JP3812463B2

JP3812463B2 - Direction detecting device and self-propelled cleaner equipped with the same

Info

Publication number: JP3812463B2
Application number: JP2002062815A
Authority: JP
Inventors: 穣荒井; 郁雄竹内; 篤志小関; 索柄川; 泰治田島
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2002-03-08
Filing date: 2002-03-08
Publication date: 2006-08-23
Anticipated expiration: 2022-03-08
Also published as: JP2003262520A

Description

【０００１】
【発明の属する技術分野】
本発明は方向検出装置に係り、特に自走式掃除機や自走式台車に好適な方向検出装置に関する。
【０００２】
【従来の技術】
自走式移動体に用いる従来の位置検出装置の例が、特開平７−３１１０４１号公報に記載されている。この位置検出装置は、自律的に現在位置を把握するために、駆動輪を有する移動体の上面に平面的に所定距離離れた位置に２つの受光部を取り付けている。これらの受光部は旋回可能になっている。それとともに基準局の側面には、平面的に所定距離離れた位置に２つの発光部を取付けている。移動体上の受光部が旋回しながらサンプリングすると受光量が変化する。受光量のピークとなった旋回角に基づいて、相対位置と相対的な姿勢角を求めている。
【０００３】
【発明が解決しようとする課題】
上記公報に記載の位置検出方法では、移動体に２組の旋回可能な受光軸を設けているので、受光部の構成が複雑になっている。そのため、家庭用の掃除機等にこれらの受光体を搭載するときには、小型化の阻害要因となっている。
【０００４】
本発明は、上記従来技術の不具合に鑑みなされたものであり、その目的は移動体に搭載する方向検出装置を小型化することにある。本発明の他の目的は、安価な方向検出装置を実現することにある。
【０００５】
【課題を解決するための手段】
上記目的を達成するため本発明は、光を発光し固設された発光体と、移動体に搭載された光センサユニットとを備えた方向検出装置において、前記光センサユニットに、発光体から発光された光を受光する複数の第１の受光手段と、この第１の受光手段よりも受光可能な入射範囲が狭い第２の受光手段と、を備え、前記移動体を回転させ前記第２の受光手段が前記発光体を検出した方向に基づいて、前記発光体が各方向に存在するときの各前記第１の受光手段の受光強度の比と対応する評価関数の値と評価関数を求めるために前記第１の受光手段のうちどの素子を用いたかが記録される方向検出データベースが構築され、前記発光体の方向は前記方向検出データベースのデータに基づいて検出されるものである。
【０００７】
上記目的を達成するための他の特徴として、移動体を自走式掃除機とし、上記いずれかの特徴の方向検出装置を搭載したものである。
【０００８】
【発明の実施の形態】
以下本発明に係る方向検出装置の一実施例を、自走式掃除機に搭載した例について図面を用いて説明する。図１に、自走式掃除機の模式図を示す。自走式掃除機４の上部には、赤外線を発光する光センサユニット１が取り付けられている。自走式掃除機４から離れた位置に、発光体５が固定されている。光センサユニット１は、発光体５から照射される変調された赤外線１１を受けるために、広指向角の受光素子２と狭指向角の受光素子３とを備えている。これらの受光素子２、３の個々の受光強度情報は、自走式掃除機４内部に設けた演算手段７に送られる。
【０００９】
演算手段７は、自走式掃除機４を駆動する駆動系の制御部６に接続されている。駆動系は一対の駆動輪１０を有しており、演算手段７は、駆動輪１０の回転速度と回転量を駆動系制御部６に指令する。演算手段７の指令に応じた回転速度と回転量で駆動輪１０が回転すると、駆動系制御部６から演算手段７に実際の駆動輪１０の回転速度と回転量の情報が送られる。自走式掃除機４の前下部には掃除機部８が設けられており、自走式掃除機４の移動とともに床面に散乱したごみ等を吸い込む。演算手段７はこの掃除機部８にも接続されており、掃除機部８の運転と停止を制御する。演算手段７はさらに、記憶手段９と接続されている。記憶手段９は、広指向角の受光素子２の受光強度と、発光体５に対する光センサユニット１の姿勢角の関係についての情報を記憶する。演算手段７の指令情報および記憶手段に記憶される情報は、この自走式掃除機４に設けた図示しない入力手段または、この自走式掃除機４とは別体に設けたリモコンから入力される。
【００１０】
このように構成した自走式掃除機に搭載される光センサユニットの詳細を、図２および図３に示す。図２は、光センサユニットの斜視図である。光センサユニット１は、円筒形状をしており、その外周部に広指向角の受光素子２と狭指向角の受光素子３が配置されている。図３に、光センサユニット１の横断面図を示す。広指向角の受光素子２を、円周方向６０度おきに６個配置する。各受光素子２の受光可能な入射角範囲は、光軸から左右にそれぞれ６０度以上になっており、入射角で１２０度以上の範囲については、発光体５からの赤外光１１を検出できる。これにより、３６０度どの方向に発光体５が存在しても、いずれかの隣り合う２個の広指向角の受光素子２が、赤外光１１を検出できる。
【００１１】
狭指向角の受光素子３は、円周方向に１か所だけ設けられており、広指向角の受光素子２、２の中間に位置している。狭指向角の受光素子３の前面には図示しないスリットが形成されている。このスリットは、発光体５が発光する赤外光１１の受光可能な範囲、すなわち入射角の方向と広さを調整する。これにより、狭指向角の受光素子３の受光範囲を、広指向角の受光素子２の受光範囲に比べて狭くしている。
【００１２】
図４に、図１に示した自走式掃除機４の上面図を示す。光センサユニット１は、２個の駆動輪１０の中央部の真上に位置している。駆動輪１０の一方を正転させ、もう一方を同じ速度で逆転させると、自走式掃除機は光センサユニット１を中心に、その場で回転する。
【００１３】
広指向角の受光素子２の赤外線１１に対する感度Ｓと入射角θの関係を、図５に示す。受光素子２の感度は、受光素子２に垂直な方向からの入射時にピークとなり、入射角が垂直方向からずれるにつれて急激に感度が低くなる。図６および図７を用いて、光センサユニット１の受光範囲を説明する。図６の位置に発光体５が位置した場合には、広指向角の受光素子２ａ、２ｂの２つの受光素子が受光可能である。このときの受光素子２ａ、ｂの感度Ｓ_２ａ、Ｓ_２ｂを示したのが、図５である。
【００１４】
光センサユニット１と発光体５との距離が充分に離れている場合は、各受光素子２ａ、２ｂから発光体５までの距離はほぼ等しいとみなされる。そこで、発光体５までの距離が略等しい関係から各受光素子２ａ、２ｂが光センサユニット１の中央にあると摸擬する。そして、各受光素子２ａ、２ｂの受光強度の比を用いて光センサユニット１の中央部における受光強度を求め、光センサユニット１に対する発光体５の方向を求める。
【００１５】
本方法を用いれば、発光体５がどの方向にあっても広指向角の受光素子２のうち２個以上が受光可能となる。したがって、受光量が上位２個の素子を選んで受光量の比を求めれば、発光体５の方向を定めることができる。さらに円周上に配置した全部の広指向角の受光素子２の受光強度を同時に検出できるようにすれば、自走式掃除機４の走行中にも、発光体５の位置を検出できる。
【００１６】
狭指向角の受光素子３の感度特性を、図８に示す。図８の細い実線は、スリットを形成しないときの感度分布特性であり、太い実線はスリットを形成した場合である。図７にこの狭指向角の受光素子３で発光体５を検出する様子を示す。スリットを形成したことにより、狭指向角の受光素子３は略垂直に入射する発光素子５ｂからの赤外光しか受光できない。すなわち図７に示すように、発光体５が狭指向角の受光素子３の垂直面から離れた方向にある発光体５ａのときは、感度は図８に示すように略０となる。
【００１７】
なお、狭指向角の受光素子３が赤外線１１を検出したかどうかにより、発光体５が光センサユニット１の所定方向にあるかどうかを判別する。狭指向角の受光素子３の分解能は、受光素子３の検出可能な入射角の範囲により定まる。また、受光素子の特性が図８において細線で示したように左右対称であっても、受光可能な入射角の範囲はスリットにより定まる。
【００１８】
図９に、自走式掃除機４が狭指向角の受光素子３を用いて発光体５を検出する例を示す。自走式掃除機４をその場で回転させ、狭指向角の受光素子３が赤外線１１を検出した方向を発光体５の方向とみなす。狭指向角の受光素子３の受光可能範囲が要求される分解能よりも広い場合には、自走式掃除機４をその場で回転させる際に、狭指向角の受光素子３が赤外線１１を検出し始めた方向と赤外線１１を検出できなくなった方向との２つの方向の中間の方向を発光体５の方向とみなす。
【００１９】
図１０に、発光体５の方向を検出する際の情報の流れを示す。狭指向性の受光素子３の受光量に基づいて演算手段７が受光の有無を判定する。受光素子３が受光していると判定したときは、そのときの発光体５の方向を角度情報として記憶し、走行経路を計画するときに用いる。一方、広指向性の受光素子２の受光強度を、記憶手段９に記憶されている方向検出データベースと比較するために、比較可能な形に変換する。つまり、広指向性の受光素子２のなかで最も受光強度が強い素子と、２番目に受光強度が強い素子の受光強度の比から評価関数を決定し、データベースの記憶値と比較する。評価関数は受光強度の比と１対１に対応するものであれば良い。
【００２０】
評価関数の値と評価関数を求めるためにどの素子の受光強度を用いたかの情報とを、方向検出データベースと照合する。方向検出データベースには、発光体５が各方向に存在するときの評価関数の値と評価関数を求めるためにどの素子を用いたかが記録されている。方向検出データベースと評価関数を照合するときは、評価関数の値を求めるのに用いた素子のデータを、データベースから検索する。次に検索されたデータを補間もしくは外挿する。これにより、評価関数の値に対応する方向が求められる。この方向は走行経路を計画するときに用いられる。
【００２１】
広指向角の受光素子２は方向検出データベースのデータに基づいて発光体５の方向を検出する。経年変化や光学系の汚れなどで素子の特性が変化したときは、方向検出データベースを再構築する。図１１に、方向検出データベースの再構築のフローチャートを示す。
【００２２】
ステップ１００で再構築を開始する。狭指向角の受光素子３を用いて、正確な発光体５の方向を検出する(ステップ１１０)。次に上述した評価関数を計算する(ステップ１２０)。発光体５の方向、評価関数の値および評価関数の値を求めるのに用いた広指向角の受光素子２の番号を記憶手段９に記憶する(ステップ１３０)。
【００２３】
所定の角度だけ自走式掃除機４を、その場で回転させる。このときの回転の角度は駆動輪１０に取り付けたエンコーダから求める（ステップ１４０）。方向検出データベースの再構築を始めてから、自走式掃除機４を合計３６０度以上回転したか否かを判断する(ステップ１５０)。３６０度以上回転していれば方向検出データベースの再構築を終了する（ステップ１６０）。自走式掃除機４の回転が３６０度に満たない場合は、ステップ１２０に戻る。以下、上述したステップを繰り返す。
【００２４】
以上の動作を実行すると、広指向角のセンサ２が発光体５の方向を正確に検出できる。方向検出データベースをユーザが任意に再構築することもできるし、自走式掃除機４を起動するごとに再構築しても良い。また、狭指向角の受光素子３が発光体５の方向を検出し、広指向角の受光素子２も発光体５の方向を検出したときであって、２種の受光素子２、３の検出角度の差が大きくなったときに自動的に実行するようにしても良い。なお、この場合、データベースを再構築せずに、ユーザに対してデータベースの再構築を促す表示をするようにしてもよい。
【００２５】
図１２に、発光体５を基準にして位置を検出する方法を示す。発光体５ｃ、５ｄを自走式掃除機４の使用環境に設置する。発光体５ｃ、５ｄが発する赤外線１１、１１は、それぞれ異なる変調周波数で変調されている。この変調周波数の違いにより、発光源を区別できる。自走式掃除機４は、図の左方であるＡの位置で発光体５ｃ、５ｄの方向を検出する。この点Ａから距離Ｌだけ右方に離れた位置Ｂまで自走式掃除機４が走行したことを計測するのに、自走式掃除機４の駆動輪１０に取り付けたエンコーダ(図示せず)を使用する。
【００２６】
位置Ｂで、再度発光体５ｃ、５ｄの方向を検出する。この動作により、自走式掃除機４の移動方向に対する発光体５ｃ、５ｄの方向が求められる。すなわち、発光体５ｃの位置Ａにおける方向はθAcであり、発光体５ｄの位置Ａにおける方向はθAdであり、発光体５ｃの位置Ｂにおける方向はθBcであり、発光体５ｄの位置Ｂにおける方向はθBdである。これらの角度と、自走式掃除機４の移動距離Ｌとから、三角測量の原理を用いて、発光体５ｃ、５ｄと自走式掃除機４の相対的な位置関係が求められる。なお、発光体５ｃ、５ｄの座標が既知であれば、位置Ａ、Ｂの座標を求めることもできる。
【００２７】
なお、上記実施例では移動体として自走式掃除機を例に取り説明したが、工場内で使用される無人搬送車や各種自走ロボットに本発明を適用できることは言うまでもない。無人搬送車の場合、発光体位置を求めるのが容易であり、かつ通常搬送路は概略定まっているので、高精度に搬送車の位置決め等が可能になる。
【００２８】
【発明の効果】
以上述べたように本発明によれば、予め設定した発光体の移動体に対する方向角度を三角測量の原理を用いて求めることができるので、方向検出装置の可動部品数を低減でき、方向検出装置の信頼性を高めるとともに、安価に方向検出装置を実現できる。
【図面の簡単な説明】
【図１】本発明に係る自走式掃除機の一実施例の模式図。
【図２】図１に示した自走式掃除機に用いられる光センサユニットの斜視図。
【図３】図２の光センサユニットの横断面図。
【図４】図１に示した自走式掃除機の上面図。
【図５】第１の受光手段の感度を説明するグラフ。
【図６】第１の受光手段を説明する図。
【図７】第２の受光手段を説明する図。
【図８】第２の受光手段の感度を説明するグラフ。
【図９】図１に示した自走式掃除機の動作を説明する図。
【図１０】方向検出時の情報の流れを説明するブロック図。
【図１１】方向検出データベースの再構築の手順を説明するフローチャート。
【図１２】図１に示した自走式掃除機の動作を説明する図。
【符号の説明】
１…光センサユニット、２、２ａ、２ｂ…広指向角の受光素子(第１の受光手段)、３…狭指向角の受光素子(第２の受光手段)、４…移動体、５、５ａ、５ｂ、５ｃ、５ｄ…発光体、６…駆動系制御部、７…演算手段、９…記憶手段、１０…駆動輪。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a direction detection device, and more particularly to a direction detection device suitable for a self-propelled cleaner or a self-propelled carriage.
[0002]
[Prior art]
An example of a conventional position detection device used for a self-propelled moving body is described in Japanese Patent Laid-Open No. 7-311041. In order to autonomously grasp the current position, this position detection device has two light receiving units attached to a top surface of a moving body having drive wheels at a position that is a predetermined distance in plan. These light receiving parts can be turned. At the same time, two light-emitting portions are attached to the side surface of the reference station at a position that is a predetermined distance in plan. When sampling is performed while the light receiving unit on the moving body is turning, the amount of received light changes. The relative position and the relative attitude angle are obtained based on the turning angle at which the amount of received light is peaked.
[0003]
[Problems to be solved by the invention]
In the position detection method described in the above publication, since two sets of pivotable light receiving shafts are provided on the moving body, the configuration of the light receiving unit is complicated. For this reason, when these photoreceptors are mounted on a household vacuum cleaner or the like, this is an obstacle to downsizing.
[0004]
The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to downsize a direction detection device mounted on a moving body. Another object of the present invention is to realize an inexpensive direction detecting device.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a direction detecting device including a light emitter fixed by emitting light, and a light sensor unit mounted on a moving body. The light sensor unit emits light from the light emitter. A plurality of first light receiving means for receiving the received light, and a second light receiving means having a narrow incident range capable of receiving light than the first light receiving means, and rotating the movable body to provide the second light receiving means . In order to obtain the evaluation function value and evaluation function corresponding to the ratio of the received light intensity of each of the first light receiving means when the light emitting body exists in each direction based on the direction in which the light receiving means detects the light emitting body. A direction detection database that records which element of the first light receiving means is used is constructed, and the direction of the light emitter is detected based on the data of the direction detection database.
[0007]
As another feature for achieving the above object, the mobile body is a self-propelled cleaner, and the direction detection device having any one of the above features is mounted.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of a direction detection device according to the present invention mounted on a self-propelled cleaner will be described with reference to the drawings. In FIG. 1, the schematic diagram of a self-propelled cleaner is shown. An optical sensor unit 1 that emits infrared rays is attached to the upper part of the self-propelled cleaner 4. A light emitter 5 is fixed at a position away from the self-propelled cleaner 4. The optical sensor unit 1 includes a light receiving element 2 having a wide directional angle and a light receiving element 3 having a narrow directional angle in order to receive the modulated infrared ray 11 emitted from the light emitter 5. Information on the received light intensity of each of the light receiving elements 2 and 3 is sent to a calculation means 7 provided in the self-propelled cleaner 4.
[0009]
The calculation means 7 is connected to a control unit 6 of a drive system that drives the self-propelled cleaner 4. The drive system has a pair of drive wheels 10, and the calculation means 7 instructs the drive system control unit 6 on the rotation speed and the rotation amount of the drive wheels 10. When the drive wheel 10 rotates at the rotation speed and the rotation amount according to the command from the calculation means 7, information on the actual rotation speed and rotation amount of the drive wheel 10 is sent from the drive system control unit 6 to the calculation means 7. A vacuum cleaner unit 8 is provided at the front lower part of the self-propelled cleaner 4, and sucks dust and the like scattered on the floor surface with the movement of the self-propelled cleaner 4. The calculation means 7 is also connected to the cleaner unit 8 and controls the operation and stop of the cleaner unit 8. The computing means 7 is further connected to the storage means 9. The storage unit 9 stores information on the relationship between the light receiving intensity of the light receiving element 2 having a wide directivity angle and the attitude angle of the optical sensor unit 1 with respect to the light emitter 5. The command information of the calculation means 7 and the information stored in the storage means are input from an input means (not shown) provided in the self-propelled cleaner 4 or a remote controller provided separately from the self-propelled cleaner 4. The
[0010]
Details of the optical sensor unit mounted on the self-propelled cleaner configured as described above are shown in FIGS. FIG. 2 is a perspective view of the optical sensor unit. The optical sensor unit 1 has a cylindrical shape, and a light receiving element 2 having a wide directivity angle and a light receiving element 3 having a narrow directivity angle are disposed on the outer periphery thereof. FIG. 3 shows a cross-sectional view of the optical sensor unit 1. Six light receiving elements 2 with wide directivity are arranged every 60 degrees in the circumferential direction. The incident angle range in which each light receiving element 2 can receive light is 60 degrees or more on the left and right from the optical axis, and the infrared light 11 from the light emitter 5 can be detected in the range where the incident angle is 120 degrees or more. . Thus, regardless of which direction the light emitter 5 is 360 degrees, any two adjacent light-receiving elements 2 having a wide directivity angle can detect the infrared light 11.
[0011]
The light receiving element 3 with a narrow directivity angle is provided only in one place in the circumferential direction, and is positioned between the light receiving elements 2 and 2 with a wide directivity angle. A slit (not shown) is formed on the front surface of the light receiving element 3 having a narrow directivity angle. This slit adjusts the range in which the infrared light 11 emitted from the light emitter 5 can be received, that is, the direction and width of the incident angle. As a result, the light receiving range of the light receiving element 3 with a narrow directivity angle is made narrower than the light receiving range of the light receiving element 2 with a wide directivity angle.
[0012]
FIG. 4 shows a top view of the self-propelled cleaner 4 shown in FIG. The optical sensor unit 1 is located immediately above the center of the two drive wheels 10. When one of the drive wheels 10 is rotated forward and the other is rotated at the same speed, the self-propelled cleaner rotates around the optical sensor unit 1 on the spot.
[0013]
FIG. 5 shows a relationship between the sensitivity S of the light receiving element 2 having a wide directivity angle to the infrared ray 11 and the incident angle θ. The sensitivity of the light receiving element 2 peaks when incident from a direction perpendicular to the light receiving element 2, and the sensitivity rapidly decreases as the incident angle deviates from the vertical direction. The light receiving range of the optical sensor unit 1 will be described with reference to FIGS. 6 and 7. When the light emitter 5 is positioned at the position shown in FIG. 6, the two light receiving elements 2a and 2b having wide directivity can receive light. FIG. 5 shows the sensitivities S _2a and S _2b of the light receiving elements 2a and _2b at this time.
[0014]
When the distance between the optical sensor unit 1 and the light emitter 5 is sufficiently large, the distances from the light receiving elements 2a and 2b to the light emitter 5 are considered to be substantially equal. Therefore, it is simulated that each light receiving element 2a, 2b is in the center of the optical sensor unit 1 because the distance to the light emitter 5 is substantially equal. Then, the received light intensity at the center of the optical sensor unit 1 is obtained using the ratio of the received light intensity of each of the light receiving elements 2a and 2b, and the direction of the light emitter 5 with respect to the optical sensor unit 1 is obtained.
[0015]
If this method is used, two or more of the light receiving elements 2 having a wide directivity angle can receive light regardless of the direction of the light emitter 5. Therefore, the direction of the light emitter 5 can be determined by selecting the top two elements with the light reception amount and determining the ratio of the light reception amounts. Further, if the light receiving intensities of all the light receiving elements 2 having wide directivity angles arranged on the circumference can be detected simultaneously, the position of the light emitter 5 can be detected even while the self-propelled cleaner 4 is traveling.
[0016]
FIG. 8 shows the sensitivity characteristics of the light receiving element 3 having a narrow directivity angle. The thin solid line in FIG. 8 is the sensitivity distribution characteristic when the slit is not formed, and the thick solid line is the case where the slit is formed. FIG. 7 shows how the light emitter 5 is detected by the light receiving element 3 having a narrow directivity angle. By forming the slit, the light receiving element 3 with a narrow directivity angle can receive only infrared light from the light emitting element 5b that is incident substantially vertically. That is, as shown in FIG. 7, when the light emitter 5 is a light emitter 5a in a direction away from the vertical plane of the light receiving element 3 having a narrow directivity angle, the sensitivity is substantially zero as shown in FIG.
[0017]
Whether or not the light emitter 5 is in a predetermined direction of the optical sensor unit 1 is determined depending on whether or not the light receiving element 3 having a narrow directivity angle has detected the infrared ray 11. The resolution of the light receiving element 3 having a narrow directivity angle is determined by the range of incident angles that can be detected by the light receiving element 3 . Even if the characteristics of the light receiving element are symmetrical as shown by thin lines in FIG. 8, the range of incident angles at which light can be received is determined by the slits.
[0018]
FIG. 9 shows an example in which the self-propelled cleaner 4 detects the light emitter 5 using the light receiving element 3 having a narrow directivity angle. The self-propelled cleaner 4 is rotated on the spot, and the direction in which the light receiving element 3 with a narrow directivity angle detects the infrared rays 11 is regarded as the direction of the light emitter 5. When the light receivable range of the light receiving element 3 with the narrow directivity is wider than the required resolution, the light receiving element 3 with the narrow directivity detects the infrared rays 11 when the self-propelled cleaner 4 is rotated on the spot. The direction between the two directions of the direction in which the infrared rays 11 can no longer be detected is regarded as the direction of the light emitter 5.
[0019]
FIG. 10 shows the flow of information when detecting the direction of the light emitter 5. Based on the amount of light received by the light receiving element 3 having a narrow directivity, the calculation means 7 determines whether light is received. When it is determined that the light receiving element 3 is receiving light, the direction of the light emitter 5 at that time is stored as angle information and used when planning a travel route. On the other hand, the received light intensity of the wide directional light receiving element 2 is converted into a comparable form for comparison with the direction detection database stored in the storage means 9. In other words, the evaluation function is determined from the ratio of the light receiving intensity of the element having the strongest light receiving intensity and the element having the second highest light receiving intensity among the light receiving elements 2 having the wide directivity, and compared with the stored value of the database. The evaluation function only needs to have a one-to-one correspondence with the ratio of received light intensity.
[0020]
The direction detection database is collated with the value of the evaluation function and information indicating which element's received light intensity is used to obtain the evaluation function. In the direction detection database, the value of the evaluation function when the light emitter 5 exists in each direction and which element is used to obtain the evaluation function are recorded. When collating the direction detection database with the evaluation function, the data of the element used for obtaining the value of the evaluation function is searched from the database. Next, the retrieved data is interpolated or extrapolated. Thereby, the direction corresponding to the value of the evaluation function is obtained. This direction is used when planning a travel route.
[0021]
The light receiving element 2 having a wide directivity angle detects the direction of the light emitter 5 based on the data of the direction detection database. When the element characteristics change due to secular change or contamination of the optical system, the direction detection database is reconstructed. FIG. 11 shows a flowchart of rebuilding the direction detection database.
[0022]
In step 100, reconstruction is started. Using the light receiving element 3 having a narrow directivity angle, the accurate direction of the light emitter 5 is detected (step 110). Next, the above-described evaluation function is calculated (step 120). The direction of the light emitter 5, the value of the evaluation function, and the number of the light receiving element 2 with a wide directivity used for obtaining the value of the evaluation function are stored in the storage means 9 (step 130).
[0023]
The self-propelled cleaner 4 is rotated on the spot by a predetermined angle. The rotation angle at this time is obtained from an encoder attached to the drive wheel 10 (step 140). After the reconstruction of the direction detection database is started, it is determined whether or not the self-propelled cleaner 4 has rotated a total of 360 degrees or more (step 150). If the rotation is 360 degrees or more, the reconstruction of the direction detection database is terminated (step 160). If the rotation of the self-propelled cleaner 4 is less than 360 degrees, the process returns to step 120. Thereafter, the above steps are repeated.
[0024]
When the above operation is executed, the sensor 2 with a wide directivity angle can accurately detect the direction of the light emitter 5. The direction detection database can be arbitrarily reconstructed by the user, or may be reconstructed every time the self-propelled cleaner 4 is activated. The light receiving element 3 with a narrow directivity angle detects the direction of the light emitter 5, and the light receiving element 2 with a wide directivity angle also detects the direction of the light emitter 5. It may be automatically executed when the angle difference becomes large. In this case, the user may be prompted to reconstruct the database without reconstructing the database.
[0025]
FIG. 12 shows a method for detecting the position with the light emitter 5 as a reference. The light emitters 5c and 5d are installed in an environment where the self-propelled cleaner 4 is used. Infrared rays 11 and 11 emitted from the light emitters 5c and 5d are modulated at different modulation frequencies. The light source can be distinguished by the difference in the modulation frequency. The self-propelled cleaner 4 detects the direction of the light emitters 5c and 5d at the position A on the left side of the figure. An encoder (not shown) attached to the drive wheel 10 of the self-propelled cleaner 4 is used to measure that the self-propelled cleaner 4 has traveled to a position B that is separated from the point A by a distance L to the right. Is used.
[0026]
At the position B, the direction of the light emitters 5c and 5d is detected again. By this operation, the direction of the light emitters 5c and 5d with respect to the moving direction of the self-propelled cleaner 4 is obtained. That is, the direction at the position A of the light emitter 5c is θAc, the direction at the position A of the light emitter 5d is θAd, the direction at the position B of the light emitter 5c is θBc, and the direction at the position B of the light emitter 5d is θBd. From these angles and the moving distance L of the self-propelled cleaner 4, the relative positional relationship between the light emitters 5c and 5d and the self-propelled cleaner 4 is obtained using the principle of triangulation. If the coordinates of the light emitters 5c and 5d are known, the coordinates of the positions A and B can be obtained.
[0027]
In the above embodiment, the self-propelled cleaner is taken as an example of the moving body, but it goes without saying that the present invention can be applied to automatic guided vehicles and various self-propelled robots used in factories. In the case of an automatic guided vehicle, it is easy to obtain the position of the light emitter, and since the normal transport path is roughly determined, it is possible to position the transport vehicle with high accuracy.
[0028]
【The invention's effect】
As described above, according to the present invention, since the direction angle of the preset light emitter with respect to the moving body can be obtained using the principle of triangulation, the number of movable parts of the direction detection device can be reduced, and the direction detection device The direction detection device can be realized at a low cost.
[Brief description of the drawings]
FIG. 1 is a schematic view of an embodiment of a self-propelled cleaner according to the present invention.
FIG. 2 is a perspective view of an optical sensor unit used in the self-propelled cleaner shown in FIG.
3 is a cross-sectional view of the photosensor unit of FIG.
4 is a top view of the self-propelled cleaner shown in FIG. 1. FIG.
FIG. 5 is a graph for explaining the sensitivity of the first light receiving means.
FIG. 6 is a diagram illustrating a first light receiving unit.
FIG. 7 is a diagram illustrating a second light receiving unit.
FIG. 8 is a graph for explaining the sensitivity of the second light receiving means.
FIG. 9 is a diagram for explaining the operation of the self-propelled cleaner shown in FIG. 1;
FIG. 10 is a block diagram illustrating the flow of information when detecting a direction.
FIG. 11 is a flowchart for explaining a procedure for reconstructing a direction detection database;
12 is a diagram for explaining the operation of the self-propelled cleaner shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical sensor unit 2, 2a, 2b ... Light receiving element (first light receiving means) with wide directivity angle, 3 ... Light receiving element with narrow directivity angle (second light receiving means), 4 ... Moving body, 5, 5a 5b, 5c, 5d ... luminous body, 6 ... drive system controller, 7 ... computing means, 9 ... storage means, 10 ... drive wheel.

Claims

In a direction detection device including a light emitter fixed by emitting light and a light sensor unit mounted on a moving body, a plurality of first light receiving light emitted from the light emitter is received by the light sensor unit. And a second light receiving means having a narrow incident range capable of receiving light than the first light receiving means ,
Based on the direction in which the moving body is rotated and the second light receiving means detects the light emitting body, the evaluation corresponding to the light reception intensity ratio of each first light receiving means when the light emitting body exists in each direction. A direction detection database in which which element of the first light receiving means is used to obtain the function value and the evaluation function is recorded, and the direction of the light emitter is detected based on the data of the direction detection database. that direction detecting apparatus.

The direction detecting device according to claim 1, wherein the moving body is provided with means for detecting a moving amount of the moving body.

The first and second light receiving means are provided on an outer peripheral portion of a light receiving surface formed substantially on a cylinder, and the second light receiving means is provided in the traveling direction of the moving body or in the opposite direction. The direction detection device according to claim 1, wherein

The said mobile body is a self-propelled cleaner, The self-propelled cleaner characterized by mounting the direction detection apparatus of Claim 1 .