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The autonomous dump truck must judge whether the backhoe is ready for loading the sediment for smooth and safe cooperation with the human-operated backhoes. Analyzing time-series data of the human-...

Engineering to produce stimuli that trigger an organism’s habits allows us to control it noninvasively. Because canines already have the habit to follow a light spot, light is a good stimulus for controlling their motion. We employed green laser beams to successfully control canine motion indoors. We developed a suit equipped with laser beam devices that face front, left, and right. The canine wore the suit and followed a light spot on the ground. Its trajectory was controlled remotely by switching the lights on the suit. However, this laser beam spot was too weak and small to be visible in grassy fields outdoors. Here, we propose a spotlight device that irradiates a bright and large spot (70 mm in diameter) for outdoor environments. The proposed spotlight device consists of a high brightness LED and a convex lens. To evaluate its performance, we conducted indoor and outdoor experiments using three canines. In the indoor experiments, the success rates of controlling the canine’s motions were 100%, 83.3%, and 93.3% for each of the three canines, respectively. In outdoor experiments, these rates were 100%, 57.1%, and 62.5%, respectively. Hence, the proposed spotlight devices are effective for controlling a canine even in outdoor environments.

Aerial robotics is a fast-growing field of robotics and has been successfully used in various applications. Still, it faces many challenges, such as dealing with unavoidable obstacles in a cluttered environment. Recently, a flying robot with a protective shell that can rotate passively was introduced. The passive rotating mechanism is intended to reduce the impact force on the attitude of the UAV. However, such a system also has some limitations. Because the shell rotates passively, the ability to physically interact outside the shell is limited, and the onboard camera and other remote sensors are constantly obstructed. In this letter, a new idea is introduced in response to the limitations of the previous system while retaining the protective shell and maintaining some degrees of passive rotation of the shell. It is proposed to position two passive rotating hemispherical shells in each rotor to directly protect the propeller. This letter presents the concept, discusses the design and proof of concept, and validates the concept through experiments. Various experiments are conducted to demonstrate the capabilities of the proposed flying robot, resolve the problem of physical interaction and camera obstruction, and introduce new advantages.

Backhoe loads sediment onto the bed of dump trucks during earthmoving work. The prediction of backhoe loading time is essential for ensuring safe cooperation between the backhoe and dump trucks. However, it is difficult to predict the instant at which the backhoe is ready to load sediment, because of the similarity in motions observed during gathering sediment. Moreover, since operators have different skill levels, the prediction requires a unique model for each operator. In this study, we attempt to predict the instant at which the backhoe is ready to load sediment into the dump truck. For this purpose, the beta-process hidden Markov model (BP-HMM) is employed to build a backhoe motion model for a specific operator. Time series data of backhoe loading motions for crushed rocks and wood chips, which were measured using 6-axis inertial measurement unit (IMU) sensors equipped at the cab, boom, and arm of the backhoe, were used for modeling with the BP-HMM. Several primitive motions of the backhoe, which occur at the completion of preparation before the loading process begins, were discovered as a result of the motion modeling based on the BP-HMM. We developed the prediction of the instant using three primitive motions. At best, the proposed method could predict the instant with a probability of 67% and 100%, at 6.0 s and 0.7 s before the loading motions began, respectively. This phased prediction can be used to reduce the idle time and risk for dump trucks during earthmoving work with the backhoe.

Sensing position and orientation of construction vehicle is an important issue for automation of construction process. We aim to develop sensing and visualization technologies for construction vehicles. Our target construction vehicle is backhoes. Construction vehicles are usually rented in construction fields. However, construction vehicles that can be rented do not have the sensing function. It is too hard to obtain backhoe position and manipulator pose without sensing information. This paper proposes an attachable sensor box that can measure backhoe position and orientation and the manipulator pose. The sensor boxes can be attached on backhoe metal surface by magnetic force without any additional manufacturing on the construction vehicle surface. By using WiFi communication and mobile battery the sensor box can be easily attached on large-size backhoe without wiring. After the work is done, it is easily detached by changing magnetic force power. At loading and scooping motion, backhoe arm and boom have large force exceeding 16 G. To attach the sensor boxes to the arm and boom, we designed an additional magnetic frame that can generate force of 1960 N. The sensor boxes were firmly attached to each joint and prevented to drop by any force from backhoes movement. We also measured the behavior of the backhoe in loading works in hot conditions over 30 °C and visualized backhoe pose and tip manipulator position.

Infrastructure is vital for economic development and growth and the destruction of infrastructure could lead to economical losses and fatalities. Periodic inspection and maintenance must be performed to avoid such incidents. However, inspection, which was traditionally performed manually, is laborious, expensive, time-consuming, and unsafe for the human inspector. UAVs have been proposed in recent studies as an alternative for conducting infrastructure inspection. In this paper, a system comprising a quadrotor UAV, passive rotating shell mechanism, horizontal rotor, and hammering device is proposed to provide a robust solution for performing hammer test in an infrastructure — a complex-structured site. Each subsystem is responsible for a vital function. The UAV acts as the main platform for efficient and safe inspection, the passive rotating hemispherical shell mechanism ensures protection and better stability during a collision with the obstacle, the horizontal rotor helps with the hammering action, and the hammering device performs the task. The paper describes the general idea, design and analysis of main subsystems, fabricated prototype, and conducted flight experiments. The capabilities of the proposed system were verified by conducting flight experiments. The passive rotating shell mechanism is shown to be effective against obstacles while the horizontal rotor is helpful in hammering action.

The aim of this work is to investigate rotational millimeter wave sensor for autonomous navigation in extreme environmental and weather conditions. The proposed research describes the development and deployment of efficient millimeter wave radar system for mobile robotics as a primary range sensor to allow for localization and mapping. In fact, in highly demanding weather conditions, conventional sensors for outdoor navigation, like ultrasound, lasers and optical sensors have known limitations, that may be at least overcome using the Millimeter Wave Radars. Specifically, our contribution focuses on the extraction of range and velocity information from the data collected by rotating the antennas of a millimeter wave radar at different speed profiles: 360° rps, 180° rps and 36° rps. Experimental validation was performed in foggy conditions to test the robustness of the proposed sensor in a realistic scenario, showing that distances can be acquired in the range of 1 to 40m, at a suitable rate.

It is a significant challenge to detect a transparent object using conventional visual sensors. In this paper, we show that the characteristics of transparent objects under different lighting conditions (normal light and laser light) can be exploited for improved detection accuracy. The authors analyzed the object characteristics and found a novel method for transparent object detection. GrabCut[11] method is used for the image segmentation. However, the transparent object cannot be detected from color or depth images using GrabCut, because transparent objects always shows the color of background. So, we propose a method of transparent object detection using not only color image but also laser reflectance intensity image. Highlight spots from color image can be used for detection candidate areas of transparent objects. These candidate areas is used for GrabCut as bounding rectangle input. Thereafter, segmentation by GrabCut is applied to depth images and laser reflectance intensity images. Bottle-shaped transparent objects are correctly detected within short distance by the visual sensor using the proposed method. In addition, other evaluations show the robustness and the limits of our method for different shapes, materials, distance and background.

The authors developed a robotic control vehicle for measuring the radiation in the Fukushima Daiichi Nuclear Power Plant. There are a lot of hotspots in the nuclear power plant (over several tens mSv/h). Heavy radiation prevents humans from searching and reconstructing it. It is essential to measure the radiation to ensure worker safety. The developed robotic control vehicle can measure radiation using a γ-cam and TALON with a radiation sensor. A heavily shielded operation box was built for reducing the exposure of radiation to 1/3. Two operators control the TALON and the γ-cam from the shielded operation box. Because of its pinhole mechanism, the γ-cam needs to know the distance to the targets. The 3-D light detection and ranging (LIDAR) was built for distance measurement. It has wide measurement range of up to 20m. Using the 3-D LIDAR and the shielded operation box can reduce the exposure during radiation measurement. The use of the developed robotic control vehicle can realize safe radiation measurement.

The authors are researching about Three dimensional mapping using mobile robot and 3-D laser scanner. We developed 3-D laser scanner which can measure whole 3-D shape with a combination of 2-D laser scanner and Pan-Tilt base. However, measuring surrounding areas using the scanner on mobile robot, there are some areas where can't measure whole 3-D shape caused by overview camera and wireless LAN's aerial mounted on a robot. In this paper, 3-D laser scanner can measure uniform and whole 3-D shape, which tilts constant value around pitch axis and then rotates one revolution around yaw axis. We propose measuring method that decrease effects of hidden objects by making offset between 2-D laser scan plane and pitch axis.

This thesis describes a new method that in real time predicts fall and collision in order to support remote control of a tracked vehicle with sub-tracks. A tracked vehicle has high ability of getting over rough terrain. However, it is difficult for an operator at a remote place to control the vehicle's moving direction and speed. Hence, we propose a new path evaluation system based on the measurement of environmental shapes around the vehicle. In this system, the candidate paths are generated by operator inputs and terrain information. For evaluating the traversability of the path, we estimate the pose of the robot on the path and contact points with the ground. Then, the combination of translational and rotational velocity is chosen.

The authors aim at the development of a 3D laser scanner that can measure uniform and dense 3D shape of static objects in dynamic environment. The 3D scanner was composed of a 2D Laser Range Finder (LRF) and Pan-Tilt base. 3D shape is measured by rotating 2D LRF that is tilted around the two axes. The laser point trajectory shows cross scan. Use of cross scan achieved the wide view angular and the uniform 3D scan. The proposed 3D scanner can adjust the measurement area and the density of 3D point clouds by changing the angle and angular velocity of the pan-tilt mechanism. The 3D scanner can decrease 3D measurement time. In addition, this 3D scanner measures same area twice during one 3D scan. Comparing these two measurement distances, the moving object can be detected.

A tracked mobile robot has high mobility and stability to get over rough terrain by changing its form according to environments. However, it is hard for an operator to control the mechanism skillfully by remote control. One of the solutions of the problem is an implementation of an autonomous control system. A detection of distributed contact points between the crawlers and an environment enable the autonomous control. In this paper, the authors propose a distributed contact sensor for tracked vehicle. In order to apply touch sensors to each track shoe, a problem of electric wirings has to be solved because the crawler is rotating continuously. In our proposed method, contact points are detected by measuring inclination of track shoes optically. For optical sensing of the inclination, a special reflector is designed and evaluated. The authors developed a method for distributed contact sensing of tracked vehicle, and examined whether the sensor can detect contact point during the step climbing motion.

A rescue crawler robot having flipper arm has high ability to get over rough terrain, but it is hard to control its flippers in remote control. The authors aim at development of a semi-autonomous control system for the crawler robot. In the system, moving direction is specified by an operator at remote place. Joypad (Sony PS2 controller) is used as input devise. For increasing its stability and robustness about change of the environment, its flippers are controlled according to sensor informations which can be obtained in real-time. Concretely, the robot recognizes the environment (upward step or downward step) using its physical model, its postural information, flippers' contact and distance between the body and ground, and controls these flippers. In this movie, we show you performance of our proposed control method using "Aladdin".

A rescue crawler robot with flipper arms has high ability to get over rough terrain, but it is hard to control its flipper arms in remote control. The authors aim at development of a semi-autonomous control system for the solution. In this paper, the authors propose a sensor reflexive method that controls these flippers autonomously for getting over unknown steps. Our proposed method is effective in unknown and changeable environment. The authors applied the proposed method to Aladdin, and examined validity of these control rules in unknown environment.

A new phase contrast imaging system that permits a quantitative observation of phase distribution of a general object is proposed and experimentally demonstrated. This is realized by implementing the phase shifting technique in the phase contrast imaging system. A dye-doped nematic liquid-crystal (NLC) is newly employed for this purpose as a variable phase filter in contrast to the constant phase plate employed in the conventional phase contrast microscope (PCM). The dye-doped NLC provides a practical advantage to the system that realizes an alignment-free optical system for the phase plate. The self-alignment property of the phase filter is realized by utilizing the local phase transition from the liquid-crystal to liquid, which is induced by the relatively strong incident light of the specular component of the object. In the experiment, the fundamental phase modulation property and the response of phase modulation ability were measured as a function of incident power of light. Next, the phase measurements were performed with several phase gratings and composite objects having different phase amplitudes and absorption. As an experimental result, the usefulness of the proposed method was confirmed, and the accuracy of the phase measurement was estimated to be λ/40. In addition, it was also demonstrated that the phase information could be obtained independently from the absorption component of the object.