Effect of force feedback on a bulldozer-type robot
Utilizing remote-controlled robots in damage restoration activities in disaster-affected areas such as those affected by a debris avalanche or an earthquake has significantly increased. Various types of remote-controlled robots have been successfully used along with construction machines in damage restoration activities in disaster-affected areas. Recently, a bulldozer-type robot removed the earth and sand deposited over a wide area because of a debris avalanche. To enable prompt damage restoration activities in disaster-affected areas, an efficient remote operation using robots is required. We study a remote-controlled bulldozer-type robot that moves objects using a system wherein the status of the stress applied on the bulldozer blade is provided as a force feedback to the operator. After conducting evaluation experiments, we could verify that the operating system providing force feedback to the operator shortened the operation time compared with the one that displayed visual information only on the operating screen.
Effects of visual information on a remote-controlled mobile robot
To efficiently perform work using a remote-controlled robot, an image display device that allows the operator to verify the working area from a single view is necessary. Furthermore, this device should provide high-resolution images of locations so that the operator can recognize depths in detail. To meet these requirements, conventional three-dimensional image devices used multiple cameras and display screens for the right and left eye. In this study, we developed a video device that employs a camera and a display, which records a wide range while providing high resolution for the central part of the images using a mirror. The effectiveness of our device was confirmed through an evaluation experiment using a remote-controlled work robot. The results indicated that using the transmitted complex display, the operator can utilize high-precision space information and respond to a wide range of changes in the surrounding environment. It was thus confirmed that the remote-controlled operation could be conducted with improved accuracy and in a shorter time.
Palm oil shell aggregate for lightweight concrete
Publisher Summary Increased agricultural production and the development of agro-based industries in many countries of the world have brought about the production of large quantities of agricultural wastes, most of which are not adequately managed and utilized. Low-cost building materials can be produced using inexpensive indigenous raw materials. Agricultural wastes that are renewable and are found in abundance in many countries present an interesting alternative to the traditional and sometimes imported building materials, particularly for low-cost construction. The use of agricultural wastes as aggregates in lightweight concrete can provides an alternative to conventional methods for the production of lightweight concrete. Lightweight concrete results in a reduction in the overall deadweight of a structure and provides a significant saving in the overall cost of construction. The use of less expensive alternative lightweight aggregates in the production of the concrete can provide further reductions in expense. The material properties and structural performance of lightweight concrete with palm oil shells as aggregates are similar to lightweight concrete produced using the more common lightweight aggregates such as clinker, foamed slag, and expanded clay. The palm oil shells are hard and are received as crushed pieces because of the process used to release the oil. Manual sieving is necessary to remove the large amount of fine particles. The shells are then air-dried before use. Because the palm oil shells are lighter than the cement matrix, the shells tend to segregate in wet concrete mixes. On the other hand, dry mixes using palm oil shells are relatively more difficult to work with when compared to ordinary concrete. Trial mixes are necessary to achieve a good mix design.