The Rh-1 full-size humanoid robot: Design, walking pattern generation and control

摘要

This paper is an overview of the humanoid robot Rh-1, the second phase of the Rh project, which was launched by the RoboticsLab at the Carlos III University of Madrid in 2002. The robot mechanical design includes the specifications development inorder to construct a platform, which is capable of stable biped walking. At first, the robots' weights were calculated in orderto obtain the inverse dynamics and to select the actuators. After that, mechanical specifications were introduced in order toverify the robot's structural behaviour with different experimental gaits. In addition, an important aspect is the joints designwhen their axes are crossed, which is called 'Joints of Rectangular Axes' (JRA). The problem with these joints is obtainingtwo or more degrees of freedom (DOF) in small space. The construction of a humanoid robot also includes the design ofhardware and software architectures. The main advantage of the proposed hardware and software architectures is the useof standardised solutions frequently used in the automation industry and commercially available hardware components. Itprovides scalability, modularity and application of standardised interfaces and brings the design of the complex controlsystem of the humanoid robot out of a closed laboratory to industry. Stable walking is the most essential ability for thehumanoid robot. The three dimensional Linear Inverted Pendulum Model (3D-LIPM) and the Cart-table models had beenused in order to achieve natural and dynamic biped walking. Humanoid dynamics is widely simplified by concentratingits mass in the centre of gravity (COG) and moving it following the natural inverted pendulum laws (3D-LIPM) or bycontrolling the cart motion (Cart-table model). An offline-calculated motion pattern does not guarantee the walking stabilityof the humanoid robot. Control architecture for the dynamic humanoid robot walking was developed, which is able to makeonline modifications of the motion patterns in order to adjust it to the continuously changing environment. Experimentalresults concerning biped locomotion of the Rh-1 humanoid robot are presented and discussed.