JP4323758B2 - Work transfer system - Google Patents

Description

同様にして、ステーションＢについては表２に、ステーションＣについては表３に示すようになっている。
【表２】

【表３】

これら表１〜表３の接続形態は、接続情報として各ステーションコントローラ６に記憶されている。
【００３９】
ステーションコントローラ６は、ステーション５を介して自走式ワーク搬送パレット２と通信しこの自走式ワーク搬送パレット２の制御を行う制御手段である。図１に示すように、本実施形態では上述のステーション５Ａ，５Ｂ，５Ｃに対応して符号６Ａ，６Ｂ，６Ｃで示す３つのステーションコントローラ６が設けられており、各ステーションコントローラ６Ａ〜６Ｃが各ステーション５Ａ〜５Ｃ毎に対応することで分散制御できるようになっている。本実施形態のステーションコントローラ６は他のステーションコントローラ６および上位装置７と接続された状態でいわゆるバス型のネットワークを形成する。
【００４０】
またステーションコントローラ６は、処理手順プログラムを記憶する記憶手段と、この処理手順プログラムを実行する実行手段を備えており、自走式ワーク搬送パレット２に対し処理手順プログラムに基づく動作信号を送信し、前進あるいは後退等の動作を指示する。動作信号は、自走式ワーク搬送パレット２ごとに異なる動作をさせるように、自走式ワーク搬送パレット２の記憶手段に記憶されている固有情報に基づいて送信される。またステーションコントローラ６はステーション５を介して自走式ワーク搬送パレット２と通信する通信手段２６、および自走式ワーク搬送パレット２や上位装置７との間でデータ授受を行うデータ授受手段を有しており、対応する作業ステーション上の自走式ワーク搬送パレット２の有無を検出する手段を有する。さらにこのステーションコントローラ６Ａ〜６Ｃは、対応する作業ステーション５Ａ〜５Ｃ上の自走式ワーク搬送パレット２の固有情報をこの作業ステーション５Ａ〜５Ｃを経由して読み出す。加えて、ステーションコントローラ６Ａ〜６Ｃは自走式ワーク搬送パレット２の固有情報を基に適切な動作信号を送信する。ステーションコントローラ６は、上位装置７からの所定の処理手順プログラムを受信する受信手段を備えている。
【００４１】
上位装置７はステーションコントローラ６とネットワーク接続され、処理手順プログラムを各ステーションコントローラ６に送信するサーバとしての送信手段を有した装置で、本実施形態の場合は各ステーションコントローラ６と図１に示すように接続されてバス型ネットワークを構築している。ただし、この上位装置７は常にステーションコントローラ６と接続されている必要はなく、処理手順プログラムを送信するなどの必要時のみ接続されていれば足りる。上位装置７は、ステーションコントローラ６との間でデータ授受するためのデータ授受手段を有している。なお、上位装置７は処理手順プログラムを入力するための入力手段を有していればプログラムを直接入力することも可能となる点で好ましい。また、上位装置７はステーションコントローラ６に送信された処理手順プログラムによる自走式ワーク搬送パレット２の動きをシミュレーションできるシミュレーション手段を有していれば実際に自走式ワーク搬送パレット２を走行させる前に走行状態を模擬することができて好適である。さらに、上位装置７はステーションコントローラ６に送信された処理手順プログラムを実行しあるいは中断することができるように設けられていれば、ステーションコントローラ６からだけでなくこの上位装置７からもプログラム実行あるいは中断が可能となって好適である。
【００４２】
続いて、本実施形態のワーク搬送システム１における自走式ワーク搬送パレット２に対する処理手順の流れを示す。各ステーションコントローラ６では、図３に示すフローチャートに基づいて処理手順プログラムを実行する。なお、ここでの処理手順プログラムは各ステーションコントローラ６において共通のものである。
【００４３】
まず、自走式ワーク搬送パレット２がステーション５に到着するまで待機する（ステップ１）。ステーションコントローラ６はステーション５上のパレット有無センサによって自走式ワーク搬送パレット２の到着を確認する。到着後、ワーク載置部９は自走式ワーク搬送パレット２の本体から外れてステーション５内の所定位置に位置決めされる。ワーク載置部９の位置決めが完了したらこのことを作業者に通知する（ステップ２）。この場合の作業者はワーク４の組立等を実際の行う者で、人間だけでなくロボットも含まれる。作業中、作業者から作業完了通知がなされるまで待機する（ステップ３）。作業完了が通知されたら、ステーションコントローラ６（例えばステーションコントローラ６Ａ）はワーク載置部９の位置決めを解除し、保有している接続情報に基づき次のステーションコントローラ６（例えばステーションコントローラ６Ｂ）に対してステーション５Ｂが占有可能か（すなわち、ステーション５Ｂが空いていて現在ステーション５Ａで待機している自走式ワーク搬送パレット２が第２のステーション５Ｂに進むことができるか）を問い合わせる（ステップ４）。問合せを受けたステーションコントローラ６（例えばステーションコントローラ６Ｂ）は、ステーション５Ｂに自走式ワーク搬送パレット２が無い場合に進入を許可する。許可を受けたステーションコントローラ６Ａは、自走式ワーク搬送パレット２に発車指示を出し（ステップ５）、接続先ステーション５（ステーション５Ｂ）に向けて発進させる。この時、現ステーション５Ａの占有が解除され、次の自走式ワーク搬送パレット２の進入が可能となり、再び自走式ワーク搬送パレット２の到着を待つ待機状態となる（ステップ１）。
【００４４】
以上から解るように、本実施形態のワーク搬送システム１では、各ステーションコントローラ６で同一の処理手順プログラムを実行しておき、表１〜表３のデータ（接続情報）をそれぞれのステーションコントローラ６で保有することで、複数の自走式ワーク搬送パレット２をあたかも同期させて搬送することが可能となり、従来１個送り加工（それぞれのワーク搬送パレットの同期をとって走行させながら行う加工）で使用されている同期送り搬送をすることができる。すなわち、▲１▼ステーションコントローラ６同士でステーション占有の可否の問合せや許可のデータ交換を行い、▲２▼上位装置７から送られた接読情報を記憶し、▲３▼その接続情報を元に処理手順プログラムを実行することで自走式ワーク搬送パレットを走行させワーク４を搬送することができる。
【００４５】
なお、自走式ワーク搬送パレット２側に車間センサが装備されている場合は次のステーションコントローラ６の許可を待たずに自走式ワーク搬送パレット２を発車させることにより、コンベア搬送におけるフリーフロー搬送（コンベアによってワークが個別で搬送されている場合にワークのみを所定位置で引っ掛けるなどして停止させる非同期搬送方法の一種）と同等の動作が可能となる。この場合は、図３に示したフローチャートにおいてステップ４を飛ばしたのと同等の動作となる。
【００４６】
続いて本発明の第二の実施形態を説明する。
【００４７】
この実施形態におけるワーク搬送システム１は、図９に示すように、ステーション５Ａ〜５Ｃが直列的に接続されている点で第一の実施形態と共通だが、ステーション５Ｃにて工程３が済んだ後、再び中央のステーション５Ｂにて別工程（工程４）が行われる点で異なる。したがってこの第二実施形態では、ステーション５Ｃまで進んだ自走式ワーク搬送パレット２はいったんステーション５Ｂまで戻り、工程４の終了後、再びステーション５Ｃを通過してその先に進むという動作をする。
【００４８】
この場合、自走式ワーク搬送パレット２がステーション５Ｃでの工程３を終えるまでの間に後続の自走式ワーク搬送パレット２がステーション５Ｂに進入してしまうと（図１０参照）、先行する自走式ワーク搬送パレット２はステーション５Ｂに戻れなくなり、後続の自走式ワーク搬送パレット２はステーション５Ｃに進めない状態となる（以下、この状態を「デッドロック」と呼ぶ）。そこで、本実施形態ではデッドロックを回避すべく、自走式ワーク搬送パレット２を以下のように動作させるようにしている。
【００４９】
すなわち、先行する自走式ワーク搬送パレット２がステーション５Ｂとステーション５Ｃのいずれかを占有し、あるいはこれらステーション５Ｂ，５Ｃ間の軌道３上に位置している限り、ステーション５Ａで待機する後続の自走式ワーク搬送パレット２をこのステーション５Ａから発車させないようにする。先行する自走式ワーク搬送パレット２は、図１１に示すようにステーション５Ｂでの工程２を終えるとステーション５Ｃに進みいったんステーション５Ｂを空けるが、工程３を終えると図１２に示すように再びステーション５Ｂに戻ってくる。この間、後続の自走式ワーク搬送パレット２は発車せずにステーション５Ａで待機し続け、この後、先行する自走式ワーク搬送パレット２が工程４を終えて移動しステーション５Ｂ及びステーション５Ｃの両方が空いたのを確認してからステーション５Ｂに向けて発車する（図１３参照）。この場合、先行する自走式ワーク搬送パレット２と後続の自走式ワーク搬送パレット２との間におけるデッドロックが回避できる。
【００５０】
本実施形態では、以上のようなデッドロック回避動作を実現するため、例えば表４に示すような工程定義表（作業工程と搬送経路との関係）を作成しこれを利用して自走式ワーク搬送パレット２等を動作させている。工程定義表は「工程番号」、「自工程までの経路」、「出発時占有ステーション」、「出発時解放ステーション」そして「次工程番号」の各項目からなる。「工程番号」は図９に示した工程１〜工程４に対応している。図示していないが、第４の作業ステーションを５Ｄとし、ここで行われる工程の番号を５としている。「自工程までの経路」は、自走式ワーク搬送パレット２が前工程から現工程（自工程）まで進むとき、どの作業ステーション５のどのポート８を通って現在の作業ステーション５まで移動してきたかを示している。「出発時占有ステーション」は、現在の作業ステーション５から出発した自走式ワーク搬送パレット２がその後に占有する（単に通過だけの場合を含む）作業ステーションを示す。「出発時解放ステーション」は、自走式ワーク搬送パレット２が現在占有している作業ステーション５であって出発することにより解放される（空きとなる）ステーションを示す。
【表４】

【００５１】
また各ステーションコントローラ６Ａ〜６Ｃは、第一の実施形態で示した接続情報に加え、ステーション５Ａ〜５Ｃに関連する工程定義表の内容を記憶している。さらに、自走式ワーク搬送パレット２は内蔵する記憶手段によって自走式ワーク搬送パレット２自身の現在の工程番号を記憶している。
【００５２】
本実施形態における各ステーションコントローラ６は、図１４に示すフローチャートに基づいたプログラムを実行する。すなわち、対応するステーション５（例えばステーションコントローラ６Ａについてはステーション５Ａ）に自走式ワーク搬送パレット２が到着するのを待ち（ステップ１１）、自走式ワーク搬送パレット２が到着したらこの自走式ワーク搬送パレット２より現在の工程番号を取得する（ステップ１２）。そして、対応ステーション５がこの取得した工程番号に対応するステーションかどうかを確認する（ステップ１３）。対応ステーション５が該当しない場合は直ちにステップ１８に進み、出発ポート８の取得を行って出発動作に移る。例えば本実施形態でいえば、工程４を終了して工程５へ向かうときの自走式ワーク搬送パレット２が単に通過するに過ぎない第３ステーション５Ｃは、自走式ワーク搬送パレット２に対し何ら組立等の作業をするわけでなくこの「対応ステーション５が該当しない場合」に当たる。
【００５３】
一方、対応ステーション５が該当することを確認した場合は、自走式ワーク搬送パレット２が到着したことを作業者に通知し（ステップ１４）、ワーク４に対する組立、加工等の作業が完了するまで待つ（ステップ１５）。また、作業を終えた自走式ワーク搬送パレット２が出発する準備として、工程番号に基づき上述の「出発時占有ステーション」及び「出発時解放ステーション」の情報を取得する（ステップ１６）。取得後、自走式ワーク搬送パレット２が記憶している工程番号を次工程番号へ書き換え更新する（ステップ１７）。
【００５４】
続いて、更新した工程番号の「自工程までの経路」データより、出発ポート８を取得（決定）する（ステップ１８）。出発ポート取得後、接統情報に基づいて次のステーション５を決定する。さらに、ステップ１６で取得した「出発時占有ステーション」及びステップ１８に基づき決定した次ステーション５が占有可能かどうか確認する（ステップ１９）。出発時占有ステーションと次ステーション５との占有が可能であることを確認できたら、自走式ワーク搬送パレット２に出発指示を出す（ステップ２０）。自走式ワーク搬送パレット２が出発することにより当該ステーション５は解放される。この後、ステーションコントローラ６は再び自走式ワーク搬送パレット２の到着を待つ状態に戻る（ステップ１１）。
【００５５】
以上から解るように、本実施形態においては、各ステーションコントローラ６に対し同一のプログラムを記憶させておき、第一の実施形態で示した接続情報および表４に示した工程定義表を各ステーションコントローラ６毎に記憶することにより、例えば上述したような戻り動作を含む複雑な搬送動作にも対応することが可能となっている。
【００５６】
なお、上述の実施形態は本発明の好適な実施の一例ではあるがこれに限定されるものではなく本発明の要旨を逸脱しない範囲において種々変形実施可能である。例えば上述の各実施形態ではネットワーク接続された上位装置７から各ステーションコントローラ６へと処理手順プログラムが送信されていたが、各ステーションコントローラ６に所望のプログラムをインストールすることが可能であればプログラムの供給形態はこれに限らず、例えばサーバからクライアントとしての各ステーションコントローラ６へプログラムを送信する形態であってもよい。この場合のサーバとしては、例えばインターネット上のサーバであって各ステーションコントローラ６に処理手順プログラムをダウンロードするネットワークサーバなどが該当する。あるいは、このようなサーバを一切介さず、ＣＤ−ＲＯＭ等の記録媒体に格納された処理手順プログラムを各ステーションコントローラ６に直接インストールするようにしても構わない。
【００５７】
また、上述した実施形態では軌道３上の直線部分に３つのステーション５Ａ〜５Ｃが直列的に接続されている形態について説明したが、ステーション５の接続形態あるいは個数は上述したものに限られない。例えば、図１５に示すように軌道３が十字に交差するとともに交差点中に設けられた方向転換機１２によって経路の変更が可能となっているワーク搬送システム１において、交差点の四方の進入口（出口）さらには交差点内にそれぞれステーション５を設けることは、交差点に進入しあるいは出てくる自走式ワーク搬送パレット２さらには交差点内に位置している自走式ワーク搬送パレット２を監視し制御することによって交差点での衝突等を防ぎ円滑なワーク搬送を確保する点で好ましい。また、図示しないが、交差点におけると同様に例えば軌道３の分岐点などにおいてステーション５を設けることも円滑なワーク搬送を確保する点で好ましい。
【００５８】
また、上述した実施形態では、ステーションコントローラ６が各ステーション５に対応して１対１で設けられていたが、これは好適な一例であって、必ずしも１対１には限られず、例えば図１５に示したように複数のステーション５を１つのステーションコントローラ６で制御するなど、ステーション５の個数や形態に合わせて適宜対応を変えることができる。
【００５９】
【発明の効果】
以上の説明より明らかなように、請求項１記載のワーク搬送システムによると、集中処理方式を採用せずに、ステーションに対応して設けられたステーションコントローラにより分散制御することとしているため、軌道配置などの変更に対し、対応するプログラムを変更すれば済み全てのプログラムを変更する必要がない。したがって、軌道配置変更や大規模化などのシステムの変更に容易に対応することができる。
【００６０】
また、請求項２記載のワーク搬送システムによると、ステーションコントローラにネットワーク接続された上位装置から各ステーションコントローラへ処理手順プログラムを送信できる。また、各ステーションコントローラが処理手順プログラムを受信した後はワーク搬送システムの稼動に上位装置を必要としないので、この上位装置をネットワークから切り離すことができる。
【００６１】
また、請求項３記載のワーク搬送システムによると、上位装置により、ワーク搬送システムの稼動中にそれぞれのステーションコントローラの状態を認識することができ、さらに、認識した結果、自走式ワーク搬送パレットをトラッキングすることができる。
【００６２】
また、請求項４記載のワーク搬送システムによると、複数の経路をワーク搬送システム上に設定するとともに、自走式ワーク搬送パレットの記憶に応じて任意の経路を選択して走行させることが可能となる。
【００６３】
また、請求項５記載のワーク搬送システム１によると、上位装置の入力手段を用いることにより処理手順プログラムの作成からプログラム送信まで連続して行うことができる。
【００６４】
また、請求項６記載のワーク搬送システムによると、上位装置のシミュレーション手段を利用することにより、ステーションコントローラにおける処理手順プログラムの妥当性をオフラインで検討することができる。また、タクトバランスを予め検討して効果的なレイアウトを容易に見つけることができる。
【００６５】
また、請求項７記載のワーク搬送システムによると、上位装置により停止、再起動するなどワーク搬送システムを一括して操作することが可能となる。
【００６６】
また、請求項８記載のワーク搬送システムによると、分岐点や交差点に進入しあるいは出てくる自走式ワーク搬送パレットさらには交差点等の内側に位置している自走式ワーク搬送パレットを監視し制御することによって交差点等での衝突等を防ぎ円滑なワーク搬送を確保しうる。
さらに、請求項９記載のワーク搬送システムによると、例えば戻り動作を含む複雑な搬送動作にも対応することが可能になる。
【図面の簡単な説明】
【図１】本発明に係るワーク搬送システムの一実施形態を示す図で、ステーション、ステーションコントローラ等の接続の一例を示すものである。
【図２】ステーションの配置例を示す図である。
【図３】自走式ワーク搬送パレットに対する処理の流れを示すフローチャートである。
【図４】自走式ワーク搬送パレットとステーションにおける各センサ等の配置例を示す側面図である。
【図５】自走式ワーク搬送パレットの正面図（背面図）である。
【図６】遮光板の側面図である。
【図７】遮光板の正面図（背面図）である。
【図８】ステーションにおける各センサ等の配置例を示す平面図である。
【図９】本発明の第二の実施形態を示す図で、各ステーションと工程との関係を示すものである。
【図１０】デッドロックが生じた状態を示す図である。
【図１１】先行する自走式ワーク搬送パレットが工程２から工程３へと向かう状態を示す図である。
【図１２】先行する自走式ワーク搬送パレットが工程３から工程４へと向かう状態を示す図である。
【図１３】工程４を終えた自走式ワーク搬送パレットがステーション５Ｃを通過する状態を示す図である。
【図１４】本発明の第二の実施形態における処理の流れを示すフローチャートである。
【図１５】軌道上の交差点およびこの交差点の進入口等に設けられたステーションを示す図である。
【符号の説明】
１ ワーク搬送システム
２ 自走式ワーク搬送パレット
３ 軌道
４ ワーク
５ ステーション
６ ステーションコントローラ
７ 上位装置
２６ 通信手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a workpiece transfer system. More specifically, the present invention relates to an improvement in a structure for monitoring, controlling, and smoothly operating a self-propelled workpiece conveyance pallet in a workpiece conveyance system.
[0002]
[Prior art]
For example, US Pat. No. 5,626,080, US Pat. No. 5,617,796 and the like as a work transfer system for transferring articles such as products and parts (referred to as “workpieces” in this specification) on the production line. A self-propelled work conveyance system is known in which a track such as a monorail is employed and a work conveyance pallet is self-propelled along the track. In such a self-propelled work conveyance system, for example, the self-propelled work conveyance pallet is run toward the work area where each process such as assembly, processing, and cleaning is performed on the work, and the work is carried in, thereby completing the work. After that, the operation such as carrying out from here is performed.
[0003]
In addition, as such a self-propelled work transfer system, for example, a centralized processing system that includes a host device capable of arithmetic processing in the center of the system and monitors and centrally controls the movement of each self-propelled work transfer pallet is adopted. There is something. Such a workpiece conveyance system has the advantage that the movement of the self-propelled workpiece conveyance pallet can be centrally managed and the host device can be accommodated in the center.
[0004]
[Problems to be solved by the invention]
However, in such a centralized processing type work transfer system, a program for the host device is created in accordance with each condition such as the position of the work work place, the number of the work and the self-propelled work transfer pallet, or the track arrangement. Because it is necessary, the program is effectively designed exclusively for the work transfer system. Therefore, for example, when a change such as changing the track arrangement is performed, the program of the host device itself needs to be changed accordingly, and there is a problem that the track arrangement change cannot be easily performed. Another problem is that centralized management becomes difficult because the number of management targets to be monitored and controlled increases as the system becomes larger.
[0005]
Accordingly, an object of the present invention is to provide a work transfer system that can easily cope with changes in the system such as a change in track arrangement and an increase in scale.
[0006]
[Means for Solving the Problems]
  In order to achieve this object, the invention according to claim 1 is a workpiece transfer system that transfers a workpiece by a self-propelled workpiece transfer pallet that is self-propelled on a track for performing steps such as assembly, processing, and cleaning on the workpiece. The workpiece transfer system is a position on the track having means for instructing the stop of the self-propelled workpiece transfer pallet.pluralA self-propelled work conveyance pallet, and a storage means storing unique information of the self-propelled work conveyance pallet, and a station controller via the station. The station is interposed between the self-propelled workpiece transfer pallet and the station controller to ensure communication between them, and the station controller is network-connected to other station controllers,Information on whether or not the station to be transported next can be occupied with the station controller corresponding to the station to be transported next.Data exchanging means for exchanging data, communication means for communicating with the self-propelled work transport pallet via the station, storage means for storing the processing procedure program for the self-propelled work transport pallet, and execution for executing the processing procedure program With meansWhen the next transfer station can be occupied by executing the processing procedure program, the self-propelled work transfer pallet is instructed to operate based on the unique information.It is characterized by that.
[0007]
This work transfer system can be distributedly controlled by a station controller provided corresponding to the station, and does not employ a centralized processing method. In this case, a program may be created for each station controller in accordance with each condition such as the position of the work work place, the quantity of the work and the self-propelled work transfer pallet, or the arrangement of the track. Further, when a change such as changing the trajectory arrangement is performed, it is only necessary to change the program in the corresponding station controller, and it is not necessary to change all the programs. Therefore, when there is a change such as an increase in the size of the transport system, the scale of the station controller does not have to be so large, and it becomes easy to deal with a design change or a specification change.
[0008]
According to a second aspect of the present invention, the work transfer system according to the first aspect includes a host device connected to the station controller via a network and having a transmission means for transmitting a processing procedure program to the station controller. A receiving means for receiving a processing procedure program from the apparatus is provided. Therefore, in this work transfer system, a processing procedure program is transmitted to each station controller from a host device connected to the station controller via a network. In addition, after each station controller receives the processing procedure program, the host device is not required for the operation of the work transfer system, so that the host device can be disconnected from the network.
[0009]
According to a third aspect of the present invention, in the work transfer system according to the second aspect, the station controller and the higher-level device have data transfer means for transferring data between the station controller and the higher-level device. Thereby, the host device can recognize the state of each station controller during operation of the work transfer system. As a result of the recognition, the self-propelled work conveyance pallet can be tracked (the current position of the self-propelled work conveyance pallet can be grasped).
[0010]
  The invention according to claim 4 is the work transfer system according to claim 1 or 2, wherein the self-propelled work transfer pallet is provided.The storage means ofStores communication information with the station controllerRukoIt is characterized by. In this case, a plurality of routes can be set on the work transfer system, and any route can be selected and traveled according to the storage of the self-propelled work transfer pallet.
[0011]
According to a fifth aspect of the present invention, in the work transfer system according to the second aspect, the host device has an input means for inputting a processing procedure program. For this reason, by using this input means, it is possible to carry out continuously from the creation of the processing procedure program to the program transmission.
[0012]
According to a sixth aspect of the present invention, in the workpiece transfer system according to the second aspect, the host device has a simulation unit capable of simulating the movement of the transfer pallet by the processing procedure program transmitted to the station controller. Therefore, the validity of the processing procedure program in the station controller can be examined offline by using this simulation means. In addition, since the tact balance (the composition ratio of the operation time in each work area and the work end waiting time in the next work area) can be examined in advance, it is easy to find an effective layout.
[0013]
A seventh aspect of the invention is characterized in that, in the work transfer system according to the second aspect, the host device is provided so as to execute or interrupt the processing procedure program transmitted to the station controller. The host device instructs the station controller to execute or interrupt the processing procedure program, and the station controller executes or interrupts the processing procedure program according to this instruction. In this case, it becomes possible to collectively operate the work transfer system such as stop and restart by the host device.
[0014]
  According to an eighth aspect of the present invention, in the workpiece transfer system according to the first aspect, a station is provided at the entrance to the branching point or intersection of the track. In this case, collisions at intersections, etc. by monitoring and controlling self-propelled workpiece conveyance pallets entering or exiting branching points and intersections, and also self-propelled workpiece conveyance pallets located inside intersections, etc. This can prevent smooth workpiece transfer.
The invention according to claim 9 is the workpiece transfer system according to claim 1, wherein the station controller stores the relationship between the work process and the transfer path, and the self-propelled workpiece transfer pallet stores the current process number. The station controller obtains the current process number of the self-propelled workpiece transfer pallet that has moved to the corresponding station, and determines the next transfer destination of the self-propelled workpiece transfer pallet based on the above relationship. In addition, the relationship includes information on the process number, work station, route to the own process, departure-occupied station, departure-open station, and own process number. In this case, for example, it is possible to cope with a complicated transport operation including a return operation.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.
[0016]
1 to 8 show an embodiment of the present invention. A workpiece transfer system 1 according to the present invention is configured to transfer a workpiece 4 to, for example, a station 5 by a self-propelled workpiece transfer pallet 2 that is self-propelled on a track 3. A station controller 6 provided correspondingly is provided. The station 5 in this specification means a position on the track 3 having means for instructing the stop of the self-propelled workpiece transfer pallet 2 and is in a work area where the workpiece 4 is assembled, processed, cleaned, and the like. It is not limited to the case where it is provided (the station in this case is called a work station) or the case where it is provided at an intersection on the track 3 as described later (see FIG. 15). it can.
[0017]
The self-propelled workpiece conveyance pallet 2 is a self-propelled conveyance means that travels along the track 3 in the workpiece conveyance system 1 and conveys the workpiece 4, and autonomously based on an operation signal transmitted from each station 5 side. The vehicle travels and stops at a predetermined position in the station 5. The self-propelled work conveyance pallet 2 includes, for example, a plate-like table positioned at a predetermined position on the main body, and has a work mounting portion 9 that can be attached to and detached from the main body. The workpiece placement unit 9 can be removed from the main body in the station 5. In this case, the workpiece placement unit 9 is positioned at a predetermined position in the station 5 and is placed on the workpiece 4. Is moved to a position where assembly or the like is performed.
[0018]
Further, the self-propelled work conveyance pallet 2 has a configuration for self-propelling on the track 3, for example, a wheel 2a that rotates along the track 3, a motor 2b that moves the wheel 2a, a battery 2c that supplies power to the motor 2b, and a control circuit 21. The communication means 26 and the like are provided. The communication means 26 is an infrared communication device or the like that communicates with the station 5 in a non-contact manner, and is installed so as to be communicable when close to each other, and with other nearby self-propelled workpiece transport pallets 2 having the same function To prevent interference. The self-propelled workpiece transfer pallet 2 can communicate with the station controller 6 via the station 5 by the communication means 26.
[0019]
In the present embodiment, the self-propelled work conveyance pallet 2 is provided with four wheels 2a to form a four-wheel vehicle, and the self-propelled work conveyance pallet 2 is caused to self-propell by driving the drive wheels in the wheels 2a. I have to. As shown in FIGS. 4 and 5, the wheel 2a is provided on each side with two front and rear wheels, and rotates on the track 3. (In FIG. 4, the self-propelled workpiece transfer pallet 2 is separated from the station side so as to be easily understood. Are shown). As the wheel 2a used for the self-propelled workpiece conveyance pallet 2 of the workpiece conveyance system 1, a tire that has little noise and dust generation and hardly slips between the tracks 3 is preferable, for example, a rubber tire. Either the front wheel or the rear wheel is a driving wheel driven by the motor 2b.
[0020]
The motor 2b is a drive source for rotating the wheel 2a to run the self-propelled workpiece conveyance pallet 2, and is built in the self-propelled workpiece conveyance pallet 2. Further, the motor 2b is provided coaxially so as to directly drive the wheel (drive wheel) 2a by a rotor without using any reduction gear such as a reduction gear. This is advantageous in that it can be reduced in size and noise, and energy loss can be reduced by regenerative absorption.
[0021]
The battery 2c is a storage battery that stores electric power necessary for driving the motor 2b. The battery 2c is fed by the non-contact power feeding means 11a and 11b and supplies electric power to the motor 2b. The battery 2c of the present embodiment is preferably composed of a capacitor that takes a short time to start charging, and more preferably has a large capacity so as to be advantageous for weight reduction and size reduction. For example, when a polyacene capacitor is used, it takes less time to start up the battery, and quick charging is possible. In addition, the self-propelled workpiece transfer pallet 2 is advantageous in terms of weight reduction and size reduction.
[0022]
The workpiece placement unit 9 is a rectangular member, for example, in plan view, which serves as a pedestal for placing and transporting the workpiece 4, and has a sufficient area for placing the workpiece 4 and performing operations such as processing. However, the size and shape can be changed as appropriate in accordance with the type and size of the workpiece 4, the size of the self-propelled workpiece conveyance pallet 2, the content of the work such as processing, and the like. Further, since the workpiece placement unit 9 can be attached to and detached from the self-propelled workpiece transfer pallet 2 and the workpiece placement unit 9 itself can be cleaned, for example, dust adhered to the workpiece placement unit 9 Can be easily washed away. Furthermore, in this embodiment, since the workpiece | work mounting part 9 can be attached or detached up and down and the isolation | separation direction is made into the upper side, it is hard to fall to the workpiece | work 4. Moreover, the mechanism for separation is relatively easy. Moreover, in order to prevent the shift | offset | difference at the time of driving | running | working on the workpiece | work mounting part 9 and the main-body part side of the self-propelled workpiece conveyance pallet 2, the workpiece | work mounting part 9 is mounted in the predetermined position on a main-body part. The positioning means is provided. The alignment means includes, for example, an engagement hole (not shown) provided on the back surface of the workpiece mounting portion 9 and an engagement protrusion (not shown) provided on the upper surface of the main body so as to be fitted into the engagement hole. Become.
[0023]
Furthermore, it is preferable that the workpiece placing unit 9 has an identification signal for each workpiece placing unit 9 or each type. In such a case, the type of the conveyance target can be identified, and work according to the type, selection of the conveyance path, instruction, and the like can be performed. Also, different types of workpieces 4 can be grouped and mixed, and further, back traces (pursuing and determining the cause and reason) of defects and variations in the object to be conveyed can be performed. As an individual signal given to the workpiece placement unit 9, a workpiece placement unit type number that is different for each type of the workpiece placement unit 9, a unique information (ID number) that is different for each workpiece placement unit 9, etc. It is also possible to assign and identify all of them. In addition, it is preferable to attach | subject an ID number also to the above-mentioned self-propelled workpiece conveyance pallet 2 similarly to this workpiece | work mounting part 9. FIG. In such a case, it becomes possible to back trace product defects and variations, and it is possible to manage the failure and life of the self-propelled workpiece transfer pallet 2 itself.
[0024]
In addition, when the self-propelled workpiece conveyance pallet 2 is stopped or passed, the workpiece conveyance system 1 is supplied with a pair of non-contact power supply from the workpiece conveyance pallet rail side to the battery 2c of the self-propelled workpiece conveyance pallet 2. The non-contact power feeding means 11 is provided. As the non-contact power supply means 11, a device that can supply power in a non-contact manner when both are within a certain distance, for example, a pair of coils 11c and 11d that can be fed by electromagnetic action is applicable (FIG. 4). reference). Of the pair of non-contact power feeding means 11, the one provided on the track 3 side (referred to as “feeding transformer 11 b”) is, for example, a U-shaped groove portion of a rail having a U-shaped cross section as an example of the track 3 as will be described later. It is provided at the bottom etc. In this case, it is preferable that the power feeding transformer 11b is installed at many points in the work transfer system 1 within a range where the system is not too complicated in order to allow the power feeding points to be distributed. On the other hand, the non-contact power feeding means (referred to as “power feeding transformer 11a”) provided on the self-propelled work conveyance pallet 2 side is a power feeding transformer 11b on the track 3 side when the self-propelled work conveyance pallet 2 is stopped or passed. It is installed on the back surface of the self-propelled work conveyance pallet 2 so as to be electromagnetically coupled and receive power (see FIG. 4). In the case of the workpiece transfer system 1 of the present embodiment, the self-propelled workpiece transfer pallet 2 is easy to run while maintaining the horizontal state by adopting the U-shaped rails and wheels 2a, and the non-contact power feeding means 11 is provided. Since they are arranged vertically so as to face each other, a gap (transformer gap) between the pair of power supply transformers 11a and 11b hardly changes, and a stable power supply operation is possible. Although not specifically shown, if a contact-type power supply means is provided in addition to the non-contact power supply means 11, the contact-type power supply means can be used only in an emergency where the non-contact power supply means 11 does not function. It is possible to charge the battery quickly by operating it.
[0025]
The control circuit 21 built in the self-propelled workpiece conveyance pallet 2 is a means for regulating the operation of the self-propelled workpiece conveyance pallet 2, such as a CPU, and controls motor forward / reverse rotation / speed control, sensor management, and communication management. Various controls such as power management (including power saving management) and parameter storage are performed. Note that the “parameter” mentioned here refers to a problem that may occur due to a difference in performance and specifications of the self-propelled workpiece conveyance pallet 2 (for example, due to variations that may occur during manufacturing), the self-propelled workpiece conveyance pallet 2 and the workpiece 4. This means a numerical value related to a dynamic change or the like in the above process, which is necessary for correction, and includes unique information (ID number) of the self-propelled work conveyance pallet 2 itself or the work placement unit 9. The control circuit 21 reads and changes each parameter according to an instruction from the station controller 6. In addition, parameters changed by the storage means can be stored permanently. As an example of power management, when the power supply to the battery 2c is insufficient, the station 5 side is notified and the self-propelled workpiece transfer pallet 2 is not started even when the work on the workpiece 4 is completed. It is done.
[0026]
The track 3 connects the stations 5 to form a travel path for the self-propelled workpiece transfer pallet 2. When the self-propelled work conveyance pallet 2 is a vehicle provided with wheels 2a, the track 3 can be a rail type. Further, the track 3 has a U-shaped groove portion like a rail having a U-shaped cross section, for example, and when the wheel 2a of the self-propelled work conveyance pallet 2 travels on the track surfaces on both sides, A part of the main body of the pallet-type workpiece transport pallet 2 is located below the raceway surface, and the center of gravity of the self-propelled workpiece transport pallet 2 is located below the raceway surface. Can be made. The track 3 is not particularly limited to the rail type that physically guides the self-propelled workpiece conveyance pallet 2 as described above, and other than that, an optical guide using light or magnetism is used. It can also be a guide.
[0027]
As described above, the station 5 refers to a position on the track 3 having means for instructing the stop of the self-propelled workpiece transfer pallet 2. For example, the work area in which the steps of assembling, processing, and cleaning are performed on the workpiece 4. In this embodiment, as shown in FIG. 2, three work stations indicated by reference numerals 5A, 5B, and 5C are arranged in series, and a track that passes through these stations 5A to 5C. It is laid in an oval shape so that 3 circulates. Note that the self-propelled workpiece transfer pallet 2 may simply pass through the station 5 and transmit and receive operation signals when passing. As the station 5, a station 5 having an intelligence for controlling the self-propelled workpiece transfer pallet 2 can be used. However, the station 5 of this embodiment does not have such an intelligence, and the station 5 stopped at a predetermined position. It is provided between the traveling work conveyance pallet 2 and the station controller 6 so as to ensure communication between them. In FIG. 2, it is assumed that each station 5 includes a station controller 6. Each station 5 is network-connected by a line 10 in FIG.
[0028]
Each station 5 is provided with means for instructing the stop of the self-propelled workpiece transfer pallet 2, and in this embodiment, a stop position reflecting plate 25 is provided. Each station 5 is connected to a station controller 6 that transmits an operation signal of the self-propelled work conveyance pallet 2 to the station 5. The station controller 6 in the present embodiment alone or in cooperation with the above-described control circuit 21 allows the workpiece placement unit ID / presence detection sensor 22, the inter-vehicle sensor 23, the stop position detection sensor 24, and the stop position reflector. 25, the communication means 26, the deceleration prohibition / departure command sensor 27, the deceleration prohibition / departure command LED 28, the vehicle speed sensor 29, the entry prohibition LED 30, the passage direction detection sensor 31, the conveyance pallet presence / absence detection sensor 32, and the like are detected and controlled.
[0029]
The workpiece placement unit ID / presence detection sensor 22 is provided on the workpiece placement unit 9 when the workpiece placement unit 9 is placed on the self-propelled workpiece transfer pallet 2 and when the workpiece placement unit 9 is placed. A sensor capable of detecting the attached ID, for example, an optical sensor provided at the upper part of the main body of the self-propelled work conveyance pallet 2. The workpiece transfer system 1 of the present embodiment is configured to automatically determine forwarding based on a signal from the workpiece placement unit ID / presence detection sensor 22 (for example, when a departure command is issued without the workpiece placement unit 9). Can be determined to go to the work station where the work placement unit 9 is loaded. The work placement unit ID / ID of the work placement unit 9 detected by the presence / absence detection sensor 22 is notified to the station controller 6 through the communication means 26. For this reason, in the workpiece conveyance system 1 of this embodiment, it is not necessary to exchange a signal directly between the workpiece | work mounting part 9 and the station 5. FIG. Further, according to the workpiece placement portion ID / presence detection sensor 22, it is possible to detect a positioning failure of the workpiece placement portion 9, and to detect a conveyance failure due to a semi-floating of the workpiece placement portion 9.
[0030]
The inter-vehicle sensor 23 is a sensor for preventing the self-propelled work conveyance pallets 2 from colliding with each other and preventing damage, vibration, and dust generation that may occur at the time of the collision. The type work conveyance pallet 2 is stopped on the track 3 other than the station 5 or restarted. In the workpiece transfer system 1 according to the present embodiment, the number of the self-propelled workpiece transfer pallets 2 is not limited to the number of stations 5 due to the operation of the inter-vehicle sensor 23, thereby matching the work time (tact time). The necessary number of self-propelled workpiece transfer pallets 2 can be simultaneously driven. Further, the inter-vehicle sensor 23 of the present embodiment also has a role of prohibiting the self-propelled workpiece transfer pallet 2 from entering the predetermined work stations 5A to 5C by receiving an entry prohibition signal generated by the entry prohibition LED 30. ing. The inter-vehicle sensor 23 is provided on at least one of the front and rear of the main body portion of the self-propelled work conveyance pallet 2, preferably on both the front and rear. In the case where they are provided on both the front and rear sides, the single self-propelled workpiece transfer pallet 2 can be moved forward and backward.
[0031]
In addition, the front and rear inter-vehicle sensors 23 and other external interfaces such as various sensors and the power feeding transformer 11a are preferably arranged so as to be point-symmetric before and after the self-propelled workpiece transfer pallet 2. In such a case, the directivity of the self-propelled workpiece transfer pallet 2 can be canceled, and the external interface can be used without any change even if the front and rear are replaced. Further, it is also preferable in that the space of the substrate can be saved and the number of sensors can be reduced. When the external interface on the self-propelled workpiece transfer pallet 2 side is arranged point-symmetrically, the interface on the station 5 side is also arranged point-symmetrically accordingly.
[0032]
The stop position detection sensor 24 is a sensor for stopping the self-propelled workpiece conveyance pallet 2 at a set position (for example, a position where work on the workpiece 4 is performed). For example, in the case of the present embodiment, two optical sensors serve as stop position detection sensors 24 in the vertical direction (main body traveling direction) on the back surface of the main body of the self-propelled workpiece transport pallet 2 as shown in FIGS. It is installed side by side. On the other hand, a stop position reflecting plate 25 serving as a marker for notifying the stop position of the self-propelled work transport pallet 2 is provided at the bottom of the work transport pallet rail and at a position facing the stop position detection sensor 24. ing. The stop position reflecting plate 25 is formed slightly longer than the installation interval of the two stop position detecting sensors 24, and both of the two stop position detecting sensors 24 are located within the area of the stop position reflecting plate 25. When this happens, the self-propelled workpiece transfer pallet 2 is stopped. Further, the surface of the band-shaped marker including the stop position reflecting plate 25 is painted into, for example, a black portion and a white portion, and the stop position detection sensor 24 is notified of the stop position by the presence or absence of reflected light. For example, in the case of this embodiment, the white portion is made to function as the stop position reflecting plate 25. According to such a stop position reflecting plate 25, the stop position of the self-propelled workpiece conveyance pallet 2 can be easily adjusted only by finely adjusting the position and length of the reflecting plate. Further, the light blocking plate 39 may be used instead of the belt-shaped marker, and the stop position detection sensor 24 may be a transmissive sensor (see FIGS. 6 and 7). When any one of the stop position detection sensors 24 reaches the stop position reflecting plate 25 while the self-propelled work transfer pallet 2 is traveling, the deceleration of the self-propelled work transfer pallet 2 is started. It is preferable that the self-propelled workpiece transfer pallet 2 can be stopped accurately and stably even when the self-propelled workpiece transfer pallet 2 is moving at high speed. In this case, the stop position detection sensor 24 also has a function as a deceleration start sensor.
[0033]
The communication means 26 includes a communication sensor 26a provided on the back surface of the main body and a communication sensor 26b provided in the station 5 so as to face the communication sensor 26a. Various information is exchanged with the station controller 6 connected to the station 5, for example, notification of presence / absence of a work placement unit / ID, departure command, status (state or status) notification of charge amount, parameter transfer, and the like. The communication sensors 26a and 26b are sensors (for example, infrared communication sensors) that perform non-contact communication, and interference with a nearby self-propelled work conveyance pallet 2 having the same function is prevented. For example, in the case of infrared communication, since the short-range communication is used, the configuration is inexpensive. Further, when the main unit and the station 5 are arranged to face each other as in the present embodiment, the communication distance can be kept constant, and the communication quality can be improved.
[0034]
The deceleration prohibition / departure command sensor 27 is a sensor that detects a passage command and a departure command issued to the self-propelled workpiece conveyance pallet 2, and as shown in FIG. It consists of a total of two sensors. Further, at a position facing the two deceleration prohibition / departure command sensors 27 on the station 5 side, a means for issuing a command, for example, two deceleration prohibition / departure command LEDs 28 that issue a command by emitting light are provided. Yes. The deceleration prohibition / departure command sensor 27 and the deceleration prohibition / departure command LED 28 prevent the self-propelled workpiece transfer pallet 2 from stopping at a station that does not need to be stopped, thereby improving or maintaining the working time (tact time).
[0035]
The vehicle speed sensor 29 is a sensor for detecting the vehicle speed of the self-propelled workpiece transfer pallet 2 or both the vehicle speed and the position. For example, in the case of this embodiment, the vehicle speed sensor 29 is automatically detected so as to detect the rotation of the wheel 2a on the non-drive side. It is comprised by sensors, such as an encoder, provided in the inside of the traveling work conveyance pallet 2.
[0036]
The entry prohibition LED 30 emits an entry prohibition signal when it is necessary to prevent the self-propelled workpiece transfer pallet 2 from entering the station 5. For example, in the workpiece transfer system 1 of the present embodiment, FIG. As shown in FIG. 8, an entry prohibition LED 30 is installed on each of the front side and the rear side of the station 5 so that light can be emitted forward and backward of the station 5. The case where it is necessary to prevent the self-propelled workpiece transfer pallet 2 from entering the station 5 side corresponds to, for example, the case where the receiving preparation posture on the station 5 side is not ready. By using the inter-vehicle sensor 23 and the entry prohibition LED 30, entry of the self-propelled workpiece transfer pallet 2 can be prohibited so as not to affect the process of the preceding vehicle by prohibiting entry when necessary. In addition, when the light emission source (entry prohibition LED 30) and the light receiving sensor (vehicle distance sensor 23) are provided separately as in the present embodiment, the light emission and the light reception are less likely to interfere with each other, and a large detection energy can be secured. There is.
[0037]
The passing direction detection sensor 31 is a sensor that detects a line malfunction by detecting the passing direction or the approaching direction of the self-propelled workpiece conveyance pallet 2 so as to face the stop position detection sensor 24 as shown in FIG. Station 5 is provided. The passing direction detection sensor 31 of the present embodiment is composed of a pair of sensors arranged in the front-rear direction as shown in the figure, and detects a signal when the stop position detection sensor 24 passes to detect a self-propelled work conveyance pallet. 2. Read the passing direction or approaching direction.
[0038]
Further, the station 5 includes a port 8 that is connected to another station 5 and forms an entrance / exit of the self-propelled workpiece transfer pallet 2. For example, if the station 5A, the code A₁1st port and symbol A₂And a first port A as shown in Table 1.₁Is the second port B of station B₂And second port A₂Is the first port C of station C₁Are connected by a track 3.
[Table 1]

Similarly, the station B is shown in Table 2, and the station C is shown in Table 3.
[Table 2]

[Table 3]

The connection forms in Tables 1 to 3 are stored in each station controller 6 as connection information.
[0039]
The station controller 6 is a control unit that communicates with the self-propelled workpiece conveyance pallet 2 via the station 5 and controls the self-propelled workpiece conveyance pallet 2. As shown in FIG. 1, in this embodiment, three station controllers 6 indicated by reference numerals 6A, 6B, and 6C are provided corresponding to the above-described stations 5A, 5B, and 5C. Distributed control can be performed by corresponding to each of the stations 5A to 5C. The station controller 6 of the present embodiment forms a so-called bus-type network while being connected to other station controllers 6 and the host device 7.
[0040]
The station controller 6 includes storage means for storing the processing procedure program and execution means for executing the processing procedure program, and transmits an operation signal based on the processing procedure program to the self-propelled work transport pallet 2. Instruct to move forward or backward. The operation signal is transmitted based on the unique information stored in the storage means of the self-propelled work conveyance pallet 2 so as to perform a different operation for each self-propelled work conveyance pallet 2. Further, the station controller 6 has communication means 26 for communicating with the self-propelled work conveyance pallet 2 via the station 5 and data exchange means for exchanging data with the self-propelled work conveyance pallet 2 and the host device 7. And a means for detecting the presence or absence of the self-propelled workpiece transfer pallet 2 on the corresponding work station. Further, the station controllers 6A to 6C read out the unique information of the self-propelled workpiece transfer pallet 2 on the corresponding work stations 5A to 5C via the work stations 5A to 5C. In addition, the station controllers 6 </ b> A to 6 </ b> C transmit appropriate operation signals based on the unique information of the self-propelled work conveyance pallet 2. The station controller 6 includes receiving means for receiving a predetermined processing procedure program from the host device 7.
[0041]
The host device 7 is a device connected to the station controller 6 over the network and having a transmission means as a server for transmitting the processing procedure program to each station controller 6. Connected to a bus network. However, the host device 7 does not always need to be connected to the station controller 6 and only needs to be connected when necessary, such as to transmit a processing procedure program. The host device 7 has data exchange means for exchanging data with the station controller 6. Note that it is preferable that the host device 7 has an input means for inputting a processing procedure program, because the program can be directly input. Further, if the host device 7 has a simulation means capable of simulating the movement of the self-propelled workpiece conveyance pallet 2 by the processing procedure program transmitted to the station controller 6, before the self-propelled workpiece conveyance pallet 2 actually travels. It is preferable that the running state can be simulated. Further, if the host apparatus 7 is provided so that the processing procedure program transmitted to the station controller 6 can be executed or interrupted, the program is executed or interrupted not only from the station controller 6 but also from the host apparatus 7. Is possible and suitable.
[0042]
Then, the flow of the process sequence with respect to the self-propelled workpiece conveyance pallet 2 in the workpiece conveyance system 1 of this embodiment is shown. Each station controller 6 executes a processing procedure program based on the flowchart shown in FIG. The processing procedure program here is common to each station controller 6.
[0043]
First, it waits until the self-propelled work conveyance pallet 2 arrives at the station 5 (step 1). The station controller 6 confirms the arrival of the self-propelled workpiece transfer pallet 2 by the pallet presence / absence sensor on the station 5. After arrival, the workpiece placement unit 9 is detached from the main body of the self-propelled workpiece conveyance pallet 2 and positioned at a predetermined position in the station 5. When the positioning of the workpiece placement unit 9 is completed, this is notified to the operator (step 2). The worker in this case is a person who actually assembles the workpiece 4 and includes not only humans but also robots. During the work, it waits until a work completion notification is made from the worker (step 3). When the completion of the work is notified, the station controller 6 (for example, the station controller 6A) cancels the positioning of the work placement unit 9, and the next station controller 6 (for example, the station controller 6B) is based on the connection information that is held. An inquiry is made as to whether the station 5B can be occupied (that is, whether the self-propelled workpiece transfer pallet 2 that is currently in the station 5A and is waiting at the station 5A can proceed to the second station 5B) (step 4). Upon receiving the inquiry, the station controller 6 (for example, the station controller 6B) permits entry when the station 5B does not have the self-propelled workpiece transfer pallet 2. Upon receiving the permission, the station controller 6A issues a departure instruction to the self-propelled workpiece transfer pallet 2 (step 5), and starts toward the connection destination station 5 (station 5B). At this time, the occupation of the current station 5A is released, the next self-propelled workpiece transfer pallet 2 can be entered, and a waiting state is again awaited for the arrival of the self-propelled workpiece transfer pallet 2 (step 1).
[0044]
As can be seen from the above, in the work transfer system 1 of the present embodiment, the same processing procedure program is executed in each station controller 6, and the data (connection information) in Tables 1 to 3 is stored in each station controller 6. By holding it, it is possible to transport multiple self-propelled workpiece transfer pallets 2 as if they were synchronized, and conventionally used for single-feed processing (processing performed while each workpiece transfer pallet is synchronized) Synchronous feed conveyance can be performed. That is, (1) the station controller 6 inquires about whether or not the station can be occupied and exchanges permission data, (2) stores the reading information sent from the host device 7, and (3) based on the connection information. By executing the processing procedure program, the self-propelled workpiece conveyance pallet can be run and the workpiece 4 can be conveyed.
[0045]
If a self-propelled workpiece conveyance pallet 2 is equipped with an inter-vehicle sensor, the self-propelled workpiece conveyance pallet 2 is started without waiting for permission from the next station controller 6, thereby allowing free flow conveyance in conveyor conveyance. An operation equivalent to (a kind of asynchronous transfer method in which only the workpiece is stopped at a predetermined position when the workpiece is individually transferred by the conveyor) is enabled. In this case, the operation is equivalent to skipping step 4 in the flowchart shown in FIG.
[0046]
Next, a second embodiment of the present invention will be described.
[0047]
As shown in FIG. 9, the workpiece transfer system 1 in this embodiment is common to the first embodiment in that the stations 5A to 5C are connected in series, but after the step 3 is completed in the station 5C. The difference is that another process (process 4) is performed again at the central station 5B. Therefore, in this second embodiment, the self-propelled workpiece transfer pallet 2 that has advanced to the station 5C once returns to the station 5B, and after the step 4, the operation of passing through the station 5C and proceeding further is performed.
[0048]
In this case, if the subsequent self-propelled workpiece conveyance pallet 2 enters the station 5B before the self-propelled workpiece conveyance pallet 2 finishes step 3 at the station 5C (see FIG. 10), The traveling workpiece conveyance pallet 2 cannot return to the station 5B, and the subsequent self-propelled workpiece conveyance pallet 2 cannot proceed to the station 5C (hereinafter, this state is referred to as “deadlock”). Therefore, in the present embodiment, the self-propelled workpiece transfer pallet 2 is operated as follows in order to avoid deadlock.
[0049]
That is, as long as the preceding self-propelled workpiece transfer pallet 2 occupies either the station 5B or the station 5C, or is positioned on the track 3 between the stations 5B and 5C, the subsequent self-propelled workpiece pallet 2 waits at the station 5A. The traveling work conveyance pallet 2 is not allowed to leave the station 5A. As shown in FIG. 11, the preceding self-propelled workpiece transfer pallet 2 proceeds to station 5C when step 2 at station 5B is completed, and once empties station 5B, but once step 3 is completed, station 2 is again turned on as shown in FIG. Come back to 5B. During this time, the subsequent self-propelled work transfer pallet 2 does not leave and continues to stand by at the station 5A, and thereafter, the preceding self-propelled work transfer pallet 2 moves after finishing the step 4 and moves to both the station 5B and the station 5C. After confirming that the vehicle is free, the vehicle departs toward the station 5B (see FIG. 13). In this case, deadlock between the preceding self-propelled work conveyance pallet 2 and the subsequent self-propelled work conveyance pallet 2 can be avoided.
[0050]
  In the present embodiment, in order to realize the above deadlock avoidance operation, for example, a process definition table as shown in Table 4(Relationship between work process and transport route)Is used to operate the self-propelled workpiece transfer pallet 2 and the like. The process definition table includes items of “process number”, “route to own process”, “occupied station at departure”, “release station at departure”, and “next process number”. “Process number” corresponds to steps 1 to 4 shown in FIG. Although not shown, the fourth work station is 5D, and the number of the process performed here is 5. The “path to the own process” is that the self-propelled workpiece transport pallet 2 has moved to the current work station 5 through which port 8 of which work station 5 when proceeding from the previous process to the current process (self process). Is shown. “Occupied station at departure” indicates a work station that is occupied by the self-propelled workpiece transfer pallet 2 that departs from the current work station 5 (including a case where it passes only). The “departure release station” is a work station 5 currently occupied by the self-propelled work transfer pallet 2 and is a station that is released (empty) by starting.
[Table 4]

[0051]
Each station controller 6A to 6C stores the contents of the process definition table related to the stations 5A to 5C in addition to the connection information shown in the first embodiment. Further, the self-propelled workpiece conveyance pallet 2 stores the current process number of the self-propelled workpiece conveyance pallet 2 itself by a built-in storage means.
[0052]
Each station controller 6 in the present embodiment executes a program based on the flowchart shown in FIG. That is, it waits for the self-propelled workpiece transfer pallet 2 to arrive at the corresponding station 5 (for example, station 5A for the station controller 6A) (step 11). The current process number is acquired from the transport pallet 2 (step 12). Then, it is confirmed whether the corresponding station 5 is a station corresponding to the acquired process number (step 13). If the corresponding station 5 does not correspond, the process immediately proceeds to step 18 where the departure port 8 is acquired and the departure operation is started. For example, in the present embodiment, the third station 5 </ b> C in which the self-propelled workpiece transfer pallet 2 just passes through when the process 4 ends and goes to the step 5 is not compared with the self-propelled workpiece transfer pallet 2. This is the case where the corresponding station 5 is not applicable, without performing assembly work or the like.
[0053]
On the other hand, if it is confirmed that the corresponding station 5 is applicable, the operator is notified that the self-propelled workpiece transfer pallet 2 has arrived (step 14), and the assembly, processing, etc. of the workpiece 4 are completed. Wait (step 15). In addition, as a preparation for starting the self-propelled workpiece transport pallet 2 that has finished the work, information on the above-mentioned “occupation station at departure” and “release station at departure” is acquired based on the process number (step 16). After acquisition, the process number stored in the self-propelled workpiece transfer pallet 2 is rewritten and updated to the next process number (step 17).
[0054]
Subsequently, the departure port 8 is obtained (determined) from the “route to own process” data of the updated process number (step 18). After obtaining the departure port, the next station 5 is determined based on the connection information. Further, it is confirmed whether the “departure occupied station” acquired in step 16 and the next station 5 determined based on step 18 can be occupied (step 19). When it is confirmed that the occupation station at the departure time and the next station 5 can be occupied, a departure instruction is issued to the self-propelled workpiece transfer pallet 2 (step 20). The station 5 is released when the self-propelled workpiece transfer pallet 2 starts. Thereafter, the station controller 6 returns to the state of waiting for the arrival of the self-propelled workpiece transfer pallet 2 (step 11).
[0055]
As can be seen from the above, in the present embodiment, the same program is stored in each station controller 6, and the connection information shown in the first embodiment and the process definition table shown in Table 4 are stored in each station controller. By storing every six, it is possible to cope with a complicated transport operation including a return operation as described above, for example.
[0056]
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in each of the above-described embodiments, the processing procedure program is transmitted from the network-connected higher-level device 7 to each station controller 6, but if a desired program can be installed in each station controller 6, the program The supply form is not limited to this. For example, the form may be such that the program is transmitted from the server to each station controller 6 as a client. The server in this case corresponds to, for example, a network server that is a server on the Internet and that downloads a processing procedure program to each station controller 6. Alternatively, a processing procedure program stored in a recording medium such as a CD-ROM may be directly installed in each station controller 6 without using any such server.
[0057]
Further, in the above-described embodiment, the form in which the three stations 5A to 5C are connected in series to the linear portion on the track 3 is described, but the connection form or the number of the stations 5 is not limited to the above. For example, as shown in FIG. 15, in the workpiece transfer system 1 in which the track 3 intersects the cross and the path can be changed by the direction changer 12 provided in the intersection, the four entrances (exit points) at the intersection ) Furthermore, providing each station 5 in the intersection monitors and controls the self-propelled workpiece conveyance pallet 2 entering or exiting the intersection, and further the self-propelled workpiece conveyance pallet 2 located in the intersection. This is preferable in that it prevents collisions at intersections and ensures smooth workpiece conveyance. Further, although not shown, it is preferable to provide the station 5 at the branching point of the track 3 as in the intersection from the viewpoint of ensuring smooth workpiece conveyance.
[0058]
In the above-described embodiment, the station controllers 6 are provided on a one-to-one basis corresponding to the stations 5. However, this is a preferred example, and is not necessarily limited to one-to-one. For example, FIG. As shown in the above, the correspondence can be appropriately changed according to the number and form of the stations 5 such as controlling the plurality of stations 5 by one station controller 6.
[0059]
【The invention's effect】
As is clear from the above description, according to the workpiece transfer system according to claim 1, the centralized processing method is not adopted, and the distributed control is performed by the station controller provided corresponding to the station. For example, if the corresponding program is changed, it is not necessary to change all the programs. Therefore, it is possible to easily cope with a change in the system such as a change in orbital arrangement or an increase in scale.
[0060]
According to the work transfer system of the second aspect, the processing procedure program can be transmitted to each station controller from a host device connected to the station controller via a network. In addition, after each station controller receives the processing procedure program, the host device is not required for the operation of the work transfer system, so that the host device can be disconnected from the network.
[0061]
According to the workpiece transfer system of claim 3, the host device can recognize the state of each station controller while the workpiece transfer system is in operation, and as a result of the recognition, the self-propelled workpiece transfer pallet Can be tracked.
[0062]
Moreover, according to the workpiece conveyance system of Claim 4, while setting a some path | route on a workpiece conveyance system, it is possible to drive | work by selecting arbitrary paths according to the memory | storage of a self-propelled workpiece conveyance pallet. Become.
[0063]
Moreover, according to the workpiece conveyance system 1 of Claim 5, it can perform continuously from preparation of a process procedure program to program transmission by using the input means of a high-order apparatus.
[0064]
According to the workpiece transfer system of the sixth aspect, the validity of the processing procedure program in the station controller can be examined offline by using the simulation means of the host device. Further, an effective layout can be easily found by examining the tact balance in advance.
[0065]
Moreover, according to the workpiece conveyance system of Claim 7, it becomes possible to operate the workpiece conveyance system collectively, such as stopping and restarting by the host device.
[0066]
  According to the workpiece transfer system of claim 8, the self-propelled workpiece transfer pallet entering or exiting the branching point or intersection, or the self-propelled workpiece transfer pallet located inside the intersection or the like is monitored. By controlling, it is possible to prevent a collision at an intersection or the like and to ensure smooth workpiece conveyance.
Furthermore, according to the workpiece transfer system of the ninth aspect, it is possible to cope with a complicated transfer operation including a return operation, for example.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a work transfer system according to the present invention, which shows an example of connection of stations, station controllers, and the like.
FIG. 2 is a diagram illustrating an arrangement example of stations.
FIG. 3 is a flowchart showing a flow of processing for a self-propelled workpiece transfer pallet.
FIG. 4 is a side view showing an arrangement example of sensors and the like in a self-propelled workpiece transfer pallet and a station.
FIG. 5 is a front view (rear view) of a self-propelled workpiece transfer pallet.
FIG. 6 is a side view of a light shielding plate.
FIG. 7 is a front view (back view) of the light shielding plate.
FIG. 8 is a plan view showing an arrangement example of sensors in the station.
FIG. 9 is a diagram showing a second embodiment of the present invention and showing a relationship between each station and a process.
FIG. 10 is a diagram showing a state where a deadlock has occurred.
FIG. 11 is a diagram showing a state in which the preceding self-propelled workpiece transfer pallet heads from step 2 to step 3;
FIG. 12 is a diagram showing a state in which a preceding self-propelled workpiece transfer pallet heads from step 3 to step 4;
FIG. 13 is a diagram showing a state in which the self-propelled workpiece transfer pallet that has finished Step 4 passes through the station 5C.
FIG. 14 is a flowchart showing the flow of processing in the second embodiment of the present invention.
FIG. 15 is a diagram showing an intersection on a track and a station provided at an entrance of the intersection and the like.
[Explanation of symbols]
1 Work transfer system
2 Self-propelled workpiece transfer pallet
3 orbit
4 Work
5 stations
6 Station controller
7 Host device
26 Communication means

Claims (9)

In a workpiece transfer system that transfers the workpiece by a self-propelled workpiece transfer pallet that self-propels on a track for performing each process such as assembly, processing, and cleaning on the workpiece, the workpiece transfer system includes the self-propelled workpiece transfer pallet. along with comprising a station controller which is provided corresponding to the plurality of stations and the station is a location on the track having means for instructing to stop the self-propelled workpiece transport pallet, unique the free-Hashishiki workpiece conveying pallet Storage means for storing information, and communication means for communicating with the station controller via the station, the station being interposed between the self-propelled workpiece transfer pallet and the station controller Communication is ensured, and the station controller Controller and with the networked owns the connection information indicating a connection form of the station, then the next station for transporting to and from the station controller support station for transporting can occupy whether information Data exchanging means for exchanging, communication means for communicating with the self-propelled work transfer pallet via the station, storage means for storing a processing procedure program for the self-propelled work transfer pallet, and the processing procedure program And executing means for instructing the self-propelled workpiece transfer pallet to operate based on the unique information when the next transfer station can be occupied by executing the processing procedure program. Work transfer system.   A host device connected to the station controller via a network and having a transmission means for transmitting the processing procedure program to the station controller; and the station controller is provided with a receiving means for receiving the processing procedure program from the host device. The workpiece transfer system according to claim 1, wherein the workpiece transfer system is provided.   3. The work transfer system according to claim 2, wherein the station controller and the host device have data transfer means for transferring data between the station controller and the host device.   The work transport system according to claim 1, wherein the storage unit of the self-propelled work transport pallet stores communication information with the station controller.   3. The workpiece transfer system according to claim 2, wherein the host device has an input unit for inputting the processing procedure program.   3. The workpiece transfer system according to claim 2, wherein the host device includes a simulation unit capable of simulating the movement of the transfer pallet according to the processing procedure program transmitted to the station controller.   3. The workpiece transfer system according to claim 2, wherein the host device is provided to execute or interrupt a processing procedure program transmitted to the station controller.   The work transfer system according to claim 1, wherein the station is provided at an entrance to a branch point or an intersection of the track. The station controller stores the relationship between the work process and the transfer path, the self-propelled work transfer pallet stores the current process number, and the station controller has moved to the corresponding station. Obtaining the current process number of the self-propelled workpiece transfer pallet, and determining the next transfer destination of the self-propelled workpiece transfer pallet based on the relationship, the relationship includes a process number, a work station, 2. The workpiece transfer system according to claim 1, further comprising information on a route to the own process, an occupying station at departure, an opening station at departure, and an own process number.

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