JP3413579B2 - Rotation speed control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of the rotational speed of a rotary engine, and more particularly to the control of the rotational speed by operating an actuator of a fuel rack by feedback control. The present invention relates to a rotation speed control device. [0002] Conventionally, the control of the rotational speed of a rotary engine has
As shown in FIG. 4, it is common to perform feedback control so as to reach a preset target rotational speed, and so-called PID (Proportional, Integral, Derivati).
(initial of ve) Control is being performed. That is, the rotating engine 50
Is detected by a detector 51, and the detected rotation speed is sent to a calculation unit 52. The calculation unit 52 calculates a deviation from a target value and sends it to a control calculation unit 53. By adjusting the amount by which the fuel rack control actuator 54 is operated in accordance with deviations due to so-called P operation (proportional operation), I operation (integration operation), and D operation (differential operation), and outputting the result to the fuel rack control actuator 54, The control of the rotary engine 50 is performed. [0003] However, in the conventional PID control, the PID constants (proportional band, integration time, and differentiation time) are set in advance to be optimal.
Since the rotation speed is made to correspond to the load fluctuation due to the disturbance, if the load fluctuates suddenly, there is a problem that the rotation speed fluctuates and it takes time to stabilize. For example, as shown in FIG. 5, when the load suddenly decreases, the rotational speed rapidly increases, and a time t required for the rotational speed to reach a constant value requires a long time. That is, the time t
Is determined by a PID constant, and the PID constant is set so as to perform optimal control with respect to a normal speed fluctuation. It takes a longer time to stabilize than normal fluctuations. [0005] In addition, there is a certain limit to the excessive amount of rotation speed (hereinafter referred to as overshoot) θ shown in FIG. 5, and if this limit is exceeded, damage to component parts, disturbance in control, etc. There is a problem that the problem described above occurs. SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides feedback means for feedback-controlling the rotational speed of a rotary engine to a target rotational speed, and feed-forward signal detecting a disturbance. A first and a second feedback means set so that the operation amounts are different, in a rotation speed control device for operating the fuel rack control actuator by the feed forward means for sending out
Switching means for switching to one of the first and second feedback means, load detection means for detecting a load acting on the engine based on the actuator position and rotation speed, comparison means for comparing the load signal with a predetermined value, and a load signal A feed-forward means having a function generator for outputting a feed-forward signal according to the following, and an operation of adding a signal from the first or second feedback means and the feed-forward signal to generate a signal to a fuel rack control actuator. And wherein the first feedback means is set so that the operation amount is larger than the second feedback means, and the feedforward means comprises:
When the load signal exceeds a predetermined value, the switching means is switched to the first feedback means for a predetermined time, and the feedforward signal is added to the arithmetic unit. According to the above means, the feedforward means always detects a change in the load acting on the rotary engine, such as the rotational speed and the position of the actuator, as a load signal, and this load signal is compared with a predetermined value. When the load signal is equal to or less than the predetermined value, the feedforward means does not operate, and the switching means is connected to the second feedback means. By operating a rack actuator, the rotational speed of the rotary engine is controlled. When the load signal exceeds a predetermined value, the feedforward means issues a switching signal, the switching means is switched to the first feedback means, and the feedforward signal corresponding to the load signal is added to the arithmetic unit. Then, the signal is added to the signal from the first feedback means and output from the calculation unit. By controlling the rotational speed of the rotary engine by operating the actuator of the fuel rack, the delay of the settling time due to the time delay of the control system is reduced. To prevent it. An embodiment of a rotation speed control device according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, an embodiment according to the present invention comprises a first feedback means 1a and a second feedback means 1b constituting a feedback means 1, a changeover switch 2 for switching between both, and a changeover switch 2
And feed-forward means 3 for applying a feed-forward signal to the output from the changeover switch 2. The target value of the rotational speed of the rotary engine 4 is issued and transmitted from a command device (not shown). When the changeover switch 2 is connected to the first feedback means side terminal 2a, the applied target value is controlled by the first feedback means 1a, and the changeover switch 2 is connected to the second feedback means side terminal 2b. In this case, control is performed by the second feedback means 1b. First and second feedback means 1a, 1b
Detects the rotation speed of the rotary engine 4 by the detection unit 5, feeds back the detection signal to generate an operation signal from the deviation from the target value, and operates the fuel rack control actuator 6 of the engine to operate the rotary engine 4 It controls the rotation speed. These controls are controlled by PID control, and by setting different PID constants, the amount of operation of the fuel rack control actuator 6 is made different. P constituting the first feedback means 1a
The PID constant of the ID control is set for a sudden load change. That is, the PID constant is set so that the rotational speed of the rotary engine 4 returns to the target value as soon as possible when the rotational speed overshoot exceeds a predetermined value due to a sudden change in load. For example, the output of the fuel rack control actuator 6 for controlling the rotation speed is proportional to the deviation and inversely proportional to the proportional band (P). Therefore, the proportional operation is strengthened by setting the value of the proportional band (P) small. Then, the ratio of the output of the fuel rack control actuator 6 to the deviation increases, and the attenuation ratio of the deviation decreases. The shorter the integration time (I), the stronger the offset operation. The longer the differentiation time (D), the greater the output of the fuel rack control actuator 6 in proportion to the speed at which the deviation changes. Accordingly, the PID constants of the PID control constituting the first feedback means 1a are P1, I1, D1
When the PID constants of the PID control constituting the second feedback means 1b are P2, I2, and D2, respectively,
For example, if P1 <P2, I1 <I2, D1> D2 is set, the output for operating the fuel rack control actuator 6 increases in response to a sudden change in the load, so that the rotational speed becomes oscillatory. Can approach the target value in a short time. As shown in FIG. 1, for example, the feedforward means 3 includes a noise filter 8 for removing noise of the load signal sent from the load signal detecting means 7 and a change rate of the load signal from which the noise has been removed. Differentiator 9 that calculates
And a converter 10 that takes the absolute value of the change rate signal output from the differentiator 9, and compares the absolute value signal output from the converter 10 with a comparison value set in advance by a comparison value setting device 11, A comparison means 13 comprising a comparator 12 which outputs an operation signal when the value of the value signal exceeds the comparison value
An off-delay timer 14 for issuing an operation signal for switching the changeover switch 2 to the first feedback means side terminal 2a according to the output of the comparator 12;
A function generator 15 operated by the output of the second generator 2 to generate a function corresponding to the output from the differentiator 9;
A changeover switch 16 for connecting or disconnecting the output from the
An off-delay timer 17 for issuing an operation signal for switching the changeover switch 16 based on the output of the comparator 12 is provided. The function generator 15, as shown in FIG. 1, comprises a noise filter 15a and a gain 15b, operates upon receiving the output of the comparator 12, and outputs the output from the differentiator 9 as shown in FIG. As a function of
This function expresses the relationship between the operation amount of the fuel rack control actuator 6 and the output time. The operation amount and the output time are proportional to the output from the differentiator 9 and the speed / torque with respect to the load of the rotary engine 4. These are set individually according to the characteristics of the engine such as the characteristics. That is, since the characteristics are different depending on the type of the engine, it is necessary to set the operation amount and the output time according to the characteristics of each engine even if the output from the differentiator 9 is the same. The function generator 15 may be set so as to generate an output obtained by simply amplifying the output of the differentiator 9 for a predetermined time. The changeover switch 16 is connected to the comparator 12
Generates an operation signal, the off-delay timer 17 generates an operation signal for a certain period of time. At this time, the function generator 15 also receives the operation signal from the comparator 12 and generates the function shown in FIG. 2, so that the function is added to the calculation unit 18. The changeover switch 2 is also connected to the first feedback means 1 side terminal 2a by the off-delay timer 14 for a certain period of time by receiving the operation signal of the comparator 12, so that the first feedback means 1a
Is added to the signal from the function generator 15 and output to the fuel rack control actuator 6. The operation of the embodiment of the present invention having the above configuration will be described below. From the load signal input from the load signal detecting means 7, noise is removed by a noise filter 8,
Differentiated by a differentiator 9. Since the output of the differentiator 9 is the speed at which the load changes, the output increases as the load changes rapidly. The output from the differentiator 9 is output from the converter 1
The value is converted to an absolute value at 0, and is compared with the output of the comparison value setting unit 11 at the comparator 12. The comparator 12 outputs an operation signal to the off-delay timers 14 and 17 and the function generator 15 when the absolute value of the output of the differentiator 9 exceeds the comparison value of the comparison value setting device 11. Further, the off-delay timers 14 and 17
An operation signal is generated to the changeover switches 2 and 16 for a fixed time after the output signal of the comparator 12 is received. The operation signal generation time of the off-delay timers 14 and 17 is set according to the characteristics of the engine. For example, if the operation signal generation time of the off-delay timers 14 and 17 is set long, the operation signal is connected to the first feedback means 1a. The operation time of the fuel rack control actuator 6 becomes sharper because of the longer time, but for example, the rotation speed hunts because the integration time is set shorter, or the proportional band is set smaller. Because the differential time is set to be long, it becomes oscillating, and it takes time until the rotation speed is settled. Conversely, if the operation signal generation time of the off-delay timers 14 and 17 is short, the time required for the fuel rack control actuator 6 to operate sharply will be short, and the time required for the rotation speed due to load fluctuation to approach the target value will be short. It takes. The operation time of the off-delay timers 14 and 17 is determined in accordance with the output time generated from the function generator 15, but may be set to a time shorter than the output time of the function generator 15 if necessary. Is set. Off delay timer 1
When the operation time of the fuel rack control actuator 6 is adjusted to the output time of the function generator 15, the signal output from the first feedback means 1a is further loaded with a signal for operating the fuel rack control actuator 6. The amount will be larger. For example, as shown in FIG. 3, when the operation signal generation time of the off-delay timers 14 and 17 is made longer, the operation time of the first feedback means 1a which operates sharply becomes longer, and the operation of the fuel rack control actuator 6 becomes longer. The amount of operation increases. For this reason, the rotation speed is apt to be hunted easily, so that it becomes difficult to stabilize (curve a in the figure). As described above, when the off-delay timers 14 and 17 are activated by the output of the comparator 12,
When the changeover switches 2 and 16 are switched and controlled by the first feedback means 1a, the output from the feedforward means 3 is added by the arithmetic unit 18 so that the operation amount of the fuel rack control actuator 6 increases,
As shown in FIG. 3, when the load suddenly decreases, it is possible to prevent a rapid increase in the rotation speed. When the operation of the off-delay timers 14 and 17 is completed, the control system returns to the state shown in FIG. 1 and returns to the normal control state. As described above, according to the present invention, a sudden change in load is detected, and a feedforward signal of an operation amount corresponding to the amount of the change is added to the feedback signal to provide a fuel rack. By outputting the control signal to the control actuator, control delay can be prevented, and the time until a rapid change in the rotational speed stabilizes can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing one embodiment of a rotation speed control device according to the present invention. FIG. 2 is a graph showing a function output from a function generator. FIG. 3 is a graph showing a relationship between a load fluctuation and a rotation speed according to the embodiment. FIG. 4 is a block diagram showing a conventional rotation speed control device. FIG. 5 is a graph showing a function of load fluctuation and rotation speed. [Description of Signs] 1 Feedback means 1a First-stage feedback means 1b Second-stage feedback means 2 Changeover switch 3 Feedforward means 4 Rotary engine 6 Fuel rack control actuator 7 Load signal detection means 13 Comparison means 15 Function generator 18 Arithmetic unit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomio Shigaki 1-19-17 Minami-Ochiai, Suma-ku, Kobe (56) References JP-A-2-264302 (JP, A) JP-A-58-167833 (JP) , A) JP-A-63-208642 (JP, A) JP-A-1-124355 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05B 11/32 G05B 11/36 501 G05D 13/62 F02D 41/14 330

Claims (1)

(57) [Claims 1] Fuel rack control by feedback means for feedback-controlling the rotation speed of a rotary engine to a target rotation speed, and feed-forward means for detecting a disturbance and transmitting a feed-forward signal. A rotation speed control device for operating the actuator, wherein first and second feedback means set to have different operation amounts, switching means for switching to one of the first and second feedback means, an actuator position,
Load detecting means for detecting a load acting on the engine based on the rotation speed, feed-forward means comprising a comparing means for comparing the load signal with a predetermined value, and a function generator for outputting a feed-forward signal according to the load signal; , The first
Or a calculation unit that adds a signal from the second feedback unit and the feedforward signal to generate a signal to the fuel rack control actuator, wherein the first feedback unit has a smaller operation amount than the second feedback unit. The feed-forward means is set so as to switch the switching means to the first feedback means for a predetermined time and to add the feed-forward signal to the arithmetic unit when the load signal exceeds a predetermined value. A rotation speed control device characterized by being performed.