This article described on the implementation of impedance control with the adaptive elements and compliant walking mechanism in hydraulically driven hexapod robot named COMET-IV. The main issue when applying impedance control in this robot is the body attitude stability during walking on the uneven terrain that contains of major soft surface. The impedance controller is derived for each leg from vertical motion changes. In addition self-tuning stiffness method is proposed as an adaptive element from the changes of the robot's body attitude vector (magnitude), to ensure the robot is self-adapted with the changes of stepped ground. On the other hand, compliant walking mechanism is designed for force-based walking trajectory and proposed impedance controller integration. The proposed controller and mechanism are verified by running the robot on the designed uneven terrain (extremely soft surface) in the laboratory using critical condition of side walking setting.

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This article described on implementation of selrtuning impedance control with adaptive element from environment identification to provide compliant body balance for hydraulic-actuated hexapod robot, With force-based walking control, this impedance control is applied to provide stable final stepping during walking phases by adapted the environment stifl}iess and force applied, Proposed selfi tuning impedance control is desigried with variable stiffiiess tuning method using time division method and exponential tlme reduction. The case of study is focused on walking on the soft terrain which is crucial part for this robot. The propose controller is verified with walking experiments on several layers of square rubber plate to represent soft terrain such as wet ground, Ker wortis: SeijCtuning leg stiffiiess, environrnent leyel estimation, sofithard terrain 'ProceedingsofMOVIC201OAugusM7-2e,2010,fokyo,Japan

This paper presents the mathmatical modcling of hydrau ［ ic−actuated hexapod robot ． 「 11he robo しnamely COM 田 ： IV which is operate f ( )r hazardous operation assistance in outdoor application ． Current ］ y COME 「 ILIV positien angLe is contrQlled using P 星 D controllen However this controller is not enough し o perforfn robustness for nontinearities of the hydraulic system ， Thereforc the mathematica 】model is dcrivod f〔〕r each link ofeach ］ eg of COME ' ILIV using Iden し iiicatiGn 山eory ， The goal of this derivation and modeling is to identify the states that possib ］ e to be controllcd ． Thus from Ulis iden 面 ed states ， new robustness controller for angle contro 【 can be designed ． Key Words ： Hexapod Robot ， Systcm ldentitication ， Hydrau］ ic − actuated robot