A generalized Newton method for identification of closed-chain excavator arm parameters

Abstract

A robust and fast yet simple approach for experimental identification of the link (mass, inertia and length) parameters and friction coefficients for a full-scale closed-chain excavator arm is developed. The approach is based on a generalized Newton method, an excavation arm dynamic model and measured data. The new approach can be used where the number of equations is different from the number of variables, or if the Jacobian cannot be assumed nonsingular. The parameters are needed for improving the control actions in autonomous solution for excavation tasks and contributing to excavator design evaluation. Using experimental data obtained while moving the links of an instrumented full-scale combat engineer excavator, the values of the link parameters and friction coefficients for various links were successfully identified. The identified parameters are compared with physical values, and they are in agreement. Further, the joint torques and positions computed by the developed model using the identified parameters are validated against measured data, also showing excellent agreement. The experimental data was obtained in collaboration with QinetiQ. The novel technique presented in this paper is general and can be applied to a wide range of heavy-duty closed chain hydraulic manipulators.