JP3599498B2 - Guidance control device for mobile vehicles - Google Patents

Description

【００５０】
そして、作業車を次の走行経路ｋの始端部に移動させた後に、自動誘導制御が開始されるが、図１０に示すように、それに先立って、先ず、現走行経路用の磁界検出部ＧＫ_１ として機能する側部磁界センサ（図１の場合には左側のセンサ１３Ｌ）を初期設定する（ステップ１）と共に、その走行経路において適用される前記制御定数を設定する（ステップ２）。
この制御定数の設定について説明を加えると、現在の走行経路の始端部における左右側部磁界センサ１３Ｒ，１３Ｌの夫々の検出値の差分値Ｚｎを求め、この差分値Ｚｎと、前記初回走行経路における差分値Ｚ_１ 並びに前記基準制御定数Ｇ_１ に基づいて、下記〔数２〕に基づいてこの走行経路における制御定数Ｇｎを算出する。尚、前記各差分値Ｚｎ，Ｚ_１ は夫々、各走行経路において設定サンプリング時間毎にサンプリングされた複数の検出値の平均値として算出するようにしている。
【００５１】
【数２】
Ｇｎ＝（Ｚ_１ ／Ｚｎ）・Ｇ_１
【００５２】
このような制御定数の設定は各走行経路毎に、その経路の始端部において実行されることになる。
【００５３】
そして、作業用の走行速度で作業車Ｖを走行させながら、前記メモリＭに記憶される磁界検出情報と、走行距離センサ１０の検出情報とに基づいて、走行経路ｋ上の現時点における磁界の強さの目標値を求めて、現走行経路用の磁界検出部ＧＫ_１ として機能する側部磁界センサ１３Ｌの検出値と前記目標値との偏差に制御定数を乗じて操向操作量を求め、この操向操作量になるように、操向用電動モータ９を駆動制御する（ステップ３）。
この誘導走行制御が実行される際に、次走行経路用の磁界検出部ＧＫ_２ として機能する次走行経路側の側部磁界センサ（図１の場合には右側のセンサ１３Ｒ）の検出情報を走行距離センサ１０の検出情報と対応させた状態で、メモリＭに逐次書き込み記憶させる（ステップ４）。
【００５４】
中央磁界センサ１４の検出情報に基づいて、走行経路ｋの終端部に達したことが検出されると、走行経路数ｎをカウントアップし（ステップ５，６）、カウント値が圃場１内での設定経路数ｎｓに達していなければ（ステップ７）、前記メモリＭに書き込み記憶された磁界の強さの最大値Ｘｍが、ゲイン調整用設定上限値Ｓ_ＧＭを越えていれば、現行のゲインよりも１段低いゲインの増幅器が選択されるようにアナログスイッチＡＳ_４，ＡＳ_５ に対して選択信号を指令して、出力ゲインが下げ側に変更される（ステップ８，９）。前記最大値Ｘｍが、ゲイン調整用設定下限値Ｓ_ＧＬを下回っていれば、現行のゲインよりも１段高いゲインの増幅器が選択されるように、アナログスイッチＡＳ_４，ＡＳ_５ に対して選択信号を指令して、出力ゲインが上げ側に変更される（ステップ１０，１１）。尚、このように出力ゲインが変更された場合には、前記制御定数も変更量に対応して適宜修正されることになる（ステップ１２，１３）。
【００５５】
このようにして、磁界の強さの検出値や出力ゲインの変更状況に応じて、常に適切な制御定数にて電動モータを駆動制御するようにして、制御のハンチングや検出誤差の発生を極力、抑制するようにしている。
【００５６】
次に、現走行経路用の磁界検出部ＧＫ_１ として機能する側部磁界センサを、反対側のもの（右側のセンサ１３Ｒ）に切り換える（ステップ１４）。車体の向きの変化によりそれらの位置関係が反転するからである。
【００５７】
次に、車体を次走行経路ｋの始端部に位置させるべく回向走行させる旋回制御を実行する（ステップ１５）。
図１３（イ）に示すように、走行経路ｋの終端位置から設定距離だけ操向操作を中立状態に維持したままで直進走行させた後に、方位センサ１１をリセットして、車体の方位が１８０度反転したことが検出されるまで、最大切れ角にて旋回走行させ、その後、中央磁界センサ１４の検出情報に基づいて次の走行経路ｋの始端部に達したことが検出されるまで直進走行させる（ステップ１６）。
【００５８】
尚、次の走行経路の経路始端側箇所では、図１３（ロ）に示すように、現走行経路ｋ用の磁界検出部として機能する側部磁界センサの検出情報と、前記メモリＭに記憶されている記憶情報とに基づいて、次走行経路に沿う状態になるように車体を旋回しながら前進させて幅寄せを行う必要があるが、このとき、次走行経路用の磁界検出情報が、屈曲した状態となるが、この領域においては、初回走行経路の検出情報と、上述したような磁界変化具合の検出情報とに基づいて、適正な状態に補正するようにしている。その後、その走行経路に沿わせる状態で誘導走行制御を実行することになる。
【００５９】
そして、前記中央磁界センサ１４の検出情報に基づいて、次の走行経路ｋの始端部に達したことが検出された後に、現走行経路用の磁界検出部ＧＫ_１ の検出値と目標値（記憶情報）との偏差が設定範囲内に収まってから設定時間経過して、安定したときに、上述したような制御定数の設定を実行する。つまり、現在の走行経路における左右側部磁界センサ１３Ｒ，１３Ｌの夫々の検出値の差分値Ｚｎと、前記初回走行経路における差分値Ｚ_１ 並びに前記基準制御定数Ｇ_１ に基づいて、上記〔数２〕に基づいてこの走行経路における制御定数Ｇｎを算出する。尚、現走行経路における前記差分値Ｚｎは、始端側での検出情報に基づいて算出されることになる。
【００６０】
以後、上述したような誘導走行制御を実行するが、このとき、ステップ９，１１にてゲインが変更されていれば、メモリＭに記憶されている検出情報に対しても、変化量に対応したゲインを掛けて走行用目標値を求めることになる。
そして、ステップ２〜１５を繰り返して、各走行経路ｋに沿わせて順次、作業車Ｖを誘導走行させ、設定経路数ｎｓに達すると制御が終了する（ステップ７）。
【００６１】
現走行経路ｋにおいては、前回走行経路ｋを走行する際に記憶されている磁界の強さと現走行経路ｋでの検出磁界とが同じになるように制御され、しかも、前記各側部磁界センサ１３Ｒ，１３Ｌの設置間隔は、ロータリー耕耘装置６の対地作業幅よりも幅狭に設定されているので、ロータリー耕耘装置６による作業領域が各走行経路ｋでラップすることになり、未作業領域が発生しないようになっている。又、各側部磁界センサ１３Ｒ，１３Ｌの設置間隔を変更調整自在に構成されている。
【００６２】
〔別実施形態〕
（１）上記実施形態では、圃場１の長尺方向に沿う両側の畦に沿って設置される各誘導線２ａ，２ｃが畦を囲うようにループ状に設置される場合を例示したが、短尺方向に沿う両側の畦に設置される各誘導線２ｂ，２ｄを、畦を囲うようにループ状に設置する構成としてもよい。
そして、各予定走行経路に沿わせる移動車の誘導走行制御、並びに、各予定走行経路の端部を検出する制御の夫々に磁界検出情報を用いる上記実施形態の構成に代えて、いずれかの制御にのみ磁界検出情報を用いてもよい。
【００６３】
又、この場合、誘導走行制御にのみ用いる場合、端部検出の構成として、例えば、経路端部にて横方向にレーザー光を照射させて、このレーザー光を検出するセンサにて経路端部を検出するようにしてもよく、又、地上に固定の制御部から無線情報にて経路端部に至ったことを移動車側に指令する構成等、各種の構成にて実施してもよい。
【００６４】
そして、端部検出にのみ、磁界検出情報を用いる場合には、移動車の誘導制御として、走行経路に沿わせてレーザー光を照射させて、このレーザー光を検出するセンサにて常にレーザー光を検出するように誘導走行させる形態としてもよく、又、無線操縦による誘導制御であってもよい。
【００６５】
（２）上記実施形態では、ゲイン調整手段として、４段階の増幅率に切り換える構成としたが、段数を変更してもよく、又、増幅率の段数を変更して実施してもよく、更に、増幅率を無段階に変更調整する構成としてもよい。更に、このような出力ゲインの自動調整を行わない構成としてもよい。
【００６６】
（３）上記実施形態では、誘導対象エリアの左右両側に誘導線が設置される場合を例示したが、片側にのみ誘導線が設けられる構成としてもよく、この場合において、誘導走行制御は、誘導線に近い方の走行経路から順次、遠い側の経路に誘導させてもよく、誘導線に遠い方の走行経路から順次、近い側の経路に誘導させてもよい。
【００６７】
（４）上記実施形態では、移動車として四輪型で左右前輪が操向揺動自在に設けられる構成としたが、四輪全てが操向揺動自在に設けられて、前後車輪が互いに異なる方向に揺動する小旋回半径での旋回を行う形態や、前後車輪が同じ方向に揺動して移動車が斜め方向に平行移動するような走行形態を採ることが可能な構成であってもよい。又、左右一対のクローラ走行装置を備え、片側に制動を加える操向操作構成を有する構成であってもよい。
【００６８】
（５）上記実施形態では、移動車としてロータリー耕耘装置を備えた構成としたが、苗移植装置や薬剤散布装置等を備えたものであってもよく、又、このような作業装置を備えない、運搬車等の移動車であってもよい。
【図面の簡単な説明】
【図１】誘導状態を示す平面図
【図２】誘導線の設置状態を示す図
【図３】磁界強度分布を示す図
【図４】制御ブロック図
【図５】磁界検出部の構成図
【図６】信号処理部の構成図
【図７】誘導線の設置状態を示す平面図
【図８】誘導線の電気回路図
【図９】出力ゲインを切り換えた場合の出力特性を示す図
【図１０】制御動作のフローチャート
【図１１】移動車の平面図
【図１２】磁界検出状態を示す図
【図１３】旋回制御状態を示す図
【符号の説明】
２ 誘導線
２_ＯＬ 往路部分
２_ＦＬ 復路部分
３ 電流供給源
１２ 制御手段
ＧＫ 磁界検出手段
ＳＳ 走行操作手段
ＴＵ ゲイン調整手段
Ｖ 移動車[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, on the ground side, an induction wire to which current is supplied from a current supply source is installed,
On the moving car side,
Traveling operation means capable of controlling the traveling state,
Magnetic field detecting means for detecting the strength of the magnetic field formed by the current as separation distance information from the induction wire,
Control means for controlling the traveling operation means to guide the traveling vehicle on a plurality of scheduled traveling paths separated from the guidance line based on the separation distance information detected by the magnetic field detection means. The present invention relates to a vehicle guidance control device.
[0002]
[Prior art]
According to the guidance control device for a mobile vehicle having the above configuration, the strength of the magnetic field formed by the current supplied to the guide wire has a characteristic determined according to the distance from the guide wire. Based on the detection information, the mobile vehicle can be guided to run.
[0003]
In the guidance control device having the above configuration, conventionally, as shown in Japanese Patent Application No. 6-184337 filed by the present applicant, a closed circuit of a current supplied from a current supply source is conventionally provided with an induction wire and a ground. There was one that was configured with a closed circuit passing through the inside.
[0004]
[Problems to be solved by the invention]
In the guidance control device having the above-described configuration, in order to supply a current to the induction wire, when configuring a closed circuit for passing a current, the ground is effectively used, and when a long guidance wire is installed, In addition, it is possible to reduce the work of construction for installing the guide wire.
[0005]
However, in such a configuration in which the current flows through the ground, if the installation location of the guide wire is different, the ground resistance to the ground changes due to soil properties, moisture content, etc. There is a high possibility that the current supplied to the device will fluctuate. As a result, there is a possibility that the magnitude of the current serving as a reference for the guidance control of the mobile vehicle fluctuates, and the guidance control of the mobile vehicle cannot be performed properly.
[0006]
Therefore, in order to avoid such disadvantages, it is necessary to perform a special grounding work to adjust the grounding resistance to be within an allowable range, or to adjust the grounding resistance every time the guidance control is executed. However, there is a disadvantage that the installation work for installing the guide wire requires rather troublesome work, and there is room for improvement in this respect.
[0007]
The present invention has been made by paying attention to this point, and its purpose is to minimize the trouble of installing the guide wire as much as possible, and to always maintain the proper position regardless of the change in the installation place of the guide wire. Another object of the present invention is to provide a guidance control device for a mobile vehicle, which can perform various types of guidance control.
[0008]
[Means for Solving the Problems]
According to the characteristic configuration of the first aspect, the guide wire to which the current for guiding the mobile vehicle is supplied forms a forward path portion thereof and a closed loop through which the current supplied from the current supply source flows. And the return path portion for performing the return is installed on the ground side in a state where it is appropriately spaced in plan view.
[0009]
Therefore, the current supplied from the current supply source flows through each of the forward path portion of the guide line located on the moving vehicle side and the return path portion of the guide line for forming a closed loop. In other words, by configuring a series of closed circuits through which current can flow through only the induction wire, the installation location is different from when the current flows through the underground as in the conventional configuration. Even in such a case, the possibility that the electric resistance in the closed circuit fluctuates due to soil properties, ground resistance, and the like is reduced, and the current supplied to the induction wire is stabilized accordingly.
[0010]
In addition, no special construction is required for grounding the guide wire underground, and the installation of the guide wire can be reduced.
[0011]
As a result, the time required for installing the guide line is small, and even if the target location of the mobile vehicle is different, the current flowing through the guide line is stable without largely fluctuating from a preset current value. Therefore, it is possible to always perform appropriate guidance control.
[0012]
According to the characteristic configuration described in claim 2, the outgoing path portion of the guide line is installed along the respective scheduled traveling paths, and the return path portion is parallel or substantially parallel to the outgoing path portion. The control means is configured to control the traveling operation means to guide the traveling vehicle along each of the scheduled traveling paths based on the separation distance information detected by the magnetic field detection means. Have been.
[0013]
In other words, the strength of the magnetic field detected by the magnetic field detecting means is the same if the outward path is installed along the respective planned traveling paths and the distance from the guide line is constant. In a planned traveling route separated from the guidance line by a set distance, for example, by performing guidance control such that the detection value of the magnetic field detection unit is maintained at the target value of the magnetic field strength corresponding to the set distance, Guidance traveling along the planned traveling route can be performed.
[0014]
Further, since the return path portion is installed so as to be parallel or substantially parallel to the forward path portion, a magnetic field formed by a current flowing through the return path portion and a current flowing through the forward path portion are reduced. The combined magnetic field with the magnetic field formed by the magnetic field becomes the strength of the magnetic field in the planned traveling route. However, since the outgoing path portion and the returning path portion are installed in parallel or almost parallel, the magnetic field becomes large as the vehicle travels on the planned traveling route. Does not change, and the guidance control can be performed in a more stable state.
[0015]
According to the characteristic configuration described in claim 3, the outgoing path portion of the guide line is installed along a direction intersecting with each of the planned traveling routes, and the return path portion is provided in the outgoing path portion. The control unit determines that the moving vehicle is located at the end of each of the planned traveling paths based on the separation distance information detected by the magnetic field detecting unit. Then, the control state of the traveling control means is switched.
[0016]
In other words, the forward path portion is installed along the direction intersecting with each of the planned traveling routes, and a point separated by a set distance from the guide line is located at an end of the planned traveling route, for example. When the detection value of the magnetic field detection means reaches the target value of the magnetic field strength corresponding to the set distance, it can be determined that the moving vehicle is located at the end of the planned traveling route, and for example, the vehicle starts turning. It is possible to switch the control state of the travel control means, such as to make a turn or end a turn.
[0017]
Further, since the return path portion is installed so as to be parallel or substantially parallel to the forward path portion, a magnetic field formed by a current flowing through the return path portion and a current flowing through the forward path portion are reduced. The combined magnetic field with the magnetic field formed at the end of the planned traveling route becomes the strength of the magnetic field. However, since the forward portion and the returning portion are installed in parallel or almost in parallel, each of the plurality of planned traveling routes The magnetic field does not greatly change at the end positions, and it is possible to position each end position with as high accuracy as possible.
[0018]
According to the characteristic configuration described in claim 4, the agricultural work vehicle performs the work while the mobile vehicle travels along a plurality of planned traveling routes in the field, wherein the guide line is one of the width direction of the ridge in the field. It is installed on the ground side in a state where the outgoing path portion is located along a side portion and the return path portion is located along another side portion in the width direction of the ridge.
[0019]
When the agricultural work vehicle is guided along each planned traveling route, the work is performed in the field. Further, the outgoing path portion of the guide line is located along one side in the width direction of the ridge, and the return path portion is installed along the other side in the width direction of the ridge. That is, it is installed using the boundary between the ridge and the field.
[0020]
Therefore, even when the agricultural work vehicle travels in the field, the guide line does not interfere with the farm work vehicle, and the worker who assists the work or the farm work vehicle moves on the ridge. Also in such cases, the possibility that the guide wire interferes can be minimized.
[0021]
As a result, by adopting a rational installation form of the guide wire, it has become possible to effectively control the guidance of the mobile vehicle without disadvantage such as being damaged by interference with external objects. .
[0022]
According to the characteristic configuration of the fifth aspect, the guide wire is installed so as to be mounted on the ground surface on the ground side.
[0023]
Therefore, the guide wire can be installed simply by placing it on the ground surface, for example, it can be easily installed without troublesome work such as embedding in the ground over a long distance, and when it is removed, However, simple operations can be performed without any hassle.
[0024]
According to the configuration described in claim 6, the output signal of the intensity of the magnetic field detected by the magnetic field detection unit and input to the control unit is set to an appropriate level for the control operation of the control unit. And a gain adjusting means for adjusting an output gain of the magnetic field detecting means.
[0025]
Since the direction of the current flowing in the forward path and the direction of the current flowing in the return path of the guide wire are opposite to each other, the magnetic fields formed by the respective lines act so as to cancel each other out, and are formed on the scheduled traveling path. The strength of the combined magnetic field is smaller than that of the conventional configuration in which only one induction wire is present. However, the output gain of the magnetic field detection means is adjusted by the gain adjustment means, and the output signal of the strength of the magnetic field is controlled by the control means. Adjustment can be made to be at an appropriate level for the control operation, and appropriate guidance control can be executed.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a guidance control device for a mobile vehicle according to the present invention will be described.
As shown in FIG. 1, the guidance control device for a mobile vehicle moves a work vehicle V as an example of a mobile vehicle parallel to each other along a longitudinal direction of the field 1 in a rectangular field 1 as an example of a guidance area. Each of the plurality of travel paths k is configured to be able to guide and drive in an unmanned state.
[0027]
On each side (ridge) in the outer peripheral portion of the field 1, a guide wire 2 having a length substantially equal to the length of the ridge is installed along the longitudinal direction of the ridge. An alternating current having a predetermined frequency is supplied by the current supply source. That is, alternating currents of the frequency fa (Hz) and the frequency fc (Hz) are supplied to the respective guide lines 2 a and 2 c installed along the ridges on both sides along the long direction of the field 1 by the respective current supply sources 3. Alternating currents of frequency fb (Hz) and frequency fd (Hz) are supplied by the current supply sources 3 to the respective guide wires 2b and 2d that are supplied and installed on the ridges on both sides along the short direction. The frequency is set to about several hundred Hz to several tens KHz.
[0028]
Each of the guide lines 2a and 2c has a forward part 2_OLAnd a return path portion 2 for forming a closed loop through which a current supplied from the current supply source 3 flows._FLAre installed on the ground side in a state where they are appropriately spaced from each other in plan view. Specifically, as shown in FIG. 2, the forward path portion 2 extends along one side in the width direction of the ridge AZ in the field._OLIs located along the other side in the width direction of the ridge AZ._FLIs located on the ground surface on the ground side in a state where_FLBut the outgoing route part 2_OLIt is installed so as to be parallel or almost parallel to. In other words, it is installed in a loop by effectively utilizing the boundary between the ridge AZ and the field scene.
[0029]
When a current flows through the guide wire installed as described above, a magnetic field is formed by the current. The theoretical value of the magnetic field strength with respect to the separation distance from the guide wire 2 can be obtained by calculation. The strength of the magnetic field is inversely proportional to the square of the distance from the guide wire 2. And the outgoing path portion 2_OLCurrent flowing to the home and return path part 2_FLThe currents flowing in the opposite directions are opposite to each other, and the magnetic fields formed act so as to cancel each other in the opposite directions. However, since the magnetic fields are arranged at appropriate intervals in plan view, as shown in FIG. The change characteristic of the magnetic field strength with respect to the distance from the guide wire 2 is determined, and the magnetic field strength at a certain point in the field 1 becomes almost constant.
[0030]
FIG. 3 shows actual measurement data by the present applicant. A current of about 3 amps is supplied to the induction wire,_OLAnd return section 2_FLEach have a length of about 80 meters, and their spacing in plan view is about 1 meter._OLThe distance from the guide line and the strength of the magnetic field at that point are measured at approximately the middle position of the line.
[0031]
The work vehicle V is provided with a rotary tillage device 6 as a ground work device at a rear portion of the four-wheeled traveling vehicle body 5, and is an agricultural work vehicle such that the work on the ground 1 (tiling work) can be performed while traveling. It is configured as An engine is mounted on the traveling vehicle body 5, and the power of the engine is transmitted to each wheel via a transmission equipped with a forward / reverse switching mechanism 7 capable of turning on and off the power transmission so that the vehicle travels. The power of the engine is transmitted to the rotary tilling device 6. The left and right front wheels are provided so as to be steerable by an electric motor 9.
[0032]
The work vehicle V has a traveling distance sensor 10 as a distance detecting means including, for example, a rotary encoder for detecting the traveling distance of the vehicle body by detecting the rotation speed of the axle, and a direction detecting means for detecting the direction of the vehicle body. And a control device 12 using a microcomputer as control means for controlling operations of the forward / reverse switching mechanism 7, the steering electric motor 9, and the like. The forward / reverse switching mechanism 7 and the steering electric motor 9 constitute a traveling operation means SS capable of operating the traveling state of the work vehicle.
[0033]
Also, at the front of the traveling vehicle body 5, as information on the position (separation distance) of the work vehicle with respect to each of the guide lines, three magnetic field strengths formed by alternating current supplied to each of the guide lines are detected. Are provided in a state where they are arranged side by side along the vehicle width direction. Of these, the side magnetic field sensors 13R and 13L located on the left and right sides are arranged along ridges on both sides along the long direction of the field 1. Position information (separation distance information) from each of the installed guide wires 2a and 2c is configured to be detected as the strength of a magnetic field formed by an alternating current having a frequency fa and a frequency fc, and is located on the left and right center sides. The central magnetic field sensor 14 uses the position information from each of the guide lines 2b and 2d installed along the ridges on both sides along the short direction of the field 1 as the frequency fb and the strength of the magnetic field formed by the alternating current at the frequency fd. Will be detected as It is configured.
[0034]
The control device 12 guides the work vehicle V along each traveling route k on each of the plurality of traveling routes k based on the detection information from the respective side magnetic field sensors 13R and 13L as the magnetic field detecting means GK. When the guidance traveling control to be performed is performed, and based on the detection information from the central magnetic field sensor 14, it is detected that the traveling route k has reached the terminal end or the starting end, and if it is detected that the traveling route k has reached the terminating end, the work is performed. The vehicle V is configured to perform turning control to cause the vehicle V to turn around and guide the vehicle V to enter an adjacent next traveling route.
[0035]
That is, as shown in FIG. 4, the outputs of the respective side magnetic field sensors 13R and 13L and the central magnetic field sensor 14 are respectively processed by the signal processing unit 15 and then provided to the control device 12, and the magnetic field detection information is obtained. The electric motor 9 for steering is controlled so as to be guided along each traveling path k based on the information, and at the end of the traveling path k, the magnetic field detection information and the detection of the direction sensor 11 and the traveling distance sensor 10 are performed. On the basis of the information, the steering electric motor 9, the forward / reverse switching mechanism 7, and the like are controlled so as to make a turning travel.
[0036]
As shown in FIG. 5, the central magnetic field sensor 14 has a detection coil 16a in which an induced electromotive force is generated by an alternating magnetic field formed by an alternating current flowing through the induction wires 2b and 2d, and a predetermined output from the detection coil 16a. Amplifier 16b that amplifies the current to a level, a band-pass filter BPF as a frequency filter that passes only the output corresponding to the frequencies fb and fd of the current flowing through each of the induction wires 2b and 2d among the outputs of the detection coil 16a, It is configured to include a DC conversion circuit DC for converting into a signal.
[0037]
The side magnetic field sensors 13R and 13L respectively include a vertical direction detecting coil 17 for detecting a magnetic field component of an alternating magnetic field formed by an alternating current flowing through the induction wires 2a and 2c along the vehicle body vertical direction, and a magnetic field along the vehicle body width direction. A width direction detection coil 18 for detecting the components, amplifiers 19 and 20 for amplifying the output of each of these detection coils to a predetermined level, and the current of each of the induction lines 2a and 2c among the outputs of each of the detection coils 17 and 18. A band-pass filter BPF as a frequency filter that passes only outputs corresponding to the frequencies fa and fc, a DC conversion circuit DC that converts the output to a DC signal, and vertical and horizontal components corresponding to the frequencies fa and fc. It is configured to include calculation units 21 and 22 for calculating the strengths of the respective magnetic fields based on the components.
As shown in FIG. 12, the calculation units 21 and 22 calculate the strength of the composite magnetic field r by performing calculations based on the vehicle vertical component p and the width component q based on the triangle theorem. It is configured.
[0038]
With such a configuration, for example, as shown in FIG. 12A, when one side of the wheel enters the concave portion while the work vehicle V is traveling, the vehicle body is inclined at an angle θ from the horizontal posture to an oblique posture. Even in this case, the magnetic field formed by the current supplied to the induction wire is detected in two orthogonal components, and the resultant magnetic field is calculated as shown in FIG. , The accurate magnetic field strength, that is, the separation distance from the guide wire can be accurately detected.
[0039]
As described above, the detection information corresponding to each of the frequency fa and the frequency fc is output from each of the side magnetic field sensors 13R and 13L, and the center magnetic field sensor 14 corresponds to each of the frequency fb and the frequency fd, respectively. Although the detection information is output, the signal processing unit 15 selectively outputs the detection information having the higher detection level, that is, the detection information closer to the guide line to which the work vehicle V corresponds. It is supposed to be.
As shown in FIG. 6, the signal processing unit 15 receives the output of each of the magnetic field sensors 13R, 13L, and 14 into the control device 12, and the control device 12 outputs the output of each of the magnetic field sensors 13R, 13L, and 14 having a different frequency. Among them, three analog switches AS are provided so as to determine the output on the higher detection level side and select the output._1,AS_2,AS₃Is provided to the selection signal.
[0040]
The control device 12 calculates a separation distance from one of the guide lines 2b and 2d, which are installed on the ridge along the short direction, on the higher detection level side based on the detection information of the central magnetic field sensor 14. Then, when the separation distance reaches a set value, it is determined that the work vehicle V has reached the end position of each traveling route k.
As shown in FIG. 7, the guide lines 2b and 2d installed in the ridges along the short direction are installed in a state where both ends are bent in a substantially L shape toward the inside of the field 1. . With this configuration, at the point where the separation distance of the guide lines 2b and 2d from the intermediate portion t is the set distance, the strength of the magnetic field becomes substantially the same over the entire length of the guide lines 2b and 2d. It is set as the end position of k. This end position is a point located on the inward side of the field 1 by a set distance from the length L of the end bent portion. Incidentally, according to the experiment by the applicant, if the length H of the bent end portion is, for example, 3 m, the end portion is located at a distance of 5 m from the guide wire.
The induction wires 2b and 2d form a current closed circuit by using the underground as a return path through which a current flows.
[0041]
As described above, the reason why the end position of the traveling route k is set on the inner side than the end of the field 1 is that, as shown in FIG. In the magnetic field strength distribution at the same point, the relation of the magnetic field strength to the separation distance is not linear near the end of the guide wire, and there is a possibility that guidance control based on the magnetic field strength may not be performed well. It is.
[0042]
As shown in FIG. 8, each of the induction wires 2 is supplied to the induction wire as a frequency filter which is an example of a current suppressing unit that suppresses a current flowing through another induction wire from flowing through the ground. And a band-pass filter 23 that allows only the frequency of the current to pass therethrough. The band-pass filter 23 is configured by a resonance circuit in which a coil 23a and a capacitor 23b are connected in series, and is configured such that its resonance frequency corresponds to the frequency of the current. Therefore, even if a current of a different frequency flows through the ground from another induction wire, the inflow current is suppressed from flowing through the induction wire, and the possibility that each magnetic field sensor detects erroneous information is minimized. I have.
[0043]
The signal processing unit 15 controls the magnetic field detecting means so that the output signal of the strength of the magnetic field detected by the magnetic field detecting means GK and input to the control device 12 becomes an appropriate level for the control operation of the control device 12. A gain adjusting means TU for adjusting the output gain of the GK is provided.
More specifically, each analog switch AS corresponding to the detection information of each of the side magnetic field sensors 13R and 13L.₁, AS₃The amplification gain for amplifying the output of is controlled to be changed and adjusted in a plurality of steps (four steps) based on the switching information from the control device 12. That is, the analog switch AS for inputting any one of the outputs of the four amplifiers 24, 25, 26, and 27 having different amplification gains to the control device 12.₄, AS₅, The control device 12 is configured to instruct selection contents.
As described above, the strength of the magnetic field formed by the current supplied to the induction wire greatly changes with the change in the separation distance, and when the amplification gain is kept constant, the strength is appropriate over the entire range. Since it is difficult to detect with a high resolution and the detection accuracy may be reduced, when the input level to the control device 12 changes, for example, as shown in FIG. In other words, the amplification gain is automatically adjusted so that an appropriate change in magnetic field strength can be identified, in other words, an appropriate output range having an appropriate resolution can be obtained.
[0044]
Each of the side magnetic field sensors 13R and 13L is installed at a set interval in the vehicle body width direction, and one of the side magnetic field sensors detects whether the work vehicle V is one of a plurality of traveling paths k. When the vehicle travels along the traveling route k, the magnetic field detecting unit GK for the current traveling route for detecting the strength of the magnetic field for executing the guidance control along the traveling route k during traveling.₁When the work vehicle travels along the next adjacent traveling route k, the other side magnetic field sensor functions as the magnetic field detecting unit GK for the current traveling route.₁Magnetic field detecting section GK for the next traveling route for detecting the strength of the magnetic field to be detected by₂It is configured to function as.
In other words, the other side magnetic field sensor sequentially detects the magnetic field of the next traveling route k while traveling on the current traveling route k, and this detection information is the distance information detected by the traveling distance sensor 10. In such a state, the information is sequentially stored in a memory M as a storage means.
[0045]
The control device 12 controls the magnetic field detection information stored in the memory M and the travel distance from the end position of the travel path k detected by the travel distance sensor 10 in the next travel path k in which the magnetic field detection information is stored. Based on the information, a target value of the magnetic field strength at each point on the travel route k is determined, and the target value and the magnetic field detector GK for the current travel route are determined.₁It is configured to execute guided traveling control for controlling the driving of the traveling electric motor 9 based on the deviation from the detection value of the side magnetic field sensor functioning as the driving unit.
[0046]
The control device 12 also controls the magnetic field detection unit GK for the current traveling route when the vehicle is guided along the next traveling route k based on the magnetic field detection information stored in the memory M.₁Is set, and the output gain is automatically adjusted to the target value prior to the guided travel on the next travel route k. Specifically, if the maximum value of the magnetic field strength stored in the memory M exceeds the set upper limit for gain adjustment, an amplifier having a gain one stage lower than the current gain is selected, and If the value is smaller than the lower limit for gain adjustment, the analog switch AS is selected so that an amplifier having a gain one stage higher than the current gain is selected.₄, AS₅Is instructed with a selection signal. In addition, each analog switch AS₄, AS₅Are always adjusted to the same value.
The set upper limit value and the set lower limit value for the gain adjustment are set as upper and lower limit ranges in which the linearity of the output change as an analog value is guaranteed.
[0047]
The control device 12 also includes a magnetic field detection unit GK for the current traveling route.₁The steering operation amount, that is, the target operation amount of the electric motor is obtained by multiplying a deviation between the detection value of the side magnetic field sensor functioning as the target value and the target value by a control constant. Then, the magnetic field detection unit GK for the current traveling route₁And magnetic field detector GK for next traveling route₂Is configured to correct the control constant based on the detection information of the magnetic field strength detected at the time of traveling on the next traveling route so that the operation amount is within an appropriate range.
[0048]
Next, the control operation of the control device 12 will be described.
When the work vehicle V is guided to travel in the field 1, prior to the automatic guidance control by the control device 12, the work vehicle V is manually driven on the first travel route k in a state of being along the appropriate travel route k. Let it. At this time, as the traveling is started from the starting end position of the traveling route k, the detection information of the side magnetic field sensor on the next traveling route side (the right sensor 13R in FIG. 1) and the detection of the traveling distance sensor 10 The information is sequentially written and stored in the memory M in a state where the information is associated with the information.
In addition, among a plurality of data sampled at every set time as the vehicle travels on the first travel route, a plurality (n) of the respective detection values of the left and right side magnetic field sensors 13R and 13L near the center of the travel route. Sampling data α₁… Α_n, Β₁…… β_nIs calculated, and a control constant for steering control on the traveling route is determined as a reference control constant G based on the average value and a constant γ set in advance based on an experiment or the like.₁Asking. Specifically, the calculation is performed based on the following [Equation 1].
[0049]
(Equation 1)

[0050]
Then, after moving the work vehicle to the start end of the next traveling route k, the automatic guidance control is started. Prior to that, as shown in FIG. 10, first, the magnetic field detecting unit GK for the current traveling route₁The side magnetic field sensor (the left sensor 13L in the case of FIG. 1) functioning as the initial setting is set (step 1), and the control constant applied to the traveling route is set (step 2).
To explain the setting of the control constants, a difference value Zn between the detection values of the left and right side magnetic field sensors 13R and 13L at the start end of the current travel route is obtained, and the difference value Zn and the first travel route are determined. Difference value Z₁And the reference control constant G₁, The control constant Gn for this traveling route is calculated based on the following [Equation 2]. The difference values Zn, Z₁Are calculated as an average value of a plurality of detection values sampled at each set sampling time in each traveling route.
[0051]
(Equation 2)
Gn = (Z₁/ Zn) · G₁
[0052]
Such setting of the control constants is executed for each traveling route at the beginning of the traveling route.
[0053]
Then, while the work vehicle V is traveling at the traveling speed for work, the strength of the magnetic field at the present time on the traveling route k is determined based on the magnetic field detection information stored in the memory M and the detection information of the traveling distance sensor 10. Of the magnetic field detector GK for the current traveling route₁The steering operation amount is obtained by multiplying the deviation between the detection value of the side magnetic field sensor 13L functioning as the target value and the target value by a control constant, and the drive control of the steering electric motor 9 is performed so that the steering operation amount is obtained. (Step 3).
When the guidance traveling control is executed, the magnetic field detection unit GK for the next traveling route is used.₂The detection information of the side magnetic field sensor (the right sensor 13R in the case of FIG. 1) on the side of the next traveling route that functions as the information is sequentially written and stored in the memory M in a state where the detection information corresponds to the detection information of the traveling distance sensor 10 Step 4).
[0054]
When it is detected based on the detection information of the central magnetic field sensor 14 that the end of the travel route k has been reached, the number of travel routes n is counted up (steps 5 and 6). If the set number of paths ns has not been reached (step 7), the maximum value Xm of the magnetic field strength written and stored in the memory M is equal to the set upper limit value S for gain adjustment._GM, The analog switch AS is selected so that an amplifier having a gain one stage lower than the current gain is selected.₄, AS₅, A selection signal is instructed to change the output gain to a lower side (steps 8 and 9). The maximum value Xm is equal to the set lower limit value S for gain adjustment._GL, The analog switch AS is selected so that an amplifier having a gain one stage higher than the current gain is selected.₄, AS₅, A selection signal is instructed to change the output gain to the higher side (steps 10 and 11). When the output gain is changed in this way, the control constant is also appropriately corrected according to the change amount (steps 12 and 13).
[0055]
In this way, the drive control of the electric motor is always performed with an appropriate control constant in accordance with the detection value of the magnetic field strength and the change situation of the output gain, so that the occurrence of control hunting and detection errors is minimized. I try to suppress it.
[0056]
Next, the magnetic field detector GK for the current traveling route₁The side magnetic field sensor that functions as the switch is switched to the opposite one (the right sensor 13R) (step 14). This is because their positional relationship is reversed by a change in the direction of the vehicle body.
[0057]
Next, a turning control for turning the vehicle in a turning direction so as to be positioned at the start end of the next traveling route k is executed (step 15).
As shown in FIG. 13 (a), after the vehicle travels straight ahead while maintaining the steering operation in the neutral state for a set distance from the end position of the traveling route k, the direction sensor 11 is reset, and the direction of the vehicle body is 180 degrees. The vehicle travels at the maximum turning angle until it is detected that the vehicle has reversed, and then travels straight until it is detected that the vehicle has reached the start end of the next traveling route k based on the detection information of the central magnetic field sensor 14. (Step 16).
[0058]
At the beginning of the next traveling route, as shown in FIG. 13 (b), the detection information of the side magnetic field sensor functioning as the magnetic field detecting unit for the current traveling route k is stored in the memory M. Based on the stored information, it is necessary to move the body forward while turning so as to be in a state along the next traveling route, and to perform width shifting. At this time, the magnetic field detection information for the next traveling route is However, in this region, the state is corrected to an appropriate state based on the detection information of the initial traveling route and the detection information of the magnetic field change state as described above. After that, the guidance traveling control is executed in a state of being along the traveling route.
[0059]
Then, based on the detection information of the central magnetic field sensor 14, after it is detected that the starting point of the next traveling route k has been reached, the magnetic field detecting unit GK for the current traveling route is detected.₁When the set time elapses after the deviation between the detected value and the target value (stored information) falls within the set range, and becomes stable, the above-described setting of the control constant is executed. That is, the difference value Zn between the detection values of the left and right side magnetic field sensors 13R and 13L in the current traveling route and the difference value Z in the first traveling route are different.₁And the reference control constant G₁, The control constant Gn for this travel route is calculated based on the above [Equation 2]. The difference value Zn in the current travel route is calculated based on the detection information on the start end side.
[0060]
Thereafter, the above-described guided traveling control is executed. At this time, if the gain has been changed in steps 9 and 11, the detection information stored in the memory M also corresponds to the amount of change. The running target value is obtained by multiplying the gain.
Then, steps 2 to 15 are repeated, and the work vehicle V is sequentially guided along each traveling path k, and when the number of the set paths reaches ns, the control ends (step 7).
[0061]
In the current travel route k, the strength of the magnetic field stored when the vehicle travels the previous travel route k is controlled to be the same as the detected magnetic field in the current travel route k. Since the installation intervals of 13R and 13L are set to be narrower than the ground work width of the rotary cultivator 6, the work area by the rotary cultivator 6 wraps on each traveling path k, and the unworked area becomes It does not occur. Further, the installation intervals of the side magnetic field sensors 13R and 13L are configured to be changeable and adjustable.
[0062]
[Another embodiment]
(1) In the above embodiment, the case where the guide lines 2a and 2c installed along the ridges on both sides along the long direction of the field 1 are installed in a loop so as to surround the ridges has been exemplified. The guide wires 2b and 2d installed on the ridges on both sides along the direction may be arranged in a loop so as to surround the ridges.
Then, instead of the configuration of the above-described embodiment using the magnetic field detection information for each of the guidance traveling control of the moving vehicle along each scheduled traveling route and the control for detecting the end of each scheduled traveling route, any control is performed. The magnetic field detection information may be used only for
[0063]
Also, in this case, when used only for guidance traveling control, as a configuration of edge detection, for example, a laser beam is irradiated in the lateral direction at the edge of the route, and the edge of the route is detected by a sensor that detects this laser beam. Detection may be performed, or various configurations may be used, such as a configuration in which a control unit fixed on the ground instructs the mobile vehicle to reach the end of the route by wireless information.
[0064]
When the magnetic field detection information is used only for edge detection, as a guidance control for a moving vehicle, a laser beam is radiated along a traveling route, and the laser beam is always detected by a sensor that detects the laser beam. The vehicle may be guided to detect the vehicle, or may be guided by radio control.
[0065]
(2) In the above embodiment, the gain adjustment means is configured to switch the gain to four stages. However, the number of stages may be changed, or the number of stages of the gain may be changed. Alternatively, the amplification factor may be changed and adjusted steplessly. Further, a configuration in which such automatic adjustment of the output gain is not performed may be adopted.
[0066]
(3) In the above-described embodiment, the case where the guide lines are installed on both the left and right sides of the guidance target area is exemplified. However, a configuration in which the guide lines are provided on only one side may be adopted. The travel route closer to the line may be sequentially guided to a route on the far side, or the travel route farther to the guide line may be sequentially guided to a route on the closer side.
[0067]
(4) In the above-described embodiment, the mobile vehicle is a four-wheel vehicle and the left and right front wheels are configured to be steerable and swingable. However, all four wheels are provided to be steerable and swingable, and the front and rear wheels are different from each other. A configuration that can take a form in which the vehicle turns with a small turning radius that swings in the direction or a configuration in which the front and rear wheels swing in the same direction and the moving vehicle moves in parallel in an oblique direction. Good. Further, a configuration including a pair of left and right crawler traveling devices and a steering operation configuration for applying braking to one side may be employed.
[0068]
(5) In the above embodiment, the rotary vehicle is provided with the rotary tilling device as the moving vehicle. However, the mobile vehicle may be provided with a seedling transplanting device, a chemical spraying device, or the like, or without such a working device. Or a moving vehicle such as a transport vehicle.
[Brief description of the drawings]
FIG. 1 is a plan view showing a guidance state.
FIG. 2 is a diagram showing an installation state of a guide wire;
FIG. 3 is a diagram showing a magnetic field intensity distribution.
FIG. 4 is a control block diagram.
FIG. 5 is a configuration diagram of a magnetic field detection unit.
FIG. 6 is a configuration diagram of a signal processing unit.
FIG. 7 is a plan view showing an installation state of a guide wire.
FIG. 8 is an electric circuit diagram of an induction wire.
FIG. 9 is a diagram showing output characteristics when the output gain is switched.
FIG. 10 is a flowchart of a control operation.
FIG. 11 is a plan view of a moving vehicle.
FIG. 12 is a diagram showing a magnetic field detection state.
FIG. 13 is a diagram showing a turning control state.
[Explanation of symbols]
2 Guidance line
2_OL              Outbound part
2_FL              Return section
3 Current source
12 control means
GK magnetic field detection means
SS running operation means
TU gain adjustment means
V moving car

Claims (6)

On the ground side, an induction wire to which current is supplied from a current supply source is installed,
On the moving car side,
Traveling operation means capable of controlling the traveling state,
Magnetic field detecting means for detecting the strength of the magnetic field formed by the current as separation distance information from the induction wire,
Control means for controlling the traveling operation means to guide the traveling vehicle on a plurality of scheduled traveling paths separated from the guidance line based on the separation distance information detected by the magnetic field detection means. A vehicle guidance control device,
The guide wire is
A movement installed on the ground side in a state where the forward path and the return path for forming a closed loop through which the current supplied from the current supply source flows are appropriately spaced in plan view. Car guidance control device. The outgoing path portion of the guide line is installed in a state along each of the planned traveling routes, and the return path portion is installed so as to be parallel or substantially parallel to the outgoing path portion,
The control means,
2. The mobile vehicle according to claim 1, wherein the mobile operating device is configured to control the traveling operation means to guide the mobile vehicle along each of the planned traveling paths based on the separation distance information detected by the magnetic field detecting means. Guidance control device. The outgoing path portion of the guide line is installed along a direction intersecting with each of the planned traveling routes, and the return path portion is installed so as to be parallel or substantially parallel to the outgoing path portion. ,
The control means,
On the basis of the separation distance information detected by the magnetic field detection means, it is configured to determine that the moving vehicle is located at the end of each of the planned traveling paths, and to switch the control state of the traveling control means. The guidance control device for a mobile vehicle according to claim 1. An agricultural work vehicle in which the moving vehicle performs work while traveling along a plurality of scheduled traveling routes in a field, wherein the guide line is located on the outward path along one side in a width direction of a ridge in the field, The guidance control device for a mobile vehicle according to any one of claims 1 to 3, wherein the control device is installed on the ground side in a state where the return path portion is located along the other side in the width direction of the ridge. The guidance control device for a mobile vehicle according to any one of claims 1 to 4, wherein the guidance line is installed so as to be mounted on a ground surface on the ground side. A gain for adjusting an output gain of the magnetic field detecting means so that an output signal of the strength of the magnetic field detected by the magnetic field detecting means and input to the control means is at an appropriate level for a control operation of the control means; The mobile vehicle guidance control device according to any one of claims 1 to 5, further comprising an adjusting unit.

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