19 accepted papers
In this paper, we propose the multi-contact locomotion planning framework for humanoid robots that leverages the target contact selection considering its long-term preferability by reinforcement learning (RL) in optimization-based motion generation with feasibility constraints. It is difficult to pr
Manipulation with whole-body contact by humanoid robots offers distinct advantages, including enhanced stability and reduced load. On the other hand, we need to address challenges such as the increased computational cost of motion generation and the difficulty of measuring broad-area contact. We the
Direct Visual Servoing (DVS) is a technique that controls the robot motion by using the pixel intensities captured by a camera. DVS demonstrates high accuracy at convergence, prompting the development of various methods aimed at expanding its convergence domain.In this paper, we propose a mathematic…
To enable humanoid robots to work robustly in confined environments, multi-contact motion that makes contacts not only at extremities, such as hands and feet, but also at intermediate areas of the limbs, such as knees and elbows, is essential. We develop a method to realize such whole-body multi-con
Multi-contact motion is important for humanoid robots to work in various environments. We propose a centroidal online trajectory generation and stabilization control for humanoid dynamic multi-contact motion. The proposed method features the drastic reduction of the computational cost by using previ
In this paper, we propose a trajectory planning framework for a robot that exploits a pre-computed database of end-effector trajectories as the guidance of optimization-based inverse kinematics. We constructed a reachable graph of a robot offline, which represents feasible end-effector paths with co…
In this letter, we propose an efficient and highly versatile loco-manipulation planning for humanoid robots. Loco-manipulation planning is a key technological brick enabling humanoid robots to autonomously perform object transportation by manipulating them. We formulate planning of the alternation a
In order for a humanoid robot to perform loco-manipulation such as moving an object while walking, it is necessary to account for sustained or alternating external forces other than ground-feet reaction, resulting from humanoid-object contact interactions. In this letter, we propose a bipedal contro
In this letter, we propose a multi-contact locomotion planning framework for a humanoid robot to traverse complex environments utilizing bilateral contact forces with reasonable computational time. We hypothesize that a bilateral contact can be approximated by a pair of surface contacts, and expand
In this paper we report the safety-oriented framework for controlling the torque in the case of robots with high reduction gears and having no joint torque feedback. This kind of robots suffer from high joint friction and low backdrivability, requiring high gains and integral feedback, which can be…
In this letter, we present an observation scheme, with proven Lyapunov stability, for estimating a humanoid's floating base orientation. The idea is to use velocity aided attitude estimation, which requires to know the velocity of the system. This velocity can be obtained by taking into account the
In this letter, we propose a graph-search based multi-contact locomotion planning method for humanoid robots, focusing on the sustainability of contacts as its key feature. We introduce the idea of sustainable contact area, which represents the area on which contacts can be maintained during contact
The simulation of static friction, and especially the effect of stiction, is cumbersome to perform in discrete-time due to its discontinuity at zero velocity and its switching behavior. However, it is essential to achieve reliable simulations of friction to develop compliant torque control algorithm…
This letter introduces the humanoid robot HRP-5P, which stands for Humanoid Robotics Platform-5 Prototype. We have been developing the HRP series humanoid robots since 2000, and HRP-5P is the latest version of the HRP series as of 2018. It is developed as a prototype for our next generation humanoid
This paper focuses on a stabilization control for multi-contact motion which enables a humanoid robot to locomote by realizing dynamic contact transitions on non-flat environment. In the stabilization process of the multi-contact motion, the desired Zero-Moment Point (ZMP) is modified by the positio…
The dynamics of a humanoid robot cannot be correctly described independently from the external forces acting on it. These forces have to be reconstructed to enable the robot to control them or to compensate for them. Force sensors are usually used to measure these forces, but because of their cost,…
In order to accurately reach a target position while executing a task which imposes occlusion or constraints of the posture, a humanoid robot requires an adaptive locomotion system, which can comprehensively integrate localization, environmental mapping, global locomotion planning and local error co…
We propose a control framework for torque controlled humanoid robots that efficiently minimizes the tracking error in a Quadratic Programming (QP)formulated as multiobjective weighted tasks with constraints. It results in an optimal dynamically-feasible reference that can be tracked robustly, with e…
This paper presents the method to retarget human motion. The method can evaluate the ability of the preservation of the original characteristics of human motion data. It enables to compute the joint trajectories of the human corresponding with the retargeted ones of the robot at the same time, by ut…