Yuichi Murase

Developing a service robot with communication abilities

A service robot designed to be of practical use in offices and commercial environments has been developed. The robot features 4-degree-of-freedom arms, grippers, a pan-tilt mechanism with eight cameras, and three microphones to recognize speech and the direction of a sound source. It moves itself around on wheels. The robot can be operated by, and communicates with, a natural voice that is synthesized using the prosody of a natural voice. The CPU, DSP, vision board, and local processors communicate with each other through an embedded LAN. This paper describes the hardware features, applications, communications, and self-charging capabilities that together realize the practicality of this robot.

Humanoid robot simulator for the METI HRP Project

A simulator of humanoid robots and a controller of their whole body motions in METI’s Humanoid Robotics Project are developed. The simulator can emulate the dynamics of the motions of the robots whose structure may vary, and generate a sequence of the fields of view from the eyes of the robot according to the motions. The structure-varying system is managed by introducing virtual links. The controller can handle a biped locomotion, a dynamic balance control at the standing position and collision avoidance motions for the robots. These software modules are integrated via CORBA, which enables the Internet clients to use the software. A humanoid robot testbed has also been developed to verify the accuracy of the simulation by experiments in the real world. We call the system Virtual Humanoid Robot Platform , which we expect is the virtual counterpart of the hardware robot platform for humanoid robotics.

Developing a service robot

A service robot designed to be of practical use in offices and commercial environments has been developed. Moving on wheels, with a pair of four-degrees-of-freedom (DOF) arms and grippers, and a pan-tilt mechanism carrying eight cameras, the robot is designed to operate efficiently in public spaces. The robot houses a CPU board, two DSP boards, a vision board, and local processors, which form an internal LAN and communicate with each other. This paper presents the hardware features of the robot, outlines its typical applications and introduces its 3D vision-based navigation system, which is central to the execution of its tasks.

Immediately-available Input Method Using One-handed Motion in Arbitrary Postures

Abstract This paper presents an input method, which enables the user to immediately interact with services using one-handed motion in arbitrary postures. This method is mainly targeted at workers who work with dirty hands or hold tools in their hands. To allow the workers to control applications as intended without handheld devices while they operate their hand work in various postures, we propose intentional segmentation, motion trajectory estimation of the wrist, and three types of inputs using wrist motions. The segmentation controller enables users to intentionally distinguish input motion from normal hand work by the wrist state without limiting the range of upper limb motion and immediately start performing the input motion. We estimate the motion trajectories of the wrist in the input segment using inertial sensors attached to the wrist, and recognize gestures from the trajectories without training data sets. The users can control various applications by three types of inputs: continuous inputs linked to the wrist motions, discrete inputs by gestures, and specific inputs generated from these. We also developed a wristwatch-like wearable device to evaluate the effectiveness of the proposed method. Through the two experimental evaluations, we showed the ease of learning the proposed method and achieved a mean recognition rate of 94.3% in various postures for six defined gestures.

Calibration of a rotating 2D LRF in unprepared environments by minimizing redundant measurement errors

This paper proposes a calibration method for a 3D laser scanning system built with a rotating 2D laser rangefinder (LRF) in unprepared environments. Although the combination of a 2D LRF with a rotating unit yields a low-cost and compact 3D scanner, construction misalignments must be calibrated to reduce measurement error. Existing calibration techniques are generally used either with a special target object or in prepared environments with flat surfaces, and this imposes a limitation on the applicable domain of the system. To solve this problem, we propose a novel calibration method using redundant measurements of 3D point clouds. The main idea of the proposed method is to focus on the fact that rotating LRF systems observe the same object twice during a single rotation at different times. Therefore, by minimizing the extent of misalignment of these redundant measurements, we can estimate the calibration parameters without using any special target object. We formulate this calibration by redundant measurements as a non-linear cost minimization problem. The results of the simulation and real-world experiments in challenging, real environments show that the proposed method works well in unprepared and even cluttered environments.

Power assist method for a nonholonomic mobile robot using both ZMP criterion and impedance control

In this paper, we describe a power assist method for a nonholonomic mobile robot designed to carry out office-oriented services. We developed a new mechanism for obtaining an approximate measurement of the zero moment point (ZMP) using three single-axis force sensors so that a robot pushed from any direction by a human can detect the direction and magnitude of the external force. We also propose impedance control to generate translational and rotational motion in accordance with ZMP displacement. This control method achieves a function whereby a robot that has been given an external force from a direction differing from its translation direction will follow the direction of the external force while rotating. The robot can also return automatically to its initial pose once the external force has been released. We show though experiments that our power assist method is effective in improving the operability and usability of an office-oriented robot.