A compact model for the compliant humanoid robot COMAN

This work reports on the modelling of a compliant humanoid robot. The introduction of intrinsic compliance in some of the joints of the COmpliant huMANoid robot (COMAN) affects its dynamics making no trivial the generation of walking gaits. To permit the development of effective gait generators which take into account these additional dynamic effects due to intrinsic compliance, an appropriate model which can predict the robot motion dynamics is required. To predict the motion of the centre of mass (COM) of the compliant robot we propose a new model for compliant humanoid systems which combines the inverted pendulum model approach with a three dimensional compliant model (Cartesian) at the level of the COM. The derivation of the model is introduced followed by experimental validation which demonstrates the adequate performance achieved by the proposed reduced model. In particular the efficacy of the model was experimentally validated on the COMAN humanoid platform using a series of ZMP based walking gaits.