JP4540156B2 - Robot center of gravity control method - Google Patents

Description

【００９８】
厳密解を求める上では、ロボット１００を質点系ではなく剛体系として厳密にモデリングすることが好ましいが、その分だけ計算時間を要する。他方、ロボット１００は、トルク重量比の大きいアクチュエータと軽量の構造部材を使用している結果として、その質量の大半はアクチュエータすなわち関節部分に集中する。したがって、ロボット１００を多質点近似モデルとして扱っても、ほとんど支障がない（多質点近似モデルの詳細に関しては、後述に譲る）。
【００９９】
図８には、多質点近似モデルを用いた場合における質量分布データの算出処理手順の詳細をフローチャートの形式で示している。このフローチャート全体で、前述のステップＳ１３を構成するものと理解されたい。以下、このフローチャートの各ステップについて説明する。
【０１００】
まず、ステップＳ３１では、ロボット１００の全軸角度情報、全関節配置情報、及び全質点配置情報を入力する。これらの角度情報や配置情報は、ロボット１００の設計仕様によって定まる静的・固定的なデータであり、例えばロボット１００の設計時に作成したＣＡＤデータベースから供給を受けることができる。
【０１０１】
次いで、ステップＳ３２では、ロボット１００の左右股関節の中点を原点に設定した場合における、全関節位置情報、及び全質点位置情報を算出する。
【０１０２】
次いで、ステップＳ３３では、原点と左右各々の足底平面までの距離を算出し、判断ブロックＳ３４では、左右の足底平面のうちどちらが原点から離れているかを判断する。本実施例では、原点から離れている方の足底が、現在着床している足であるとする。
【０１０３】
右足底平面の方が離れている場合には、右足底平面がＸ−Ｙ平面となるように全質点位置を座標変換し（ステップＳ３５Ｒ）、他方、左足底平面の方が離れている場合には、左足底平面がＸ−Ｙ平面となるように全質点位置を座標変換する（ステップＳ３５Ｌ）。
【０１０４】
このように座標変換した後、全質点における質量と位置とから、ロボット１００の重心位置を算出することができる（ステップＳ３６）。
【０１０５】
図８において算出された重心位置の例を図９に示しておくので参照されたい。同図の例では、ロボット１００の重心位置は、腰部すなわち下肢よりも上方に設定されているので、ロボット１００を倒立振子とみなして動歩行時の安定姿勢制御を好適に行うことができる。倒立振子は、転倒方向に支持点を強く加速することで姿勢回復を図ることができる。歩行系においては、目標ＺＭＰを転倒方向に強く加速することに相当する。倒立振子制御を行う場合、ロボットの重心位置はむしろ高い方が、重心バランスを失ってから転倒するまでの時間すなわち倒立振子の周期が長いため、歩行制御の安定化には有利である。
【０１０６】
次いで、図７に示したフローチャートのステップＳ１６におけるロボット１００の全身運動パターンの算出処理について詳解する。ロボット１００は、通常動作する前に予め定められた全身運動パターンに従って各関節すなわちアクチュエータＡ₂，Ａ₃…を駆動制御することによって、所定の動作を実現するようになっている。
【０１０７】
ロボット１００自体は、無限すなわち連続的な質点の集合体である。但し、本実施例では、ロボット１００を有限数で離散的な質点からなる近似モデルに置き換えることにより、全身運動パターン算出の計算量の削減を図っている。ロボット１００は、トルク重量比の大きいアクチュエータと軽量の構造部材を使用している結果として、その質量の大半はアクチュエータすなわち関節部分に集中するので、多質点近似モデルとして扱っても、ほとんど支障がない
【０１０８】
図１０には、全身運動パターン算出のために導入される、ロボット１００の非干渉多質点近似モデルを図解している。
【０１０９】
図１０において、Ｏ−ＸＹＺ座標系は絶対座標系におけるロール、ピッチ、ヨー各軸を表し、また、Ｏ’−Ｘ’Ｙ’Ｚ’座標系はロボット１００とともに動く運動座標系におけるロール、ピッチ、ヨー各軸を表している。同図に示す多質点モデルでは、ｉはｉ番目に与えられた質点を表す添え字であり、ｍ_iはｉ番目の質点の質量、ｒ’_iはｉ番目の質点の位置ベクトル（但し運動座標系）を表すものとする。また、後述する腰部運動制御において特に重要な腰部質点の質量はｍ_h、その位置ベクトルはｒ’_h（ｒ’_hx，ｒ’_hy，ｒ’_hz）とし、また、ＺＭＰの位置ベクトルをｒ’_zmpとする。
【０１１０】
図１０に示す非厳密の非干渉多質点近似モデルにおいては、モーメント式は線形方程式の形式で記述され、該モーメント式はピッチ軸及びロール軸に関して干渉しない、という点を充分理解されたい。
【０１１１】
このような多質点近似モデルは、概ね以下の処理手順により生成することができる。
【０１１２】
（１）ロボット１００全体の質量分布を求める。
（２）ロボット１００を複数の領域に分割する。領域は質点を設定するためのものである。領域の分割方法は、設計者のマニュアル入力であっても、所定の規則に従った自動生成のいずれでも構わない。
（３）各領域ｉ毎に、重心を求め、その重心位置と質量ｍ_iを該当する質点に付与する。
（４）各質点ｍ_iを、質点位置ｒ_iを中心とし、その質量に比例した半径に持つ球体として表示する。
（５）現実に連結関係のある質点すなわち球体同士をワイヤーで連結する。
【０１１３】
多質点近似モデルは、言わば、ワイヤフレーム・モデルの形態でロボットを表現したものである。本実施例では、図１０を見ても判るように、この多質点近似モデルは、両肩、両肘、両手首、体幹、腰部、及び、両足首の各々を質点として設定したものである。
【０１１４】
なお、図１０に示す多質点モデルの腰部情報における各回転角（θ_hx，θ_hy，θ_hz）は、人間型ロボット１００における腰部の姿勢すなわちロール、ピッチ、ヨー軸の回転を規定するものである（図１１には、多質点モデルの腰部周辺の拡大図を示しているので、確認されたい）。
【０１１５】
図１２には、ロボット１００の全身運動パターンを算出するための処理手順をフローチャートの形式で示している。但し、以下では、図１０に示すような線形・非干渉多質点近似モデルを用いてロボット１００の各関節位置や動作を記述するものとし、且つ、計算に際し以下のようなパラメータを用いることとする。但し、ダッシュ（´）付きの記号は運動座標系を記述するものと理解されたい。
【０１１６】
【数２】

【０１１７】
また、ロボット１００の腰部高さが一定（ｒ’_hz＋ｒ_qz＝ｃｏｎｓｔ）で、且つ、膝部質点がゼロであることを前提とする。
【０１１８】
本実施例に係るロボット１００の場合、任意の足部運動パターン、ＺＭＰ軌道、体幹運動パターン、上肢運動パターン等に基づいて、安定歩行を可能とする腰部運動パターンを生成するようになっている。ここで言うＺＭＰ（Ｚｅｒｏ Ｍｏｍｅｎｔ Ｐｏｉｎｔ）軌道とは、歩行ロボットにおいて、足底（若しくは足裏）をある一点で床面に固定したとき、歩行動作中にモーメントが発生しないような点すなわちＺＭＰの軌道ことを言う（前述）。
【０１１９】
本実施例のように片足が６自由度を持つ２足歩行型ロボット（図３を参照のこと）の場合、各足部２２Ｒ／Ｌの位置と腰部の水平位置及び高さによって両脚の姿勢が一意に定まる。したがって、腰部運動パターンを生成することは、脚の姿勢すなわち下肢の「歩容」を決定することに他ならない（「歩容」とは、当業界において「関節角度の時系列変化」を意味する技術用語である）。
【０１２０】
まず、ステップＳ４１では、ステップＳ１２において設定された目標全身運動パターンに基づいて、足部（より具体的には足底）運動、足部運動から導出されるＺＭＰ軌道、体幹運動、上肢運動、腰部の姿勢や高さなど、各部の駆動・動作を実際に決定するためのパターンが設定される。より具体的には、まず足部運動パターン、次いでＺＭＰ軌道、体幹運動パターン、そして上肢運動パターンを設定する。また、腰部の運動に関しては、Ｚ’方向のみ設定し、Ｘ’及びＹ’の各方向については未知とする。
【０１２１】
次に、線形・非干渉多質点近似モデルを用いて、足部、体幹、そして上肢運動により発生する設定ＺＭＰ上でのピッチ軸、ロール軸まわりの各モーメント（Ｍ_x，Ｍ_y）を算出する（ステップＳ４２）。
【０１２２】
次いで、線形・非干渉多質点近似モデルを用いて、腰部水平面内運動（ｒ’_hx，ｒ’_hy）によって発生する設定ＺＭＰ上でのモーメントを算出する（ステップＳ４３）。
【０１２３】
次いで、設定ＺＭＰ上におけるモーメントに関する釣り合い式を、ロボットとともに動く運動座標系Ｏ’−Ｘ’Ｙ’Ｚ’上で導出する（ステップＳ４４）。より具体的には、足部、体幹、そして上肢運動により発生するモーメント（Ｍ_x，Ｍ_y）を既知変数の項として右辺に、腰部質点の水平運動に関する項（ｒ_hx，ｒ_hy）を未知変数の項として左辺にまとめ、下式に示すような線形・非干渉なＺＭＰ方程式（１）を導出する。
【０１２４】
【数３】

【０１２５】
但し、以下が成立するものとする。
【０１２６】
【数４】

【０１２７】
次いで、上記のＺＭＰ方程式（１）を解いて、腰部水平面内軌道を算出する（ステップＳ４５）。例えば、オイラー法やルンゲ・クッタ法などの数値的解法（周知）を用いてＺＭＰ方程式（１）を解くことで、未知変数としての腰部の水平絶対位置（ｒ_hx，ｒ_hy）の数値解を求めることができる（ステップＳ４６）。ここで求められる数値解は、安定歩行可能な腰部運動パターンの近似解であり、より具体的にはＺＭＰが目標位置に入るような腰部水平絶対位置である。ＺＭＰ目標位置は、通常（例えば静歩行時）、着床した足底に設定される。
【０１２８】
算出された近似解上では予め設定した体幹・上肢運動が実現できない場合には、体幹・上肢運動パターンの再設定・修正を行う（ステップＳ４７）。この際、膝部の軌道を算出してもよい。
【０１２９】
次いで、上述のようにして得られた全身運動パターンを代入して、厳密モデル（すなわち、剛体、若しくは非常に多くの質点からなるロボット１００の精密なモデル）における設定ＺＭＰ上のモーメント（ｅＭ_x，ｅＭ_y）を算出する（ステップＳ４８）。非厳密モデルでは上記の［数４］が成立することを前提としたが、厳密ではかかる前提を要しない（すなわち時間の変化に対して一定である必要はない）。
【０１３０】
厳密モデルにおけるモーメント（ｅＭ_x，ｅＭ_y）は、腰部運動の発生するモーメント誤差である。続くステップＳ４９では、このモーメント（ｅＭ_x，ｅＭ_y）が非厳密モデルにおける近似モーメントの許容値（εＭ_x，εＭ_y）未満か否かを判定する。許容値ε未満であれば、腰部安定運動パターンの厳密解及び安定歩行を実現できる全身運動パターンを得ることができたので（ステップＳ５０）、本処理ルーチン全体を終了する。
【０１３１】
他方、厳密モデルにおけるモーメント（ｅＭ_x，ｅＭ_y）が近似モデルにおけるモーメントの許容値（εＭ_x，εＭ_y）以上であった場合には、厳密モデルにおけるモーメント（ｅＭ_x，ｅＭ_y）を用いて近似モデルにおける既知発生モーメント（Ｍ_x，Ｍ_y）を修正する（ステップＳ５１）。そして、再びＺＭＰ方程式の導出を行い、許容値ε未満に収束するまで、腰部運動パターンの近似解の算出と修正を繰り返し実行する。
【０１３２】
また、図１３には、本実施例に係るロボット１００において目標運動パターンを基に全身運動パターンを算出するための処理手順に関する他の例をフローチャートの形式で示している。但し、上述と同様に、線形・非干渉多質点近似モデルを用いてロボット１００の各関節位置や動作を記述するものとする（同上）。以下、このフローチャートの各ステップについて説明する。
【０１３３】
まず、ステップＳ６１では、ステップＳ１２において設定された目標全身運動パターンに基づいて、足部（より具体的には足底）運動、足部運動から導出されるＺＭＰ軌道、体幹運動、上肢運動、腰部の姿勢や高さなど、各部の駆動・動作を実際に決定するためのパターンが設定される。より具体的には、まず足部運動パターン、次いでＺＭＰ軌道、体幹運動パターン、そして上肢運動パターンを設定する。また、腰部の運動に関しては、Ｚ’方向のみ設定し、Ｘ’及びＹ’の各方向については未知とする。
【０１３４】
次に、線形・非干渉多質点近似モデルを用いて、足部、体幹、そして上肢運動により発生する設定ＺＭＰ上でのピッチ軸、ロール軸まわりの各モーメント（Ｍ_x，Ｍ_y）を算出する（ステップＳ６２）。
【０１３５】
次いで、腰部水平面内運動（ｒ’_hx，ｒ’_hy）をフーリエ級数展開する（ステップＳ６３）。当業界において既に周知のように、フーリエ級数展開することにより、時間軸成分を周波数成分に置き換えて演算することができる。すなわち、この場合には腰部の動きを周期的な動きとして捉えることができる。また、フーリエ展開することにより、ＦＦＴ（高速フーリエ変換）を適用することができるので、計算速度を大幅に向上させることができる。
【０１３６】
次いで、設定ＺＭＰ上でのピッチ軸、ロール軸まわりの各モーメント（Ｍ_x，Ｍ_y）についてもフーリエ級数展開する（ステップＳ６４）。
【０１３７】
次いで、腰部水平面内軌道のフーリエ係数を算出し、さらに逆フーリエ級数展開することで（ステップＳ６５）、腰部運動の近似解が求まる（ステップＳ６６）。ここで求められる近似解は、安定歩行可能な腰部運動パターンを規定する腰部の水平絶対位置の近似解（ｒ_hx，ｒ_hy）であり、より具体的にはＺＭＰが目標位置に入るような腰部水平絶対位置である。ＺＭＰ目標位置は、通常（例えば静歩行時）、着床した足底に設定される。
【０１３８】
算出された近似解によって予め設定した体幹・上肢運動が実現できない場合には、体幹・上肢運動パターンの再設定・修正を行う（ステップＳ６７）。この際、膝部の軌道を算出してもよい。
【０１３９】
次いで、上述のようにして得られた全身運動パターンを代入して、厳密モデル（すなわち、剛体、若しくは非常に多くの質点からなるロボット１００の精密なモデル）における設定ＺＭＰ上のモーメント（ｅＭ_x，ｅＭ_y）を算出する（ステップＳ６８）。非厳密モデルでは上記の［数４］が成立することを前提としたが、厳密モデルではかかる前提を要しない（すなわち時間の変化に対して一定である必要はない）。
【０１４０】
厳密モデルにおけるモーメント（ｅＭ_x，ｅＭ_y）は、腰部運動の発生するモーメント誤差である。続くステップＳ６９では、このモーメント（ｅＭ_x，ｅＭ_y）が近似モデルにおけるモーメントの許容値（εＭ_x，εＭ_y）未満か否かを判定する。許容値ε未満であれば、腰部安定運動パターンの厳密解及び安定歩行を実現できる全身運動パターンを得ることができたので（ステップＳ７０）、本処理ルーチン全体を終了する。
【０１４１】
他方、厳密モデルにおけるモーメント（ｅＭ_x，ｅＭ_y）が近似モデルにおけるモーメントの許容値（εＭ_x，εＭ_y）以上であった場合には、厳密モデルにおけるモーメント（ｅＭ_x，ｅＭ_y）を用いて非厳密モデルにおける既知発生モーメント（Ｍ_x，Ｍ_y）を修正して（ステップＳ７１）、再びフーリエ級数展開して、許容値ε未満に収束するまで、腰部運動パターンの近似解の算出と修正を繰り返し実行する。
【０１４２】
図１６には、ロボット１００の重心位置（バッテリの搭載位置）を決定する処理手順の他の例をフローチャートの形式で示している。以下、このフローチャートの各ステップについて説明する。
【０１４３】
まず、ステップＳ８１では、ロボット１００のＺ軸方向重心位置の存在可能範囲を算出する。
【０１４４】
ロボット１００の重心位置の可動範囲はバッテリ・パックの搭載位置によって決定されることは既に述べた通りである。例えは図５に示す例では、長穴２２５ａ〜２２５ｄの長軸寸法によってＺ軸方向の存在範囲が決定される。また、図６に示す例では、ボール螺子３３１のストローク範囲に応じて重心位置のＺ軸方向の存在範囲が決定される。
【０１４５】
次いで、ステップＳ８２では、先行ステップＳ８１において求められた存在可能なＺ軸方向の重心位置の各々において、ロボット１００の最大歩行速度と最小基本パターン数を算出する。
【０１４６】
次いで、ステップＳ８３では、最大歩行速度と最小基本パターン数で構成される評価関数を基にして、各Ｚ軸方向重心位置における評価値を算出する。
【０１４７】
次いで、ステップＳ８４では、評価値が最も低くなるようなＺ軸方向重心位置を選択して、これをロボット１００の最適なＺ軸方向重心位置として出力する（ステップＳ８５）。
【０１４８】
このようにして求められたロボット１００の最適な重心位置に基づいて、バッテリ・パックの最適な搭載位置を逆算することができる。この逆算された結果に従って、バッテリ・パックの位置を調整すればよい。該位置調整機構については、図５又は図６を参照されたい。
【０１４９】
［追補］
以上、特定の実施例を参照しながら、本発明について詳解してきた。しかしながら、本発明の要旨を逸脱しない範囲で当業者が該実施例の修正や代用を成し得ることは自明である。すなわち、例示という形態で本発明を開示してきたのであり、限定的に解釈されるべきではない。本発明の要旨を判断するためには、冒頭に記載した特許請求の範囲の欄を参酌すべきである。
【０１５０】
なお、本発明の要旨を判断する上で、２足歩行のロボット１００についての関節等の呼び名は、図３を厳格に適用するのは妥当ではなく、現実のヒトやサルなどの２足直立歩行動物の身体メカニズムとの対比により柔軟に解釈されたい。
【０１５１】
参考のため、人間型ロボットの関節モデル構成を図１４に図解しておく。同図に示す例では、肩関節５から上腕、肘関節６、前腕、手首７及び手部８からなる部分を「上肢」と呼ぶ。また、肩関節５から股関節１１までの範囲を「体幹部」と呼び、ヒトの胴体に相当する。また、体幹部のうち特に股関節１１から体幹関節１０までの範囲を「腰部」と呼ぶ。体幹関節１０は、ヒトの背骨が持つ自由度を表現する作用を有する。また、股関節１１より下の大腿部１２、膝関節１４、下腿部１３、足首１５及び足部１６からなる部分を「下肢」と呼ぶ。一般には、股関節より上方を「上体」と呼び、それより下方を「下体」と呼ぶ
【０１５２】
また、図１５には、人間型ロボットの他の関節モデル構成を図解している。同図に示す例は、体幹関節１０を有しない点で図１４に示した例とは相違する。各部の名称については図を参照されたい。背骨に相当する体幹関節が省略される結果として人間型ロボットの上体の動きは表現力を失う。但し、危険作業やなお作業の代行など、産業目的の人間型ロボットの場合、上体の動きを要しない場合がある。なお、図１４及び図１５で用いた参照番号は、それ以外の図面とは一致しない点を理解されたい。
【０１５３】
【発明の効果】
以上詳記したように、本発明によれば、例えばヒトやサルなどの直立歩行型の身体メカニズムや動作を模した構造を有する、優れた脚式移動型ロボットを提供することができる。
【０１５４】
また、本発明によれば、２足直立歩行による脚式移動を行うとともに下肢の上には体幹や上肢、頭部などのいわゆる上半身が搭載されてなり、歩行運動や、その他体幹や上肢などを含んだ全身協調運動時において好適な重心位置を設定することができる、優れた直立歩行・脚式移動型ロボットを提供することができる。
【図面の簡単な説明】
【図１】本発明の実施に供される人間型ロボット１００を前方から眺望した様子を示た図である。
【図２】本発明の実施に供される人間型ロボット１００を後方から眺望した様子を示た図である。
【図３】本実施例に係る人間型ロボット１００が具備する自由度構成モデルを模式的に示した図である。
【図４】本実施例に係る人間型ロボット１００の制御システム構成を模式的に示した図である。
【図５】バッテリの位置調整機構に関する第１の例を示した図である。
【図６】バッテリの位置調整機構に関する第２の例を示した図である。
【図７】ロボット１００の重心位置（バッテリの搭載位置）を決定するための処理手順を示したフローチャートである。
【図８】多質点近似モデルを用いた場合の質量分布データの算出処理手順を示したフローチャートである。
【図９】図８に示すフローチャートに従って算出されたロボット１００の重心位置を例示した図である。
【図１０】全身運動パターン算出のために導入される、ロボット１００の非干渉多質点近似モデルを示した図である。
【図１１】図１０に示したロボット１００の多質点近似モデルにおける腰部周辺の拡大図である。
【図１２】ロボット１００の全身運動パターンを算出するための処理手順を示したフローチャートである。
【図１３】ロボット１００の全身運動パターンを算出するための処理手順の他の例を示したフローチャートである。
【図１４】人間型ロボットについての関節モデル構成の一例を模式的に示した図である。
【図１５】人間型ロボットについての関節モデル構成の他の例を模式的に示した図である。
【図１６】ロボット１００の重心位置（バッテリの搭載位置）を決定する処理手順の他の例を示したフローチャートである。
【符号の説明】
１…頭部，２…首関節ヨー軸
３…首関節ピッチ軸，４…首関節ロール軸
５…体幹ピッチ軸，６…体幹ロール軸
７…体幹ヨー軸，８…肩関節ピッチ軸
９…肩関節ロール軸，１０…上腕ヨー軸
１１…肘関節ピッチ軸，１２…前腕ヨー軸
１３…手首関節ピッチ軸，１４…手首関節ロール軸
１５…手部，１６…股関節ヨー軸
１７…股関節ピッチ軸，１８…股関節ロール軸
１９…膝関節ピッチ軸，２０…足首関節ピッチ軸
２１…足首関節ロール軸，２２…足部（足底）
３０…頭部ユニット，４０…体幹部ユニット
５０…腕部ユニット，５１…上腕ユニット
５２…肘関節ユニット，５３…前腕ユニット
６０…脚部ユニット，６１…大腿部ユニット
６２…膝関節ユニット，６３…脛部ユニット
８０…制御ユニット，８１…主制御部
８２…周辺回路
９１，９２…接地確認センサ
９３…姿勢センサ
１００…人間型ロボット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a realistic robot mechanism having a structure simulating a biological mechanism and action, and in particular, a legged mobile type having a structure simulating an upright walking body mechanism and action such as a human or a monkey. It relates to the mechanism of the robot.
[0002]
More specifically, the present invention is a mechanism of an upright walking / legged mobile robot in which a legged movement is performed by biped upright walking and a so-called upper body such as a trunk, upper limb, and head is mounted on the lower limb. In particular, the present invention relates to a mechanism of an upright walking / legged mobile robot capable of setting a preferred center of gravity position during walking movement and other whole body coordinated movements including the trunk and upper limbs.
[0003]
[Prior art]
It is said that the word “robot” comes from the Slavic word ROBOTA (slave machine). In Japan, robots started to spread from the end of the 1960s, but many of them are industrial robots such as manipulators and transfer robots for the purpose of automating and unmanned production operations in factories. Met.
[0004]
Recently, research and development on legged mobile robots simulating the body mechanisms and movements of biped upright walking such as humans and monkeys has progressed, and expectations for practical use are also increasing. Legged movement with two legs standing up is unstable and difficult to control posture and walking compared to crawler type, four-legged or six-legged type, but flexible walking / running operation such as climbing stairs and getting over obstacles Is superior in that it can be realized.
[0005]
Legged mobile robots have a history of starting with research on legged movements using only the lower limbs as an elemental technology, rather than being equipped with all five bodies standing upright.
[0006]
For example, Japanese Patent Application Laid-Open No. 3-184782 discloses a joint structure applied to a structure corresponding to a lower part of a torso of a legged walking robot.
[0007]
Japanese Patent Laid-Open No. 5-305579 discloses a walking control device for a legged mobile robot. The walking control device described in this publication controls ZMP (Zero Moment Point), that is, a point on the floor where the moment caused by the floor reaction force when walking is zero to coincide with the target value. However, as can be seen from FIG. 1 of the same publication, the body 24 acting on the moment is made into a black box, and not all five bodies are completed, but a proposal of legged movement as an elemental technology. Stay.
[0008]
However, it goes without saying that the ultimate purpose of the legged mobile robot is not limited to the walking motion by the lower limb alone, but the realization of various whole body-emphasized motion patterns by the structure fully equipped with five bodies. That is, an upright walk with two legs is performed by a structure composed of a lower limb for biped walking, an upper limb made of arms and the like, and a trunk that connects the lower limb and the upper limb. The robot that has completed the five bodies presupposes upright and legged movement work using two legs, and controls posture stability so that the upper limbs, lower limbs, and trunk are operated cooperatively according to a predetermined priority in each scene. There is a need.
[0009]
A legged mobile robot that emulates a human biological mechanism or movement is particularly called a “humanoid” or “humanoid robot”. The humanoid robot can provide, for example, life support, that is, support for human activities in various situations in daily life such as a living environment.
[0010]
The significance of researching and developing robots called humanoids or humanoids can be understood from, for example, the following two viewpoints.
[0011]
One is a human scientific viewpoint. In other words, through the process of creating a robot with a structure resembling human lower limbs and / or upper limbs, devising its control method and simulating human walking motion, the mechanism of human natural motion including walking Can be elucidated in engineering. Such research results can be largely reduced to the progress of other research fields dealing with human movement mechanisms, such as ergonomics, rehabilitation engineering, or sports science.
[0012]
The other is the development of a robot that, as a human partner, supports daily activities, that is, supports human activities in various situations in the living environment and other daily lives. This kind of robot needs to learn how to adapt to a person or an environment with different personalities while learning from humans in various aspects of the human living environment, and needs to grow further in terms of functionality. At this time, it is considered that the robot having the “human shape”, that is, the same shape or the same structure as the human, functions effectively for smooth communication between the human and the robot.
[0013]
For example, when teaching a robot how to go through a room while avoiding obstacles that can't be stepped on, rather than having a completely different structure than the one you are teaching, such as a crawler or quadruped robot A biped robot with the same appearance will be much easier to teach and teach for robots (for example, “Control of a biped robot” by Takanishi (Automotive Technology Association Kanto) Branch <High Plastic> No. 25, 1996 APRIL)). In the first place, since most of the human living environment is formed according to the form and behavior of human beings, having a humanoid form increases the affinity with the human living environment. It can be said that it is essential above.
[0014]
One of the uses of the humanoid robot is to perform various difficult operations in industrial activities and production activities. For example, maintenance work at nuclear power plants, thermal power plants, petrochemical plants, transportation and assembly work of parts at manufacturing plants, cleaning of high-rise buildings, substitution of dangerous work and difficult work such as rescue at fire sites etc. . However, robots specializing in this type of industrial use have the ultimate design and production theme of realizing specific uses or functions, and are supposed to be biped, but humans and monkeys stand upright. It is not always necessary to faithfully reproduce the body mechanisms and movements inherent to walking animals as mechanical devices. For example, in order to realize a specific application, the degree of freedom of the hand and the operation function are strengthened, while the degree of freedom of the head and the waist, which is relatively unrelated to the application, is limited or omitted. As a result, biped walking and so-called edo may remain unnatural for humans in terms of the appearance of robot work and operations, but this point must be compromised.
[0015]
Further, as another use of the humanoid robot, there is a use that is close to life, that is, “symbiosis” with a human, rather than life support such as substitution of difficult work. This type of robot is designed to faithfully reproduce the whole body cooperative movement mechanism inherent in animals that walk on two legs upright, such as humans and monkeys, and to achieve its natural and smooth movement. To do. In addition, as long as it emulates highly intelligent upright animals such as humans and monkeys, it is desirable that the expression of movement using the extremities is rich. Furthermore, not only to faithfully execute the pre-input motion pattern, but also to realize a lively motion expression that responds to the opponent's language and attitude (such as “praise”, “speak”, “beat”). Is also required. In this sense, an entertainment robot that imitates humans is just right to call it a “humanoid robot”.
[0016]
As already known, the human body has hundreds of joints, or hundreds of degrees of freedom. It is preferable to give almost the same degree of freedom in order to give the movement to the legged mobile robot as close as possible to a human, but this is extremely difficult technically. This is because it is necessary to arrange at least one actuator for each degree of freedom. However, mounting several hundred actuators on a mechanical device called a robot is difficult in terms of manufacturing cost. This is impossible from the design point of view. In addition, when the degree of freedom is large, the amount of calculation for position / motion control, posture stability control, and the like increases exponentially. For this reason, it is common to construct a humanoid robot with joint degrees of freedom of about several tens, which is much smaller than the human body. Therefore, it can be said that one of the important issues in the design and control of a humanoid robot is how to realize a more natural motion using a small degree of freedom.
[0017]
In addition, legged mobile robots that perform biped upright walking are superior in that they can realize flexible walking and running operations (for example, raising and lowering stairs and getting over obstacles), but the center of gravity is higher, so Posture control and stable walking control become difficult by the amount. In particular, in the case of robots that are closely linked to daily life, postures and stable walking must be controlled while richly expressing natural movements and emotions in intelligent animals such as humans and monkeys. Many emotion expressions by movement use the upper body of the upper limbs and the head, and the position of the center of gravity of the robot during the movement period dynamically changes.
[0018]
Numerous techniques related to posture control and stable walking have been proposed for robots of the type that perform legged movement by biped walking. Stable “walking” in this context can be defined as moving with legs without falling down. At the time of walking, gravity, inertial force, and these moments act on the road surface from the walking system due to gravity and acceleration caused by walking motion. According to the so-called “Dalambert principle”, they balance with the floor reaction force and the floor reaction force moment as a reaction from the road surface to the walking system. As a result of the dynamic reasoning, there is a point where the pitch and roll axis moment become zero on the side of the support polygon formed by the sole contact point and the road surface, or “ZMP (Zero Moment Point)”.
[0019]
Many of the proposals regarding the stable walking of the robot use this ZMP as a standard for determining the stability of walking. The biped walking pattern generation based on the ZMP norm has advantages such that a foot landing point can be set in advance and it is easy to consider the kinematic constraint conditions of the foot according to the road surface shape.
[0020]
For example, the legged mobile robot described in Japanese Patent Application Laid-Open No. 5-305579 is designed to perform stable walking so that a point on the floor surface where ZMP becomes zero coincides with a target value.
[0021]
Further, in the legged mobile robot described in Japanese Patent Laid-Open No. 5-305581, the ZMP is at least a predetermined margin from the inside of the support polyhedron (polygon) or from the end of the support polyhedron (polygon) when landing or getting off the floor. It was comprised so that it might be in the position which has. As a result, even if a disturbance or the like is received, there is a margin of ZMP for a predetermined distance, and walking stability can be improved.
[0022]
Japanese Patent Laid-Open No. 5-305583 discloses that the walking speed of a legged mobile robot is controlled by the ZMP target position. That is, the legged mobile robot described in the publication uses the walking pattern data set in advance to drive the leg joint so that the ZMP matches the target position and to detect the inclination of the upper body. The discharge speed of the walking pattern data set according to the detection value is changed. As a result, when the robot leans forward, for example, by stepping on unexpected irregularities, the posture can be recovered by increasing the discharge speed. In addition, since the ZMP can be controlled to the target position, there is no problem even if the discharge speed is changed during the both-leg support period.
[0023]
Japanese Patent Laid-Open No. 5-305585 discloses that the landing position of a legged mobile robot is controlled by the ZMP target position. That is, the legged mobile robot described in the publication detects a deviation between the ZMP target position and the actually measured position and drives one or both of the legs so as to eliminate it, or around the ZMP target position. A stable walking is performed by detecting the moment and driving the leg so that it becomes zero.
[0024]
Japanese Patent Application Laid-Open No. 5-305586 discloses that the tilting posture of a legged mobile robot is controlled by the ZMP target position. In other words, the legged mobile robot described in the publication detects a moment around the ZMP target position, and when a moment is generated, drives the leg so that the moment becomes zero, so that a stable walking is performed. It has become.
[0025]
When considering stable walking control of a biped walking robot, the robot performs an action of “static walking” in which the center of gravity of the robot is always in the ground contact range of the sole during walking, or the center of gravity of the robot is It is an important question whether it is "dynamic walking" that goes out of the bottom. That is, when the biped walking robot walks stably, the center of gravity of the system needs to be placed on the soles of the supporting legs if it is a static walking. In dynamic walking, for example, if the control method uses ZMP as a stable walking norm, the ZMP must be controlled to follow the target trajectory.
[0026]
During the former static walking, from the request that the center of gravity of the robot be within the ground contact range of the sole during walking, it is better to arrange heavy objects as low as possible among the components of the robot and lower the center of gravity position, Stability control of walking becomes easy. On the other hand, the concept of so-called “inverted pendulum” is introduced during the latter dynamic walking. The inverted pendulum can recover its posture by strongly accelerating the support point in the fall direction. In the walking system, this corresponds to accelerating the target ZMP strongly in the direction of falling. When performing inverted pendulum control, the higher the center of gravity position of the robot, the longer the time from losing the balance of the center of gravity to falling over, that is, the period of the inverted pendulum, which is advantageous for stabilizing the walking control.
[0027]
By the way, since the robot is composed of an actuator having a large torque-weight ratio and a relatively light structural member, most of the mass is concentrated on the actuator. Needless to say, each actuator corresponds to the degree of freedom of joint of the robot, and its installation location is almost fixed and cannot be used for adjusting the position of the center of gravity.
[0028]
Examples of the component whose installation location for the system system does not particularly depend on the structure of the robot include a control board that performs drive control of the actuator, a power supply device that supplies power to various electrical systems such as the actuator and the control board, and the like. .
[0029]
As the control board, a CPU (Central Processing Unit) chip such as “Pentium” of Intel Corporation, a memory chip and other main circuit components of a computer are usually used. The motherboard weighs only a few hundred grams at most and does not contribute much to the adjustment of the center of gravity.
[0030]
On the other hand, the power supply device depends on an AC power supply (general commercial power supply), or is a self-sustained drive type using a battery, and has a large weight. In the former case, circuit components such as an orthogonal transformer and a transformer are mounted on approximately one printed wiring board, so that a heavy object that affects the position of the center of gravity of the entire robot is not configured. On the other hand, in the latter case, since the power supply apparatus includes dozens to dozens of battery cells, it can be a heavy object that affects the position of the center of gravity of the entire robot. In particular, since an excessive inrush current is required during the initial driving of the actuator, a nickel-cadmium battery having a large instantaneous supply current is superior to a lithium ion battery having a high weight energy density. A power supply device using a nickel-cadmium battery has a weight of about several kilograms. This occupies about 10 to 20% of the weight of a small biped robot.
[0031]
If it is a self-sustained drive type using a battery, the physical action radius of the humanoid robot is not restricted by the power cable, and can walk freely. In addition, during various exercises including walking and other upper limbs, it is not necessary to consider the interference between the upper limbs and lower limbs of the robot and the power cable, thereby facilitating operation control.
[0032]
[Problems to be solved by the invention]
An object of the present invention is to provide an excellent legged mobile robot having a structure simulating an upright walking type body mechanism or operation such as a human or a monkey.
[0033]
A further object of the present invention is to perform legged movement by biped upright walking and a so-called upper body such as the trunk, upper limbs, head, etc. mounted on the lower limbs. It is an object of the present invention to provide an excellent upright walking / legged mobile robot capable of setting a suitable center-of-gravity position at the time of whole body coordinated exercise including the above.
[0034]
[Means for Solving the Problems]
The present invention has been made in consideration of the above-mentioned problems, and the first side surface thereof is composed of at least a lower limb and an upper body disposed above the lower limb, and is movable by the movement of the lower limb. A robot,
The robot is characterized in that a heavy object that affects the position of the center of gravity of the entire robot is attached to the upper body so as to be freely displaceable.
[0035]
Further, the second aspect of the present invention is a robot which is composed of at least a lower limb and an upper body disposed above the lower limb, and is movable by movement of the lower limb,
A power supply means capable of supplying a driving power for driving at least a part of the robot and having a weight that affects the position of the center of gravity of the entire robot;
Power supply attachment means for detachably attaching the power supply means to the upper body;
It is a robot characterized by comprising.
[0036]
In the robot according to the second aspect of the present invention, the power supply means is composed of, for example, one or more nickel-based battery cells. The nickel-based battery refers to, for example, a nickel cadmium battery or a nickel metal hydride battery. Although this type of nickel-based battery has a low weight energy density (that is, has a relatively large weight), it has an output characteristic capable of supplying an inrush current and is suitable for driving an actuator.
[0037]
Further, the power supply attaching means attaches the power supply means, that is, the battery pack so as to be displaceable on at least one of a yaw axis and a roll axis of the robot. The yaw axis here is the Z axis, and the robot can be regarded as an inverted pendulum by moving the installation position of the battery pack as a heavy object upward. The inverted pendulum can recover its posture by strongly accelerating the support point in the fall direction. In the walking system, this corresponds to accelerating the target ZMP strongly in the direction of falling.
[0038]
In addition, a third aspect of the present invention is a robot that includes at least a lower limb and an upper body disposed above the lower limb, and is movable by the movement of the lower limb,
The robot is characterized in that the center of gravity of the entire robot is moved upward by attaching a driving battery for driving at least a part of the robot to the upper body.
[0039]
The fourth aspect of the present invention is a center-of-gravity position control method for a robot that is composed of at least a lower limb and an upper body disposed above the lower limb and is movable by movement of the lower limb,
(A) setting at least one gravity center position in the Z-axis or X-axis direction of the robot;
(B) setting a target whole body motion pattern of the robot;
(C) calculating a whole body motion pattern of the robot based on the target whole body motion pattern;
(D) when an error between the calculated whole body motion pattern and the target whole body motion pattern is within an allowable range, determining the set center of gravity position as an optimum center of gravity position;
A method of controlling the center of gravity of the robot.
[0040]
In the robot center-of-gravity position control method according to the fourth aspect of the present invention, when the calculated whole-body motion pattern is out of an allowable range with respect to the target whole-body motion pattern, the center-of-gravity position of the robot is reset. It may further include the step of setting and recalculating the whole body movement pattern.
[0041]
Further, the robot has a heavy object that affects the position of the center of gravity of the entire robot attached to the upper body so as to be freely displaceable.
You may make it determine the attachment position of this heavy article so that the optimal gravity center position determined by the said step (d) may be formed.
[0042]
In addition, the robot is
A power supply means capable of supplying a driving power for driving at least a part of the robot and having a weight that affects the position of the center of gravity of the entire robot;
Power supply attachment means for detachably attaching the power supply means to the upper body;
Comprising
The attachment position of the power supply means by the power supply attachment means may be determined so as to form the optimum center-of-gravity position determined in the step (d).
[0043]
[Action]
The humanoid robot is usually composed of a lower limb for performing legged movement and an upper body disposed above the lower limb. The upper body is further divided into a trunk that is connected to the lower limbs by a hip joint, an upper limb, and a head.
[0044]
As a driving power source for driving at least a part of the robot, a battery pack comprising a nickel-based battery cell capable of supplying an inrush current of the actuator is used. It accounts for about 10 to 20% of the total weight.
[0045]
By attaching such a battery pack to the upper body of the robot instead of the lower limbs, the center of gravity of the entire robot is moved upward, facilitating dynamic walking control regarded as an inverted pendulum. The posture can be recovered by accelerating the support point strongly. Further, by variably attaching the battery pack in the Z-axis direction, it becomes possible to set / reset the center of gravity position adapted to various movement patterns such as walking, running, and dancing.
[0046]
Other objects, features, and advantages of the present invention will become apparent from a more detailed description based on embodiments of the present invention described later and the accompanying drawings.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0048]
FIG. 1 and FIG. 2 show a state in which the humanoid or humanoid robot 100 used for carrying out the present invention is viewed from the front and the rear. Further, FIG. 3 schematically shows the joint degree-of-freedom configuration of the humanoid robot 100.
[0049]
As shown in FIG. 3, the humanoid robot 100 connects an upper body including two arms and a head 1, a lower limb including two legs that realize a moving operation, and an upper limb and a lower limb. Consists of the trunk.
[0050]
The neck joint that supports the head 1 has three degrees of freedom: a neck joint yaw axis 2, a neck joint pitch axis 3, and a neck joint roll axis 4.
[0051]
Each arm portion includes a shoulder joint pitch axis 8, a shoulder joint roll axis 9, an upper arm yaw axis 10, an elbow joint pitch axis 11, a forearm yaw axis 12, a wrist joint pitch axis 13, and a wrist joint roll. It comprises a shaft 14 and a hand portion 15. The hand portion 15 is actually a multi-joint / multi-degree-of-freedom structure including a plurality of fingers. However, since the movement of the hand portion 15 has little contribution or influence on the posture control or walking control of the robot 100, it is assumed in this specification that the degree of freedom is zero. Therefore, it is assumed that each arm portion has seven degrees of freedom.
[0052]
The trunk has three degrees of freedom: a trunk pitch axis 5, a trunk roll axis 6, and a trunk yaw axis 7.
[0053]
In addition, each leg portion constituting the lower limb includes a hip joint yaw axis 16, a hip joint pitch axis 17, a hip joint roll axis 18, a knee joint pitch axis 19, an ankle joint pitch axis 20, and a yawning joint roll axis 21. , And a foot (plantar) 22. Assume that the intersection point of the hip joint pitch axis 17 and the hip joint roll axis 18 defines the hip joint position of the robot 100 according to the present embodiment. The human foot (sole) 22 is actually a structure including a multi-joint / multi-degree-of-freedom sole, but the sole of the humanoid robot 100 according to the present embodiment has zero degrees of freedom. . Accordingly, each leg is configured with 6 degrees of freedom.
[0054]
In summary, the entire humanoid robot 100 according to the present embodiment has a total of 3 + 7 × 2 + 3 + 6 × 2 = 32 degrees of freedom. However, the humanoid robot 100 for entertainment is not necessarily limited to 32 degrees of freedom. It goes without saying that the degree of freedom, that is, the number of joints, can be increased or decreased as appropriate in accordance with design and manufacturing constraints and required specifications.
[0055]
Each degree of freedom of the humanoid robot 100 as described above is actually implemented using an actuator. It is preferable that the actuator be small and light in light of demands such as eliminating the appearance of extra bulges on the appearance and approximating the shape of a human body, and performing posture control on an unstable structure such as biped walking. . In this embodiment, a small AC servo actuator of a gear direct connection type and a servo control system of a single chip built in a motor unit is mounted. This type of AC servo actuator is disclosed in, for example, Japanese Patent Application No. 11-33386, which has already been assigned to the present applicant.
[0056]
FIG. 4 schematically shows a control system configuration of the humanoid robot 100. As shown in the figure, the humanoid robot 100 performs adaptive control for realizing cooperative operation between each mechanism unit 30, 40, 50R / L, 60R / L and each mechanism unit representing human limbs. It is comprised with the control unit 80 to perform (however, each of R and L is a suffix which shows each of right and left, and so on).
[0057]
The entire operation of the humanoid robot 100 is controlled by the control unit 80 in an integrated manner. The control unit 80 exchanges data and commands between a main control unit 81 composed of main circuit components (not shown) such as a CPU (Central Processing Unit) chip and a memory chip, and each component of the power supply device and the robot 100. And a peripheral circuit 82 including an interface (not shown) for performing the above.
[0058]
In this embodiment, the power supply apparatus has a configuration (not shown in FIG. 4) including a battery for driving the robot 100 autonomously. If it is a self-supporting drive type, the physical action radius of the humanoid robot 100 can be freely walked without being restricted by the power cable. Further, during various exercises including walking and other upper limbs, it is not necessary to consider interference with the power cable, and operation control is facilitated.
[0059]
In this embodiment, the battery is connected to each actuator A. ₂ , A _Three It is composed of nickel cadmium battery cells that can supply the inrush current. For this reason, the power supply apparatus occupies about 10 to 20% of the weight of the entire robot 100.
[0060]
It is worthy to note that the position of the center of gravity of the robot 100 is set to the upper body by arranging the power supply device, which is a heavy object, above the upper body of the robot 100, that is, above the hip joint. This is because the structure called the robot 100 can be regarded as a so-called inverted pendulum and controlled during an operation such as dynamic walking. The inverted pendulum can recover its posture by strongly accelerating the support point in the fall direction. In the walking system, this corresponds to accelerating the target ZMP strongly in the direction of falling. When performing inverted pendulum control, the higher the center of gravity position of the robot, the longer the time from losing the balance of the center of gravity to falling over, that is, the period of the inverted pendulum, which is advantageous for stabilizing the walking control.
[0061]
Each degree of freedom of joint in the robot 100 shown in FIG. 3 is realized by a corresponding actuator. That is, the head unit 30 includes a neck joint yaw axis actuator A that represents the neck joint yaw axis 2, the neck joint pitch axis 3, and the neck joint roll axis 4. ₂ , Neck joint pitch axis actuator A _Three , Neck joint roll axis actuator A _Four Is arranged.
[0062]
The trunk unit 40 includes a trunk pitch axis actuator A that represents the trunk pitch axis 5, the trunk roll axis 6, and the trunk yaw axis 7. _Five , Trunk roll axis actuator A ₆ , Trunk yaw axis actuator A ₇ Is deployed.
[0063]
Further, the arm unit 50R / L is subdivided into an upper arm unit 51R / L, an elbow joint unit 52R / L, and a forearm unit 53R / L, but the shoulder joint pitch axis 8, the shoulder joint roll axis 9, and the upper arm Shoulder joint pitch axis actuator A representing the yaw axis 10, the elbow joint pitch axis 11, the elbow joint roll axis 12, the wrist joint pitch axis 13, and the wrist joint roll axis 14. ₈ , Shoulder joint roll axis actuator A ₉ , Upper arm yaw axis actuator A _Ten , Elbow joint pitch axis actuator A ₁₁ , Elbow joint roll axis actuator A ₁₂ , Wrist joint pitch axis actuator A ₁₃ Wrist joint roll axis actuator A ₁₄ Is deployed.
[0064]
The leg unit 60R / L is subdivided into a thigh unit 61R / L, a knee unit 62R / L, and a shin unit 63R / L, but the hip joint yaw axis 16, the hip joint pitch axis 17, the hip joint Hip joint yaw axis actuator A representing each of roll axis 18, knee joint pitch axis 19, ankle joint pitch axis 20, and ankle joint roll axis 21 ₁₆ Hip joint pitch axis actuator A ₁₇ , Hip joint roll axis actuator A ₁₈ , Knee joint pitch axis actuator A ₁₉ , Ankle joint pitch axis actuator A ₂₀ , Ankle joint roll axis actuator A _{twenty one} Is deployed.
[0065]
Each actuator A ₂ , A _Three Is more preferably a small AC servo actuator (described above) of a gear direct connection type and a servo control system that is mounted on a motor unit in a single chip.
[0066]
For each mechanism unit such as the head unit 30, trunk unit 40, arm unit 50, and leg unit 60, sub-control units 35, 45, 55, and 65 for actuator drive control are provided. Furthermore, grounding confirmation sensors 91 and 92 for detecting whether or not the soles of the leg portions 60R and 60L have landed are mounted, and a posture sensor 93 for measuring posture is provided in the trunk unit 40. ing. The control targets can be dynamically corrected by detecting the landing and leaving periods of the sole 22, the inclination of the trunk portion, and the like based on the outputs of the sensors 91 to 93.
[0067]
The main control unit 80 performs adaptive control on the sub-control units 35, 45, 55, and 65 in response to outputs from the sensors 91 to 93, and controls the upper limbs, trunk, and lower limbs of the humanoid robot 100. Realize coordinated operation. The main control unit 81 sets a foot movement, a ZMP (Zero Moment Point) trajectory, a trunk movement, an upper limb movement, a waist height, and the like according to a user command and the like, and instructs an operation in accordance with these setting contents. The command to be transferred is transferred to each sub-control unit 35, 45, 55, 65.
[0068]
And each sub-control part 35, 45 ... interprets the received command from the main control part 81, and each actuator A ₂ , A _Three A drive control signal is output to. Here, “ZMP” refers to a point on the floor where the moment due to floor reaction force during walking is zero, and “ZMP trajectory” refers to, for example, during the walking motion of the robot 100. It means the trajectory that ZMP moves.
[0069]
Next, a battery position adjusting mechanism in the above-described humanoid robot 100 will be described. FIG. 5 illustrates a first example of the battery position adjustment mechanism.
[0070]
The illustrated battery position adjustment mechanism 200 is attached to the upper body part of the robot 100 and is preferably housed in the trunk unit 40.
[0071]
The battery pack 210 includes, for example, several to several tens of nickel / cadmium battery cells, and has a weight of about several kilograms. The battery pack 210 is fixed on the battery pack mounting plate 215.
[0072]
Slots 221a and 221b and slots 221c and 221d are formed at substantially the left and right ends of the battery pack mounting plate 215, respectively. As shown in FIG. 5, the L-shaped plates 203 </ b> A and 203 </ b> B can be fixed to the left and right ends of the battery pack mounting plate 215 by inserting screws into the respective long holes 221 a. At this time, each of the long holes 221a extends in the X axis, that is, in the roll axis direction of the robot 100. It is possible to adjust within the range.
[0073]
On the other hand, the pair of support plates 201A and 201B are connected to each other at a predetermined interval via the pair of connection plates 205A and 205B. Although not shown in FIG. 5, it is understood that the support plates 201 </ b> A and 201 </ b> B are integrally attached to the trunk unit 40 of the robot 100 (or form a part of the trunk unit 40).
[0074]
Four long holes 225a to 225d are formed in each of the support plates 201A and 201B, and the L-shaped plates 203A and 203B can be fixed by inserting screws through the long holes. At this time, each of the long holes 225a extends in the Z axis, that is, the yaw axis direction of the robot 100. It can be adjusted within the range of dimensions.
[0075]
In summary, the mounting position of the battery pack 210 on the support plates 201A and 201B, that is, the trunk unit 40, can be adjusted in each direction of the X axis and the Z axis. It should be understood that since the battery pack 210 occupies several percent to several tens of percent of the total weight of the robot 100, the position of the center of gravity of the robot 100 can be set by adjusting the mounting position.
[0076]
FIG. 6 illustrates a second example of the battery position adjustment mechanism. Hereinafter, a description will be given with reference to FIG. However, it should be understood that the illustrated battery position adjusting mechanism 300 is attached to the upper body portion of the robot 100 and is preferably housed in the trunk unit 40 (same as above).
[0077]
The battery pack 310 includes, for example, several to several tens of nickel cadmium battery cells and has a weight of about several kilograms. The battery pack 210 is fixed on the battery pack mounting plate 315.
[0078]
As illustrated, the battery pack mounting position 315 is restricted from moving in the Z-axis direction by the four guide rails 321a to 321b. The guide rails 321a to 321b are attached to a pair of opposing support plates 341 and 342. It should be understood that the support plates 341 and 342 are integrally attached to the trunk unit 40 of the robot 100 (or form part of the trunk unit 40).
[0079]
The battery pack mounting position 315 includes a bearing 332 through which a ball screw 331 is inserted. Therefore, by rotating the ball screw 331 by the drive motor 333, the position of the battery pack support plate 315, that is, the battery pack 310 in the Z-axis direction can be moved. The drive control of the drive motor 333 is performed in the main control unit 80, for example.
[0080]
Since the battery pack 310 occupies several percent to several tens of percent of the total weight of the robot 100 (same as above), the center of gravity position of the robot 100 is dynamically set by adjusting the mounting position using the drive motor 333.・ Please understand that it can be reset.
[0081]
According to the battery position adjusting mechanism as shown in FIG. 5 or FIG. 6, the position of the center of gravity of the humanoid robot 100 having the center of gravity of the upper body can be further adaptively controlled. However, the optimum center-of-gravity position is determined according to the whole body motion pattern (for example, “walking”, “running”, “jumping”, “dancing”, etc.) performed by the robot 100. Below, the determination method of a gravity center position (in other words, battery mounting position) is demonstrated.
[0082]
FIG. 7 shows a processing procedure for determining the gravity center position (battery mounting position) of the robot 100 in the form of a flowchart. Hereinafter, each step of this flowchart will be described.
[0083]
First, the center of gravity position of the robot 100 in the Z-axis (yaw axis) and X-axis (roll axis) directions is set (step S11), and the target whole body motion pattern of the robot 100 is set (step S12).
[0084]
As already described in the section of “PRIOR ART”, the robot 100 is composed of an actuator A having a large torque / weight ratio. ₂ , A _Three ... and a relatively lightweight structural member, most of the mass is concentrated on the actuator. However, each actuator corresponds to the degree of freedom of joint, and the installation location is almost fixed, so it cannot be used for adjusting the position of the center of gravity. Therefore, the setting of the center of gravity position in step S11 referred to here is substantially the same as setting the mounting position of the battery pack. As described above with reference to FIG. 5 or 6, the mounting position of the battery pack in the Z-axis and X-axis directions can be adjusted.
[0085]
The target whole body motion pattern is a motion pattern such as “walking”, “running”, “jumping”, “dancing”, and the like. For example, the robot 100 can be taught by a method such as teaching / playback or offline teaching. To the main control unit 80.
[0086]
Next, in step S13, the current mass distribution data of the robot 100 is calculated based on the mounting position of the battery pack set in the preceding step S11. The mass distribution data obtained in this step is used in the subsequent calculation processing in step S16 and the like. The mass distribution data can be calculated using a multi-mass point approximate model of the robot 100, which will be described in detail later.
[0087]
Next, in step S14, the motion performance required for each joint of the robot 100 for realizing the motion pattern is calculated. The exercise performance mentioned here includes the movable angle of the joint, the maximum torque, the maximum speed, and the like.
[0088]
However, actuator A used in each joint ₂ , A _Three In ..., allowable motion performance or rated motion performance is defined. If the required motion performance obtained in step S14 exceeds the allowable motion performance, the process goes to the branch No in decision block S15 and resets the center of gravity position of the robot 100 (that is, the battery pack mounting position). (Step S21), the same processing as described above is repeatedly executed.
[0089]
Next, in step S16, the whole body motion pattern of the robot 100 is calculated using the target whole body motion pattern input in the preceding step S12. The whole body motion pattern can be calculated using, for example, a multi-mass point approximation model of the robot 100, and details will be described later.
[0090]
Next, in a determination block S17, it is determined whether or not the calculated whole body motion pattern can be realized within the range of allowable motion performance of each joint, that is, an actuator. When deviating from the permissible motion performance, the process goes to the branch No of the determination block and resets the center of gravity position of the robot 100 (that is, the battery pack mounting position) (step S21), and then the same processing as above Repeatedly.
[0091]
Next, in step S18, an error E between the target whole body motion pattern and the calculated whole body motion pattern is calculated.
[0092]
Then, in a determination block S19, it is determined whether or not the error E is within an allowable range. If it deviates from the allowable range, the process goes to the branch No of the determination block and resets the center of gravity position of the robot 100 (that is, the battery pack mounting position) (step S21), and then performs the same processing as above. Run repeatedly.
[0093]
On the other hand, if the error E is within the allowable range, the set center-of-gravity position is output as the optimum center-of-gravity position of the robot 100 (step S21), and the entire processing routine is terminated.
[0094]
Based on the optimum center-of-gravity position of the robot 100 thus obtained, the optimum mounting position of the battery pack can be calculated backward. The position of the battery pack may be adjusted according to the result of the reverse calculation. Refer to FIG. 5 or FIG. 6 for the position adjusting mechanism.
[0095]
Next, the mass distribution data calculation process in step S13 of the flowchart shown in FIG. 7 will be described in detail.
[0096]
As already known in the field of dynamics and the like, the gravity center position R of the structure can be calculated by the following equation (wherein ρ (x, y, z) is a point (x, y) , Z).
[0097]
[Expression 1]

[0098]
In order to obtain an exact solution, it is preferable to strictly model the robot 100 as a rigid system rather than a mass system, but it requires much calculation time. On the other hand, as a result of using an actuator having a large torque-weight ratio and a lightweight structural member, most of the mass of the robot 100 is concentrated on the actuator, that is, the joint portion. Therefore, even if the robot 100 is handled as a multi-mass point approximation model, there is almost no hindrance (details of the multi-mass point approximation model will be described later).
[0099]
FIG. 8 shows the details of the mass distribution data calculation processing procedure when the multi-mass point approximate model is used in the form of a flowchart. It should be understood that the entire flowchart constitutes step S13 described above. Hereinafter, each step of this flowchart will be described.
[0100]
First, in step S31, all axis angle information, all joint arrangement information, and all mass point arrangement information of the robot 100 are input. The angle information and the arrangement information are static and fixed data determined by the design specifications of the robot 100, and can be supplied from, for example, a CAD database created when the robot 100 is designed.
[0101]
Next, in step S32, all joint position information and all mass point position information when the midpoint of the left and right hip joints of the robot 100 is set as the origin are calculated.
[0102]
Next, in step S33, the distance from the origin to the left and right sole planes is calculated, and in decision block S34, it is determined which of the left and right sole planes is away from the origin. In the present embodiment, it is assumed that the sole away from the origin is the currently landing foot.
[0103]
When the right sole plane is far away, the coordinates of the whole mass point position are transformed so that the right sole plane becomes the XY plane (step S35R). On the other hand, when the left sole plane is far away. Converts the coordinates of all mass point positions so that the left plantar plane becomes the XY plane (step S35L).
[0104]
After coordinate conversion in this way, the center of gravity position of the robot 100 can be calculated from the mass and position at all mass points (step S36).
[0105]
An example of the position of the center of gravity calculated in FIG. 8 is shown in FIG. In the example shown in the figure, the center of gravity of the robot 100 is set above the waist, that is, the lower limbs, so that stable posture control during dynamic walking can be suitably performed with the robot 100 regarded as an inverted pendulum. The inverted pendulum can recover its posture by strongly accelerating the support point in the fall direction. In the walking system, this corresponds to accelerating the target ZMP strongly in the direction of falling. When performing inverted pendulum control, the higher the center of gravity position of the robot, the longer the time from losing the balance of the center of gravity to falling over, that is, the period of the inverted pendulum, which is advantageous for stabilizing the walking control.
[0106]
Next, the calculation process of the whole body motion pattern of the robot 100 in step S16 of the flowchart shown in FIG. 7 will be described in detail. The robot 100 is connected to each joint or actuator A according to a predetermined whole body motion pattern before normal operation. ₂ , A _Three By controlling the drive, a predetermined operation is realized.
[0107]
The robot 100 itself is an infinite or continuous collection of mass points. However, in this embodiment, the calculation amount for calculating the whole body motion pattern is reduced by replacing the robot 100 with an approximate model composed of a finite number of discrete mass points. Since the robot 100 uses an actuator with a large torque to weight ratio and a light-weight structural member, most of its mass is concentrated on the actuator, that is, the joint, so that it can be handled as a multi-mass point approximation model with little trouble.
[0108]
FIG. 10 illustrates a non-interfering multi-mass point approximation model of the robot 100 introduced for calculating the whole body motion pattern.
[0109]
In FIG. 10, the O-XYZ coordinate system represents the roll, pitch, and yaw axes in the absolute coordinate system, and the O′-X′Y′Z ′ coordinate system represents the roll, pitch, Each axis of yaw is represented. In the multi-mass model shown in the figure, i is a subscript representing the i-th given mass, m _i Is the mass of the i-th mass point, r ' _i Represents the position vector of the i-th mass point (however, the motion coordinate system). The mass of the lumbar mass point, which is particularly important in lumbar motion control described later, is m _h The position vector is r ′ _h (R ' _hx , R ' _hy , R ' _hz ) And the position vector of ZMP is r ′ _zmp And
[0110]
In the inexact non-interfering mass point approximation model shown in FIG. 10, it should be fully understood that the moment formula is described in the form of a linear equation, and the moment formula does not interfere with the pitch axis and the roll axis.
[0111]
Such a multi-mass point approximation model can be generated by the following processing procedure.
[0112]
(1) The mass distribution of the entire robot 100 is obtained.
(2) The robot 100 is divided into a plurality of areas. The area is for setting the mass point. The region dividing method may be either manual input by the designer or automatic generation according to a predetermined rule.
(3) For each region i, the center of gravity is obtained, and the position of the center of gravity and mass m _i Is assigned to the relevant mass point.
(4) Each mass point m _i , The mass position r _i Is displayed as a sphere with a radius proportional to its mass.
(5) Mass points that are actually connected, that is, spheres are connected by a wire.
[0113]
The multi-mass point approximation model is a representation of a robot in the form of a wire frame model. In the present embodiment, as can be seen from FIG. 10, this multi-mass point approximation model is set with each of shoulders, elbows, wrists, trunk, waist, and both ankles as mass points. .
[0114]
Note that each rotation angle (θ in the waist information of the multi-mass model shown in FIG. _hx , Θ _hy , Θ _hz ) Regulates the posture of the waist in the humanoid robot 100, that is, the rotation of the roll, pitch, and yaw axes (FIG. 11 shows an enlarged view around the waist of the multi-mass model, so please confirm it) ).
[0115]
FIG. 12 shows a processing procedure for calculating the whole body motion pattern of the robot 100 in the form of a flowchart. However, in the following, each joint position and operation of the robot 100 will be described using a linear / non-interference multi-mass point approximation model as shown in FIG. 10, and the following parameters will be used in the calculation. . However, it should be understood that symbols with a dash (') describe a motion coordinate system.
[0116]
[Expression 2]

[0117]
Further, the waist height of the robot 100 is constant (r ′ _hz + R _qz = Const) and the knee mass point is assumed to be zero.
[0118]
In the case of the robot 100 according to the present embodiment, a lumbar motion pattern that enables stable walking is generated based on an arbitrary foot motion pattern, ZMP trajectory, trunk motion pattern, upper limb motion pattern, and the like. . The ZMP (Zero Moment Point) trajectory here refers to a point where no moment is generated during walking motion when the sole (or sole) of the walking robot is fixed to the floor at a certain point, that is, the trajectory of ZMP Say (above).
[0119]
In the case of a biped robot (see FIG. 3) with one foot having six degrees of freedom as in this embodiment, the posture of both legs depends on the position of each foot 22R / L and the horizontal position and height of the waist. Determined uniquely. Therefore, generating the lumbar movement pattern is nothing but determining the leg posture, that is, the “gait” of the lower limb (“gait” means “time-series change of joint angle” in the art). Technical term).
[0120]
First, in step S41, based on the target whole body motion pattern set in step S12, a foot (more specifically, plantar) motion, a ZMP trajectory derived from the foot motion, a trunk motion, an upper limb motion, Patterns for actually determining the driving and operation of each part such as the posture and height of the waist are set. More specifically, first, a foot movement pattern, then a ZMP trajectory, a trunk movement pattern, and an upper limb movement pattern are set. Regarding the movement of the waist, only the Z ′ direction is set, and the X ′ and Y ′ directions are unknown.
[0121]
Next, using the linear / non-interference multi-mass point approximation model, moments around the pitch axis and roll axis on the set ZMP generated by the foot, trunk, and upper limb movements (M _x , M _y ) Is calculated (step S42).
[0122]
Next, the motion in the lumbar horizontal plane (r ′ _hx , R ' _hy ) To calculate the moment on the set ZMP (step S43).
[0123]
Next, a balance equation relating to the moment on the set ZMP is derived on the motion coordinate system O′-X′Y′Z ′ that moves with the robot (step S44). More specifically, the moment generated by the foot, trunk, and upper limb movements (M _x , M _y ) On the right side as a term of a known variable, and a term (r _hx , R _hy ) On the left side as unknown variable terms, and a linear and non-interfering ZMP equation (1) as shown in the following equation is derived.
[0124]
[Equation 3]

[0125]
However, the following shall hold.
[0126]
[Expression 4]

[0127]
Next, the above-mentioned ZMP equation (1) is solved to calculate the waist horizontal plane trajectory (step S45). For example, by solving the ZMP equation (1) using a numerical solution (well-known) such as the Euler method or the Runge-Kutta method, the horizontal absolute position of the waist (r _hx , R _hy ) Can be obtained (step S46). The numerical solution obtained here is an approximate solution of a waist motion pattern that enables stable walking, and more specifically, a waist horizontal absolute position where ZMP enters the target position. The ZMP target position is normally set at the planted sole (for example, during a quiet walk).
[0128]
If the trunk / upper limb movement set in advance cannot be realized on the calculated approximate solution, the trunk / upper limb movement pattern is reset / corrected (step S47). At this time, the knee trajectory may be calculated.
[0129]
Next, the whole body motion pattern obtained as described above is substituted, and the moment (eM on the set ZMP in the exact model (that is, a precise model of the robot 100 consisting of a rigid body or a very large number of mass points). _x , EM _y ) Is calculated (step S48). In the inexact model, it is assumed that the above [Equation 4] holds, but in the strict case, such an assumption is not required (that is, it is not necessary to be constant with respect to the change in time).
[0130]
Moment in exact model (eM _x , EM _y ) Is a moment error generated by the waist motion. In the subsequent step S49, this moment (eM _x , EM _y ) Is the allowable value of the approximate moment in the inexact model (εM _x , ΕM _y ) It is determined whether it is less than. If it is less than the allowable value ε, the whole body exercise pattern capable of realizing the exact solution of the waist stable exercise pattern and the stable walking can be obtained (step S50), and the entire processing routine is terminated.
[0131]
On the other hand, the moment in the exact model (eM _x , EM _y ) Is the allowable moment (εM) in the approximate model _x , ΕM _y ) Or more, the moment in the exact model (eM _x , EM _y ) To the known generated moment (M _x , M _y ) Is corrected (step S51). Then, the ZMP equation is derived again, and the calculation and correction of the approximate solution of the waist motion pattern are repeatedly executed until the ZMP equation converges below the allowable value ε.
[0132]
FIG. 13 is a flowchart showing another example of a processing procedure for calculating a whole body motion pattern based on the target motion pattern in the robot 100 according to the present embodiment. However, as described above, the joint positions and operations of the robot 100 are described using a linear / non-interference multi-mass point approximation model (same as above). Hereinafter, each step of this flowchart will be described.
[0133]
First, in step S61, based on the target whole body motion pattern set in step S12, a foot (more specifically, plantar) motion, a ZMP trajectory derived from the foot motion, a trunk motion, an upper limb motion, Patterns for actually determining the driving and operation of each part such as the posture and height of the waist are set. More specifically, first, a foot movement pattern, then a ZMP trajectory, a trunk movement pattern, and an upper limb movement pattern are set. Regarding the movement of the waist, only the Z ′ direction is set, and the X ′ and Y ′ directions are unknown.
[0134]
Next, using the linear / non-interference multi-mass point approximation model, moments around the pitch axis and roll axis on the set ZMP generated by the foot, trunk, and upper limb movements (M _x , M _y ) Is calculated (step S62).
[0135]
Next, exercise in the lumbar horizontal plane (r ′ _hx , R ' _hy ) Is expanded into a Fourier series (step S63). As already well known in the art, the time series component can be replaced with the frequency component for calculation by expanding the Fourier series. That is, in this case, the movement of the waist can be regarded as a periodic movement. Moreover, since FFT (Fast Fourier Transform) can be applied by performing Fourier expansion, the calculation speed can be greatly improved.
[0136]
Next, each moment (M _x , M _y ) Is also expanded by Fourier series (step S64).
[0137]
Next, the Fourier coefficient of the orbit in the lumbar horizontal plane is calculated, and further developed by inverse Fourier series (step S65), an approximate solution of the lumbar motion is obtained (step S66). The approximate solution obtained here is an approximate solution of the horizontal absolute position of the waist (r _hx , R _hy More specifically, it is the waist horizontal absolute position where ZMP enters the target position. The ZMP target position is normally set at the planted sole (for example, during a quiet walk).
[0138]
When the trunk / upper limb movement set in advance cannot be realized by the calculated approximate solution, the trunk / upper limb movement pattern is reset / corrected (step S67). At this time, the knee trajectory may be calculated.
[0139]
Next, the whole body motion pattern obtained as described above is substituted, and the moment (eM on the set ZMP in the exact model (that is, a precise model of the robot 100 consisting of a rigid body or a very large number of mass points). _x , EM _y ) Is calculated (step S68). In the inexact model, it is assumed that the above [Equation 4] holds, but in the inexact model, such an assumption is not required (that is, it is not necessary to be constant with respect to a change in time).
[0140]
Moment in exact model (eM _x , EM _y ) Is a moment error generated by the waist motion. In the subsequent step S69, this moment (eM _x , EM _y ) Is the allowable moment (εM) in the approximate model _x , ΕM _y ) It is determined whether it is less than. If it is less than the allowable value ε, the whole body motion pattern that can realize the exact solution and stable walking of the waist stable motion pattern has been obtained (step S70), and the entire processing routine is terminated.
[0141]
On the other hand, the moment in the exact model (eM _x , EM _y ) Is the allowable moment (εM) in the approximate model _x , ΕM _y ) Or more, the moment in the exact model (eM _x , EM _y ) To the known moment (M _x , M _y ) Is corrected (step S71), the Fourier series expansion is performed again, and the calculation and correction of the approximate solution of the lumbar motion pattern are repeated until convergence to below the allowable value ε.
[0142]
FIG. 16 shows another example of the processing procedure for determining the center of gravity position (battery mounting position) of the robot 100 in the form of a flowchart. Hereinafter, each step of this flowchart will be described.
[0143]
First, in step S81, the possible range of the center of gravity position in the Z-axis direction of the robot 100 is calculated.
[0144]
As described above, the movable range of the gravity center position of the robot 100 is determined by the mounting position of the battery pack. For example, in the example shown in FIG. 5, the existence range in the Z-axis direction is determined by the major axis dimensions of the elongated holes 225a to 225d. In the example shown in FIG. 6, the existence range of the center of gravity position in the Z-axis direction is determined according to the stroke range of the ball screw 331.
[0145]
Next, in step S82, the maximum walking speed and the minimum number of basic patterns of the robot 100 are calculated for each of the possible center-of-gravity positions in the Z-axis direction obtained in the preceding step S81.
[0146]
Next, in step S83, an evaluation value at each center of gravity in the Z-axis direction is calculated based on an evaluation function composed of the maximum walking speed and the minimum number of basic patterns.
[0147]
Next, in step S84, the Z-axis direction center of gravity position with the lowest evaluation value is selected, and this is output as the optimum Z-axis direction center of gravity position of the robot 100 (step S85).
[0148]
Based on the optimum center-of-gravity position of the robot 100 thus obtained, the optimum mounting position of the battery pack can be calculated backward. The position of the battery pack may be adjusted according to the result of the reverse calculation. Refer to FIG. 5 or FIG. 6 for the position adjusting mechanism.
[0149]
[Supplement]
The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the gist of the present invention. In other words, the present invention has been disclosed in the form of exemplification, and should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims section described at the beginning should be considered.
[0150]
In determining the gist of the present invention, it is not appropriate to strictly apply FIG. 3 for the names of joints and the like for the biped robot 100, and biped upright walking such as humans and monkeys in reality. It should be interpreted flexibly by contrast with the animal's physical mechanism.
[0151]
For reference, the joint model configuration of a humanoid robot is illustrated in FIG. In the example shown in the figure, a portion including the shoulder joint 5 to the upper arm, the elbow joint 6, the forearm, the wrist 7 and the hand portion 8 is referred to as an “upper limb”. The range from the shoulder joint 5 to the hip joint 11 is called a “trunk” and corresponds to the human torso. In addition, a range from the hip joint 11 to the trunk joint 10 among the trunk is referred to as a “lumbar region”. The trunk joint 10 has an effect of expressing the degree of freedom of the human spine. Further, a portion including the thigh 12, the knee joint 14, the crus 13, the ankle 15, and the foot 16 below the hip joint 11 is referred to as “lower limb”. Generally, the upper part of the hip joint is called the “upper body” and the lower part is called the “lower body”.
[0152]
FIG. 15 illustrates another joint model configuration of a humanoid robot. The example shown in the figure is different from the example shown in FIG. 14 in that the trunk joint 10 is not provided. Refer to the figure for the names of each part. As a result of the omission of the trunk joint corresponding to the spine, the upper body movement of the humanoid robot loses its expressive power. However, in the case of a humanoid robot for industrial purposes such as dangerous work or substitution of work, there is a case where movement of the upper body is not required. It should be understood that the reference numerals used in FIGS. 14 and 15 do not match those in the other drawings.
[0153]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide an excellent legged mobile robot having a structure simulating an upright walking type body mechanism or operation such as a human or a monkey.
[0154]
In addition, according to the present invention, legged movement is performed by biped upright walking, and a so-called upper body such as the trunk, upper limbs, and head is mounted on the lower limbs, so that walking movement, other trunks and upper limbs are mounted. It is possible to provide an excellent upright walking / legged mobile robot capable of setting a suitable center-of-gravity position during whole body coordinated motion including the above.
[Brief description of the drawings]
FIG. 1 is a view showing a state in which a humanoid robot 100 used for carrying out the present invention is viewed from the front.
FIG. 2 is a view showing a state in which a humanoid robot 100 used for carrying out the present invention is viewed from behind.
FIG. 3 is a diagram schematically illustrating a degree-of-freedom configuration model included in the humanoid robot 100 according to the present embodiment.
FIG. 4 is a diagram schematically showing a control system configuration of the humanoid robot 100 according to the present embodiment.
FIG. 5 is a diagram showing a first example related to a battery position adjusting mechanism;
FIG. 6 is a diagram showing a second example regarding a battery position adjustment mechanism;
FIG. 7 is a flowchart showing a processing procedure for determining the position of the center of gravity (battery mounting position) of the robot.
FIG. 8 is a flowchart showing a calculation processing procedure of mass distribution data when a multi-mass point approximation model is used.
9 is a diagram illustrating the center of gravity position of the robot 100 calculated according to the flowchart shown in FIG.
FIG. 10 is a diagram showing a non-interfering multi-mass point approximation model of the robot 100 introduced for calculating the whole body motion pattern.
11 is an enlarged view around the waist in the multi-mass point approximate model of the robot 100 shown in FIG.
12 is a flowchart showing a processing procedure for calculating a whole body motion pattern of the robot 100. FIG.
13 is a flowchart showing another example of a processing procedure for calculating a whole body motion pattern of the robot 100. FIG.
FIG. 14 is a diagram schematically illustrating an example of a joint model configuration for a humanoid robot.
FIG. 15 is a diagram schematically illustrating another example of a joint model configuration for a humanoid robot.
FIG. 16 is a flowchart showing another example of a processing procedure for determining the gravity center position (battery mounting position) of the robot.
[Explanation of symbols]
1 ... head, 2 ... neck yaw axis
3 ... Neck joint pitch axis, 4 ... Neck joint roll axis
5 ... trunk pitch axis, 6 ... trunk roll axis
7 ... trunk yaw axis, 8 ... shoulder joint pitch axis
9 ... Shoulder joint roll axis, 10 ... Upper arm yaw axis
11 ... Elbow joint pitch axis, 12 ... Forearm yaw axis
13 ... wrist joint pitch axis, 14 ... wrist joint roll axis
15 ... hand, 16 ... hip yaw axis
17 ... Hip pitch axis, 18 ... Hip roll axis
19 ... Knee joint pitch axis, 20 ... Ankle joint pitch axis
21 ... Ankle joint roll axis, 22 ... Foot (plantar)
30 ... head unit, 40 ... trunk unit
50 ... arm unit, 51 ... upper arm unit
52 ... Elbow joint unit, 53 ... Forearm unit
60 ... Leg unit, 61 ... Thigh unit
62 ... knee joint unit, 63 ... shin unit
80 ... control unit, 81 ... main control unit
82. Peripheral circuit
91, 92 ... Grounding confirmation sensor
93 ... Attitude sensor
100 ... humanoid robot

Claims (5)

A center of gravity position control method for a robot that is composed of at least an upper limb, a lower limb, a foot, a trunk and a waist, and is movable by movement of the lower limb,
(A) setting the position of the center of gravity in the movement trajectory of at least one of the robots in the Z-axis or X-axis direction of the robot;
(B) setting a target whole body motion pattern of the robot;
(C) calculating a stabilization whole body motion pattern of the robot based on the target whole body motion pattern;
(D) When the calculated whole-body motion pattern has an error in an orbit with respect to the target whole-body motion pattern within an allowable range, the set center-of-gravity position is set as the optimum center-of-gravity position in the target whole-body motion pattern A step to determine;
Have
The step (c)
(C-1) replacing the robot with a multi-mass point approximation model composed of a finite number of discrete mass points based on the set barycentric position;
(C-2) a step of setting a foot movement, trunk movement, upper limb movement, waist posture and height for realizing the target whole body movement pattern set in step (b);
(C-3) setting a ZMP trajectory based on the foot movement set in step (c-2);
(C-4) calculating a moment generated on the ZMP by the foot movement, trunk movement, and upper limb movement set in the step (c-2) using the multi-mass approximation model;
(C-5) calculating a moment generated on the ZMP by a waist motion using the multi-mass approximate model;
(C-6) obtaining a solution of a waist motion in which moments on the ZMP calculated in the steps (c-4) and (c-5) are balanced;
And generating a whole body motion pattern of the robot consisting of a solution of the foot motion, trunk motion, upper limb motion set in step (c-2) and the lumbar motion,
A method for controlling the position of the center of gravity of a robot. When the calculated whole body motion pattern has an error from the target whole body motion pattern outside the allowable range, the method further comprises the step of resetting the center of gravity position in the motion trajectory of the robot and recalculating the whole body motion pattern. ,
The method for controlling the position of the center of gravity of a robot according to claim 1. The robot has a heavy object that affects the position of the center of gravity of the entire robot attached to the upper body so as to be freely displaceable.
Determining the attachment position of the heavy load so as to form the optimum center-of-gravity position determined in step (d);
The method for controlling the position of the center of gravity of a robot according to claim 1. The robot is
A power supply means capable of supplying a driving power for driving at least a part of the robot and having a weight that affects the position of the center of gravity of the entire robot;
Power supply attachment means for detachably attaching the power supply means to the upper body;
Comprising
Determining the mounting position of the power supply means by the power supply mounting means so as to form the optimum center-of-gravity position determined in step (d);
The method for controlling the position of the center of gravity of a robot according to claim 1. The power supply means is detachably attached to the power supply means on at least one of a yaw axis or a roll axis of the robot.
The method for controlling the center of gravity position of a robot according to claim 4.

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