Ichiro Kawabuchi

Pinching at Fingertips for Humanoid Robot Hand

It is difficult to generate the action of stably pinching paper or needle, etc. with the finger tips, which is one of the important functions to be realized by humanoid robot hands. In this paper, therefore, the authors firstly propose a small-sized and light-weight robotic hand designed according to the concept of extracting required minimum motor functions and implementing them to the robot, and secondly propose a new robot hand capable of properly realizing a pinching motion with finger tips, by adding the minimum required degree of supplementary freedom which can be realized only with a machine. In the new robot hand, the authors mainly focus on additions of the degrees of freedom of independent motion to the terminal fingers and the degree of freedom of twisting motion to the thumb. Experiments were carried out to investigate force control characteristics of the finger tip joint. The results showed that providing the finger tip with rich force control performance even with weak force is effective for securing delicate control characteristics in a humanoid robot hand. Key words— humanoid robot hand, pinching and grasping, addition of degree of freedom to finger tip, twisting mechanism of

Stable pinching with fingertips in humanoid robot hand

It is difficult to generate the action of stably pinching paper or needle, etc. with the finger tips, which is one of the important functions to be realized by humanoid robot hands. In this paper, therefore, the authors firstly propose a small-sized and light-weight robotic hand designed according to the concept of extracting required minimum motor functions and implementing them to the robot, and secondly propose a new robot hand capable of properly realizing a pinching motion with finger tips, by adding the minimum required degree of supplementary freedom which can be realized only with a machine. In the new robot hand, the authors mainly focus on additions of the degrees of freedom of independent motion to the terminal fingers and the degree of freedom of twisting motion to the thumb. Experiments were carried out to investigate force control characteristics of the finger tip joint. The results showed that providing the finger tip with rich force control performance even with weak force is effective for securing delicate control characteristics in a humanoid robot hand.

Development and Control of a High Maneuverability Wheeled Robot with Variable-Structure Functionality

Common wheeled robots face many difficulties when traveling in complex environments, especially its incapability to climb over obstacles higher than its wheel radius. Many alterations were made to these robots to allow them to travel in rough terrains or conquer high obstacles, nevertheless, most designs are complex in nature and lost several original wheeled robot advantages by gaining others. In this paper, we propose a novel wheeled type robot with variable structure functionality. It is designed with simple structure consisting of three main robot parts, the main body, the left and right wheel-arm units. The robot could achieve five locomotion modes that allows the robot to travel in various environments and climb over high obstacles. Moreover, the fast-speed advantage in flat floor condition that common wheeled robot originally hold is still remained. The confirmation of the effectiveness of the robots maneuverability is shown by several experimental results

Mechanism of Humanoid Robot Arm with 7 DOFs Having Pneumatic Actuators

Pneumatic pressure, which is easy enough to be handled in comparison with hydraulic pressure and is endowed with high safety, is available for a power source of a robot arm to be utilized in concert with human beings to do various types of work. But pneumatic pressure is so low in comparison with hydraulic pressure that an air cylinder having a diameter long enough and stroke wide enough is required to obtain great output power. In this study, therefore, the investigation was made with layout of air cylinders and transmission mechanisms of the motion power directed toward the driving joints to be followed by development of a new humanoid robot arm with seven degrees of freedom in which air cylinders are compactly incorporated. To be concrete with this, contrivance was made with an endoskeleton structure allowing almost all of the structure materials of the individual arm joints to be shared by the air cylinder with incorporation of the air cylinder in the axes of the upper arm joint and forearm joints by paying attention to the fact that the cylinder itself has high strength. The evaluation experiments driving the robot arm referred to above were conducted by means of I-PD control. The results suggested that the mechanism of the robot with seven degrees of freedom having pneumatic actuators proposed in this study is useful as the humanoid robot arm. The quick and accurate motions were accomplished with I-PD control which is relatively easy to be dealt with but not suitable for non-linear actuator system.

Double-layer slider-crank mechanism to generate pulling or pushing sensation without an external ground

When a small object in a hand-held device moves periodically and prismatically with asymmetric acceleration (strong in one direction and weak in the other), the holder typically experiences the kinesthetic illusion of being pushed or pulled continuously by the held device. We investigated this perceptual effect for its potential application to a hand-held, non-grounded, haptic device that can convey a sense of a continuous translational force in one direction, which is a yet missing tile in haptics research. A one-degree of freedom haptic device based on two symmetric slider-crank mechanism was constructed to convert the single-speed rotational cyclic movement of a motor into asymmetric translational cyclic movement with asymmetric acceleration and to cancel unwanted side acceleration. We verified our previous results with the haptic device and investigated the effect of the gross weight of the device on force perception.

Dexterous robot hand with pinching function at fingertips

Delicate actions such as picking up paper or a needle with the fingertips an important function for robot hands - are extremely difficult. We propose a lightweight robot hand based on extracting minimum required motor functions and implementing them in a robot. We also propose a robot hand that realizes appropriate pinching by adding the minimum required degree of supplementary freedom realizable only mechanically. In the robot hand, we focus mainly on adding degrees of freedom for independent finger motion to the terminal joints and a degree of freedom for twisting by the thumb. The results showed that providing the fingertip with a joint with broad force control even with weak force effectively ensures delicate fingertip control in a humanoid robot hand

A humanoid robotic hand performing the sign language motions

In this paper, studies have been made in five for the purpose of realization of the robot hand that is capable of conveying feelings and sensitivities by finger movement. First, a small-sized and light-weight robot hand was developed to be used as the humanoid according to the concept of extracting required minimum motor functions and mounting them to the robot. Second, basic characteristics of movements were checked by experiments, simple feedforward control mechanism was designed based on speed control, and a system capable of tracking joint time-series change command with arbitrary shape was realized. Third, tracking performances with regard to sinusoidal input with different frequencies were studied for evaluation of the system thus realized, and space- and time-related accuracy were investigated. Fourth, finger character movements by signal language were generated as examples of information transmission by finger movements. A series of results thus obtained indicated that this robot hand is capable of transmitting information promptly with comparatively high accuracy through movements. Finally, the remote control was enabled through data glove with regressive model obtained by the singular value decomposition.

Pinching at finger tips by humanoid robot hand

It is difficult to generate the action of stably pinching paper or needle, etc. with the finger tips, which is one of the important functions to be realized by humanoid robot hands. In this paper, therefore, the authors firstly propose a small-sized and light-weight robotic hand designed according to the concept of extracting required minimum motor functions and implementing them to the robot, and secondly propose a new robot hand capable of properly realizing a pinching motion with finger tips, by adding the minimum required degree of supplementary freedom which can be realized only with a machine. In the new robot hand, the authors mainly focus on additions of the degrees of freedom of independent motion to the terminal fingers and the degree of freedom of twisting motion to the thumb. Experiments were carried out to investigate force control characteristics of the finger tip joint. The results showed that providing the finger tip with rich force control performance even with weak force is effective for securing delicate control characteristics in a humanoid robot hand.

TORSO: completion of egocentric telegnosis system

We have proposed a system that can acquire natural and comfortable visual information and can accurately track the head motion of the person. The conventional imaging device for head-mounted display was only able to express the 3-axis rotation of the neck but our device has expressed the head motion as well as the translation motion of the neck.

Control of generated force and stiffness in pneumatic air cylinder actuator

The authors developed an automatic choke valve where the unidirectional valve is arranged as bypassing so that the air of the high pressure will flow into the air cylinder and the piston can move at high velocity, and where the valve is automatically choked to decrease each flow so that a passive stiffness by spring effect or damping effect of the internal air is obtained. Then, we carried out experiments for evaluation of the system, using a humanoid robot arm with 7 degrees of freedom as double-acting air cylinder actuators with automatic choke valves and with I-PD control. The experimental results showed that an overshoot was approximately ten percents against the target angle but the joint was controlled with an error under one degree about follow-up to the target angle and with a time constant less than one second, even when five joints were simultaneously controlled under the influence of their respective motions