JPH0665248B2 - Distance detection method using wave type sensor in mobile agricultural machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a distance detection method using a wave type sensor,
Specifically, a wave type sensor such as an ultrasonic sensor is provided in the front part of the machine body of a combine farm or other mobile agricultural machine, and the reception part of the sensor receives the reflected wave from the grain stem of the wave generated diagonally forward from the transmission part of the sensor. The present invention relates to a distance detection method used for direction control of a mobile agricultural machine, which measures a round trip time of a wave to detect a distance between a sensor and a grain culm, and corrects and controls the direction of a machine body according to the distance.

(B) Conventional technology Conventionally, the direction control at the time of mowing work of a mobile agricultural machine such as a combine is performed by installing a grain culm sensor in a divider in the front part of the machine body, and detecting the contact of the grain culm with the grain culm sensor, thereby making The relative distance to the grain culm was detected, and based on that, the orientation of the aircraft was corrected so as to be along the row or line of grain culm, but with this one the control method that could not predict the planting condition in the front Therefore, depending on the condition of planting, the line could be cut off and the grain culms could not be properly cut along the line. Therefore, instead of the distance detection method by mechanical contact, the distance is measured by using the reflection phenomenon of waves such as ultrasonic waves, light, or radio waves, and the direction control of the mobile agricultural machine is performed while predicting the front planting state. The method of performing is recently put into practical use.

(C) Problems to be solved by the present invention By the way, in the distance detection method using the above-described wave reflection phenomenon, for example, when ultrasonic waves are used, ultrasonic waves are transmitted and reflected by the grain culms, Since it was a method that faithfully counts the round-trip time of ultrasonic waves until it is received and detects the distance based on it, the measurement circuit becomes extremely complicated, and it is also applicable to direction control of mobile agricultural machines. Was too precise and expensive.

(D) Means for Solving the Problems The present invention aims to solve the above-mentioned problems,
A measurement pulse signal generating means 30 for generating a predetermined measurement pulse signal E ₁ , ... By receiving the reflected wave by the object, and a first time T ₁ from the time when the wave is transmitted until the first time T ₁ elapses.
First reference signal generating means 22 for generating the reference signals F ₁ , ...
And second reference signal generating means 23, 25, 26, 27 for generating the second reference signals I ₁ , ... After the lapse of the second time T ₂ after the first time T _1. The first comparison means 31a for comparing the first reference signal F ₁ , ... And the measurement pulse signal E ₁ , ..., The second reference signal I ₁ , ... And the measurement pulse signal E ₁ ,. And a second comparing means 31b for comparing
Of the measuring pulse by the comparing means 31a and the second comparing means 31b of the above, until the first time T ₁ elapses from the time when the wave is transmitted or after the second time T ₂ elapses. signals E _1, it is determined whether or not ... has occurred, the measurement pulse signal E _1, ... is to detect the distance between the sensor and the object by the time zone generated, is characterized by.

(E) Action By adopting the above-mentioned means, when the wave type sensor installed in the divider is approaching the grain culm, that is, the object when cutting with a combine, for example, the measurement pulse generated by the reception of the reflected wave by the grain culm. Since the signals are generated within the time T ₁ during which the first reference signal is generated, it is detected and output by these signals that the sensor is close to the grain stem. Similarly, when the sensor is separated from the grain stalk by a predetermined distance or more, the measurement pulse signal is generated after the time T ₂ when the second reference signal is generated, so that the sensor causes the grain culm to be detected by these signals. It is detected that there is a long distance apart from and is output. Then, when the sensor is located at an appropriate distance with respect to the grain culm, the measurement pulse signal is within the time T _{1 to} T ₂ in which the first reference signal and the second reference signal are not generated. Because it occurs in
Each of the above outputs is not generated, and the sensor detects that it is at an appropriate distance from the grain culm.

(F) Examples Hereinafter, examples in which the present invention is embodied will be described.

As shown in FIG. 1, the combine 1 has a pre-processing unit 6 in which a divider 3, a grain culm raising device 5 and the like are arranged in the front part of the machine body 2. Inside the divider 3 on the side, as shown in FIG. 4, ultrasonic waves for measuring the distance to the grain stem so that the combine 1 is controlled along the grain lines I, II .. Sensor 7
Is installed to emit ultrasonic waves diagonally forward. The sensor 7 is composed of a transmitter 9 having a sounding body that emits ultrasonic waves, and a receiver 10 having a microphone that receives the ultrasonic waves reflected by the grain stems. The section 10 is housed in each of the tubular tubes 11 and 11 so as to be protected from adhesion of water droplets and dust, and to prevent diffused reflected ultrasonic waves from being received by the receiving section 10 and to improve directivity. It is configured. Further, as shown in detail in FIG. 2, a guide body 12 is attached to the tip ends of the cylindrical pipes 11 and 11 so as to substantially coincide with the guide direction of the divider 3 with respect to the grain culm. The culm or the like hits the sensor 7 so that the set angle of the sensor 7 does not change, or the grain culm guided by the divider 3 is caught by the sensor 7 so that the flow of the grain culm is not disturbed. Further, the sensor 7 can be attached to the rear of the raising device 5 so that the mounting angle of the sensor 7 can be adjusted with respect to the divider 3 by an appropriate mechanism, and the sensor 7 can be removed from the divider 3 when necessary and shown by a chain line in FIG. The position of the divider 3 with respect to the grain culms can be easily changed by each of them, and it is possible to cope with a field having many spilled grain culms.

Then, the transmitter 9 and the receiver 10 of the ultrasonic sensor 7 described above.
Is connected to a control unit 16 as shown in FIG. 5 which is housed inside the operation panel 15 in front of the control unit 13 of the combine 1 so that the distance between the grain stems can be measured and the direction of the machine body 6 can be controlled. It has become.

Hereinafter, the configuration and operation of the control unit 16 will be described mainly with reference to FIGS. 5 and 6.

By the drive of the oscillator 17, the ultrasonic wave signals C ₁ , C _2, ... Of a frequency suitable for detecting the grain culm are transmitted from the transmitter 9, and at that time, the ultrasonic wave signals C ₁ , C _{2 ,} . T ₀ and transmission duration t ₀ are the signal A of the multivibrator 19 and the monostable multi, respectively, in consideration of the inter-plant distance l of the grain culm to be detected (see FIG. 4) and the traveling speed of the combine 1 at the time of cutting. It is set by the signal B of 20. In addition, the ultrasonic wave transmission angle θ (see FIG. 4) is also the ultrasonic wave signal that is transmitted in consideration of the inter-plant distance l of the grain stem to be detected and the traveling speed of the combine 1 at the time of cutting.
The angles are set so that C ₁ , C _2, ... Are constantly reflected by the grain culms to be detected. On the other hand, during the period from the transmission of the ultrasonic signals C ₁ , C ₂ , ... Until the predetermined time (first time) T ₁ elapses, the monostable multi (first reference signal generating means) 22 is used. First reference signals F ₁ , F ₂ , ... Are generated. As shown in FIG. 6, the first reference signals F ₁ , F ₂ , ... Have a waveform that is turned off only during a predetermined time T ₁ . Further, similarly, the monostable multi 23 forms signals G ₁ , G ₂ ... Which are turned off for a time T ₂ after the start of the ultrasonic signals C ₁ , C _{2 ,} .
Are formed by the signals H ₁ , H ₂ , ... Which are turned off from the time when the ultrasonic signals C ₁ , C ₂ , ... Are transmitted until the predetermined time T ₃ elapses.
The signals H ₁ , H ₂ , ... Are synthesized by passing the signals G ₁ , G ₂ , ... Inverted through the inverter 26 and the signals G ′ ₁ , G ′ ₂ ,. As shown in FIG. 6, the second reference signal I _{1 is} turned off from the time ( _second time) T ₂ after the predetermined time T ₁ has elapsed to the time (third time) T _{3 has} elapsed. , I ₂ , ... Is formed. That is, the above-described monostable multi-circuits 23, 25, the inverter 26, and the OR element 27 constitute second reference signal generating means for generating the second reference signals I ₁ , I ₂ , .... The above times T ₁ , T ₂ and T ₃ are convected to the setting of the distance range of the divider 3 with respect to the grain lines to be detected, and the dial on the operation panel 15 is operated to change the setting appropriately. I'm supposed to get it. Further, in the time chart of FIG. 6, the time T ₀ is shown to be relatively short with respect to the times T ₁ , T ₂ , and T ₃ , but this is for convenience of illustration only, and the time T ₀ is actually shown. Is sufficiently longer than the time T ₃ etc. (for example, T ₀ ≧ 2T ₃ ), and the time T ₁ , T ₂ , T ₃ is, for example, T ₁ = T ₃ −T ₂ = 3 (T ₂ −T ₁ ). Have a relationship. Then, the transmitted ultrasonic signals C ₁ , C _2, ... Are reflected by the grain culms of the strip to be detected, and the ultrasonic signals C ₁ , C _{2 ,} .
After the time T _X from the time when the signal is transmitted, the reception signals D ₁ , D ₂
However, since the signals D ₁ , D ₂ ... are attenuated and have an irregular waveform while propagating in the air, they are amplified and amplified by the amplifier 29 and the detection / waveform shaper 30.
After being shaped, the measurement pulse signals E ₁ , E _2, ... In the off state having a predetermined width are formed as shown in FIG. Thus
The generated measurement pulse signals E ₁ , E ₂ ... Are input to the first AND element 31a and the second AND element 31b, respectively,
In the first AND element 31a, it is compared with the first reference signals F ₁ , F ₂ ... And in the second AND element 31b, it is compared with the second reference signals I ₁ , I ₂ . It

When the combine 1 is used for cutting, the divider 3 is closer than the distance set to the grain I of the grain culvert as shown by the solid line a in FIG. 4 (see the Y line corresponding to the time T ₁ ). If there is, the ultrasonic signal C ₁ transmitted from the transmitter 9
Is reflected by the grain culm Ia, and the measurement panel signal E ₁ is generated within the generation time 0 to T ₁ of the first reference signal F ₁ as shown in FIG. The AND element 31a determines the approaching state of the divider 3 and
A pulse signal J indicating the approaching state is output from the AND element 31a. The pulse signal thus generated is expanded to a predetermined time width by the monostable multi-unit 32a, then amplified and then input to, for example, the clutch solenoid SL for controlling the direction of the combine 1, and the combine 1 is connected to the grain stem. Article I
In order to maintain a proper distance with respect to, the turning control is performed in the direction away from the grain culm. Similarly, the divider 3 sets the separation distance range set for the grain I of the grain as shown by the one-dot chain line b in FIG. 4 (line roll, line ha corresponding to time T _{2 to} T _3). (Range covered by), the measurement pulse signal
E ₂ is the generation time T _{2 of the second} reference signal I ₂ as shown in FIG.
To be generated in ~T _3, it is determined that their separated state of the divider 3 by the second AND element 31b by the off state, a pulse signal K indicating the separating state is output, the pulse signal K is monostable It is expanded to a predetermined time width by 32b, and after being amplified in the next, input to solenoid SLl,
The combine 1 is controlled to turn so as to approach an appropriate distance.
Next, when the divider 3 is in the proper distance range (the range between the line Y corresponding to the time T _{1 to} T ₂ and the line rolling),
Since the measurement pulse signal E ′ ₁ (see FIG. 6) is generated during the time T _{1 to} T ₂ when the first reference signal F ₁ and the second reference signal I _{1 in} the off state are not present, The AND element 31a and the second AND element 31b do not output any control pulse,
Therefore, the combine 1 is not controlled by any direction and the grain I
Keep straight along. In this case, even if the divider 3 is located within the proper distance range as shown by the solid line c in FIG. It goes without saying that the turning control is executed. In addition, the divider 3 is not controlled by the distance (time T ₃
, The measured pulse signal E ″ ₁ (see FIG. 6) is again the off-state first reference signal F ₁ and second reference signal I. ₁ is generated after time T _{3 when} it does not exist, so that combine 1 maintains the straight traveling state. The above description is provided for the sake of convenience, and the above control is actually performed by divider 3 in the case of a grain stem. When traveling straight along the appropriate distance range along I, for example, the grain culm Ia of Article I is missing and the ultrasonic signal passes through Article I and detects the adjacent grain cultivar IIa of Article II. If it does, or if the ultrasonic signal is diffusely reflected and received by the receiving unit 10 with a considerable delay, it is executed.

In addition, in this example, the combine 1
, The second reference signals I ₁ , I ₂ ... Are generated from time T _{2 up} to time T ₃ corresponding to the set distance range after time T _{1 in} order to prevent erroneous direction control. Although described as a signal, in order to identify and detect the distance from the sensor 7 to the grain culm, that is, the object into three sections of short distance, proper distance and long distance, the second reference signals I ₁ and I ₂ described above are used. … Time T
_It may be a signal generated after ₁ and after time T ₂ .

Further, in the present embodiment, the one in which the direction of the combine is detected by detecting the distance to the grain culm by the sensor is disclosed,
In the above method, the sensor is installed at an appropriate place in the pretreatment unit 6,
It can also be applied to cutting height control.

(G) Effect of the Invention As described above, according to the present invention, as a method for determining whether or not the distance between the sensor grains is within a predetermined range,
After the reference signal F ₁ , ... Is generated for a predetermined time (for example, T ₁ ) with respect to the time point when the wave is transmitted, the reference signal F
_1, ... and the measurement pulse signal E _1, the measurement pulse signal E ₁ within the predetermined time by comparing ... and, since ... has adopted a method of determining whether generated easily using only gate element The circuit can be configured, which facilitates integration, resulting in small size and low cost. That is, when the time difference between the generation time of the measurement pulse signal E ₁ , ... And the wave transmission time is calculated and then the time difference is compared with the reference signal, an integrating circuit such as a pulse width voltage converter is required. However, since it is necessary to take timing with respect to the pulse signal, the circuit configuration becomes complicated, and if the timing is deviated, an accuracy error occurs, but since the present invention does not require such an integrating circuit, The circuit configuration is simple and there is no accuracy error.

Further, the time for generating the first reference signal F ₁ is T ₁ , the time for generating the second reference signal I ₁ is time T ₂ or later, and the time T ₂ is later than the time T _1. , Even more time
T _{1 to} T ₂ were set as appropriate time (appropriate distance). That is, since this appropriate time (appropriate distance) has a certain width, it is possible to perform distance detection and control in accordance with practical use. For example, even if the distance detection method is applied to the direction control of a mobile agricultural machine, the appropriate distance acts as a kind of dead zone, and therefore there is no problem that the mobile agricultural machine or the like is finely direction-controlled and the riding comfort is deteriorated.

Furthermore, when the above measuring method is applied to the direction control of the combine, when the detected distance is a short distance and a long distance, the direction can be controlled so that the aircraft is directed to an appropriate distance, and the detected distance is When the vehicle is at an appropriate distance, it becomes possible to move the aircraft straight.

[Brief description of drawings]

FIG. 1 is a partial plan view of a mobile agricultural machine to which the present invention is applied,
The figure shows a side view of the sensor seen from the direction of the arrow X in FIG.
FIG. 4 is a partial side view of the pretreatment unit as seen from the direction of arrow Y in FIG. 1, FIG. 4 is a diagram showing the positional relationship between the sensor on the divider and the grain stem, and FIG. FIG. 6 is a block diagram showing an example, and FIG. 6 is a time chart of each signal in the control block shown in FIG. 7: Wave type sensor, 9: Transmitter, 10: Receiver, 22
...... First reference signal generating means (monostable multi), 23 ……
Second reference signal generating means (monostable multi), 25 ... Second
Reference signal generating means (monostable multi), 26 ... Second reference signal generating means (inverter), 27 ... Second reference signal generating means (OR element), 30 ... Measuring pulse signal generating means (detection) .Waveformer, 31a ... first comparing means (first
AND element), 31b ... second comparing means (second AND element), C ... transmitting signal, D ... reception signal, I, II ...
Object (cereal stalk), E ... measurement pulse signal, F ... first
Reference signal, I ... second reference signal

Claims (1)

[Claims] 1. A distance in a mobile agricultural machine in which a wave reflected from an object such as a grain culm of a wave emitted from the wave sensor is received by the wave receiver and the distance between the sensor and the object is detected. In the detection method, a measurement pulse signal generating means for generating a predetermined measurement pulse signal by reception of a reflected wave by the object, and a first pulse until a first time elapses from the point of time of transmitting the wave.
The first reference signal generating means for generating the second reference signal, and the second reference signal generating means for generating the second reference signal after the passage of the second time after the first time. A first comparing means for comparing the first reference signal with the measurement pulse signal; and a second comparing means for comparing the second reference signal with the measurement pulse signal. By the comparison means and the second comparison means,
It is determined whether the measurement pulse signal is generated until the first time elapses from the time when the wave is transmitted or after the second time is elapsed, and the measurement pulse signal is generated. A distance detection method using a wave-type sensor, wherein the distance between the sensor and the object is detected according to the time zone.