A field-programmable gate array (FPGA) using a crystalline oxide semiconductor of c-axis-aligned crystal indium-gallium-zinc oxide (CAAC-IGZO) has been developed, which is capable of subthreshold operation used for energy harvesting. To achieve subthreshold operation, the CAAC-IGZO FPGA has a structure designed as an extension of a boosting pass gate using a CAAC-IGZO FET and employs overdriving of a programmable routing switch and a programmable power switch for power gating (PG). A CAAC-IGZO FET is used to give an ideal floating gate with excellent charge retention. A chip fabricated using a 0.8-μm CAAC-IGZO/0.18-μm CMOS hybrid process achieves subthreshold operation while maintaining the features required for normally off computing proposed in our previous study. Specifically, these features are realized by fine-grained PG for individual programmable logic elements (PLEs), fast configuration switching between contexts, and load/store between a volatile register and a nonvolatile shadow register in the PLEs. The chip operation at a minimum operating voltage of 180 mV with a combinational circuit configuration is demonstrated. With a sequential circuit configuration, the chip operates at a minimum operating voltage of 190 mV with 12.5 kHz, and the minimum power-delay product is 3.40 pJ/operation at 330 mV.

We have proposed and developed a new quadruped walking robot with a spherical shell, called “QRoSS”. QRoSS is a transformable robot that can store its legs in the spherical shell. The shell not only absorbs external forces from all directions, but also improves mobile performance because of its round shape. In rescue operations at a disaster site, carrying robots into a site is dangerous for operators because doing so may result in a second accident. If QRoSS is used, instead of carrying robots in, they are thrown in, making the operation safe and easy. We developed QRoSS-I and conducted basic experiments to verify performance which includes landing, rising and walking through a series of movements. This paper reports details of a mechanical design to perform a rotational locomotion using spherical shell and development of the prototype model of QRoSS-II. We discuss the rising motion and the rotational locomotion from the results of Basic experiments.

A boosting pass gate (BPG) suitable for a programmable routing switch including a$c$-axis aligned crystal In-Ga-Zn-O (CAAC-IGZO) field effect transistor (FET) is proposed. The CAAC-IGZO is one of crystalline oxide semiconductors (OS). The proposed BPG (OS-based BPG, OS BPG) has a combination of a pass gate (PG) and a configuration memory (CM) cell utilizing a CAAC-IGZO FET with extremely low OFF-state current and a storage capacitor. This OS BPG achieves a routing switch with fewer transistors than a conventional routing switch having a combination of a PG and an static RAM (SRAM) cell. Owing to the boosting effect, the switching characteristics, at not only positive transition but also negative transition of input signals, of the OS BPG are improved without using overdriving. In circuits fabricated with a hybrid process of a CMOSFET and a CAAC-IGZO FET with gate lengths of 0.5 and 1.0$\mu $m, the net delays of the OS BPG, 75 and 58 ns, at driving voltages of 2.0 and 2.5 V have been found to be less than those of the conventional routing switch (SRAM-based PG, SRAM PG) by about 79% and 62%, respectively. It has also been confirmed that a field-programmable gate array (FPGA) chip utilizing the OS BPG as a routing switch reduces the layout areas of routing switches and the whole chip by 61% and 22%, respectively, and increases the maximum operating frequencies at driving voltage of 2.0 and 2.5 V by about 2.8 times and 1.6 times of those of the FPGA chip utilizing the SRAM PG as a routing switch.

In the literature, mobile robots featuring both omni-directional and rough-terrain mobility are typically realized by heavy and complicated mechanisms. In considering real outdoor applications, such as hazardous site-inspections or scientific investigations, however, it is desired to develop small and light-weight robots by focusing on the mechanical simplicity and toughness. The primary objective of this study is to investigate and to realize an omni-directional mobile robot on unpaved rough terrain by small, light-weight, simple mechanism. For this purpose, we propose a new concept of wheel structure as well as an omni-directional moving robot. The new wheel, named globular metal spring wheel and composed simply of several super-elasticity-material rods, has not only omni-directional functionality but also properties of light weight, mechanical simplicity and external shock absorbing function. With this globular wheel, a new omni-directional mobile robot, “Eggbeater”, is also developed to evaluate the mobility performance. This paper presents our proposal and development of the globular metal spring wheel and the omni-directional rough-terrain mobile robot, and discusses performance evaluation experiments.

In this paper, two types of biologically inspired educational robots based on gliding locomotion are presented. Gliding locomotion utilizes the difference between two orthogonal reaction forces to propel. Since this locomotion principle is very interesting and difficult to intuitively understand, its way of locomotion effectively evokes intellectual curiosity of students. One actuated degree of freedom (DOF) fish-like educational robot and its lecture program are developed for primary, junior high and high school students. And a snake-like educational robot which can connect arbitrary number of units, and its lecture program are developed for university students. We carried out these programs through several lectures. The results are also discussed in this paper.

Japan is planning to send a rover to the moon to investigate the moon surface in the near future. Therefore, considerable researches and developments about the subject are being done. We particularly have continued to propose expandable three-wheeled rovers, and to develop them. This paper proposes the new concept of the three-wheeled rover “Tri-Star IV” composed of three spring wheels and two rotating arms, and describes its mechanical design.

Falcon-III is a robotic personal vehicle that has been designed for uneven terrain usage. It has a two-degree-of-freedom suspension mechanism that allows the passenger's seat orientation (pitch and roll) to be controlled by actively adjusting the height of its wheels. This paper discusses the motion control of such a vehicle on rough terrain. In particular, we show that a feedback control law that measures the vehicle seat attitude and acts to correct it, aiming at maintaining the horizontal seat posture during the traversing of uneven terrain, is by itself insufficient to provide satisfactory performance on certain types of terrain. Therefore, we propose a predictive motion control strategy, in addition to the feedback control law, that dynamically controls the vehicle suspension in order to facilitate the negotiation of obstacles - the motion executed is somewhat similar to that performed by a cyclist when overcoming a step-like obstacle. When tall step-like obstacles have to be negotiated, it may be necessary to dynamically lift one of the wheels from the ground, in which case a gait pattern emerges.

Many crawler vehicles for rescue use have been researched so far. In the near future, if this type of research is to advance to the next stage, experiments in realistic environments are necessary. Particularly, dustproof and waterproof capabilities are necessary to operate in a real environment. The existing sealing technology for the driving parts is difficult to be used for robots whose outputs are small because the friction loss is not small. This paper describes proposal of the high strength retractable skin and development of the closed type crawler vehicle covered by it.

With the appearance of many personal vehicles developed for urban environments, it seems pertinent to address the development of off-road personal vehicles as well. This paper discusses this exact topic, and proposes a three-wheeled configuration which stabilizes the horizontal posture of the vehicle's driver in rough terrain. The merits of such a machine are examined; in addition, a mechanism here called sliding-rod-end is introduced, and the reasons for its use instead of regular rod ends are explained. A full-scale prototype of the machine was built and is briefly presented.

Slim slime robot (SSR), that looks like an active cord mechanism (snake like robot) and is composed by units that can stretch, shrink and bend actively, is meant to be used for several tasks in narrow spaces such as moving under collapsed houses or for inspection of pipelines in plants. We propose a new concept named "bridle drive", that was developed from the prototype model of the units of the SSR-2.3 that has units of the bridle bellows composed of a large caliber bellows and wire lock systems. The use of the bellows allows to produce a high output using air pressure, and its shape can be changed by controlling the length of the wires. In this paper, to solve problems of the previous model of the bridle bellows, we modified its brake systems and propose a new control method named PCBS.

Slim slime robot (SSR), looks like an active cord mechanism (the snake-like robot) and composes units that can stretch, shrink and bend actively, is for several tasks in narrow spaces such as to move under collapsed houses or for inspection of pipelines in plants. In this paper, we propose the new concept, which is named "bridle drive". We developed the prototype model of the units of the SSR-2.3. Each unit has a bridle bellows composed of a large caliber bellows and wire lock system. The use of bridle bellows allows to produce a high output using air pressure, its shape can be changed by controlling the length of the wires.

This paper introduces a new concept in snake like robots, namely the Slim Slime Robot 2 (SSR-II), which has an added degree of freedom to stretch the body segment. The active cord mechanism (snake like robot) is capable of performing several tasks in narrow spaces, such as moving under collapsed houses, and inspection of pipelines at plants. Conventional snake robot mechanisms are designed as a series of connected articulated segments that have two degrees of freedom each. The SSR-II, with Bridle Bellows units composed of a large caliber bellows and a wire lock system, is explained. Bridle Bellows is an example of the "Bridle drive" which is introduced in this paper. The Bridle Bellows are able to change shape by controlling wire length and air pressure and produce large power. Therefore, from the experiment, SSR-II is shown to be effective for moving mechanisms at rough forging, which can transfer several locomotion forms.

In this research, we discuss how to automatically generate the motion sequence of actuators for error recovery, including parallel path divergence in the programmable logic control (PLC). Since the sequential path in PLC can be expressed by a state flow, the goal of our research is to find an optimal shortest path from the initial state to the final state. In order to solve this problem, we propose a new search strategy, which consists of two search stages. In the first stage, real-time A* (RTA*) algorithm is used to find a suboptimal sequential path from the initial state to the final state. Based on the suboptimal solutions found by RTA*, the second stage tries to pick up some underlying parallel path divergences among solutions obtained in the first stage. From some simulation results, we have verified that our proposed method could search a suboptimal motion sequence including parallel path divergences with less computational amount.

Presents a method for control of autonomous mobile robots to acquire fine actions based on real-time search. In the proposed method, the information criterion for the environment is defined based on the Kullback-Leibler divergence, which measures the quality of the environmental information used for the action search. The robot searches suitable actions based on the environmental information which is improved step by step in the sense of this criterion. According to this, we can harmonize the trade-off between the calculation amount and information quality, and make the search process faster. The proposed method is applied to the moving obstacles avoidance problem, and its usefulness is shown through some simulation results.

As highly complicated interaction dynamics exist, it is therefore extremely difficult to design controllers for legged robots. Evolutionary robotics is one of the most promising approaches, but there still exist several problems that have to be solved. One of the critical problems is that evolved agents generally tend to over adapt to their given environments through the evolutionary process. In other words, they lack rich adaptability. Therefore, it is highly necessary to establish a method that enables one to efficiently construct adaptive controllers that can cope with different situations. For this purpose we introduce the concept of neuromodulators, allowing the evolvement of neural networks which can adjust not only the synaptic weights, but also the structure of the neural network by blocking and/or activating synapses or neurons. We apply this concept to create an adaptive controller for a quadruped robot which not only can walk forward but also regulate the torque output applied to each joint, according to the current situation.

We propose a method based on a real-time search for the proper action of an autonomous mobile robot using the framework of the Anytime Algorithm. This is available for a real-time search in a dynamic environment. In order to apply the Anytime Algorithm to the multi-objective real-time search in the dynamic situation around the autonomous mobile robot, we adopt prediction, a switching evaluation function technique, the action watch dog and an evolution strategy. These enable the robots to realize the real time search. The paper explains the proposed method and shows the feasibility through experimental results using real robots.

We propose a method based on a real-time search for the optimal action of an autonomous mobile robot using an evolution strategy. By searching the optimal action for the facing situation in real time the robots need not suffer from the problem of categorization of the situations and problem of pre-definition of rules. The basic idea of the proposed real time search technique is to harmonize computational amount with a property of solution. In order to realize this requirement we adopt a two-stage evaluation technique. The proposed method also adopts the prediction and action watch dog systems. These function enable the robots to realize the real time search. The paper explains the proposed method and shows the feasibility through the experimental results using the real robot.

The principal aim of this study is to show how an autonomous mobile robot can acquire the optimal action to avoid moving obstacles through the interaction with the real world. In this paper, we propose a new architecture using the hierarchical fuzzy rules, fuzzy evaluation system and learning automata. By using our proposed method the robot acquires the fine behavior on how to move to the goal avoiding moving obstacles using the steering and velocity control inputs, simultaneously. Also we show the experimental results to confirm the feasibility of our method.