Modeling Friction for a Snake-Like Robot

An elliptical model for anisotropic friction, taken from solid mechanics, is incorporated into the field of simulating and modeling snakes and snake-like robots for the first time. This model avoids the theoretical and empirical pitfalls the decoupled model previously used in the field encountered. Simulations show that the elliptical friction model better mimics qualitative aspects of snake and snakebot motion, i.e., motion smoothness and the tracing of the same path by all parts of the snake. Further, it is also shown that the elliptical model requires less computational effort than the decoupled model.     

Impact Analysis of a Dual-Crawler-Driven Robot

This paper presents the impact analysis of a new dual-crawler-driven robot. This dual-crawler-driven robot is realized by connecting rigidly two crawler modules. In this newly proposed crawler module, a planetary gear reducer is deployed as the power transmission device to give two different outputs with just one actuator. Compared with the crawler driven by two actuators, our crawler module driven by one actuator could show good impact absorption when the robot collides with an obstacle due to the fact that there exists an output redundancy in each module. To determine what the advantage of our mechanism to the impact absorption is, impact analysis of the robot is conducted from the external components of the robot to its internal transmission parts while the robot encounters a collision with obstacles. The results of impact effect to the actuators in our mechanism are correspondingly derived in comparison with that in the conventional mechanism where each output is provided by one actuator. Numerical results are used to demonstrate the advantage of our mechanism on impact absorption.     

Development of a Hybrid Wheel-Legged Mobile Robot WR-3 Designed for the Behavior Analysis of Rats

This paper presents the design and development of a bio-inspired mobile robot called WR-3 (Waseda Rat no. 3). The purpose of the robot is to work as an experimental tool to study social interaction between rats and robots. According to the results of the analysis of the motion of rats, their behavior can be divided into two phases: movement and interaction. Therefore, a novel hybrid mechanism that uses wheels during the movement phase and legs while interacting has been designed to actuate WR-3. Consequently, the robot can move at a high speed using its wheels, and reproduce the rat's interaction behavior using its legs and other parts. Based on body structure of a mature rat, WR-3 has been designed with similar dimensions and shape as a mature rat, and the quality of the shape imitation has been verified by the experiments of a rat's interestingness to the robot and stuffed rat. Evaluation experiments show that WR-3 is capable of reproducing a rat's actions such as chasing, rearing, grooming, mounting, etc., similar to a real rat. Furthermore, preliminary social interaction tests with living rats reveal that WR-3 is to some extent able to evoke natural reactions form a real rat and is therefore able to perform a certain level of realistic interaction.     

Inverse Dynamics Analysis of a 4-d.o.f. Parallel Robot H4

This paper addresses the inverse dynamics of a 4-d.o.f. parallel robot, H4. Simplified inverse dynamics models have been proposed so far in which the inertia of a rod is neglected. Computation of the inertia of the rod was a heavy load for past computers and, hence, the simplified inverse dynamics were useful for online computation. However, owing to the recent great progress in computer hardware, online computation of the full dynamics is no longer a heavy load for modern computers. Therefore, a detailed inverse dynamics model of H4 is proposed in this paper. The Newton–Euler method is adopted for generating inverse dynamics solutions for H4 which have four (S–S)₂ (two spherical–spherical) chains in each rod. In order to evaluate the proposed inverse dynamics model, three controllers are tested: (i) PD controller, (ii) PD controller with velocity feed-forward and (iii) dynamic compensation controller based on the proposed dynamics model. The experimental results are presented and analyzed. It is also shown that the simplified dynamics model can be used without clear deterioration of control quality.     

A Modular Platform for In-plane Ground Reaction Forces Detection in a Mouse Model: Design,Development and Verification

Movement and behavior analysis is a key research area in the domain of biomedical engineering and in many other medical research domains aiming at the understanding of physiological motor and cognitive basic mechanisms. The systematic application of robotic and mechatronic technologies to realize new tools and measurement methods for quantitatively assessing motor and cognitive functions in humans, as well as in animal models is gaining increasing popularity. This work represents a first step towards the development of a sensorized environment for behavioral phenotyping of animal models. In particular, this paper focuses on tremor analysis in Reeler mice, an emerging potential animal model for anatomical and behavioral traits observed in autism. Ground reaction force (GRF) sensing is indeed the most direct means of measuring tremor. Although force platforms have extensively been used for large-size animals, only a few attempts have been made to measure GRFs at a single paw for animals as small as mice or rats. Under the hypothesis that in-plane GRF components are directly connected to tremor, a small-size, modular, mechanically simple, two-axis force sensor for measuring the in-plane components of GRFs was designed and developed. Special care was paid to design a structure that allowed self-aligned assembly, for repeatability and modularity for combining multiple platforms for a sensorized floor. Preliminary testing was performed with both Reeler and wild-type mice. Fourier analysis validated the hypothesis of a direct connection between tremor and in-plane GRFs. Data analyzed and filtered highlight a peculiar spectrum frequency in Reeler mice tremor, centered around 21 Hz. This tremor, which was never quantitatively observed and measured before, is completely absent in wild-type mice.     

Design and Development of an Emotional Interaction Robot,Mung

The purpose of this study is to develop an interactive and emotional robot that is designed with passive characteristics and a delicate interaction concept using the interaction response: 'Bruises and complexion color due to emotional stimuli'. In order to overcome the mismatch of cue realism issues that cause the Uncanny Valley, an emotional interaction robot, Mung, was developed with a simple design composed of a body and two eyes. Mung could recognize human emotions from human–robot or human–human verbal communications. The developed robot expresses its emotions according to its emotional state modeled by a mass-spring-damper system with an elastic-hysteresis spring. The robot displays a bruise when it is in a negative emotional state, the same as a human becomes bruised when being physically hurt, and the robot shows a natural complexion when its emotional wound is removed. The effectiveness of the emotional expression using color with the concepts of bruising and complexion colors is qualified, and the feasibility of the developed robot was tested in several exhibitions and field trials.     

Development of a Modular Crawler for Tracked Robots

This paper presents the design and experiments for a novel crawler module, in which a planetary gear reducer is employed as the transmission device and provides two outputs in different forms with only one actuator. This underactuated crawler can absorb impact energy that might be transmitted to the actuator when it moves in a rough environment. To enable the use of this crawler more widely in robot systems, a modular design for the crawler is, thus, proposed and its mechanical model is developed. Experiments demonstrate that a single-crawler module can effectively perform the proposed three locomotion modes.     

Development of a Novel Live-Line Inspection Robot System for Post Insulators at 220-kV Substations

Based on investigating existing on-line detection methods for energized ceramic post insulators, this paper proposes a new live-line work robot involving ultrasonic detection for flaws in porcelain post insulators at 220-kV high-voltage (HV) substations. Owing to the HV, strong electromagnetic field and space conditions, the robot would be a special one. Thus, on the basis of studying correlative technologies — mechanism design, visual alignment and location, HV insulation, electromagnetic compatibility, automatic control, and wireless communication — each part of the robot system is designed and analyzed. The experiment and trial operation results show that the designed robot can work normally in 220-kV substations, and cracks in porcelain post insulators can be detected effectively, safely and conveniently by the robot.     

家庭服务机器人的人脸检测、跟踪与识别研究

本文介绍了一个用于家庭服务机器人完成人脸检测、跟踪、识别的双目视觉系统。该系统首先采用人脸肤色模型结合相似度来检测人脸;然后通过基于颜色信息的CAMSHIFT算法跟踪运动的人脸;最后利用嵌入式隐马尔可夫模型对人脸进行识别。实验结果表明该系统能自动地检测、跟踪、识别人脸,而且该系统具有较良好的实时性和鲁棒性。     

Development of Biped Robot MARI-3 for Jumping

A biped robot, MARI-3, for jumping is developed, of which the ultimate objective is fast walking and running. Its mechanical structure including the joint configuration and specification, the knee joint, and the speed reduction mechanism are described in detail. A specific control system RON (RObot Network) for MARI-3 that is a serial and distributed network and consists of a microcontroller, host unit, servo units, sensor units and servo amplifiers is presented as well as the sensor system. With the developed biped robot MARI-3, one-leg jumping of 110 ms jumping time and 4.0 cm jumping height was implemented as initiative and verification experiments. Furthermore, by comparison of MARI-3 with other jumping or running robots, MARI-3's potential ability for fast walking, jumping and running becomes clear.     

Development of a Positioning Technique for an Urban Area Using Omnidirectional Infrared Camera and Aerial Survey Data

This paper describes an outdoor positioning system for vehicles that can be applied to an urban canyon by using an omnidirectional infrared (IR) camera and a digital surface model (DSM). By means of omnidirectional IR images, this system enables robust positioning in urban areas where satellite invisibility caused by buildings hampers high-precision GPS measurements. The omnidirectional IR camera can generate IR images with an elevation of 20–70° for the surrounding area of 360°. The image captured by the camera is highly robust to light disturbances in the outdoor environment. Through the IR camera, the sky appears distinctively dark; this enables easy detection of the border between the sky and the buildings captured in white due to the difference in the atmospheric transmittance rate between visible light and IR rays. The omnidirectional image, which includes several building profiles, is compared with building-restoration images produced by the corresponding DSM in order to determine the self-position. Field experiments in an urban area show that the proposed outdoor positioning method is valid and effective, even if high-rise buildings cause satellite blockage that affects GPS measurements.     

Construction of a Gait Adaptation Model in Human Split-Belt Treadmill Walking Using a Two-Dimensional Biped Robot

A number of studies have measured kinematics, dynamics and oxygen uptake while a person walks on a treadmill. In particular, during walking on a split-belt treadmill, in which the left and right belts have different speeds, remarkable differences in kinematics are observed between normal subjects and subjects with cerebellar disease. In order to construct a gait adaptation model of such human split-belt treadmill walking, we proposed a simple control model and developed a new two-dimensional biped robot walk on a split-belt treadmill. We combined the conventional limit-cycle-based control consisting of joint PD control, cyclic motion trajectory planning and a stepping reflex with a newly proposed adjustment of P-gain at the hip joint of the stance leg. The data obtained in experiments on the robot (normal subject model and cerebellum disease subject model) have highly similar ratios and patterns to data obtained in experiments on normal subjects and subjects with cerebellar disease carried out by Bastian et al. We also showed that the P-gain at the hip joint of the stance leg was the control parameter of adaptation for symmetric gaits in split-belt walking and that P-gain adjustment corresponded to muscle stiffness adjustment by the cerebellum. Consequently, we successfully proposed a gait adaptation model for human split-belt treadmill walking, and confirmed the validity of our hypotheses and the proposed model using the biped robot.     

Snake-Like Robot for Rescue Operations — Proposal of a Simple Adaptive Mechanism Designed for Ease of Use

Rescue operations are one of most effective applications for robots and various rescue robots operated by rescue staff have been developed. However, in large-scale disasters, there is a significant problem, i.e., a shortage of operators. In this paper, we consider this problem and propose a snake-like rescue robot which is designed for non-professional volunteer operators. To realize the rescue robot simply, we focus on mechanical design, and realize usability by utilizing properties of its body and the real world. Experiments have been carried out to demonstrate the effectiveness of the proposed robot.     

On the Design and Development of a Quadruped Robot Platform

In this paper, we describe the development of a quadruped robot named HuboDog. The objective of this project is to develop a reliable and robust quadruped robot platform that enables the implementation of stable and fast static/dynamic walking on even or uneven terrain, and walking while carrying a payload. A lightweight but highly rigid platform is achieved via a frame-type structure and double-supported beam-type joint design. A small, light but high output power joint actuator is designed with a harmonic reduction gear and electric motor that has high speed and a high output power. A distributed control system is used since it can reduce the computational burden of the main computer and easily extend the electrical components. Microprocessor-based subcontrollers are developed for motor control and sensor signal feedback. The main computer, which is mounted on the trunk, communicates with the subcontroller via the CAN (Controller Area Network) protocol. We used Windows XP as the operating system and have established a real-time control system in Windows XP by using RTX (Real Time eXtension) software. This paper includes design concepts, mechanical system design, system integration and electrical system design. In order to demonstrate the performance of the robot platform, simple experiments were performed.     

基于多传感器的家庭服务机器人局部导航方法研究

本文提出了一种基于多传感器的家庭服务机器人局部导航方法。首先,采用单个摄像头获取居室内障碍物的图像信息,利用超声波传感器和红外线传感器探测障碍物的距离信息。然后,据此计算在机器人运动方向上障碍物的遮挡空间或者多个障碍物之间的实际距离,再根据机器人自身的大小计算避开障碍物应该转动的方向及角度,从而实现居室内的自主导航。最后,仿真实验结果证明了该方法的有效性。     

Production of Various Vocal Cord Vibrations Using a Mechanical Model for an Anthropomorphic Talking Robot

We developed a three-dimensional mechanical vocal cord model for Waseda Talker No. 7 (WT-7), an anthropomorphic talking robot, for generating speech sounds with various voice qualities. The vocal cord model is a cover model that has two thin folds made of thermoplastic material. The model self-oscillates by airflow exhausted from the lung model and generates the glottal sound source, which is fed into the vocal tract for generating the speech sound. Using the vocal cord model, breathy and creaky voices, as well as the modal (normal) voice, were produced in a manner similar to the human laryngeal control. The breathy voice is characterized by a noisy component mixed with the periodic glottal sound source and the creaky voice is characterized by an extremely low-pitch vibration. The breathy voice was produced by adjusting the glottal opening and generating the turbulence noise by the airflow just above the glottis. The creaky voice was produced by adjusting the vocal cord tension, the sub-glottal pressure and the vibration mass so as to generate a double-pitch vibration with a long pitch interval. The vocal cord model used to produce these voice qualities was evaluated in terms of the vibration pattern as measured by a high-speed camera, the glottal airflow and the acoustic characteristics of the glottal sound source, as compared to the data for a human.     

Development of an Earthworm Robot with a Shape Memory Alloy and Braided Tube

Peristalsis motion like an earthworm has attracted attention in recent years because the movement is useful to progress in small spaces. An earthworm robot with a shape memory alloy, the BioMetal Helix, and a polyester braided tube was studied. The BioMetal is a fiber-like actuator-like muscle tissue; the BioMetal Helix (BMX series) was chosen to obtain good unit contraction force. The BMX, elongated at room temperature, becomes stiff and sharply contracts when a current is fed through it. For the unit expansion force, a polyester braided tube was used. The braided tube maintains a long and thin shape without compression, and when an external force presses the tube in the axial direction, it becomes shorter and thicker. When the external force is removed, the tube lengthens and becomes longer and thinner again. A prototype robot consisting of four units was developed. The robot was designed with three-dimensional computer-aided design, and the expansion and contraction timing of units was calculated through computer simulations. The simulated results closely resembled the experiments and the robot was improved by adaptation according to the simulated results.     

TORSO: Development of a Telexistence Visual System Using a 6-d.o.f. Robot Head

In telexistence master–slave systems, it is important to transmit visual information from remote places to the operator. Conventional imaging devices in head-mounted displays (HMDs) can only express the three-axis rotation of the neck. However, humans can obtain broader visual fields and motion parallax information from the translational motion of their necks. We have proposed a system that can acquire natural and comfortable visual information, and can accurately track the head motion of a person. Our proposed device can express the head motion and the translation movements of the neck. We have developed a robot, called 'TORSO', and constructed a telexistence visual system with a display device, HMD. In this paper, by means of a broader field of view achieved by motion involving looking around, we demonstrate the advantage and novelty of our proposed system. In addition, we suggest the evolution of the TORSO–HMD system.     

Development of a System for Simulation and Control of an Unmanned Aerial Vehicle

Control systems of different vehicles such as helicopters, cars and boats have a lot in common. Thus, the main goal of this paper is to enable construction of a universal platform providing an opportunity of making such a system in a simplified and fast way. The designed platform operates in three different modes (SIL, MIX and HIL). The platform enables switching between different modes of operation without any changes implemented in a software layer. An embedded controller is able to schedule tasks without any delays, which involves utilization of a real-time operating system. Additionally, it is possible to remotely control and monitor the vehicle during its normal operation.     

Error Analysis and Effective Adjustment of the Walking-Ready Posture for a Biped Humanoid Robot

A walking control algorithm is generally a mixture of various controllers; it depends on the characteristics of the target system. Simply adopting one part of another researcher's algorithm does not guarantee an improvement in walking performance. However, this paper proposes an effective algorithm that can be easily adopted to other biped humanoid robots; the algorithm enhances the walking performance and stability of the robot merely by adjusting the walking-ready posture. The walking performance of biped humanoid robots is easily affected by an unsuitable walking-ready posture in terms of accuracy and repeatability. More specifically, low accuracy for the walking-ready posture may cause a large difference between an actual biped robot and its mathematical model, and the low repeatability may disturb the evaluation of the performances of balance controllers. Therefore, this paper first discusses the factors that detrimentally affect bipedal walking performance and their phenomena in the walking-ready posture. The necessary conditions for an ideal walking-ready posture are then defined based on static equilibrium and a suitable adjustment algorithm is proposed. Finally, the effectiveness of the algorithm is verified through dynamic computer simulations.