Yuki Yokokura

Stability Analysis and Experimental Validation of a Motion-Copying System

This paper examines the stability of our proposed motion-copying system in the case that the environmental mechanical impedance is changed. The system preserves and reproduces the motion of the human operator. The examination of this paper derives the transfer function of the motion-loading system considering the environmental impedance and investigates displacement of the poles with the transition of the environment. Moreover, the experiment with respect to environmental changing is carried out. These results confirm theoretically and experimentally that the motion-copying system is stable even if the environment is changed. The haptic informational processing technique by the motion-copying system is useful for industrial applications and medical engineering.

Motion copying system based on real-world haptics

Recently, motion copying technologies are important elements in order to succeed production engineering of expert engineers. The paper proposes a novel motion copying system. The motion copying system consists of a motion saving system and motion loading system. The motion saving system saves motion of human operator by bilateral controller using a quarry matrix. On the contrary, the motion loading system is realized by virtual-world master system and real-world slave system. The motion loading system operates according to saved position and force information, and reproduces saved motion. The proposed method realizes that the reproduced position and force corresponds to saved position and force data. The paper confirms that the motion saving system and motion loading system normally operates. The motion copying system achieves copy of motion of human operator.

FPGA-Based High-Performance Force Control System With Friction-Free and Noise-Free Force Observation

In this paper, a novel force-sensing method is proposed for a high-performance force control system based on friction-free and noise-free force observation. A periodic signal is inserted into the control system for friction reduction. A combination of a high-order disturbance observer (DOB) (HDOB) and a Kalman filter is constructed to perform the force sensing. The HDOB is designed to estimate the force and reject oscillatory disturbances in the estimation. The force-sensing bandwidth is improved through effective noise suppression by the Kalman filter. Additionally, this paper proposes the application of the HDOB to the bilateral control system of a different master-slave mechanism. All the control algorithms are implemented in a field-programmable gate array with a high sampling rate that also enables the widening of the bandwidth of the force control system. The effectiveness of the proposed method is verified by experimental results.

Bilateral teleoperation with dimensional scaling for realization of mobile-hapto

Multimedia technology has been widely spread as the basis for human communications. For example, telephone, television and radio broadcasting are good tools for remote communication. Recently, communication tools such as the portable telephone and Internet spread all over the world. These devices substitute humans eyes and ears. Haptic information has paid attention as the third multimedia information. Especially a transmission technique of real-world haptic information is demanded. This paper proposes a novel haptic transmission in different motion area, named ldquomobile-haptordquo. The ldquomobilehaptordquo consists of a mobile robot and a joystick. A mobile robot has infinite area for its motion. On the contrary, a joystick is fixed for operation by a human. To transmit haptic information in the ldquomobile-haptordquo, bilateral control with dimension scaling is proposed. As a result, intuitive manipulation becomes possible by using the ldquomobile-haptordquo. Effectiveness of the proposed method is verified by experimental results.

Environment copying system based on real-world haptics

This paper proposes environment copying system, which stores and reproduces haptic information in the real-world. The proposed system consists of environment saving system and environment loading system. The environment saving system stores haptic information of the environment to a environment data memory. On the other hand, the environment loading system reproduces the environmental haptic sensation using the environment data memory, and stimulates the human operator. The environment copying system proposed in this paper realizes storage and reproduction of real world haptic information without environmental mathematical model. By the experiments, the validity of the proposed method is confirmed. It will be useful for industrial applications, medical and welfare human support.

Motion copying system based on real-world haptics in variable speed

The paper proposes a novel motion copying system considering variable reproduction velocity. The motion copying system consists of motion saving system and a motion loading system. The motion saving system preserves a motion of a human operator to a motion data memory. The motion loading system operates according to saved position and force in the motion data memory, and reproduces saved motion. The reproduced position and force corresponds to stored position and force. The proposed motion copying system in this paper is able to vary the reproduction velocity. By the experiment, the paper confirmed that a reproduction velocity can be freely changed, when the motion loading system reproduces motion.

Adaptive motion-copying system based on real-world haptics

This paper proposes adaptive motion-copying system, which is capable of storage and reproduction of human motion. In the conventional method, force and position are not reproduced accurately, when the environment in the reproduction phase is different from the environment in the storage phase. To solve this problem, the proposed method reproduces the human motion according to search results provided by environmental search algorithm. Therefore, the force and position corresponding to the stored motion is able to be reproduced even if the environment is changed. By the experiment, validity of the proposed method is verified.

Real-World Haptics: Reproduction of Human Motion

In recent years, communication technologies have grown rapidly and from the communication point of view, real-world haptics is the key technology for future haptic technology. Consequently, this article focuses on the storage and reproduction methods for haptic information in the real world. The bilateral connection of haptic systems with force feedback ability makes telecommunication among remote human operators possible. This article shows a motion-copying system (MCS) as a spatiotemporal coupler of real-world haptic information. As with sound and visual information, an MCS is capable of storing and reproducing raw force and position information of human operator. Once human motion is stored using MCS, it is possible to reproduce it at any time and place. This will be useful for the digital preservation of motions by skilled experts as a haptic database.

Fine Force Reproduction Based on Motion-Copying System Using Acceleration Observer

This paper proposes a new motion-copying system that is capable of preserving and reproducing the motion of human operators. In conventional motion-copying systems, when the operator moves quickly, the reproduced force does not correspond to the stored force, owing to the large accelerations. Therefore, the motion-copying system proposed in this paper uses acceleration responses provided by acceleration observers, so the force is reproduced more accurately. The acceleration observer is based on a disturbance observer; it estimates the acceleration of an actuator without acceleration sensors. Furthermore, the estimation performance is not affected by the mechanical impedance of the target environment. In this article, the proposed motion-copying system is compared with current methods, and the validity of the method is demonstrated.

Bilateral control with communication time delay by using motion copying system

In order to realize communication and broadcasting of haptic information, bilateral control with communication time delay is important element. The paper proposes a novel bilateral control method for communication time delay. To compensate the effect of communication time delay, the proposed method applies a motion copying system. The motion copying system is able to save and reproduce motion of human operator. The reproduced position and force by the motion copying system corresponds to saved position and force. The motion copying system copies local motion to other side, in order to realize compensation of communication time delay. The paper confirms that the communication time delay compensation using the motion copying system normally operates. The viability of the proposed method is confirmed by experiments.