Shin'ichi Yuta

Development of a Laser-Range-Finder-Based Human Tracking and Control Algorithm for a Marathoner Service Robot

This paper presents a human detection algorithm and an obstacle avoidance algorithm for a marathoner service robot (MSR) that provides a service to a marathoner while training. To be used as a MSR, the mobile robot should have the abilities to follow a running human and avoid dynamically moving obstacles in an unstructured outdoor environment. To detect a human by a laser range finder (LRF), we defined features of the human body in LRF data and employed a support vector data description method. In order to avoid moving obstacles while tracking a running person, we defined a weighted radius for each obstacle using the relative velocity between the robot and an obstacle. For smoothly bypassing obstacles without collision, a dynamic obstacle avoidance algorithm for the MSR is implemented, which directly employed a real-time position vector between the robot and the shortest path around the obstacle. We verified the feasibility of these proposed algorithms through experimentation in different outdoor environments.

An implementation of landmark-based position estimation function as an autonomous and distributed system for a mobile robot

We developed APCS (autonomous position correction system) that can autonomously cancel the error of the estimated robot position from odometry by detecting flat walls using ultrasonic sensing. When it detects flat walls in the environment, this system corrects the estimated position using maximum likelihood estimation (MLE). The feature of this system is that it can correct the position not being concerned with the behavior of the robot because the system autonomously decides the trigger of the position correction. We show the algorithm and implementation of APCS, and some experimental results to confirm feasibility of the system in a disordered environment.

Use of amplitude of echo for environment recognition by mobile robots

Proposes a method of adding the amplitude of ultrasound echo from reflecting points. An omni-directional sonar which we developed, can measure accurate distance and direction of the reflecting points, and it is possible to measure amplitude of the echo which corresponds to the reflecting points. We propose a method to add information from the amplitude of the echo from the reflecting points for environment recognition. This method can give useful information such as character of reflecting objects and it makes possible to correspond each reflecting point with others using this information. We describe the proposed method and an experimental result to show its usefulness.

Development of small size 3D LIDAR

We have developed a new type of 3D LIDAR, which is small, light weight and low cost. The size and weight are important factors of the aimed sensor to use with wide range of robot vehicles, helicopters and airplane, and small vehicles. To achieve compact size and light weight construction the sensor has single pair of laser transmitter and receiver, and scanning motor on which a vibrating mirror is placed. The mirror is driven by the resonant frequency current supplied through contactless power supply unit. Experimental results of the prototype shows that the sensor of comparable size and weight with recent 2D sensors can obtain 3D range data of 8000 points in 20 Hz with 270 degree horizontal and 40 degree vertical views both in indoor and outdoor.

Volcanic ash observation in active volcano areas using teleoperated mobile robots - Introduction to our robotic-volcano-observation project and field experiments

Observation of an active volcano is very important to determine a strategy for estimating its eruptive activity and providing residents with an evacuation warning. However, it is too dangerous for humans to install cameras during eruptive activity to determine the status of a volcano. Furthermore, permanently installed cameras might be damaged by eruptions, and craters can emerge in unanticipated positions. To handle this situation, we proposed robotic observations in a volcanic area after an eruption using a multi-rotor UAV (unmanned aerial vehicle) and a small ground robot. Field experiments are effective at promoting this type of research and development. Therefore, we performed several field experiments at Mt. Asama. In this paper, we introduce our robotic observation project, and report on the field experiments conducted with teleoperated mobile robots in October 2012 at Mt. Asama.

Development and field test of teleoperated mobile robots for active volcano observation

When an active volcano erupts, a restricted area is typically set according to the eruption level. However, it is very important to observe eruption products inside of this area to predict the timing and scale of volcanic hazards, such as debris flows. Therefore, we propose a robotic observation system for active volcanoes that is composed of a multi-rotor unmanned aerial vehicle (UAV) and a mobile ground robot. To deliver the ground robot safely from the multi-rotor UAV to the ground, we implemented a sky-crane mechanism and confirmed the feasibility of the mechanism theoretically. In this paper, we introduce our volcano observation scenario as well as the observation system and sky-crane mechanism we have developed. Finally, we report on a field test conducted at Mount Asama in September 2013.

Using one bit wave memory for mobile robots' new sonar-ring sensors

This research aims at development of sensors for small size indoor mobile robots. We have proposed a new sonar-ring which can measure accurate direction and distance to reflecting points rapidly for this purpose. This new sonar-ring needs to receive echo signal by multiple receivers and to detect multiple Time-of-Flights (TOFs) in received signal at each receiver simultaneously for achieving fast and accurate measurement. However, it is impossible to satisfy them by conventional circuit. This paper proposes 30 channel 1 bit wave memory system to achieve these two points simultaneously and shows its usefulness.

Field Trial Results of Autonomous Road Crossing Mobile Robot

We have developed a fully-integrated outdoor mobile robot that is capable of crossing roads autonomously in real world urban environments. To do this, the robot travels along pedestrian sidewalks autonomously, continually detects pedestrian push button boxes and navigates to it when one is detected. It then activates the push-button using an onboard-finger, moves to the crossing zone and crosses the road after detecting the zebra stripes and pedestrian lights. In this paper, we report the results of preliminary field trial experiments where the robot was deployed in a real world environment and its performance was evaluated.

Design of an intelligent outdoor mobile robot with autonomous road-crossing function for urban environments

This paper describes the total system design and implementation of an outdoor mobile robot with an autonomous road-crossing function intended for urban environments. The developed robot is capable of navigating along sidewalks while simultaneously detecting pedestrian push-button boxes. If a button box is detected, the robot can autonomously traverse up to it with high precision and activate the push button with a finger. Next, it approaches the crossing zone, detects the zebra stripes and perceives the trajectory required to cross. Upon detecting a green signal, the robot then finally crosses the road to reach the opposite side of the road and continue to its intended destination. We tested the robot in a real and unmodified outdoor environment and obtained promising results. More application-oriented, the novelty of this work is that not only is the robot capable of crossing roads autonomously, it can also autonomously activate pedestrian push buttons in a real world outdoor environment; there are not many robots that can perform such an action in an outdoor environment.

Scan matching method using projection in dominant direction of indoor environment

In this paper, we propose a new scan matching method, which uses the feature of structure in an artificial environment where walls are located parallel or perpendicular to one another. This method can precisely obtain the relative pose between two scan data using the dominant direction with a small calculation cost. Efficacy of this method is proved by an experiment conducted in an indoor environment. Graphical Abstract