motor 14. Be able to.

  As described above, in the active damper 1 according to the present embodiment, the hydraulic cylinder 11 is fixed by causing the hydraulic cylinder 11 to share a part of the force that supports the dead weight of the vibration control object 2 (sprung mass M). A configuration that only needs to generate thrust in only the direction is adopted. The hydraulic cylinder 11 constantly generates a part of the force that supports the dead weight of the object 2 to be damped, and the inflow / outflow amount of hydraulic oil by the rotation control of the pump motor 14 based on the steady force of the dead weight support. By adjusting the control force, the control force (thrust) necessary for the vibration suppression control can be applied to the vibration suppression object 2.

  Considering the vibration transmission from the support frame 3 (unsprung mass m) to the damping object 2 (sprung mass M) in the hydraulic cylinder 11, due to the compressive action of the gas enclosed in the accumulator 15, It has the characteristic that vibration is not easily transmitted to the upper side of the spring. For this reason, by controlling the rotation of the pump motor 14, it is possible to adjust the amount of hydraulic oil flowing into and out of the accumulator 15 to apply a control force, and the response in a high frequency region that cannot be followed by the rotation control of the pump motor 14. With regard to, the structure is such that the vibration from the lower side of the spring to the upper side of the spring is less likely to be transmitted due to the compressive action of the sealed gas in the accumulator 15.

  Therefore, according to the present embodiment, the vibration component in the low frequency region that can be followed by the rotation control of the pump motor 14 acts as a control force to the upper side of the spring (the vibration suppression object 2), while the rotation of the pump motor 14 is performed. Since the vibration component in the high frequency region that cannot be tracked by the control can be absorbed by the accumulator 15, from the unsprung state (support frame) in the high frequency region where the response of the pump motor cannot track without increasing unnecessary control and wasteful loss as in the past. It is possible to suppress vibration transmission to the sprung (vibration target).

In addition, this invention is not limited to the said embodiment, The following modifications are mentioned.
(1) In the above embodiment, the case where the configuration in which the hydraulic oil is supplied from the hydraulic pump 12 only to the second chamber R2 of the hydraulic cylinder 11 is exemplified, but the present invention is not limited to this and is shown in FIG. As described above, a configuration in which hydraulic oil is supplied from the hydraulic pump 12 to both the first chamber R1 and the second chamber R2 of the hydraulic cylinder 11 may be employed.

(2) In the above embodiment, the use of the active damper 1 is assumed to be, for example, a vehicle suspension. However, the present invention is not limited to this, and a damping object such as a die cushion device provided in a press machine and a support frame, By dynamically controlling the thrust generated by the hydraulic cylinder interposed between the two, it can be widely used for the purpose of performing the damping control of the damping object.

(3) In the above embodiment, the case where the accumulator 15 is connected in the middle of the hydraulic oil supply flow path L1 (position close to the hydraulic cylinder 11) is illustrated, but the present invention is not limited to this, and the accumulator 15 is connected to the hydraulic oil. You may connect to any position of the supply flow path L1. For example, in FIG. 3, one end of the hydraulic oil supply flow path L1 is connected to the hydraulic cylinder 11 via the hydraulic hose 21, and the other end of the hydraulic oil supply flow path L1 is connected to the accumulator 15 via the hydraulic hose 22. Shows the case.

(4) In the above embodiment, the controller 18 pumps based on the pressure detection signal input from the pressure sensor 16, the pulse signal input from the pulse generator 17, and the damping force command signal input from the host controller 19. Although the case where the rotational speed control of the motor 14 is controlled has been illustrated, the present invention is not limited to this. For example, as shown in FIG. 4, the pulse generator 17 is deleted, and the pressure detection signal input from the pressure sensor 16 and the host A controller 18A that performs torque control of the pump motor 14 based on a damping force command signal input from the control device 19 (not shown in FIG. 4) may be provided. In this case, the controller 18A generates a motor drive signal (drive current) for controlling the torque of the pump motor 14 in accordance with an operation signal input from the PID calculation unit 18d, instead of the motor driver 18e, and generates the pump motor 14. Is provided with a motor driver 18f.

  DESCRIPTION OF SYMBOLS 1 ... Active damper, 2 ... Damping object, 3 ... Support stand, 11 ... Hydraulic cylinder, 12 ... Hydraulic pump, 13 ... Oil storage tank, 14 ... Pump motor, 15 ... Accumulator, 16 ... Pressure sensor, 17 ... Pulse generator (Pulse generator), 18, 18A ... controller (control device), 19 ... host control device, 20 ... relative speed detector

Claims (2)

A hydraulic cylinder interposed between the object to be controlled and the support frame;
A hydraulic pump for discharging hydraulic oil to the hydraulic cylinder;
A pump motor for driving the hydraulic pump;
An accumulator connected to a hydraulic oil supply flow path connecting the hydraulic cylinder and the hydraulic pump;
Active damper characterized by comprising. A pressure sensor that detects the pressure of the hydraulic oil supply flow path and outputs a pressure detection signal indicating the detection result;
A control device for controlling the pump motor based on a pressure detection signal input from the pressure sensor and a damping force command signal input from a host control device;
The active damper according to claim 1, further comprising:

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