Hirohiko Kawata

Development of ultra-small lightweight optical range sensor system

We have developed a 2D laser range sensor suitable for mobile robot platforms. The sensor features compactness, lightweight, high precision and low power consumption, and provides the wide scan angle with high resolution, which is very important for environment recognition by mobile robots. The basic technology for measuring the distance between the sensor and objects are; using amplitude modulation of light waves and detecting the phase difference between transmitted and the received one. This paper explains the specification of the proto-type sensor, the method of distance measurement and examples of experimental results.

Visual Information Assist System Using 3D SOKUIKI Sensor for Blind People, System Concept and Object Detecting Experiments

The purpose of this research is to develop a system which gives blind people information of the environment around them. A person is equipped with a 3D scanner and a small sized PC while walking. The scanner scans and acquires 3D range data map of the environment. The PC analyzes the range data map and detects objects which are useful for blind people in order to walk. The PC gives environmental information to them by synthesized sound. This paper first introduces the concept of the whole system and clarify the tasks for realizing the system. Secondly the method for acquisition of 3D range data and detecting objects and obstacles are described. Then the usefulness of our proposed system is examined by an experiment in which our trial system detects bumps and trenches in the experimental environment

Security Door System Using Human Tracking Method with Laser Range Finders

Recently, tracking and counting people are requested for the security purpose. In this paper, we propose a method to track and count people with laser range finders. A method to extract the walking human from the sensor data is introduced. Multi-target model and Kalman filter based estimation are employed to track the human movement and count the number of people. The proposed method is applied to a novel system to monitor the entrance area and to filter out the trespasser who enters the door without identification. Experiments for various cases are performed to verify the usefulness of developed proto-type system.

A method for estimation of lightness of objects with intensity data from SOKUIKI sensor

Recently, SOKUIKI sensor is used in various fields including robotics. SOKUIKI sensor ldquoURG-04LXrdquo can take distances by measurement. And by using special mode of the firmware, Received Light Intensity and AGC Voltage Level can be obtained. This paper describes a method to estimate Gray Level of scanned objects by using Received Light Intensity. The method uses AGC Voltage Level for accurate estimation.

Time synchronization between SOKUIKI sensor and host computer using timestamps

Time is crucial in applications such as sensor data fusion, autonomous mobility and SLAM. However clocks at end systems are rarely synchronized and often running at different speeds. Lack of synchronization therefore reduces the accuracy of sensor readings. The SOKUIKI scanning laser range finder allows acquiring time values by timestamping range readings. Our work consists in a method for time synchronization, with clock skew estimation, between a laser range finder sensor and a host computer.

A Method for Accurate Map Construction Using Time Registration from a Moving SOKUIKI Sensor

Mobile robots have various sensors that are considered as their eyes and a two-dimensional laser scanner (SOKUIKI sensor) is one of them. This sensor is commonly used for constructing environment maps or detecting obstacles. It is very important to estimate accurately the sensors position and direction when scan data is obtained in order to use correctly such a sensor for these purposes. On the other hand, scanning sensors have an essencial problem: time lag. That is, the time when the laser is transmitted to each direction is different. Thus the map has many errors if the measurement time lag problem is not resolved. This paper presents a method for laser scan data synchronization using time registration and, as a practical application, we show its effectiveness for accurate map construction.

Adaptive sensing system for human detecting with dynamic disposition

In this paper, we propose a novel human detecting system using several stationary and moving laser range finders(LRF). The occluded area where the stationary sensors cannot measure will be covered by the actively moving sensor. The occlusion is perceived by overlaying visible area of the stationary sensors. The moving sensor will move to the target position where the sensor can measure the occluded area. Finally, the measured information of all sensors will be merged for data fusion. The experimental results show the effectiveness of the system.

1P1-B15 Adaptive Human Direction Control Using Mobile Robot's Behavior

In this paper, we describe a robot system to control human detection. In our proposed system, the robot surveils a security area with equipped SOKUIKI sensor, ofdinarily. When it detect trespasser who is for the area, robot calculates his velocity vector, plans own path to forestall and interrupt him and starts to move along the obtained path. While moving the robot continues these processes for adapting change of situation. After arriving at a trespasser’s opposite position, the robot advises him not to be headed more and change his course. Our experimental results show the robot can estimate human’s future trajectory and calculate appropriate its own path.