JPS5939666A - Controller for hydraulic actuator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a hydraulic actuator that includes a servo system that operates the hydraulic actuator to match a target value.

BACKGROUND ART Conventionally, in order to bring a controlled object operated by a hydraulic actuator into agreement with a target value, a servo system has been employed in which the amount of displacement or velocity of the controlled object itself is negatively fed back to the input side. On the other hand, the displacement amount of the controlled object is detected by the pressure fluid l: that can be supplied to the hydraulic actuator, this detected value is negatively fed back to the input side, and the valve means is operated based on the deviation between this negative feedback value and the target value. There is a system that controls the pressure liquid m:e to be supplied to the hydraulic actuator. This control device is disclosed in Japanese Unexamined Patent Publication No. 115479/1983.

As mentioned above, in a control device for a hydraulic actuator that employs a servo system that indirectly detects the amount of displacement of a controlled object, 1. When a cage requires high positioning accuracy for landing on the floor, etc., there is a problem in that the cage operates in a vibratory manner, making it impossible to accurately position the controlled object to a target value.

The present invention has been made based on the above-mentioned problems, and an object of the present invention is to provide a control device for a hydraulic actuator with good positioning accuracy.

The present invention is characterized in that the valve means is operated according to the deviation between the actuation amount of the hydraulic actuator and its target value to control the hydraulic pressure supplied to the hydraulic actuator. A detection means for detecting the flow velocity of the pressure fluid corresponding to the velocity and the flow velocity change corresponding to the acceleration is provided in the hydraulic pressure supply pipeline between the hydraulic pressure actuator and the flow velocity and the flow velocity from the detection means. The amount of change is negatively fed back to comparison means to which a speed command, which is a target value, is applied.

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

Fig. 1 shows an embodiment of the device of the present invention applied to a hydraulic elevator. 5 and is raised and lowered by hydraulic oil from a tank 7 supplied by a pump 6. That is, when the cage 1 is raised, the pump 6 is activated to operate the piston 3, which supplies hydraulic oil from the tank 7 to the ram 2 via the check valve 8, thereby raising the cage 1. In this case, a command pattern signal predetermined by the pattern setter 10 for the ascending operation is inputted to the solenoid valve 11 via the speed control device 9 to excite it. For example, when this signal is an acceleration command signal, the flapper 12 approaches the nozzle 13 and the rise control valve 4
By increasing the back pressure of the engine and decreasing the opening degree of the rise control valve 4, the flow rate of hydraulic oil to the check valve 8 side is increased to perform acceleration. When a deceleration command signal is input, the flapper 12 separates from the nozzle 13 to increase the opening degree of the rise control valve 4, increasing the amount of bleed and decelerating. Also, when the cage 1 is lowered, the solenoid valve 14 and lowering control valve 5
Acceleration and deceleration are performed in a similar manner. In the map, L S + and L S 2 indicate position detection switches.

Here, in the embodiment of the present invention, the operation command pattern preset to the turn setting device is a double system including low-speed landing speed running shown in A of FIGS. 3 and 4, Pipe line 17 in the hydraulic oil supply circuit for the cylinder 3
A flow velocity/flow acceleration detector 15 is provided to detect the velocity and acceleration caused by the cage 1. Furthermore, this detector 15 is led to a signal circuit of a detection device 16 and then to a speed control device 9.

An outline of the flow velocity/flow acceleration detector 15 is shown in FIG. In the figure, inside a non-magnetic stainless steel tube 18 through which a fluid for measuring flow velocity and flow acceleration passes, a fixed orifice 19 with a shape symmetrical to the tube axis is installed on a pair of left and right rods 20A and 20.
B is attached to the support plates 21A and 21B. Each support plate has flow holes 22A and 22B, respectively;
It is fixed to the inner wall of the tube 18. On the other hand, a movable orifice 23 consisting of a movable orifice body 23A and an orifice 23B made of a ferromagnetic magnet and shaped to form a constriction between it and the fixed orifice 19 is connected to the tube 18.
With the inner wall of the movable orifice body 23A as a guide, the movable orifice body 23A is provided so as to be movable in the left and right directions in the figure along the central axis of the tube.
An orifice 23B made of a non-magnetic material that operates integrally with the movable orifice main body 23A is provided to prevent the operation of the movable orifice 23 from being hindered by adhesion of iron powder or the like mixed into the hydraulic oil.

In this embodiment, an AC excitation primary coil 25 necessary for detecting the displacement of the movable orifice 23 is provided on the outer wall surface of the tube 18, and an AC excitation primary coil 25 is provided on the outer wall surface of the tube 18.
8 are connected. On the other hand, the primary coil 2 for AC excitation
Detection secondary coils 26 and 27 are provided on both left and right sides of the movable orifice 23A for detecting movement of the movable orifice 23A in the left and right directions in the figure and outputting a signal corresponding to the amount of movement. Reference numeral 16 denotes an arithmetic device which extracts the output from the detection secondary coils 26 and 27 and distinguishes between the displacement and velocity components of the movable orifice 23. Reference numeral 22 is a flange for mounting the flow velocity/flow acceleration detector of the present invention, which is connected to the pipe line 17. The two output signals of the arithmetic device 16 are fed back to the speed control device 9 as the actual speed and acceleration signals of the car 1. Among these, the velocity feedback signal is an actual main feedback signal of the cage, and the acceleration signal of the cage is a feedback signal for damping compensation to compensate for the vibration phenomenon of the velocity and acceleration waveform of the cage when the cage lands on the floor. According to this compensation strategy, the actual velocity and acceleration waveforms of the car 1 will be as shown in FIGS. 4B and 4C for a speed pattern command signal as shown in FIG. 4A. In other words, the vibration phenomenon that occurs at the speed B and acceleration C of the conventional car shown in FIG. 3 is attenuated when changing the speed of the cage 1 and when landing on the floor, etc., thereby creating a hydraulic elevator with excellent ride comfort that is experienced as acceleration. In addition, it is possible to provide a hydraulic elevator that can perform continuous deceleration operation at -speed and land on the floor in the shortest possible time.

In this embodiment, the cage can be raised and lowered efficiently at high speed, and the consumption of power energy for operating the hydraulic equipment can be reduced. Furthermore, it is possible to obtain a comfortable ride with excellent acceleration sensation.

As described in detail above, according to the present invention, even in a servo system using indirect detection means, a controlled object can be positioned smoothly without vibration.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example in which an embodiment of the device of the present invention is applied to a hydraulic elevator, Fig. 2 is a diagram showing an example of a detector used in the present invention, and Fig. 3 is a diagram showing an example of a hydraulic elevator using a conventional device. FIG. 4 is a diagram showing the operating characteristics of a hydraulic elevator car obtained by the apparatus of the present invention. l...Cage, 2...Ram, 3...Cylinder, 4
．． 5... Ascent and descent control valve, 9... Speed control device, 1°... Pattern setting device, 17... Pipeline, 15
...Flow velocity/flow acceleration detector, 16...Detection device, 1
8...Pipe, 19...Fixed orifice, 23...Movable orifice, 24...Spring, 25...Primary coil, 26.27...Secondary coil, 28...AC voltage source. Agent Patent attorney Toshiyuki Usuda, - -RA x II ¥] Figure 2 f3 Ward Sai 4th prisoner

Claims (1)

[Scope of Claims] 1. In a device for controlling the hydraulic pressure supplied to the hydraulic actuator by operating a valve means according to the deviation between the operating amount of the hydraulic actuator and its target value, the valve means and the hydraulic A detection means for detecting the flow velocity of the pressure fluid corresponding to the velocity and the flow velocity change corresponding to the acceleration is provided in the hydraulic pressure supply pipeline between the pressure actuator and the flow velocity and the flow velocity change from the detection means. 1. A control device for a hydraulic actuator, characterized in that the amount is negatively fed back to comparison means to which a speed command, which is a target value, is applied. 2. The detection means includes a fixed orifice provided in the pipe through which the liquid flows, and a movable member that forms a throttle together with the fixed orifice and moves inside the pipe by the differential pressure generated before and after the throttle depending on the flow rate of the liquid. an orifice, a primary coil wound along the movement range of the movable orifice on the outer wall of the tube, and two secondary coils for detecting the movement displacement of the movable orifice and its rate of change. A control device for a hydraulic actuator according to claim 1. 3. The control device for a hydraulic actuator according to claim 2, wherein the movable oriice in the detection means is constructed of a ferromagnetic magnet. 4. A control device for a hydraulic actuator according to claim 2 or 3, wherein the hydraulic actuator is a cylinder operated by hydraulic pressure. 5. The control device for a hydraulic operating machine according to claim 4, wherein the hydraulic operating machine is connected to an elevator car so as to operate the elevator car.