Realisation of model reference compliance control of a humanoid robot arm via integral sliding mode control

摘要

Human safety becomes critical when robot enters the human environment.Compliant control can be used to address some safety issues in human-robotphysical interaction. This paper proposes an integral sliding mode controller(ISMC) based compliance control scheme for the Bristol Robotics Laboratory'shumanoid BERT II robot arm. Apart from introducing a model referencecompliance controller, the ISMC scheme is aimed to deal with the robot armdynamic model's inaccuracies and un-modelled nonlinearities. The controlscheme consists of a feedback linearization (FL) and an ISMC part. Inaddition, a posture controller has been incorporated to employ the redundantDOF and generate human like motion. The desired level of compliance can betuned by selecting the stiffness and damping parameters in the sliding modevariable (compliance reference model). The results show that the compliantcontrol is feasible at different levels for BERT II in simulation andexperiment. The positioning control has been satisfactorily achieved andnonlinearities and un-modelled dynamics have been successfully overcome.