JP3664780B2 - Construction machine working range restriction control device - Google Patents

Description

減速制御演算部９ｄでは、フロント姿勢演算部９ｂで計算されたモニターポイントＰ１，Ｐ２，Ｐ５のＺ座標値Ｐ１ｚ，Ｐ２ｚ，Ｐ５ｚと、制限値記憶メモリ９ｃに記憶した侵入禁止領域の境界の設定値Ｐｃｚと、制御ユニット９の記憶装置に予め記憶しておいた減速領域の範囲を示す距離（以下、減速距離という）ＬU及び減速関数（後述）とから、ブームシリンダ３ａの伸び方向と縮み方向、アームシリンダ３ｂの伸び方向と縮み方向に対する減速指令信号ＫBU1，ＫBD1，ＫAU1，ＫAD1を演算する。この演算内容を図７を参照して以下に説明する。
【００３３】
まず、モニターポイントＰ１，Ｐ２，Ｐ５のＺ座標値をＰ１ｚ，Ｐ２ｚ，Ｐ５ｚを比較し、最も大きいＺ座標値と侵入禁止領域の境界の設定値Ｐｃｚとの差を計算し、最も高い位置にあるモニターポイントと侵入禁止領域の境界との間の距離ＬMを計算する。図６ではモニターポイントＰ２が最も高い位置にあるとして距離ＬMが計算されている。次いで、この距離ＬMと減速距離ＬUとを比較し、ＬM＞ＬUであれば最も高い位置にあるモニターポイントがまだ減速領域に入っていないので、減速指令信号ＫBU1，ＫBD1，ＫAU1，ＫAD1は全て１にする。ＬM≦ＬUであれば最も高い位置にあるモニターポイントが減速領域に入っていると判断し、下記の減速関数から減速指令信号ＫBU1，ＫBD1，ＫAU1，ＫAD1を演算する。
【００３４】
ＫBU1＝ＬM／ＬU
ＫBD1＝１
ＫAU1＝ＬM／ＬU
ＫAD1＝ＬM／ＬU
上記の減速関数を図８に示す。この図から分かるように、ブームシリンダ３ａの伸び方向に対する減速指令信号ＫBD1の減速関数、アームシリンダ３ｂの伸び後行及び縮み方向に対する減速指令信号ＫAU1，ＫAD1の減速関数は、減速距離ＬU以下で距離ＬMが小さくなるにしたがって減速指令信号が１から０まで直線的に小さくなるように設定されている。
【００３５】
最大シリンダ速度演算部９ｅでは、予め制御ユニット９の記憶装置に記憶しておいたブームシリンダ３ａの伸び方向及び縮み方向の最大シリンダ速度ＶBUmax，ＶBDmaxとアームシリンダ３ｂの伸び方向及び縮み方向の最大シリンダ速度ＶAUmax，ＶADmaxと、上記で計算した減速指令信号ＫBU1，ＫBD1及びＫAU1，ＫAD1よりブームシリンダ３ａの伸び、縮み動作の減速最大シリンダ速度ＶBUmaxc，ＶBDmaxcとアームシリンダ３ｂの伸び、縮み動作の減速最大シリンダ速度ＶAUmaxc，ＶADmaxcを演算する。この演算式を以下に示す。
【００３６】
ＶBUmaxc＝ＫBU1×ＶBUmax
ＶBDmaxc＝ＫBD1×ＶBDmax
ＶAUmaxc＝ＫAU1×ＶAUmax
ＶADmaxc＝ＫAD1×ＶADmax
最大パイロット圧演算部９ｆでは最大シリンダ速度演算部９ｅで演算した減速最大シリンダ速度ＶBUmaxc，ＶBDmaxc，ＶAUmaxc，ＶADmaxcと予め制御ユニット９の記憶装置に記憶しておいた図９の（ａ），（ｂ），（ｃ）及び（ｄ）に示すようなパイロット圧とシリンダ速度のテーブルよりブームシリンダ３ａの伸び、縮み動作の減速最大パイロット圧ＰBUmaxc，ＰBDmaxcと、アームシリンダ３ｂの伸び、縮み動作の減速最大パイッロト圧ＰAUmaxc，ＰADmaxcを演算する。
【００３７】
バルブ指令演算部９ｇでは最大パイロット圧演算部９ｆで演算したＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcと予め制御ユニット９の記憶装置に記憶しておいた図１０に示すようなパイロット圧と電流値のテーブルより、ブームシリンダ３ａの伸び、縮み動作、アームシリンダ３ｂの伸び、縮み動作の速度を規定する比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂに対する第１指令電流値ｉBU1，ｉBD1，ｉAU1，ｉAD1を演算する。
【００３８】
一方、パイロット一次圧追従判定演算部９ｈでは、減速制御演算部９ｄで計算した減速指令信号ＫBU1，ＫAU1，ＫAD1の各値、すなわちＬM／ＬUが予め制御ユニット９の記憶部に記憶しておいた係数Ｋｔｒ以下であるかどうかを判定し、ＬM／ＬUがＫｔｒ以下であるならば比例電磁弁の「スプールの付着現象」を防止するためのパイロット一次圧追従制御（後述）を行うと判定し、Ｋｔｒより大きいときは当該制御を行わないと判定する。
【００３９】
ここで、Ｋｔｒはフロント装置１Ａが侵入禁止領域の境界にどのくらい近づいたらパイロット一次圧追従制御を開始するを決めるための係数であり、Ｋｔｒが１より大きいときはモニターポイントが減速領域に達していない状態でパイロット一次圧追従制御を開始し、Ｋｔｒが１以下ではモニターポイントが減速領域に達した状態でパイロット一次圧追従制御を開始することになる。ここで、Ｋｔｒが１よりあまり大き過ぎると、モニターポイントが減速領域に達する可能性がないのにパイロット一次圧追従制御が開始されてしまい、比例電磁弁が不必要に絞られ通常の作業に支障を生じることがある（後述）。また、Ｋｔｒが１より小さすぎ、０に近くなると、侵入禁止領域の境界の直前でパイロット一次圧追従制御が開始され、当該制御が有効に働かなくなる場合がある。Ｋｔｒはそれらの兼ね合いで決められ、通常はモニターポイントが減速領域に達すると同時に開始することが好ましいことから、Ｋｔｒ＝１又は１付近の値に設定される。以下において、本実施形態ではＫｔｒ＝１に設定したものとして説明する。
【００４０】
パイロット圧演算部９ｉでは、パイロット一次圧追従判定演算部９ｈで、ＬM／ＬU≦Ｋｔｒでパイロット一次圧追従制御を開始すると判定されると、圧力検出器６０ａ，６０ｂ；６１ａ，６１ｂで検出した比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂのパイロット一次圧（パイロット操作装置４ａ，４ｂから出力された操作パイロット圧）をパイロット圧ＰBU，ＰBD，ＰAU，ＰADとする演算を行い、ＬM／ＬU＞Ｋｔｒでパイロット一次圧追従制御を開始しないと判定されると、制御ユニット９の記憶装置に予め記憶したおいてパイロットポンプ４３のパイロット元圧、すなわち操作パイロット圧として供給され得る最大圧力をパイロット圧ＰBU，ＰBD，ＰAU，ＰADとする演算を行う。
【００４１】
バルブ指令演算部９ｊでは、バルブ指令演算部９ｇと同様に、図１０に示すパイロット圧と電流値のテーブルより、パイロット圧ＰBU，ＰBD，ＰAU，ＰADを得るための比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂに対する第２指令電流値ｉBU2，ｉBD2，ｉAU2，ｉAD2を演算する。
【００４２】
最小値判定演算部９ｋでは、ブームシリンダ３ａの伸び、縮み動作、アームシリンダ３ｂの伸び、縮み動作の速度を規定する比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂに対する出力用の指令電流値ｉBU，ｉBD，ｉAU，ｉADを以下の式に従って決定する。
【００４３】
ｉBU＝ｍｉｎ（ｉBU1，ｉBU2）
ｉBD＝ｍｉｎ（ｉBD1，ｉBD2）
ｉAU＝ｍｉｎ（ｉAU1，ｉAU2）
ｉAD＝ｍｉｎ（ｉAD1，ｉAD2）
なお、第１指令電流値と第２指令電流値が等しい（ｉBU1＝ｉBU2，ｉBD1＝ｉBD2，ｉAU1＝ｉAU2，ｉAD1＝ｉAD2）ときはそのいずれか一方、例えば第１指令電流値を出力用の指令電流値にするものとして予め決めておく。
【００４４】
電流出力部９ｍでは、ｉBU，ｉBD，ｉAU，ｉADに応じた電流値を電気信号として比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂに出力する。
【００４５】
ここで、減速制御演算部９ｄで計算される減速指令信号がＫBD＝１、ＫBU＝１、ＫAD＝１、ＫAU＝１のときに最大パイロット圧演算部９ｆで演算される減速最大パイロット圧ＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcは操作パイロット圧の最大圧力（パイロットポンプ元圧）に設定されており、減速制御演算部９ｄでパイロット一次圧追従制御をしないと判定されたときにパイロット圧演算部９ｉで計算されるパイロット圧ＰBU，ＰBD，ＰAU，ＰADと同じである。このため、ＫBD＝１、ＫBU＝１、ＫAD＝１、ＫAU＝１のときの第１指令電流値ｉBU1，ｉBD1，ｉAU1，ｉAD1とパイロット一次圧追従制御をしないと判定されたときの第２指令電流値ｉBU2，ｉBD2，ｉAU2，ｉAD2とは等しい。また、減速最大パイロット圧ＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcをパイロット圧の最大圧力にするときの指令電流値ｉBU，ｉBD，ｉAU，ｉADは比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂをフルオープンにする電流値である。
【００４６】
一方、ＫBD＝０、ＫBU＝０、ＫAD＝０、ＫAU＝０のときは減速最大パイロット圧ＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcを０にすることであり、このときの指令電流値ｉBU，ｉBD，ｉAU，ｉADは比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂをフルクローズにする電流値である。
【００４７】
以上の制御の流れを図１１及び図１２にフローチャートとして示す。
【００４８】
図１１において、手順４００，４１０はフロント姿勢演算部９ｂに相当し、手順２００，５００〜５３０は減速制御演算部９ｄに相当し、手順５４０は最大シリンダ速度演算部９ｅに相当し、手順６００〜６２０は最大パイロット圧演算部９ｆに相当し、手順７００はバルブ指令演算部９ｇに相当する。また、図１２において、手順８００はパイロット一次圧追従判定演算部９ｈに相当し、手順９００〜９２０はパイロット圧演算部９ｉに相当し、手順１０００はバルブ指令演算部９ｊに相当し、手順１１００は最小値判定演算部９ｋに相当し、手順１２００，１２１０は電流出力部９ｍに相当する。なお、図１１において、手順３００〜３２０は安全のための初期設定である。
【００４９】
また、以上において、比例電磁弁１０ａ，１０ｂ又は１１ａ，１１ｂはパイロット操作装置４ａ，４ｂとこれに対応する流量制御弁５ａ又は５ｂとの間に設けられ、パイロット操作装置４ａ又は４ｂから出力された操作パイロット圧を減圧して出力する電気式減圧弁を構成し、圧力検出器６０ａ，６０ｂ又は６１ａ，６１ｂは電気式減圧弁１０ａ，１０ｂ又は１１ａ，１１ｂのパイロット一次圧を検出する検出手段を構成し、制御ユニットの９のパイロット一次圧追従判定演算部９ｈ、パイロット圧演算部９ｉ、バルブ指令演算部９ｊはモニターポイントがフロント装置を減速させる減速領域へ到達する際に電気式減圧弁へ出力する指令電流値を検出手段で検出されたパイロット一次圧に追従させる出力補正手段を構成する。
【００５１】
次に、以上のように構成した本実施例の動作を説明する。フロント装置１Ａを上方に動かそうとしてオペレータがブーム用及びアーム用のパイロット操作装置４ａ，４ｂの操作レバーをそれぞれブーム上げ方向及びアームダンプ方向に操作すると、ブーム上げ側のパイロットライン４４ａ及びアームダンプ側のパイロットライン４５ｂに操作パイロット圧が生成され、油圧制御弁５ａ，５ｂが駆動され、フロント部材であるブーム１ａ及びアーム１ｂが動かされる。ブーム１ａ、アーム１ｂ及びバケット１ｃの各関節角は位置検出手段である角度検出器８ａ〜８ｃにより検出され、その検出信号が制御ユニット９のフロント姿勢演算部９ｂに入力される。フロント姿勢演算部９ｂではこの入力信号によりモニターポイントＰ１〜Ｐ５の位置を演算し、減速制御演算部９ｄでは、フロント姿勢演算部９ｂで計算されたモニターポイントＰ１，Ｐ２，Ｐ５のＺ座標値Ｐ１ｚ，Ｐ２ｚ，Ｐ５ｚのうち最も大きいＺ座標値と制限値記憶メモリ９ｃに記憶した侵入禁止領域の境界の設定値Ｐｃｚとの差から、最も高い位置にあるモニターポイント、例えばモニターポイントＰ２と侵入禁止領域の境界との間の距離ＬMを計算し、更にこの距離ＬMと減速距離ＬUとを比較して最も高い位置にあるモニターポイントＰ２が減速領域に入っているか判断する。
【００５２】
このとき、フロント装置１Ａがまだ高く上がっておらず、モニターポイントＰ２が侵入禁止領域から遠いときは、ＬM＞ＬUであるので、減速制御演算部９ｄではモニターポイントＰ２が減速領域に入っていないと判断し、ＫBU1＝１，ＫBD1＝１，ＫAU1＝１，ＫAD1＝１の減速指令信号を生成する。
【００５３】
一方、このとき、パイロット操作装置４ａ，４ｂから出力された操作パイロット圧は（比例電磁弁１０ａ，１１ｂのパイロット一次圧）は圧力検出器６０ａ，６１ｂにより検出され、その検出信号が制御ユニット９のパイロット圧演算部９ｊに入力される。また、制御ユニット９において、パイロット一次圧追従判定演算部９ｈは、減速制御演算部９ｄで計算したＬM／ＬUがＫｔｒ（＝１）以下であるかどうかでパイロット一次圧追従制御を行うかどうかを判定する。今は、ＬM＞ＬUであるのでＬM／ＬU＞１であるので、ＬM／ＬUはＫｔｒより大きく、パイロット一次圧追従制御を行わないと判定し、パイロット圧演算部９ｉでは、操作パイロット圧の最大圧力をパイロット圧ＰBU，ＰBD，ＰAU，ＰADとする演算を行い、バルブ指令演算部９ｇ，９ｊでは第１指令電流値ｉBU1，ｉBD1，ｉAU1，ｉAD1及び第２指令電流値ｉBU2，ｉBD2，ｉAU2，ｉAD2がそれぞれ同じ値として計算され、最小値判定演算部９ｋではそれらの一方、例えば第１指令電流値が選択されて指令電流値ｉBU，ｉBD，ｉAU，ｉADとなり、比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂをフルオープンする。これによりブーム用の油圧制御弁５ａ及びアーム用の油圧制御弁５ｂにはパイロット操作装置４ａ，４ｂで生成された操作パイロット圧が比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂで大きな抵抗を受けることなくそのまま伝達され、フロント装置１Ａをオペレータの操作通りに動かすことができる。
【００５４】
フロント装置１Ａが上がり、最も高い位置にあるモニターポイントＰ２が減速領域に到達すると、減速制御演算部９ｄではＬM≦ＬUとなるのでモニターポイントＰ２が減速領域に入ったと判断され、距離ＬMに従って図８に示す減速関数から１より小さい減速指令信号ＫBU1，ＫAU1，ＫAD1が生成される。
【００５５】
一方、制御ユニット９のパイロット一次圧追従判定演算部９ｈでは、ＬM／ＬU≦１となってＬM／ＬUはＫｔｒ以下で、パイロット一次圧追従制御を行うと判定され、パイロット圧演算部９ｉでは、圧力検出器６０ａ，６０ｂ；６１ａ，６１ｂで検出した比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂのパイロット一次圧（パイロット操作装置４ａ，４ｂから出力された操作パイロット圧）をパイロット圧ＰBU，ＰBD，ＰAU，ＰADとする演算を行う。そして、最小値判定演算部９ｋでは、比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂのパイロット一次圧が最大パイロット圧演算部９ｆで計算された減速最大パイロット圧ＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcより小さい間は、当該パイロット一次圧に相当する第２指令電流値ｉBU2，ｉBD2，ｉAU2，ｉAD2を出力用の指令電流値ｉBU，ｉBD，ｉAU，ｉADとし、減速最大パイロット圧ＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcが比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂのパイロット一次圧より小さくなると、第１指令電流値ｉBU1，ｉBD1，ｉAU1，ｉAD1を出力用の指令電流値ｉBU，ｉBD，ｉAU，ｉADとする。
【００５６】
このため、比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂのパイロット一次圧が減速最大パイロット圧ＰBUmaxc，ＰBDmaxc，ＰAUmaxc，ＰADmaxcより小さい間は、比例電磁弁１０ａ，１０ｂ，１１ａ，１１ｂは当該パイロット一次圧と同じパイロット二次圧が得られるよう絞られる。本願明細書ではこのことを「パイロット一次圧追従制御」という。このようなパイロット一次圧追従制御により、ブーム用の油圧制御弁５ａ及びアーム用の油圧制御弁５ｂにはパイロット操作装置４ａ，４ｂで生成された操作パイロット圧がほぼそのまま伝達される。
【００５７】
そして、減速最大パイロット圧ＰBUmaxc，ＰADmaxcが比例電磁弁１０ａ，１１ｂのパイロット一次圧より小さくなると、比例電磁弁１０ａ，１１ｂは減速制御の第１減速指令信号ｉBU1，ｉAD1に応じて絞られ、ブーム上げとアームダンプの動作速度が減じられる。また、このように減速制御に移行するとき、その前までは上記のようにパイロット一次圧追従制御の第２指令電流値ｉBU2，ｉBD2，ｉAU2，ｉAD2により比例電磁弁１０ａ，１１ｂは絞られているので、比例電磁弁の「スプールの付着現象」に影響されずに、滑らかにブーム上げとアームダンプの動作速度を減じることができる。
【００５８】
フロント装置１Ａが更に上昇し、モニターポイントＰ２が侵入禁止領域に到達すると、減速制御演算部９ｄでＫBU＝０，ＫAU＝０，ＫAD＝０の減速指令信号が生成され、比例電磁弁１０ａ，１１ａ，１１ｂをフルクローズし、ブーム及びアームを停止させる。これによりフロント装置１Ａが停止する。
【００５９】
比例電磁弁の「スプールの付着現象」及び「パイロット一次圧追従制御」によりその影響が回避される様子を図１３により更に説明する。図１３（ａ）は本発明のパイロット一次圧追従制御を行わなかった場合であり、図１３（ｂ）パイロット一次圧追従制御を行った場合である。
【００６０】
図１３（ａ）において、パイロット操作装置から出力された操作パイロット圧（比例電磁弁のパイロット一次圧）が最大パイロット圧より小さい場合には、距離ＬMがＬU以下となり減速制御に移行するとき、比例電磁弁のパイロット一次圧に対して減速制御の指令電流値（バルブ指令演算部９ｇの指令電流値）が大き過ぎる期間が発生する。この間、本発明のパイロット一次圧追従制御を行わない場合は、比例電磁弁に対する出力用の指令電流値の圧力換算値がパイロット一次圧より大きくなり、比例電磁弁のスプール１５３（図４参照）がソレノイド１５６（同）とは反対の面に強く押し付けられる状態となり、指令電流値の圧力換算値がパイロット一次圧より小さくなり、減圧し始めようとしても、すぐにはスプール１５３は移動せず、一瞬動きが悪くなってしまう。すなわち、「スプールの付着現象」が生じる。この現象が起こると、いくら電流値を低くして減圧しようとしても、図１３（ａ）にＸで示すように一瞬減圧が遅れ、減速制御の開始が遅れ、見かけ上、減速距離が短くなったことと同じことになり、このため場合によってはアクチュエータが停止するときに大きな衝撃が生じ、オペレータに不快感を与えることになる。また、バケットに荷を積んでいる場合には、積み荷をこぼしてしまう可能性がある。
【００６１】
これに対して、本発明では、図１３（ｂ）に示すように、比例電磁弁のパイロット一次圧に対して減速制御の指令電流値（バルブ指令演算部９ｇの指令電流値）が大き過ぎる間、当該パイロット一次圧に相当する第２指令電流値（バルブ指令演算部９ｊの指令電流値）が計算されてこの第２指令電流値が比例電磁弁に出力されるので、比例電磁弁に対する出力用の指令電流値の圧力換算値はパイロット一次圧とほぼ同じとなり、パイロット一次圧に対して指令電流値が大きくなり過ぎることがなく、「スプールの付着現象」の影響が緩和される。したがって、比例電磁弁による減圧動作がスムーズに行われ、アクチュエータを滑らかに停止させることができる。
【００６２】
また、モニターポイントと侵入禁止領域との距離ＬMがＫｔｒで決まる所定値（本実施形態ではＫｔｒ＝１で、ＬM＝減速距離ＬU）以下になる前は、最大パイロット圧に相当する第１指令電流値又は第２指令電流値が出力されるので、比例電磁弁はフルオープンされ、パイロット操作装置で生成された操作パイロット圧は比例電磁弁でほとんど抵抗を受けることなく油圧制御弁に伝えられ、比例電磁弁がないかのようにフロント装置を動かすことができる。
【００６３】
以上のように本実施形態によれば、モニターポイントが侵入禁止領域に近づくと徐々にフロント装置の動作速度が減じられ、侵入禁止領域直前でフロント装置の動作速度がゼロになるので、フロント部材が侵入禁止領域に侵入することがない。
【００６４】
また、モニターポイントと侵入禁止領域との距離に応じて計算された減速制御の第１指令電流値と、比例電磁弁のパイロット一次圧に相当する第２指令電流値の小さい方を選択して出力するので、減速制御を行う際、比例電磁弁のパイロット一次圧に対して電流値が大きくなり過ぎることがなく、「スプールの付着現象」の影響が緩和される。したがって、比例電磁弁による減圧動作がスムーズに行われ、アクチュエータを滑らかに停止させることができる。このため、停止時の衝撃によりオペレータに不快感を与えない。また、荷こぼれも防ぐことができる。
【００６５】
更に、モニターポイントと侵入禁止領域との距離が減速距離ＬU以下になる前は、比例電磁弁はフルオープンになるので、比例電磁弁がないかのようにフロント装置を動かすことができる。
【００６６】
なお、本発明の作業範囲制限制御装置は上述の実施形態に限定されず、種々の変形が可能である。一例としてはフロント装置１Ａの位置と姿勢に関する状態量を検出する手段として回動角を検出する角度計を用いたが、シリンダのストロークを検出してもよい。また、侵入禁止領域を上方に設定した場合について説明したが、下方、前方に設定した場合についても同様である。
【００６７】
【発明の効果】
本発明によれば、電気式減圧弁の「スプールの付着現象」の影響を緩和することができるので、アクチュエータをスムーズに停止させることができ、停止時の衝撃によりオペレータに不快感を与えない。また、荷こぼれも防ぐことができる。
【００６８】
また、本発明によれば、モニターポイントと侵入禁止領域との距離が所定値以下になる前は、比例電磁弁がないかのようにフロント装置を動かすことができる。
【図面の簡単な説明】
【図１】本発明の一実施形態による建設機械の作業範囲制限制御装置を油圧駆動装置と共に示す図である。
【図２】本発明が適用される油圧ショベルの外観を示す図である。
【図３】油圧パイロット方式の操作レバー装置の構成を示す図である。
【図４】比例電磁弁の構造を示す図である。
【図５】本実施形態の制御ユニットの制御機能を示す機能ブロック図である。
【図６】本実施形態の作業範囲制限制御で用いる座標系と領域の設定方法を示す図である。
【図７】本実施形態の作業範囲制限制御における侵入禁止領域と減速領域を示す図である。
【図８】減速制御演算におけるモニターポイントと侵入禁止領域との距離に対する減速指令信号の関係を示す図である。
【図９】最大パイロット圧演算部におけるパイロット圧とシリンダ速度の関係を示す図である。
【図１０】バルブ指令演算部におけるパイロット圧と比例電磁弁に出力する電流値との関係を示す図である。
【図１１】制御ユニットの処理内容を示すフローチャートである。
【図１２】制御ユニットの処理内容を示すフローチャートである。
【図１３】図１３（ａ）は減速制御するときの「スプールの付着現象」の影響を示す図であり、図１３（ｂ）は本発明により減速制御するときの「スプールの付着現象」の影響の緩和を示す図である。
【符号の説明】
１Ａ フロント装置
１Ｂ 車体
１ａ ブーム
１ｂ アーム
１ｃ バケット
２ 油圧ポンプ
３ａ ブームシリンダ
３ｂ アームシリンダ
４ａ〜４ｆ 操作レバー装置
５ａ〜５ｆ 流量制御弁
７ 設定器
８ａ〜８ｃ 角度検出器（位置検出手段）
９ 制御ユニット
９ａ 侵入禁止領域演算部
９ｂ フロント姿勢演算部
９ｃ 制限値記憶メモリ
９ｄ 減速制御演算部
９ｅ 最大シリンダ速度演算部
９ｆ 最大パイロット圧演算部
９ｇ バルブ指令演算部
９ｈ パイロット一次圧追従判定演算部
９ｉ パイロット圧演算部
９ｊ バルブ指令演算部
９ｋ 最小値判定演算部
９ｍ 電流出力部
１０ａ〜１１ｂ 比例電磁弁（電気式減圧弁）
５０ａ〜５５ｂ 油圧駆動部
６０ａ，６０ｂ，６１ａ，６１ｂ 圧力検出器[0001]
[Industrial application fields]
The present invention relates to a work range restriction control device for a construction machine such as a hydraulic excavator.
[0002]
[Prior art]
In a hydraulic excavator, a boom is attached to a front portion of an upper swing body, and an arm and a bucket are sequentially connected to the tip of the boom to constitute a working front device. And excavation loading work etc. are performed by operating the refraction work movement of the above-mentioned front device.
[0003]
When working with such a hydraulic excavator, there may be obstacles above and below depending on the work site. For example, electric wires are used for outdoor work, and ceilings and the like are used for indoor work. Moreover, in the excavation work when a gas pipe or a water pipe is in the ground, these become obstacles below. The operator needs to pay close attention not to touch or catch parts such as bucket toes during operation.
[0004]
In order to solve such a problem, an invention as described in JP-A-3-208923 and JP-B-6-19165 has been made. In the invention described in Japanese Patent Laid-Open No. 3-208923, an intrusion prohibition area of the front device is set in advance above, a deceleration area of the actuator is set below the intrusion prohibition area, When the part at the maximum height enters this deceleration area, the discharge rate of the hydraulic pump is reduced to reduce the operating speed of the actuator, and when reaching the entry prohibition area, the pilot pressure is cut off and the actuator operation is stopped. Thus, a part of the work machine is prevented from coming into contact with an upper obstacle.
[0005]
In addition, the invention described in Japanese Patent Publication No. 6-19165 reduces the operating pilot pressure between the pilot operating device and the flow control valve operated by the operating pilot pressure output from the pilot operating device. An electric pressure reducing valve is provided for output, and when the boom rises to a set height, an electric signal for depressurizing the electric pressure reducing valve is output to reduce the operating pilot pressure and stop the boom from rising. .
[0006]
[Problems to be solved by the invention]
In Japanese Examined Patent Publication No. 6-19165, the operation pilot pressure is reduced using the electric pressure reducing valve as described above, and when the boom rises to a set height, the rise of the boom is stopped. Further, if the electric pressure reducing valve described in Japanese Patent Publication No. 6-19165 is used in the invention of Japanese Patent Laid-Open No. 3-208923, the electric type is adjusted according to the distance between the boom and the set height (intrusion prohibited area). By adjusting the electric signal given to the pressure reducing valve, when the boom approaches the set height, the degree of pressure reduction by the electric pressure reducing valve is increased, the operating speed of the actuator is lowered, and the operating speed of the boom can be reduced. However, when performing deceleration control using an electric pressure reducing valve in this way, there are the following problems.
[0007]
When an electric pressure reducing valve is placed between the pilot operating device and the flow control valve, the operating pilot pressure output from the pilot operating device is inadvertently reduced, causing a reduction in the actuator speed that does not match the operator's will. There must be no. For this reason, the electric pressure reducing valve is usually electrically operated so that the hydraulic pressure of the pilot pump that is the hydraulic pressure source of the pilot operating device (pilot pump original pressure) can be always supplied to the flow control valve unless necessary. The maximum current flows as the current value of the signal, and the valve is fully open. Then, for example, when the boom approaches the set height or depth, the current value of the electric signal is gradually decreased, the pressure reducing valve is closed, the actuator speed is gradually decreased, and finally the operation is smoothly stopped.
[0008]
However, the electrical pressure reducing valve has a characteristic that when the current value is large relative to the applied pilot primary pressure (operating pilot pressure output from the pilot operating device), the spool is strongly pressed against the surface opposite to the solenoid. Thus, even if the spool moves to the solenoid side and tries to start depressurization, the spool does not move immediately, and the movement often deteriorates for a moment. In this specification, a phenomenon in which the movement is deteriorated by pressing the spool against one side is referred to as a “spool adhesion phenomenon”. If this phenomenon occurs, no matter how much the current value is lowered and the pilot pilot pressure is reduced, the pressure reduction is delayed for a moment, so the start of the deceleration control is delayed, which appears to be the same as the deceleration distance is shortened. In some cases, a large impact is generated when the actuator is stopped, which makes the operator uncomfortable. Moreover, when the bucket is loaded, there is a possibility of spilling the load.
[0009]
An object of the present invention is to provide a construction machine working range restriction control device capable of smoothly reducing the speed of an actuator and stopping it without being influenced by the “spool adhesion phenomenon” of an electric pressure reducing valve.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention adopts the following configuration. That is, an articulated front device configured by a plurality of front members that can rotate in the vertical direction, a plurality of hydraulic actuators that drive the plurality of front members, and an operation of the plurality of front members are instructed.By operating pilot pressure output from the operating deviceA plurality of flow control valves that are driven and control flow rates of pressure oil supplied to the plurality of hydraulic actuators;An electric pressure reducing valve that is provided between the operating device and at least one flow control valve corresponding to the operating device, and that reduces and outputs an operating pilot pressure output from the operating device,Pre-set for the front devicedidDepending on the distance between the monitor point and the preset intrusion prohibited areaFingerCalculate the command current valueFor the electric pressure reducing valveOutputAndWhen the monitor point approaches the intrusion prohibited area, the front device is decelerated.LetWhen the intrusion prohibited area is reached, the front device is stopped.Do controlIn the construction machine work range restriction control device,PreviousDetection means for detecting the pilot primary pressure of the electric pressure reducing valveIs provided between the operating device and the electric pressure reducing valve, and the detection means detects a command current value to be output to the electric pressure reducing valve when the monitor point reaches a deceleration region for decelerating the front device. Output correction means for following the pilot primary pressure.
[0011]
  In the present invention configured as described above, when the monitor point approaches the intrusion prohibited area and the distance between the monitor point and the intrusion prohibited area decreases,For example,A first command current value that decreases as the distance decreases, and the output correction means calculates a second command current value corresponding to the pilot primary pressure detected by the detection means, and the first and second command currents are calculated. The smaller value is output as an electric signal to the electric pressure reducing valve. As a result, the first command current value is selected when the front device approaches the intrusion prohibition region beyond the distance where the first command current value is smaller than the second command current value. The operation speed of the actuator is reduced, and when the intrusion prohibited area is reached, the operation speed of the actuator becomes zero and the front device stops.
[0012]
  Also, when the monitor point reaches the deceleration area (for details,Until the first command current value becomes smaller than the second command current valueHa)A second command current value corresponding to the pilot pressure primary pressure is output as an electrical signal.(Pilot primary pressure tracking control)Therefore, the command current value does not become too large with respect to the pilot primary pressure of the electric pressure reducing valve, and the spool of the electric pressure reducing valve moves quickly when shifting to the deceleration control as described above, ”Will be mitigated. Therefore, the pressure reducing operation by the electric pressure reducing valve is smoothly performed, and the actuator can be smoothly stopped.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a hydraulic excavator will be described with reference to FIGS. This embodiment is for the case where the upper range restriction control is performed.
[0017]
In FIG. 1, a hydraulic excavator to which the present invention is applied includes a hydraulic pump 2, a boom cylinder 3a, an arm cylinder 3b, a bucket cylinder 3c, a swing motor 3d, and left and right travelings driven by pressure oil from the hydraulic pump 2. Between a plurality of hydraulic actuators including motors 3e and 3f, a plurality of operation lever devices 4a to 4f provided corresponding to each of the hydraulic actuators 3a to 3f, and between the hydraulic pump 2 and the plurality of hydraulic actuators 3a to 3f. A plurality of flow control valves 5a to 5f that are connected and controlled by operation signals of the operation lever devices 4a to 4f to control the flow rate of the pressure oil supplied to the hydraulic actuators 3a to 3f, the hydraulic pump 2, and the flow control valve 5a And a relief valve 6 that opens when the pressure between ˜5f exceeds a set value. Constitute the hydraulic drive system for driving the driving member.
[0018]
As shown in FIG. 2, the hydraulic excavator includes an articulated front device 1A including a boom 1a, an arm 1b, and a bucket 1c that rotate in a vertical direction, an upper swing body 1d, and a lower traveling body 1e. It is comprised with the vehicle body 1B, and the base end of the boom 1a of 1 A of front apparatuses is supported by the front part of the upper turning body 1d. The boom 1a, the arm 1b, the bucket 1c, the upper swing body 1d, and the lower traveling body 1e are respectively driven by the boom cylinder 3a, the arm cylinder 3b, the bucket cylinder 3c, the swing motor 3d, and the left and right traveling motors 3e, 3f. The members are configured, and their operations are instructed by the operation lever devices 4a to 4f.
[0019]
  The operation lever devices 4a to 4f output pilot pressure as operation signals and drive the corresponding flow control valves 5a to 5f.OilPressure pilot systemOperating device (pilot operating device)As shown in FIG. 3, each is constituted by an operation lever 40 operated by an operator, and a pair of pressure reducing valves 41 and 42 that generate a pilot pressure corresponding to the operation amount and operation direction of the operation lever 40. The primary port side of the pressure reducing valves 41, 42 is connected to the pilot pump 43, and the secondary port side is connected to the pilot lines 44a, 44b; 45a, 45b; 46a, 46b; 47a, 47b; 48a, 48b; Are connected to hydraulic drive units 50a, 50b; 51a, 51b; 52a, 52b; 53a, 53b; 54a, 54b;
[0020]
For example, in the pilot operating device 4a for the boom, when the operating lever 40 is operated in the direction A in FIG. 3, the pilot original pressure from the pilot pump 43 is changed to a pressure proportional to the operating amount of the operating lever 40 by the pressure reducing valve 41. The pressure is output to the pilot line 44a, and this pressure is applied to the hydraulic drive unit 50a of the flow control valve 5a, whereby the spool of the flow control valve 5a is moved to the right in FIG. Thereby, the pressure oil from the hydraulic pump 2 as the main pump is supplied to the bottom side of the boom cylinder 3a, the boom cylinder 3a is driven to extend, and the boom 1a shown in FIG. 2 is moved upward. When the operation lever 40 is operated in the direction B in FIG. 3, the pilot original pressure from the pilot pump 43 is changed to a pressure proportional to the operation amount of the operation lever 40 by the pressure reducing valve 42 and output to the pilot line 44b. The spool of the flow control valve 5a is moved to the left in FIG. 1 by being given to the hydraulic drive unit 50b of the flow control valve 5a, and the pressure oil from the hydraulic pump 2 is supplied to the rod side of the boom cylinder 3a. 3a is driven to contract, and the boom 1a shown in FIG. 2 is moved downward. When the operation lever 40 is returned to the center position, the pressure reducing valves 41 and 42 connect the pilot lines 44a and 44b to the tank, the application of the pilot pressure to the flow control valve 5a is released, and the flow control valve 5a is neutral by the restoring spring. The movement of the boom 1a is stopped. The same applies to the pilot operating devices 4b and 4c for the arm and bucket. By operating the boom, arm, and bucket pilot operating devices 4a to 4c individually or in combination, the front device 1A is refracted in a desired manner to perform excavation and loading work. be able to. In the present specification, the pilot pressure output from the pilot operating devices 4a and 4b is particularly referred to as “operating pilot pressure”.
[0021]
The above-described hydraulic excavator is provided with a work range restriction control device according to the present embodiment. This work range restriction control device has a setting device 7 for instructing an area (invasion prohibition area) where the front member should not enter in advance according to work, and each rotation of the boom 1a, arm 1b, and bucket 1c. Angle detectors 8a, 8b, and 8c that are provided at the fulcrum and detect respective rotation angles as state quantities relating to the position and posture of the front device 1A, and pilot lines 44a of the boom and arm pilot operating devices 4a and 4b. 44b; 45a, 45b, pressure detectors 60a, 60b; 61a, 61b for detecting the operating pilot pressure output from the pilot operating devices 4a, 4b, setting signals from the setting device 7, angle detectors 8a, 8b, 8c and pressure detectors 60a, 60b; 61a, 61b detection signals are input and the front member must not enter A pilot unit 44a, 44b, 45a, 45b is installed on the pilot unit 44a, 44b, 45a, 45b, respectively, for setting a stop region and outputting an electric signal for restricting the work range according to the entry prohibition region. , 4b, and the proportional pilot valves 10a, 10b, 11a, and 11b that output the pilot pressure as the pilot primary pressure in accordance with the respective electric signals output from the control unit 9. ing. Note that the detection of the operating pilot pressure output from the pilot operating devices 4a and 4b by the pressure detectors 60a and 60b; 61a and 61b ultimately results in the pilot primary pressures of the proportional solenoid valves 10a, 10b, 11a and 11b. Will be detected.
[0022]
The proportional solenoid valves 10a, 10b, 11a, and 11b are electric pressure reducing valves and have a structure as shown in FIG. In the figure, 150 is an input port, 151 is an output port, 152 is a tank port, 153 is a spool, 154 is an internal passage, 155 is a pressure chamber, 156 is a solenoid, and is output from the pilot operating devices 4a and 4b to the input port 150. The operated pilot pressure is guided as the pilot primary pressure, and the pilot secondary pressure (output pressure) from the output port 152 is given to the hydraulic drive units 50a, 50b; 51a, 51b of the flow control valves 5a, 5b, and the solenoid 156 Is supplied with an electrical signal from the control unit 9.
[0023]
When the current value of the electrical signal applied to the solenoid 156 is zero, no electromagnetic force is generated in the solenoid 156, and the spool 154 is caused by the biasing force Fp due to the pilot primary pressure transmitted to the pressure chamber 155 via the internal passage 154. Moving to the right in the figure, the output port 151 is connected to the tank port 152, and the pilot secondary pressure is set to the tank pressure (full close). When the current value of the electrical signal applied to the solenoid 156 is not zero, an axial force Fs corresponding to the current value is generated, the spool 153 is moved to the left in the figure, and the biasing force Fp applied by the pressure chamber 155 The spool 153 stops at the position where it is suspended. At this time, the communication between the output port 151 and the tank port 152 is cut off, the output port 151 communicates with the input port 150 through a throttle, and the pressure reduced according to the throttle is generated at the output port 151. Output as pilot secondary pressure. Further, the pressure (pilot secondary pressure) from the output port 151 is guided to the pressure chamber 155 via the internal passage 154, and the urging force Fp has a value corresponding to the pilot secondary pressure. Then, when the current value of the electric signal applied to the solenoid 156 increases and the axial force Fs increases, the spool 153 is moved to the left in the corresponding direction, the throttle of the spool 153 weakens, and the degree of decompression is reduced. As the pressure decreases, the pressure (pilot secondary pressure) generated at the output port 151 increases. When the current value of the electrical signal applied to the solenoid 156 is maximized, the spool 153 is moved to a position where the throttle does not work at all (full open), and the pressure (pilot secondary pressure) generated at the output port 151 is It becomes the same as the pressure (pilot primary pressure).
[0024]
The setting device 7 outputs a setting signal to the control unit 9 by an operation means such as a switch provided on the operation panel or grip and instructs the setting of the intrusion prohibited area. There may be auxiliary means. Other methods such as a method using an IC card, a method using a barcode, a method using a laser, and a method using wireless communication may be used.
[0025]
The control unit 9 has a control function as shown in FIG. That is, the control unit 9 includes an intrusion prohibition region calculation unit 9a, a front posture calculation unit 9b, a limit value storage memory 9c, a deceleration control calculation unit 9d, a maximum cylinder speed calculation unit 9e, a maximum pilot pressure calculation unit 9f, and a valve command calculation unit. 9g, pilot primary pressure follow-up determination calculation unit 9h, pilot pressure calculation unit 9i, valve command calculation unit 9j, minimum value determination calculation unit 9k, and current output unit 9m.
[0026]
The intrusion prohibited area calculation unit 9a performs setting calculation of an area (intrusion prohibited area) where the front member should not enter in accordance with an instruction from the setting device 7. An example of this will be described with reference to FIG.
[0027]
In FIG. 6, a plurality of monitor points P1 to P5 are set in advance in a predetermined position on the front device 1A. The operator wants to limit the front device 1A by the operation of the operator. The heights P1z to P5z of the monitor points P1 to P5 are calculated, and the highest value is set as the set value of the boundary of the intrusion prohibited area. Here, the values of P1z to P5z are calculated by the front posture calculation unit 9b.
[0028]
In the front posture calculation unit 9b, the rotation angles of the boom, arm, and bucket detected by the angle detectors 8a to 8c and the front device 1A and the vehicle body 1B as shown in FIG. The position and orientation of the front apparatus 1A are calculated using data such as the dimensions LA1, LA2, LA3, LB1, LB2, LB3, LV1, LV2, and LV3. At this time, the position and orientation are obtained as coordinate values in the XZ coordinate system with the pivot point of the boom 1a as the origin, for example. The XZ coordinate system is an orthogonal coordinate system in a vertical plane fixed to the main body 1B.
[0029]
Here, when performing the setting calculation in the intrusion prohibition area calculation unit 9a, the front posture calculation unit 9b calculates the values of the monitor points P1 to P5 as the Z coordinate values of the XZ coordinate system, and the largest value among them is calculated. A set value (Z coordinate value = Pcz) of the boundary of the intrusion prohibited area is used. The set value (Z coordinate value = Pcz) of the boundary of the intrusion prohibited area calculated by the intrusion prohibited area calculation unit 9a is stored in the limit value storage memory 9c.
[0030]
Further, the front posture calculation unit 9b calculates the positions of the monitor points P1 to P5 even during work by upper limit control. In the present embodiment, there are three monitor points P1, P2, and P5 when performing the upper limit control. The monitor point P1 is the apex of the bent portion of the boom 1a, the monitor point P2 is the upper end of the rear end of the arm 1b, and the monitor point P5 is a radius LV1 centered on the rotation center (bucket pin) of the bucket 1c. It is the highest point of the circle (distance from bucket pin to bucket tip). Also at this time, the position of each monitor point is obtained as a value in the XZ coordinate system, and the height of each monitor point is calculated as a Z coordinate value in the XZ coordinate system.
[0031]
Here, the Z coordinate values of the monitor points P1 to P5 calculated by the front posture calculation unit 9b are expressed by the following formulas using the dimensions shown in FIG. 6 stored in the storage device from the rotation angles α, β, and γ. It is obtained by.
[0032]

In the deceleration control calculation unit 9d, the Z coordinate values P1z, P2z, and P5z of the monitor points P1, P2, and P5 calculated by the front posture calculation unit 9b and the set value of the boundary of the intrusion prohibition area stored in the limit value storage memory 9c. From the Pcz, a distance indicating the range of the deceleration area previously stored in the storage device of the control unit 9 (hereinafter referred to as a deceleration distance) L U and a deceleration function (described later), the extension direction and the contraction direction of the boom cylinder 3a, Deceleration command signals KBU1, KBD1, KAU1, and KAD1 for the extension direction and the contraction direction of the arm cylinder 3b are calculated. The contents of this calculation will be described below with reference to FIG.
[0033]
First, the Z coordinate values of the monitor points P1, P2 and P5 are compared with P1z, P2z and P5z, and the difference between the largest Z coordinate value and the set value Pcz of the boundary of the intrusion prohibited area is calculated, and is at the highest position. The distance LM between the monitor point and the boundary of the intrusion prohibited area is calculated. In FIG. 6, the distance LM is calculated on the assumption that the monitor point P2 is at the highest position. Next, the distance LM is compared with the deceleration distance LU, and if LM> LU, the highest monitoring point has not yet entered the deceleration region, so the deceleration command signals KBU1, KBD1, KAU1, and KAD1 are all 1. To. If LM ≦ LU, it is determined that the monitor point at the highest position is in the deceleration region, and deceleration command signals KBU1, KBD1, KAU1, and KAD1 are calculated from the following deceleration function.
[0034]
KBU1 = LM / LU
KBD1 = 1
KAU1 = LM / LU
KAD1 = LM / LU
The deceleration function is shown in FIG. As can be seen from the figure, the deceleration function of the deceleration command signal KBD1 with respect to the extending direction of the boom cylinder 3a and the deceleration function of the deceleration command signals KAU1 and KAD1 with respect to the following and contracting directions of the arm cylinder 3b are less than the deceleration distance LU. The deceleration command signal is set to linearly decrease from 1 to 0 as LM decreases.
[0035]
In the maximum cylinder speed calculation unit 9e, the maximum cylinder speeds VBUmax and VBDmax in the extension direction and the contraction direction of the boom cylinder 3a and the maximum cylinder in the extension direction and the contraction direction of the arm cylinder 3b, which are stored in the storage device of the control unit 9 in advance. From the speeds VAUmax, VADmax and the deceleration command signals KBU1, KBD1 and KAU1, KAD1 calculated above, the boom cylinder 3a extends and contracts at maximum deceleration cylinder speed VBUmaxc, VBDmaxc and the arm cylinder 3b expands and contracts at maximum deceleration cylinder The speeds VAUmaxc and VADmaxc are calculated. This calculation formula is shown below.
[0036]
VBUmaxc = KBU1 × VBUmax
VBDmaxc = KBD1 × VBDmax
VAUmaxc = KAU1 × VAUmax
VADmaxc ＝ KAD1 × VADmax
In the maximum pilot pressure calculation section 9f, the maximum deceleration cylinder speeds VBUmaxc, VBDmaxc, VAUmaxc, VADmaxc calculated by the maximum cylinder speed calculation section 9e and the storage unit of the control unit 9 shown in FIG. ), (C) and (d) as shown in the table of pilot pressure and cylinder speed, the boom cylinder 3a extends and contracts with maximum deceleration deceleration pilot pressures PBUmaxc and PBDmaxc, and the arm cylinder 3b expands and contracts with maximum deceleration. The pilot pressures PAUmaxc and PADmaxc are calculated.
[0037]
In the valve command calculation unit 9g, PBUmaxc, PBDmaxc, PAUmaxc, and PADmaxc calculated by the maximum pilot pressure calculation unit 9f and a pilot pressure and current value table as shown in FIG. The first command current values iBU1, iBD1, iAU1, and iAD1 are calculated for the proportional solenoid valves 10a, 10b, 11a, and 11b that regulate the speeds of the boom cylinder 3a and the arm cylinder 3b.
[0038]
On the other hand, in the pilot primary pressure follow-up determination calculation unit 9h, the values of the deceleration command signals KBU1, KAU1, and KAD1 calculated by the deceleration control calculation unit 9d, that is, LM / LU, are stored in advance in the storage unit of the control unit 9. It is determined whether or not the coefficient Ktr is equal to or less than that, and if LM / LU is equal to or less than Ktr, it is determined that pilot primary pressure follow-up control (described later) for preventing the “spool adhesion phenomenon” of the proportional solenoid valve is performed. When it is larger than Ktr, it is determined that the control is not performed.
[0039]
Here, Ktr is a coefficient for determining how far the front apparatus 1A approaches the boundary of the intrusion prohibition region to start the pilot primary pressure follow-up control. When Ktr is greater than 1, the monitor point does not reach the deceleration region. In this state, pilot primary pressure tracking control is started. When Ktr is 1 or less, pilot primary pressure tracking control is started in a state where the monitor point reaches the deceleration region. Here, if Ktr is too large, the pilot primary pressure follow-up control is started even though the monitor point may not reach the deceleration region, and the proportional solenoid valve is throttled unnecessarily, which hinders normal work. May occur (described later). If Ktr is too small and close to 0, pilot primary pressure tracking control is started immediately before the boundary of the intrusion prohibited region, and the control may not work effectively. Ktr is determined by the balance between them, and normally it is preferable to start as soon as the monitor point reaches the deceleration region, so Ktr = 1 or a value near 1 is set. In the following description, in this embodiment, it is assumed that Ktr = 1 is set.
[0040]
In the pilot pressure calculation unit 9i, when the pilot primary pressure follow-up determination calculation unit 9h determines that the pilot primary pressure follow-up control is started with LM / LU ≦ Ktr, the proportionality detected by the pressure detectors 60a and 60b; 61a and 61b. The pilot primary pressures of the solenoid valves 10a, 10b, 11a, 11b (operating pilot pressures output from the pilot operating devices 4a, 4b) are calculated as pilot pressures PBU, PBD, PAU, PAD, and LM / LU> Ktr. If it is determined that the pilot primary pressure tracking control is not started, the pilot pressure of the pilot pump 43 stored in advance in the storage device of the control unit 9, that is, the maximum pressure that can be supplied as the operating pilot pressure is set to the pilot pressure PBU, PBD. , PAU, PAD.
[0041]
In the valve command calculation unit 9j, similarly to the valve command calculation unit 9g, proportional solenoid valves 10a, 10b, and 11a for obtaining the pilot pressures PBU, PBD, PAU, and PAD from the pilot pressure and current value table shown in FIG. , 11b, the second command current values iBU2, iBD2, iAU2, and iAD2 are calculated.
[0042]
The minimum value determination calculation unit 9k outputs command current values iBU and iBD for output to the proportional solenoid valves 10a, 10b, 11a, and 11b that regulate the speed of expansion and contraction of the boom cylinder 3a and the extension and contraction of the arm cylinder 3b. , IAU, iAD are determined according to the following equations.
[0043]
iBU = min (iBU1, iBU2)
iBD = min (iBD1, iBD2)
iAU = min (iAU1, iAU2)
iAD = min (iAD1, iAD2)
When the first command current value is equal to the second command current value (iBU1 = iBU2, iBD1 = iBD2, iAU1 = iAU2, iAD1 = iAD2), for example, the first command current value is used as an output command. The current value is determined in advance.
[0044]
The current output unit 9m outputs a current value corresponding to iBU, iBD, iAU, iAD to the proportional solenoid valves 10a, 10b, 11a, 11b as an electric signal.
[0045]
Here, the deceleration maximum pilot pressure PBUmaxc calculated by the maximum pilot pressure calculation unit 9f when the deceleration command signal calculated by the deceleration control calculation unit 9d is KBD = 1, KBU = 1, KAD = 1, KAU = 1. PBDmaxc, PAUmaxc, and PADmaxc are set to the maximum operating pilot pressure (pilot pump source pressure), and are calculated by the pilot pressure calculation unit 9i when it is determined by the deceleration control calculation unit 9d that the pilot primary pressure tracking control is not performed. The pilot pressures PBU, PBD, PAU and PAD are the same. Therefore, the first command current value iBU1, iBD1, iAU1, iAD1 when KBD = 1, KBU = 1, KAD = 1, KAU = 1 and the second command when it is determined not to perform pilot primary pressure tracking control. The current values iBU2, iBD2, iAU2, and iAD2 are equal. The command current values iBU, iBD, iAU, iAD when the maximum deceleration pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc are set to the maximum pilot pressure are currents that fully open the proportional solenoid valves 10a, 10b, 11a, 11b. Value.
[0046]
On the other hand, when KBD = 0, KBU = 0, KAD = 0, KAU = 0, the maximum deceleration pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc are set to 0, and the command current values iBU, iBD, iAU at this time , IAD is a current value for fully closing the proportional solenoid valves 10a, 10b, 11a, 11b.
[0047]
The above control flow is shown as a flowchart in FIGS.
[0048]
In FIG. 11, procedures 400 and 410 correspond to the front attitude calculation unit 9b, procedures 200 and 500 to 530 correspond to the deceleration control calculation unit 9d, procedure 540 corresponds to the maximum cylinder speed calculation unit 9e, and procedures 600 to 620 corresponds to the maximum pilot pressure calculation unit 9f, and the procedure 700 corresponds to the valve command calculation unit 9g. In FIG. 12, a procedure 800 corresponds to the pilot primary pressure follow-up determination calculation unit 9h, procedures 900 to 920 correspond to the pilot pressure calculation unit 9i, procedure 1000 corresponds to the valve command calculation unit 9j, and procedure 1100 includes It corresponds to the minimum value determination calculation unit 9k, and procedures 1200 and 1210 correspond to the current output unit 9m. In FIG. 11, procedures 300 to 320 are initial settings for safety.
[0049]
  In the above, the proportional solenoid valves 10a, 10b or 11a, 11b are pilot operated devices 4a, 4b.b andAn operating pilot pressure provided between the corresponding flow control valve 5a or 5b and output from the pilot operating device 4a or 4b.DecreaseIt constitutes an electric pressure reducing valve that presses and outputs pressure detector 60a, 60b or 61a, 61bIs electricThe detection means for detecting the pilot primary pressure of the pneumatic pressure reducing valves 10a, 10b or 11a, 11b is configured, and the control unit 9The paThe pilot primary pressure follow-up determination calculation unit 9h, the pilot pressure calculation unit 9i, and the valve command calculation unit 9jWhen the monitor point reaches a deceleration region that decelerates the front device, the command current value output to the electric pressure reducing valve is made to follow the pilot primary pressure detected by the detecting means.An output correction unit is configured.
[0051]
Next, the operation of the present embodiment configured as described above will be described. When the operator operates the operation levers of the boom and arm pilot operation devices 4a and 4b in the boom raising direction and the arm dump direction, respectively, to move the front device 1A upward, the boom raising side pilot line 44a and the arm dump side An operation pilot pressure is generated in the pilot line 45b, the hydraulic control valves 5a and 5b are driven, and the boom 1a and the arm 1b, which are front members, are moved. The joint angles of the boom 1a, the arm 1b, and the bucket 1c are detected by angle detectors 8a to 8c that are position detection means, and the detection signals are input to the front posture calculation unit 9b of the control unit 9. The front posture calculation unit 9b calculates the positions of the monitor points P1 to P5 based on this input signal, and the deceleration control calculation unit 9d calculates the Z coordinate values P1z of the monitor points P1, P2, and P5 calculated by the front posture calculation unit 9b. From the difference between the largest Z coordinate value of P2z and P5z and the set value Pcz of the boundary of the intrusion prohibited area stored in the limit value storage memory 9c, the monitor point at the highest position, for example, the monitor point P2 and the intrusion prohibited area The distance LM between the boundary and the boundary is calculated, and the distance LM and the deceleration distance LU are compared to determine whether the highest monitor point P2 is in the deceleration region.
[0052]
At this time, when the front device 1A is not yet raised and the monitor point P2 is far from the intrusion prohibited area, LM> LU, so that the monitor point P2 is not in the deceleration area in the deceleration control calculation unit 9d. Judgment is made, and a deceleration command signal of KBU1 = 1, KBD1 = 1, KAU1 = 1, KAD1 = 1 is generated.
[0053]
On the other hand, the operating pilot pressure (pilot primary pressure of the proportional solenoid valves 10a and 11b) output from the pilot operating devices 4a and 4b is detected by the pressure detectors 60a and 61b. It is input to the pilot pressure calculator 9j. Further, in the control unit 9, the pilot primary pressure follow-up determination calculation unit 9h determines whether or not to perform the pilot primary pressure follow-up control depending on whether LM / LU calculated by the deceleration control calculation unit 9d is equal to or less than Ktr (= 1). judge. At present, since LM> LU and LM / LU> 1, it is determined that LM / LU is larger than Ktr and the pilot primary pressure tracking control is not performed, and the pilot pressure calculation unit 9i determines the maximum operating pilot pressure. The pressure is calculated as pilot pressures PBU, PBD, PAU, PAD, and the valve command calculation units 9g, 9j perform the first command current values iBU1, iBD1, iAU1, iAD1, and the second command current values iBU2, iBD2, iAU2, iAD2, respectively. Are calculated as the same value, and in the minimum value determination calculation unit 9k, for example, the first command current value is selected to become command current values iBU, iBD, iAU, iAD, and proportional solenoid valves 10a, 10b, 11a, 11b is fully opened. As a result, the pilot pressure generated by the pilot operating devices 4a and 4b is not subjected to large resistance by the proportional solenoid valves 10a, 10b, 11a, and 11b in the boom hydraulic control valve 5a and the arm hydraulic control valve 5b. It is transmitted as it is, and the front device 1A can be moved according to the operation of the operator.
[0054]
When the front device 1A is raised and the monitor point P2 at the highest position reaches the deceleration region, the deceleration control calculation unit 9d determines that LM ≦ LU, so that the monitor point P2 has entered the deceleration region. The deceleration command signals KBU1, KAU1, and KAD1 smaller than 1 are generated from the deceleration function shown in FIG.
[0055]
On the other hand, in the pilot primary pressure follow-up determination calculation unit 9h of the control unit 9, it is determined that LM / LU ≦ 1 and LM / LU is equal to or less than Ktr and the pilot primary pressure follow-up control is performed. In the pilot pressure calculation unit 9i, The pilot primary pressures (operating pilot pressures output from the pilot operating devices 4a and 4b) of the proportional solenoid valves 10a, 10b, 11a and 11b detected by the pressure detectors 60a and 60b; 61a and 61b are used as pilot pressures PBU, PBD and PAU. , PAD. In the minimum value determination calculation unit 9k, while the pilot primary pressures of the proportional solenoid valves 10a, 10b, 11a, and 11b are smaller than the maximum deceleration pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, and PADmaxc calculated by the maximum pilot pressure calculation unit 9f. The second command current values iBU2, iBD2, iAU2, iAD2 corresponding to the pilot primary pressure are set as output command current values iBU, iBD, iAU, iAD, and the maximum deceleration pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc are proportional electromagnetics. When the pressure is smaller than the pilot primary pressure of the valves 10a, 10b, 11a, 11b, the first command current values iBU1, iBD1, iAU1, iAD1 are set as output command current values iBU, iBD, iAU, iAD.
[0056]
For this reason, while the pilot primary pressures of the proportional solenoid valves 10a, 10b, 11a, 11b are smaller than the maximum deceleration pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc, the proportional solenoid valves 10a, 10b, 11a, 11b It is throttled to obtain the same pilot secondary pressure. In the present specification, this is called “pilot primary pressure tracking control”. By such pilot primary pressure follow-up control, the operating pilot pressure generated by the pilot operating devices 4a and 4b is transmitted almost as it is to the boom hydraulic control valve 5a and the arm hydraulic control valve 5b.
[0057]
When the maximum deceleration pilot pressures PBUmaxc and PADmaxc are smaller than the pilot primary pressures of the proportional solenoid valves 10a and 11b, the proportional solenoid valves 10a and 11b are throttled according to the first deceleration command signals iBU1 and iAD1 for deceleration control, and the boom is raised. And the arm dump operating speed is reduced. Further, when shifting to the deceleration control in this manner, the proportional solenoid valves 10a and 11b are throttled by the second command current values iBU2, iBD2, iAU2 and iAD2 of the pilot primary pressure tracking control as described above until then. Therefore, the boom raising and the arm dumping operation speed can be smoothly reduced without being affected by the “spool adhesion phenomenon” of the proportional solenoid valve.
[0058]
When the front device 1A further rises and the monitor point P2 reaches the intrusion prohibited region, the deceleration control calculation unit 9d generates deceleration command signals of KBU = 0, KAU = 0, KAD = 0, and the proportional solenoid valves 10a, 11a. , 11b are fully closed, and the boom and arm are stopped. As a result, the front device 1A stops.
[0059]
The manner in which the influence is avoided by the “spool adhesion phenomenon” and “pilot primary pressure tracking control” of the proportional solenoid valve will be further described with reference to FIG. FIG. 13A shows a case where the pilot primary pressure tracking control of the present invention is not performed, and FIG. 13B shows a case where the pilot primary pressure tracking control is performed.
[0060]
In FIG. 13 (a), when the operating pilot pressure (pilot primary pressure of the proportional solenoid valve) output from the pilot operating device is smaller than the maximum pilot pressure, the distance LM is equal to or less than LU, and when the shift to deceleration control is performed, There occurs a period in which the command current value of the deceleration control (command current value of the valve command calculation unit 9g) is too large with respect to the pilot primary pressure of the solenoid valve. During this time, when the pilot primary pressure tracking control of the present invention is not performed, the pressure conversion value of the command current value for output to the proportional solenoid valve becomes larger than the pilot primary pressure, and the spool 153 (see FIG. 4) of the proportional solenoid valve is The solenoid 156 (same as above) is strongly pressed against the surface opposite to it, and the pressure conversion value of the command current value becomes smaller than the pilot primary pressure, and even if an attempt is made to reduce the pressure, the spool 153 does not move immediately, The movement gets worse. That is, the “spool adhesion phenomenon” occurs. When this phenomenon occurs, no matter how much the current value is reduced and the pressure is reduced, the pressure reduction is delayed for a moment as shown by X in FIG. 13A, the start of the deceleration control is delayed, and the deceleration distance is apparently shortened. For this reason, in some cases, a large impact is generated when the actuator is stopped, which makes the operator uncomfortable. Moreover, when the bucket is loaded, there is a possibility of spilling the load.
[0061]
On the other hand, in the present invention, as shown in FIG. 13 (b), while the command current value of the deceleration control (command current value of the valve command calculation unit 9g) is too large with respect to the pilot primary pressure of the proportional solenoid valve. Since the second command current value (command current value of the valve command calculation unit 9j) corresponding to the pilot primary pressure is calculated and this second command current value is output to the proportional solenoid valve, The command converted value of the command current value becomes substantially the same as the pilot primary pressure, and the command current value does not become excessively large with respect to the pilot primary pressure, and the influence of the “spool adhesion phenomenon” is mitigated. Therefore, the pressure reducing operation by the proportional solenoid valve is performed smoothly, and the actuator can be stopped smoothly.
[0062]
In addition, before the distance LM between the monitor point and the intrusion prohibition area becomes equal to or less than a predetermined value determined by Ktr (in this embodiment, Ktr = 1, LM = deceleration distance LU), the first command current corresponding to the maximum pilot pressure Value or the second command current value is output, the proportional solenoid valve is fully opened, and the pilot operating pressure generated by the pilot operating device is transmitted to the hydraulic control valve with almost no resistance by the proportional solenoid valve. The front device can be moved as if there is no solenoid valve.
[0063]
As described above, according to the present embodiment, when the monitor point approaches the intrusion prohibited area, the operating speed of the front device is gradually reduced, and the operating speed of the front apparatus becomes zero immediately before the intrusion prohibited area. No entry into the intrusion prohibited area.
[0064]
Further, the smaller one of the first command current value of the deceleration control calculated according to the distance between the monitor point and the intrusion prohibited area and the second command current value corresponding to the pilot primary pressure of the proportional solenoid valve is selected and output. Therefore, when the deceleration control is performed, the current value does not become excessively large with respect to the pilot primary pressure of the proportional solenoid valve, and the influence of the “spool adhesion phenomenon” is mitigated. Therefore, the pressure reducing operation by the proportional solenoid valve is performed smoothly, and the actuator can be stopped smoothly. For this reason, an operator does not feel uncomfortable due to an impact at the time of stopping. In addition, spillage can be prevented.
[0065]
Further, the proportional solenoid valve is fully opened before the distance between the monitor point and the intrusion prohibited area becomes equal to or less than the deceleration distance L U, so that the front device can be moved as if there is no proportional solenoid valve.
[0066]
The work range restriction control device of the present invention is not limited to the above-described embodiment, and various modifications are possible. As an example, an angle meter that detects a rotation angle is used as means for detecting a state quantity related to the position and orientation of the front device 1A, but a stroke of a cylinder may be detected. Moreover, although the case where the intrusion prohibited area is set upward has been described, the same applies to the case where it is set downward and forward.
[0067]
【The invention's effect】
According to the present invention, since the influence of the “spool adhesion phenomenon” of the electric pressure reducing valve can be alleviated, the actuator can be smoothly stopped, and the operator does not feel uncomfortable due to the impact at the time of stopping. In addition, spillage can be prevented.
[0068]
Further, according to the present invention, the front device can be moved as if there is no proportional solenoid valve before the distance between the monitor point and the intrusion prohibited area becomes equal to or less than a predetermined value.
[Brief description of the drawings]
FIG. 1 is a view showing a construction machine working range restriction control device according to an embodiment of the present invention, together with a hydraulic drive device.
FIG. 2 is a diagram showing an external appearance of a hydraulic excavator to which the present invention is applied.
FIG. 3 is a diagram showing a configuration of a hydraulic pilot type operation lever device;
FIG. 4 is a diagram showing the structure of a proportional solenoid valve.
FIG. 5 is a functional block diagram showing a control function of the control unit of the present embodiment.
FIG. 6 is a diagram showing a coordinate system and a region setting method used in the work range restriction control of the present embodiment.
FIG. 7 is a diagram showing an entry prohibition area and a deceleration area in the work range restriction control of the present embodiment.
FIG. 8 is a diagram illustrating a relationship of a deceleration command signal with respect to a distance between a monitor point and an entry prohibition area in a deceleration control calculation.
FIG. 9 is a diagram showing a relationship between pilot pressure and cylinder speed in a maximum pilot pressure calculation unit.
FIG. 10 is a diagram showing a relationship between a pilot pressure and a current value output to a proportional solenoid valve in a valve command calculation unit.
FIG. 11 is a flowchart showing processing contents of the control unit.
FIG. 12 is a flowchart showing processing contents of a control unit.
FIG. 13A is a diagram showing the influence of the “spool adhesion phenomenon” when the deceleration control is performed, and FIG. 13B is a diagram of the “spool adhesion phenomenon” when the deceleration control is performed according to the present invention. It is a figure which shows relaxation of an influence.
[Explanation of symbols]
1A Front device
1B body
1a boom
1b arm
1c bucket
2 Hydraulic pump
3a Boom cylinder
3b Arm cylinder
4a-4f Operation lever device
5a-5f Flow control valve
7 Setting device
8a to 8c Angle detector (position detection means)
9 Control unit
9a Intrusion prohibited area calculation section
9b Front posture calculator
9c Limit value storage memory
9d Deceleration control calculation unit
9e Maximum cylinder speed calculator
9f Maximum pilot pressure calculator
9g Valve command calculator
9h Pilot primary pressure tracking determination calculation unit
9i Pilot pressure calculator
9j Valve command calculator
9k Minimum value judgment calculation part
9m current output section
10a-11b Proportional solenoid valve (electric pressure reducing valve)
50a-55b hydraulic drive
60a, 60b, 61a, 61b Pressure detector

Claims (2)

From a multi-joint type front device constituted by a plurality of front members rotatable in the vertical direction, a plurality of hydraulic actuators for driving the plurality of front members, and an operation device for instructing operations of the plurality of front members A plurality of flow rate control valves that are driven by the output operation pilot pressure and that control flow rates of pressure oil supplied to the plurality of hydraulic actuators; and the operation device and at least one flow rate control valve corresponding thereto An electric pressure reducing valve that is provided in between and that reduces and outputs an operation pilot pressure output from the operating device, and according to a distance between a monitor point set in advance with respect to the front device and a preset entry prohibition area wherein the calculated a directive current value is output to the electric pressure reducing valves, the monitor point approaches the forbidden entry area Te furo The winder is decelerated, in the working range limiting control system for a construction machine for performing control to stop the front device and reaches the forbidden entry area,
Detection means for detecting the pilot primary pressure before Symbol electric pressure reducing valve disposed between the operating device and the electric pressure reducing valves, the electricity when the monitoring point reaches the deceleration region for decelerating said front device A working range restriction control device for construction machinery, comprising output correction means for causing a command current value to be output to the pressure reducing valve to follow the pilot primary pressure detected by the detection means . 2. The construction machine work range restriction control device according to claim 1, wherein the output correction means is set according to a distance between the monitor point and an intrusion prohibited area, and is output so as to decrease as the distance decreases. By outputting a smaller current value of the command current value and the second command current value corresponding to the pilot primary pressure detected by the detection means to the electric pressure reducing valve, the command current value is converted into the pilot primary value. A working range restriction control device for construction machinery, characterized by following the pressure .

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