JPS59167701A - Automatic control method - Google Patents

Abstract

PURPOSE:To realize a control method where control convergence is quick and hunting is less by switching the control state with the time lag of a prescribed time when a controlled variable is shifted from a high gain control region to a low gain control region. CONSTITUTION:When the controlled variable is shifted from the high gain control region to the low gain control region, the control state is switched with the time lag of a prescribed time; and when the controlled variable is shifted from the low gain control region to the high gain control region, the control state is switched immediately. For example, the detection signal of height to ground from an ultrasonic sensor 1 is inputted to an operating part 7 of a controller 3 of a combine through an input interface 5, and the difference between this signal and a preliminarily set target value is operated as the controlled variable. The control mode is set to the low gain control region if this controlled variable is within a prescribed range of height to ground; and the control mode is set to the high gain control region if the controlled variable is outside said range, and a control signal is sent to a solenoid valve 6 through an output interface 4.

Description

[Detailed Description of the Invention] The invention is an automatic control method, and more specifically, a dual method that performs low gain control on the base circle when the controlled amount is within the range including the target value, and performs high gain control when it is in other ranges. This invention relates to an automatic gain control method.

Conventionally, this type of automatic control method performs low gain control to prevent hunting when the controlled variable is close to the target value, and responds when the controlled variable is in the vicinity of the target value. In order to reach the target value, control is often performed by switching the control gain, such as performing high gain control.

However, in the conventional dual gain automatic control method described above, switching between low gain control, high gain control, and control is simply based on the comparison result between the control amount and the target value, and the control amount is within a range of the target value needle/side. When the value falls within K, the control gain is immediately switched to low gain control, and when the value falls within a range other than this target value, the control gain is immediately switched to high gain control. In other words, the control response is good until the controlled variable reaches around the target value, but from around the target value it does not match the target value or not.
Since the control convergence until a one-point coincidence is performed by the low gain control VC, there is a drawback that overshoot occurs and the convergence takes a long time or the response time for convergence becomes long.

This invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an automatic control method that achieves rapid control convergence and reduces hunting.

In order to achieve all of the above objects, the uninvented automatic control method is such that when the control amount shifts from the above-mentioned no-gain control region to the low-gain control region, the control amount is changed from the no-gain control 1 state with a certain time lag. The present invention is characterized in that when the first control period shifts from the low gain control region to the no gain control region, the low gain control state is immediately switched to the high gain control state.

Upper Bc2. T+! Because of the f-characteristic structure, the above-mentioned excellent effect has been achieved. The control amount converges with respect to the value reliably and quickly, and after that, low gain control is performed and the control stabilizes without causing hunting after the target value is reached, and the transition from the low gain control region to the no gain control region When the control amount shifts, the control is immediately switched to high gain control, so even if the control amount deviates from the target value, the control response does not worsen. Description0 This embodiment shows an example in which the automatic control method according to the invention is applied to cutting height control in a combine harvester.

The cutting height control in this embodiment (basically,
The height above the ground is repeatedly measured using an ultrasonic sensor (1) attached to the back of the reed splitter installed at the tip of the reaping part, and this measurement result is compared with the target set in advance. This is done by comparing the measured height above the ground with a predetermined height above the ground and controlling the reaping section to move up and down using the hydraulic cylinder (2) so that the measured height above the ground matches the target value. (The structure is not shown.) As shown in Figure 1, the main part of the control system is composed of a microcomputer, and the control system (4) of the control device (3) receives the information from the ultrasonic sensor (1). The height above ground detection signal (however) is input via the input interface (5), and the difference between the suitable height above the ground set in advance and the target value (Ho) of i~ is controlled (;(( (A), and output the result as a control signal to the electromagnetic pulp (6) that operates the hydraulic cylinder (I).
7) It is configured to be output via -e.

Then, as shown in Fig. 2, if the control amount (Δ) is within a predetermined height above the ground range (c) that includes the target value (1), the control is basically performed to perform low gain control. Set the flag (MODE) that determines the mode to all 0.

On the other hand, if the control center (7) is located in a region (B) outside the predetermined height above the ground region (A), the flag (MODE)'? Set to '/2'.
Further, the control amount (the amount of control changes from the region (B) to the region (A)
If the transition is made, set all the flags (MODE) to "1', check the elapsed time (T)', and wait for the predetermined time c.
After T, ) has elapsed, the flag (MODE) is switched to 0.

The switching of each control gain of the low gain control and high gain control is performed by the value of the flag (MODE), and the cycle of the pulse current as a control signal for fully driving the electromagnetic valve (6) is also controlled by the decoupling. It is configured to be controlled by changing the ratio.

FIG. 3 is a flowchart showing the operation of the control device that completely determines the control amount and control gain described above.

[Brief explanation of drawings]

The drawings show an embodiment of the automatic control method according to the invention, and the first
Figure 2 is a block diagram of the control system for cutting height control in a combine harvester, Figure 2 is an explanatory diagram of cutting height control, and Figure 3 is an explanatory diagram of cutting height control.
The figure is a flowchart showing the operation of the control device. (4... Control amount, (A)... Low gain control region, (B)... High gain control region,
(T,)...Time lag.

Claims (1)

[Claims] This is a dual gain automatic control method in which low gain control is performed on the basic circle when the control amount (Δ) is within a region (A) including the target value (Ho), and high gain control is performed when it is in another region (B). Then, the control amount (Δ) changes from the high gain control region (Bl) to the low gain control region (B1).
When transitioning to A), there is a certain time lag (T,
), the high gain control state is switched to the low gain control state, and on the other hand, when the control amount (the control amount) shifts from the low gain control region (A) to the high gain control region (B), the low gain control state immediately changes to the high gain control state. An automatic control method characterized by switching.