Robots with high Degrees of Freedom (DoF) such as humanoids and mobile manipulators are expected to perform multiple tasks simultaneously. Hierarchical Quadratic Programming (HQP) can effectively compute a solution for strictly prioritized tasks. However, the continuity of control input is not guaranteed when the priorities of the tasks are modified during operation. This paper proposes a continuous task transition method for HQP based controller to insert, remove, and swap arbitrary tasks without discontinuity. Smooth task transition is assured because our approach uses activation parameters of the new and existing tasks without modifying control structure.The proposed approach is applied to various task transition scenarios including joint limit, singularity, and obstacle avoidance to guarantee the stable execution of the robot. The proposed control scheme was implemented on a 7-DoF robotic arm, and its performance was demonstrated by the continuity of control input during various task transition scenarios.

Whole-body manipulation for a non-holonomic mobile manipulator has potential in various fields including service and industrial robotics because it can provide a great deal of manipulation capability and mobility. This paper presents the whole-body controller of the non-holonomic mobile manipulator for achieving complex tasks effectively. The proposed controller is designed based on Hierarchical Quadratic Programming (HQP). Thus, the controller can deal with both equality and inequality tasks. Moreover, by applying the continuous task transition strategy, our controller can compute the continuous control input when the priorities of the tasks are changed. The proposed control scheme was implemented on a mobile base with a 7 DoFs robotic arm and its performance was validated during various experimental scenarios.

Reactivity to unforeseen disturbances is one of the most crucial characteristics for biped robots to walk robustly in the real world. Nevertheless, conventional walking methods generally have limited capability for generating rapid reactions to disturbances, because in these methods it is necessary to wait until the end of the preplanned time period to proceed to the next phase. In this study, to improve reactivity, we develop an event-based finite-state machine (E-FSM) for walking pattern generation. Reactivity is enhanced by determining the state transition conditions of the E-FSM only with time-independent events based on the present robot state. Moreover, in the E-FSM, the robot can walk robustly even when the center of mass and the swing foot motion are disturbed, by employing the capture point concept combined with a new swing foot position constraint. Finally, we propose to control the walking robot by incorporating the E-FSM with an inverse dynamics-based motion/force controller to achieve compliant behavior. This can provide safe responses to external disturbances. The developed method is verified by experiments on a 12-degrees-of-freedom torque-controlled biped robot while it locomotes under irregular external disturbances applied to the upper body or swing leg.

This paper presents a new full sized humanoid leg robot that combines aesthetics and design theory with practical research goals in robotics. The research goal of the robot is to create human-like and compliant motion in multiple contact situations through the use of torque controlled joints. Low gear ratio and direct connections are used at each joint for low-friction and back-drivability but without explicit joint torque sensors. On the other hand, in creating human-like motions, not only technical specifications but also aesthetic design is important as the same performance of the robot can be perceived very differently depending on the design. The aesthetic design is, in this paper, achieved by the robot design process using an integrated design and frame through multi-axis CNC machining. The unique integration of the frame and design also drastically reduces parts and complexity of assembly for easy maintenance. In this paper, the design process and features are presented with range of motion, weight, and key aesthetic decisions. Compliant motion capability is demonstrated by experimental results.