A new method for parameter identification for N-DOF hydraulic robots

Parameter identification for N-DOF hydraulic robots (e.g., BigDog, PETMAN and developing automated excavators) is not an old problem at all. Indeed, recent papers still identify difficult parameters (the bulk modulus and the flow gain coefficients) by trial and error. This paper is the first report to solve this problem. First, new structural properties of hydraulic robots are found in comparison with electric robots and then the drawbacks of the conventional methods are discussed. Second, by modifying one of the conventional methods, a scientific method is proposed and applied to an actual hydraulic manipulator. Third, the validity of the proposed method is confirmed by model validation. Remarkably, the difficult parameters are identified very well without any trial and error. The proposed method is applicable to electric robots even on the unknown inclination.