JPH0132817Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to working machines such as agricultural machines and construction/civil engineering machines, and more particularly to working machines having a hydraulic drive device that is intermittently driven by pulse commands. An example of this type of working machine is a combine harvester as shown in FIG. This type of combine harvester runs while constantly detecting the deviation of the machine relative to the grain culm row using a contact sensor for the grain culm row.
Based on the deviation detection result, the steering is performed by applying a brake to either the left or right traveling device 1, which is a hydraulic drive device, so that the vehicle can automatically follow the grain culm row. , and the braking is normally performed by intermittent driving based on a pulse command of a predetermined duty ratio. However, in such an automatic control mechanism using intermittent hydraulic drive, the responsiveness varies greatly depending on factors such as oil temperature, manufacturing variations in piping systems such as valves, or hydraulic drive devices. If the command duty ratio is fixed, there is a drawback that sufficient control performance cannot be obtained. The present invention was devised in view of the above-mentioned conventional drawbacks, and its purpose is to automatically adjust the pulse command duty so that the hydraulic drive device can always be operated for the time necessary for appropriate control. The purpose is to be able to adjust the ratio. First, an embodiment of the present invention will be described based on the drawings. FIG. 1 shows an overall schematic side view of a combine harvester as an example of a working machine according to the present invention. 3 is provided. The left and right crawler traveling devices 1, 1 are configured to be driven by a hydraulic motor (not shown) as a hydraulic drive device, and by driving both the left and right ones, It is configured to travel straight, turn left by applying the brake to the left object, and turn right by applying the brake to the right object. The braking is configured to be performed by intermittent driving based on pulse commands, as will be described later. The turning by braking can of course be performed manually, but as shown in FIG. The system is also configured to constantly detect the deviation of the grain relative to the grain culm row, and to perform automatic steering operations based on the detection results. The grain culm position detection sensor 5 is composed of a sensor box 5a and a grain culm row contact bar 5b which is attached to the sensor box 5a so as to be able to swing in the front and back direction. The position of the grain culm row relative to the aircraft body can be classified and identified into four ranges depending on the amount of oscillation. That is, three sets of switches S-LL, S-LR ₁ and S-LR ₂ , which are turned on and off as the contact bar 5b swings, are built into the sensor box 5a, as shown in the diagram below.

As shown in the table, when the grain row is in the range of , S-LL is ON, S-LR ₁ is OFF, and S-LR ₂ is
turns ON, and at this time the left turning solenoid is activated.
When it turns on, a pulse command for a left turn is issued, and the aircraft begins to turn left. Grain culm rows,
Similarly, the state and operation of each switch when the switch is in the range of . FIG. 3 is an example of a time chart during turning, and shows the state of control when the grain culm row changes from the range to the range. That is, at this time, switch S-LR ₂ maintains the ON state and switch S-LL maintains the OFF state, while switch S-LR ₁ switches from OFF to ON to command a right turn. A pulse is emitted at a predetermined duty ratio (t ₂ /T). Then, based on this pulse command, the hydraulic motor as a hydraulic drive device starts operating, and there is a certain start-up time delay.
After t ₀ ′, it is driven under constant oil pressure for t ₂ ′ (=t ₂ −t ₀ ′). The actual oil pressure during this drive is measured by a switch (12 in Figure 4) as an oil pressure detection sensor installed, for example, in the brake case or at an appropriate location in the piping system, and as a result, the oil pressure exceeds a certain level. The time t ₂ ′ at which this occurs is now detected. If this actually measured time t ₂ ' is shorter than the theoretical time τ ₂ which is preset by being stored in the microcomputer as shown in the figure,
The duty ratio of the next pulse command is (t ₂ + Δt)/T
The configuration is such that the actual measured time is automatically adjusted so as to approach the theoretical time τ ₂ by increasing the value as shown in FIG. Conversely, if the measured time t ₂ ' becomes longer than the theoretical time τ ₂ , the next pulse duty ratio is automatically adjusted to be smaller as (t ₂ −Δt)/T. FIG. 4 schematically shows the main part of the hardware configuration of a control circuit for performing such automatic adjustment, and FIG. 5 is a control flowchart thereof. In Fig. 4, 6 is a power battery;
7 is a key switch as a power switch,
This power supply 6 is connected to a voltage regulator 8 through a constant voltage device 8.
CPU (central processing unit), I/O (input/output interface), ROM (read-only memory) and
RAM (Random Access Memory) is connected,
The power source 6 also includes a threshing switch 9, a reaping switch 10, an automatic switch 11, a grain culm position detection sensor 5, and switches S-LL, S-LR ₁ ,
S- _LR2 , oil pressure detection switch 12, and manual priority switch 13 are connected. And each of these switches 9, 10, 11, S-LL, S-
The outputs of LR ₁ , S-LR ₂ , 12 and 13 are the I/O
and is processed by the CPU according to the flowchart shown in FIG. In this flowchart, (i) is a step for checking the status of various switches necessary for automatic control and checking the selection of automatic control or manual control; (ii) is a step for checking the status of various switches necessary for _automatic control; Step (iii) is a step for determining the turning direction based on the status determination of LR ₁ and S-LL; (iii) is a step for issuing a turning command; and the subsequent steps are based on the actual measurement time t ₁ ' by the oil pressure detection switch 12. (for a left turn), t ₂ ′ (for a right turn), and the theoretical time τ ₂ and one pulse cycle time T, the duty ratio of the next pulse (t ₂ /T), ( This is a step for determining t ₁ /T). As is clear from the flowchart, this decision is made on the premise that the following restriction is satisfied: τ ₂ −Δτ≦t ₁ ′ (t ₂ ′)≦τ ₂ +Δτ O≦t ₁ (t ₂ )≦T It is something that can be done. In the above embodiment, the pattern of the actual oil pressure change is determined based on the oil pressure duration time t ₁ ′ (t ₂ ) in which the oil pressure is higher than a predetermined pressure among the changes in the actual oil pressure, and the duty ratio of the next pulse is adjusted based on the pattern. However, the adjustment may be made by determining the pattern of actual oil pressure change based on the rise delay time t ₀ '. Although a travel device is illustrated as the pulse-controlled hydraulic drive device 1, various types of devices can be used, such as a pulse-controlled hydraulic drive device for adjusting the handling depth in a combine harvester. In summary, the work machine according to the present invention is equipped with a sensor that measures the actual oil pressure change in the hydraulic drive device that operates in response to a pulse command, and the actual oil pressure change that corresponds to one pulse command detected by the sensor. The present invention is characterized in that it is provided with a control device that automatically adjusts the duty ratio of the next command pulse based on the result of determining the pattern (for example, the duration of oil pressure equal to or higher than a predetermined value). With this characteristic configuration, it has become possible to automatically adjust the actual oil pressure change so that it is always in the desired state suitable for automatic control, regardless of pressure oil temperature or manufacturing variations in equipment. .

[Brief explanation of the drawing]

The drawings show an embodiment of the working machine according to the present invention, and FIG. 1 is an overall schematic side view of a combine harvester, and FIG.
3 is a diagram showing an example of a time chart during turning, FIG. 4 is a schematic diagram of the main part of the control device, and FIG. 5 is a control flow chart thereof. 1... Hydraulic drive device, 12... Oil pressure detection sensor.

Claims (1)

[Scope of utility model registration request] A work machine having a hydraulic drive device that is intermittently driven by a pulse command, and a sensor for measuring an actual oil pressure change in the hydraulic drive device that operates in response to the pulse command is provided, and the sensor detects a change in the actual oil pressure. 1. A working machine comprising a control device that automatically adjusts the duty ratio of the next command pulse based on the pattern discrimination result of the actual oil pressure change corresponding to one pulse command.