Noritaka Sato

Study on effective camera images for mobile robot teleoperation

The effectiveness of different camera images for mobile robot teleoperation is investigated. During a robot teleoperation where the operator can only control the robot through observing the camera images rather than direct-view control, the information provided by the images must be sufficient enough to allow the operator to perform the remote control efficiently. In order to understand which kind of camera images are most effective for robot teleoperation, we have conducted several experiments to examine their validness. The experimental results indicated that an image where the robot is positioned in the center of the camera view with clear survey of the surroundings shows high efficiency in remote control of a mobile robot.

Development of a high mobility wheeled rescue robot with a 1-DOF arm

Human rescuers, who carry out urban search and rescue (USAR) missions, frequently enter dangerous zones to search for survivors. In these zones, rescuers life may be threatened. For this reason, rescue robots are expected to become useful work partner for urban search and rescue missions. This paper presents platform design of FUMA, which is a four-wheeled rescue robot with a 1-DOF arm for environment information gathering. Only one arm of FUMA has two benefits for both mobility and teleoperation. Using this arm, FUMA can climb higher obstacles than simple four-wheeled robot. Human rescuers can operate FUMA at a safe distance while the missions are carried out. To teleoperate robot systems efficiently, the key is the interface between the robot systems and operators. During rescue operation, an operator of FUMA usually relies on the images from two fish-eye cameras installed at the top of the arm, as they provide wide images of the environment with the robot included in those views.

Treaded control system for rescue robots in indoor environment

We developed a rescue robot system, which allows efficient utilization of the potentials of a robot, by effectively switching between tele-operation mode and autonomous mode based on the task and the operation environment. Rescue robots are mobile sytems which can perform search for human lives, on behalf of rescue personnel, in dangerous environments like earthquack disaster zones or areas with chemical hazards. As a pre-requisite of the system, we consider that the robot is equipped with capability of autonomous mobility, laser range finder for environment mapping and infra-red camera to detect victims. In situations when the remote operation of the robot is difficult due to un-suitable condition of wireless communication or the visibility is low, the autonomous mode based search operation is performed. In the autonomous mode, the locomotion is based on the distance sensor data and the infra-red camera to search and navigate towards a victim and inform the operator about the potion and condition of the victim. In the case of complex environmental situations, like a staircase, or in cases that the infrared camera information may not be reliable to detect a victim, the operators decisions become essential and the operation mode is switched to the tele-operation mode. In the case on tele-operation mode, the operator may use the information from the optical camera and operate the robot with a joystick. By switching between the tele-operation mode and autonomous mode the weak points of each mode can be compensated. We developed a robot, called KAMUI, which is equipped with the above mentioned pre-requisites. KAMUI is designed to have high mobility in uneven surface conditions and enhanced sensor systems for victim identification. We participated in RoboCupRescue league and evaluated the effectiveness of the developed system in real situations.

Utilization of Robot Systems in Disaster Sites of the Great Eastern Japan Earthquake

In this paper, we report our activities in the real disaster areas damaged by the Great Eastern Japan Earthquake. From March 18–21, 2011, we tried to apply a ground rescue robot to the real disaster sites at Aomori Prefecture and Iwate Prefecture. On March 18, we carried out inspection mission in a damaged gymnasium. From March 19–21, we went to other sites to identify possibility of usage of robots, and we found the potential needs for not only ground robots but also underwater robots. Then, after the first activity we established a joint United States-Japanese team for underwater search. From April 19–23, 2011 the joint team brought four ROVs to Miyagi Prefecture for port inspection and to Iwate Prefecture for searching for submerged bodies. The joint team returned to Miyagi Prefecture October 22–26 with an AUV and two ROVs for cooperative debris mapping needed to assist with resuming fishing. Based on these experiences, we discuss the effectiveness and problems of applying the rescue robot in the real disaster sites.

Development of Robot Teleoperation System in Bad Viewing Condition

In robot teleoperation there is a mounted camera on a robot and the operation is usually performed from a remote site using captured images by the mounted camera. Even though color cameras provide many useful information of a remote site, robot teleoperation using color cameras are highly effected by environmental conditions such as lighting, colors, smoke, etc. and there might be a case that cameras might become useless during an operation such as in dark places. In this paper we have developed a robot teleoperation system which does not fully rely on color camera images and works well in bad viewing condition for operating a robot and searching for a victim. A laser rangefinder is used for sensing surroundings of a robot and a thermal camera is used for victim detection. An operator can control a robot in a remote site only using environmental contour figure information around a robot without color camera images. The augmented image interface consists of color and thermal camera images are used for victim detection. We have executed a victim searching task in different lighting conditions with different sensor configurations to show the effectiveness of developed system.

Path planning for an autonomous mobile robot considering a region with a velocity constraint in a real environment

Recently, many research projects and competitions have attempted to find an autonomous mobile robot that can drive in the real world. In this article, we consider a path-planning method for an autonomous mobile robot that would be safe in a real environment. In such a case, it is very important for the robot to be able to identify its own position and orientation in real time. Therefore, we applied a localization method based on a particle filter. Moreover, in order to improve the safety of such autonomous locomotion, we improved the path-planning algorithm and the generation of the trajectory so that it can consider a region with a limited maximum velocity. In order to demonstrate the validity of the proposed method, we participated in the Real World Robot Challenge 2010. The experimental results are given.

The Relationship between Physical Function and Postural Sway during Local Vibratory Stimulation of Middle-aged People in the Standing Position

[Purpose] The purpose of this study was to examine the relationship between physical function and postural sway during local vibratory stimulation of middle-aged subjects in an upright position. [Subjects] The subjects were 25 healthy community-dwelling middle-aged people. [Methods] We measured postural sway using a Wii board while vibratory stimulations of 30, 60, or 240 Hz were applied to the subjects’ lumbar multifidus or gastrocnemius muscles. Physical function was evaluated by 5-m usual gait speed and grip strength. [Results] Gait speed was strongly correlated to the anteroposterior body sway in the upright position during 30 Hz gastrocnemius muscles vibration (GMV). [Conclusion] Postural sway during 30 Hz GMV was strongly associated with gait speed and showed a posterior displacement. These findings show that the lower leg’s response to balance control under 30 Hz proprioceptive stimulation might be a good indicator of declining gait function.

Clinical Evaluation of Training System for Recovery of Motor Function after Stroke in Patients with Hemiplegia

We developed a training system (URSystem: Useful and Ultimate Rehabilitation System) for recovery of motor function of the upper limb after stroke in patients with hemiplegia. Clinical evaluation of the therapeutic effect of the URSystem was performed in eight patients. Active ranges of motion (A-ROMs) of elbow extension and supination of the forearm were improved after training with the URSystem within two weeks. Moreover, the modified Ashworth scale scores for elbow extension and supination of the forearm were increased. This means that spastic paralysis was reduced. These effects persisted for one month after the training. These results show the effectiveness of training with the URSystem for recovery of motor function of the upper limb.

Tele-operation system for rescue robot by inputting target position of end-effector

Recently, tele-operated robots are expected to search and rescue victims in a disaster area. However, there is a problem that the operation of rescue robots is too complex. One of this reasons is that an operator has to operate the mobile platform and the manipulator of a rescue robot simultaneously when the operator finds victims. In this study, a control method to coordinate locomotion and manipulation is proposed in order to simplify the tele-operation of a robot. In our system, once the operator only inputs the target position of the end-effector of the manipulator on an image from the camera mounted on the robot, the robot automatically moves to achieve the target position. The manipulator avoids the degradation of manipulability while following the target trajectory of the end-effector by using redundancy of the manipulator. The vehicle avoids “No Entry Areas” while following the target trajectory of the end-effector by our modified artificial potential method. We verify the effectiveness of our proposed system by simulations and experiments.

Development of crawler type rescue robot with 2 DOF flipper arms

Crawler type rescue robots with flipper arms have good running ability for rough terrains. Each flipper of these robots has a pitch DOF. The pitching motion of the flipper arms is effective to climb up a step obstacles. However, most of rescue robots cannot easily turn on stairs or steep ramps. In this paper, we developed a crawler type rescue robot that has a steering mechanism on each flipper arm. The flipper arm has 2 DOF and the flipper arm can move not only up and down but also left and right. We evaluate the displacement by sliding when the robot runs on the horizontal ramp with/without yawing motion.