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Teaching robots object manipulation skills is a complex task that involves multimodal perception and knowledge about processing the sensor data. In this paper, we show a concept for humanoid robots in household environments with a variety of related objects and actions. Following the paradigms of Programming by Demonstration (PbD), we provide a flexible approach that enables a robot to adaptively...
In this paper, we propose a novel way of constructing a humanoid robot interface by embedding a low-dimensional command space into observed high-dimensional joint angle action space. It is almost impossible for users to independently and simultaneously control all the joints of a humanoid robot. On the other hand, for a given target task, not all the degrees of freedom (DOFs) of the robot may necessarily...
We address the problem of robustly tracking a desired workspace trajectory with a humanoid robot. The proposed solution is based on the suitable definition of a controlled output, which represents an averaged motion of the torso after cancellation of the sway oscillation. In particular, two different techniques are presented for extracting the averaged motion. For control design purposes, a unicycle-like...
Generating diverse behaviors with a humanoid robot requires a mix of human supervision and automatic control. Ideally, the user's input is restricted to high-level instruction and guidance, and the controller is intelligent enough to accomplish the tasks autonomously. Here we describe an integrated system that achieves this goal. The automatic controller is based on real-time model-predictive control...
This paper presents a method for reactive walking allowing visual servoing and adaptation of footsteps trajectories in real-time. This is done by building upon recent advances in the fields of optimal control for a walking pattern generator [1] and planning for a nonholomic robot with field-of-view constraints [2]. Herdt et al. [1] provided a controller where a humanoid robot is driven by its Center-of-Mass...
In this research, an approach to implement a collaborative task between a humanoid robot (Hubo) and a human is presented. Velocity control using motion data generated from a motion capture system (MoCap) is used to control Hubo's lower body movement. The difference in moving direction and speed between the robot and a worker produced a step distance and turning angle of subsequent steps. For upper...
Direct transfer of human motion trajectories to humanoid robots does not result in dynamically stable robot movements due to the differences in human and humanoid robot kinematics and dynamics. We developed a system that converts human movements captured by a low-cost RGB-D camera into dynamically stable humanoid movements. The transfer of human movements occurs in real-time. As need arises, the developed...
This paper studies the use of Cooperative Dual-Task Space (CDTS) as an efficient approach for the whole-body motion balancing problem for humanoid robots. The CDTS variables have been used efficiently to describe and control coordinated motions of dual-arms. Similarly, the concept of CDTS variables can be extended to describe the constraints and the control of humanoid legs. When the leg motion is...
Bipedal humanoid robots will fall under unforeseen perturbations without active stabilization. Humans use dynamic full body behaviors in response to perturbations, and recent bipedal robot controllers for balancing are based upon human biomechanical responses. However these controllers rely on simplified physical models and accurate state information, making them less effective on physical robots...
We develop fast reinforcement learning (RL) framework using the approximated dynamics of a humanoid robot. Although RL is a useful non-linear optimizer, applying it to real robotic systems is usually difficult due to the large number of iterations required to acquire suitable policies. In this study, we approximate the dynamics using data from a real robot with sparse pseudo-input Gaussian processes...
Humanoid robots should be capable of adjusting their walking speed and walking direction. Due to the huge design space of the controller, it is very difficult to control the balance of humanoids walk. The position of the Zero Moment Point (ZMP) is widely used for dynamic stability measurement in biped locomotion. The reference trajectory of the Center of Mass (CoM) of a humanoid can be computed from...
This paper presents our progress toward a user-guided manipulation framework for High Degree-of-Freedom robots operating in environments with limited communication. The system we propose consists of three components: (1) a user-guided perception interface which assists the user to provide task level commands to the robot, (2) planning algorithms that autonomously generate robot motion while obeying...
We address in this paper a hierarchical framework for planning and simulating dynamic motions of humanoid robots in cluttered environments. The robot is aimed to realize a dynamic multi-step motion via a series of support (contact or grasp) configurations. In this framework, a global CoM (Center of Mass) trajectory is firstly generated which ensures the balance during the motion; the whole-body collision-free...
Adapting human motion data for humanoid robots can be an efficient way to let them conduct specific tasks or perform visually intriguing movements. However adapting movements which involve close interactions between body parts / objects has been a difficult problem if we try to make the motions sufficiently similar to the original ones without causing undesired collisions and fall-overs. To solve...
This paper tries to improve a balance control based on the Capture Point (CP) control. First the characteristics of the conventional balance controller are shown to be essentially the same as the CP controller. Then we analyze the transfer function of the balance controller. We introduce a new state variable with the CP integration to the CP and the ZMP (Zero-Moment Point) in order to trim a long...
Manipulation tasks are characterized by continuous motion trajectories containing a set of key phases. In this paper, we propose a probabilistic method to autonomously segment the motion trajectories for estimating the key phases embedded in such a task. The autonomous segmentation process relies on principal component analysis to adaptively project into one of the low-dimensional subspaces, in which...
Planning collision-free, dynamically-balanced movements for humanoid robots is a challenging problem. An effective approach consists of first planning a motion satisfying geometric and kinematic constraints (such as collision avoidance, joint angle limits, velocity limits, etc.) and, in a second stage, modifying this motion so that it respects dynamic balance criteria, such as those relative to the...
This paper describes a method of whole body motion pattern generation for biped humanoid robots. The walking pattern is generated on the basis of preview control and compensatory motion control. It enables the robot to walk with arm swings. According to the waist motion, hand motion, and foot motion, the angles of the whole body are calculated by inverse kinematics. In order to verify the effectiveness...
This paper proposes the analysis of two strategies for motion imitation of articulated systems with balance constraint. The two systems have different dynamic characteristics and their respective motions are restricted to the sagittal plane. The first strategy is based on nonlinear time scaling of joint trajectories ensuring that the balance of the imitating system is maintained through the motion...
Manipulation of structured objects connected to the environment by a kinematics chain involves two problems: (a) The objects have movable directions and unmovable directions. An undesired reaction force in the unmovable directions prevents a robot from successful manipulation; (b) The reaction forces from the objects could fluctuate during manipulation. Related works have enabled robots to manipulate...
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