Maximum Working Area Research Articles

Advancement in Thermoelectric Innovation: Crafting a Portable Climate Control System

Greenhouse gas emissions are on the rise globally due to increasing demands for electricity, vehicle usage, desertification, and inadequate waste management practices. In response to these challenges, a portable heater and cooler utilizing the thermoelectric effect have been developed. This device comprises four thermoelectric Peltier modules, a heat sink with four fans, two batteries, a charge controller, and a solar panel. The four Peltier modules, each capable of 50 watts, are interconnected in series and parallel configurations on the cover of a thermocol box. To ensure effective heating and cooling throughout the workspace, all modules are equipped with heat sinks and fans operating at 12V and 0.28A. To optimize thermal transfer, the Peltier modules are sandwiched between heat sinks using thermal paste, resulting in one side becoming hot and the other cold when power is supplied. These sandwich configurations are placed atop the thermocol box. Testing of the portable cooler and heater was conducted under various load conditions, including no load, 1 liter of water, and 2 liters of water, with batteries, for both cooling and heating. The fully charged batteries can power the entire experimental setup for 21 hours in each scenario. During cooling, the device achieved a minimum working area temperature (thermocol box) of 18.8°C under no load conditions and a minimum water temperature of 18.6°C for 1 liter of water. In heating mode, the experimental setup reached a maximum working area temperature of 42.4°C and a maximum water temperature of 33.3°C for 1 liter of water.

Development and evaluation of advanced safety algorithms for excavators using virtual reality

This study focuses on the development and evaluation of advanced safety algorithms for excavators using virtual reality (VR). An excavator typically operates under a stationary state with its working parts rotating 360° in coordination with nearby workers. During excavation, a fatal accident can occur due to operator carelessness and work site blind spots. Accidents due to collisions with nearby workers have been increasing. Accordingly, we presented safety system algorithms to prevent collisions with surrounding objects and secure the maximum working area in this study. We also evaluated the performance of safety system algorithms using VR. For risk assessment, we calculated the predicted working area through a kinematic analysis of the excavator’s working parts and accordingly conducted target selection of risk factors. We used time-to-collision and warning indices as safety indices for the safety assessment of the selected target and divided the excavator’s working modes into three categories: Safe, warning, and emergency braking modes. Control inputs, such as alarms and braking, were appropriately defined for each working mode. Under warning mode, workers can avoid collisions because a safety system will alert them of dangerous situations through an alarm. Under emergency braking mode, an emergency braking input signal is dispatched with an alarm to automatically prevent collisions. The advanced safety algorithm proposed in the study was developed in MATLAB/Simulink environment. The VR application was developed using a physics engine. On the basis of this application, the performance evaluation of the safety system algorithms was conducted on the frequently occurring sticking scenario.

Layer-Cluster Topology Sensor Node Deployment for Large-Scale Multi-Nodes of WSN

In the process of data collection for wireless sensor networks based on large-area multiple nodes, the utilization rate and energy efficiency of existing methods of nodes deployed in the network are relatively low. Therefore we propose hybrid layer-cluster topology method for large multi-node deployment in wireless sensor network in this paper. Data acquisition for each region is assigned to each cluster which is composed of cluster head node and ordinary nodes divided by the hexagon deployment strategy. Star-structure network is adopted between ordinary nodes and cluster head node, each cluster is connected by mesh-structure network. On this basis, the hybrid hop routing method is used to communicate with base station based on critical distance, which saves the cost and improves the efficiency of the network perception. The experimental results show that the layer cluster hybrid topology model based on hexagon partition can reach the coverage rate of 100 % with the energy utilization rate increasing by 5.4 and 8.6 % on the condition of relatively few deployed sensor nodes, compared to quadrilateral partition and random deployment model. This method overcomes the disproportion of the energy consumption and improves the information redundancy in the process of transmission, and can cover the maximum working area along with the longest survival time of the network by reducing energy consumption. This method is an effective solution to the problem of node deployment of large-scale sensor nodes in wireless sensor networks.

CNC Paths Optimization in Laser Texturing of Free Form Surfaces

Laser Texturing and Laser Engraving of free form surfaces are interesting alternative to EDM and micro milling in the fabrication of moulds and dies. The material removal rate of this process is typically very low and the maximum working area is limited by the maximum travel range of the galvanometric scanning head and also by the maximum deflection of the scanner or the surface curvature. As a consequence, in order to manufacture large or free form surfaces, a set of placements of the scanning head respect to the work piece must be calculated and controlled by the CNC.The number of these placements can be quite high due the small amount of material removed in each of them and the non-operative time spent to move the scanning head can be relevant compared to the overall time. In this work a method based on the solution of the Traveling Salesman Problem is proposed with the aim to optimise the number of displacements of the scanning head and generally in order to reduce the number of movement of the numerically controlled axes.The method that takes into account both the architecture and the dynamic characteristics of a 5 axis CNC system was implemented in the CALM (Computer Aided Laser Manufacturing) software used to program the laser path for part texturing and applied in industrial cases.

Influence of Sportswear Shape on Dressing Motion and Muscle Activity in Dummy Elderly Persons

The long-term goal of this study is to design sportswear for the elderly. Previously, we reported dressing motion and muscle activity on young and dummy elderly persons while they are putting on four different styles of sportswear: long-sleeved, sleeveless, zippered, and zipper-less. In the part of the study reported in the present paper, we photographed their movements while they were putting on the four styles of sportswear and measured the wearing time, maximum working area, and muscle activity. Further, we investigated how the sportswear style influenced the psychological burden. From motion analysis, we found that, when the dummy elderly persons pass an arm through the sportswear at process (2), the wearing times for sleeveless sportswear were lower than those for long-sleeved sportswear. In addition, the maximum working area and %MVC (percentage maximum voluntary contraction) values for zippered sportswear were higher than those for zipper -less sportswear. When wearing the sportswear at process (3), the maximum working area and %MVC values for zipper-less sportswear were higher than those for zippered sportswear. From these results, it was concluded that the sportswear style influences wearing time, maximum working area, and muscle activity.

Workspace and sensitive postures of planar open-loop manipulators

In this paper, the equation of reachable area of planar 3-arm robots and the recursive algorithms for calculating the accessible area of planar n-arm robots are presented. The optimum link ratio leading to the maximum working area is investigated and the resulted design charts are provided. The rate of change of the accessible area with respect to an input angle is proposed to measure the sensitivity or dexterity of a posture to an input angle. Examples showing the most sensitive postures and their positions in the workspace are also given.

人間機械系に関する研究 : 上肢の作業域について

Machines and tools in a work situation should be within the reach of arm movements of the operator in his sitting posture. In other words, the operator should not be required to leave his normal working position to operate his machine. The normal working area and maximum working area of the arm in three dimensions were measured. The equations related or a nomograph was constructed from the measurement data, from which can be known the necessary values associated with the total span. This nomograph would be of aid to designers of various industrial machines. In arm movement the shoulder or elbow does not stay at a fixed point, but rather moves outward or upward. The movement of the scapula occurs with that of humerus. The arrangement of controls in the working area should be evaluated also from other aspects.

Decomposition constant of polonium: E. v. Schweidler ( Verh. Deutch. Phys. Ges., xiv, 536)

Laser Texturing and Laser Engraving of free form surfaces are interesting alternative to EDM and micro milling in the fabrication of moulds and dies. The material removal rate of this process is typically very low and the maximum working area is limited by the maximum travel range of the galvanometric scanning head and also by the maximum deflection of the scanner or the surface curvature. As a consequence, in order to manufacture large or free form surfaces, a set of placements of the scanning head respect to the work piece must be calculated and controlled by the CNC.The number of these placements can be quite high due the small amount of material removed in each of them and the non-operative time spent to move the scanning head can be relevant compared to the overall time. In this work a method based on the solution of the Traveling Salesman Problem is proposed with the aim to optimise the number of displacements of the scanning head and generally in order to reduce the number of movement of the numerically controlled axes.The method that takes into account both the architecture and the dynamic characteristics of a 5 axis CNC system was implemented in the CALM (Computer Aided Laser Manufacturing) software used to program the laser path for part texturing and applied in industrial cases.