Operator Cabin Research Articles

A method for assessment of degradation of task visibility from operator cabins of field machines

Operator field of view is of primary importance for ergonomic, efficient and safe operation of field machines such as tractors, forest harvesting machines, and earthmoving equipment. This paper describes a technique that could be used for an objective assessment of operator cabin features that degrade the field of view.

Influence of forest machine function on operator exposure to whole-body vibration in a cut-to-length timber harvester

The influence of machine function (tree felling and processing, and machine movement over the terrain) on operator exposure to whole-body vibration in a cut-to-length (CTL) timber harvester was evaluated. Vibrations were measured on the seat and the cabin chassis in three orthogonal (x, y, z) axes for the tree felling and processing, and during motion on a test track. It was found that the level of vibration transmitted to the operator during felling and processing was mainly affected by the tree size (diameter). For tree diameter at breast height (dbh) range of 0.25 – 0.35 m that was investigated, the vertical (z-axis) vibration component during processing increased by up to 300%, and increased by 50% during felling. However, the associated vibration levels were not sufficient to pose any serious health risks to the operator for an exposure limit of 8 h. Vibration at the operator seat and cabin chassis was predominant in the lateral (y-axis) and vertical (z-axis) respectively, during vehicle motion over the standard test track. Vibration peaks of approximately 0.20 and 0.17 ms−2 occurred at 5 and 3.2 Hz respectively.

Influence of tyre inflation pressure on whole-body vibrations transmitted to the operator in a cut-to-length timber harvester

The influence of tyre inflation pressure on whole-body vibrations transmitted to the operator during the movement of a cut-to-length timber harvester was evaluated. Vibration measurements were taken in three orthogonal ( x, y, z) axes at tyre pressure settings of 138, 345 and 414 kPa. Vibration was predominant in the vertical (z) direction with the peak rms acceleration value for the operator seat (0.281 m s −2) occurring at approximately 3.2 Hz.The corresponding peak value for the operator cabin chassis was 0.425 m s −2 at 4 Hz.At 414 kPa, there was potential health risk on the operator for exposures above 8 h duration. The vibration total values recorded for the operator seat at the maximum tyre inflation pressure setting were classed as “fairly uncomfortable” (ISO standard 2631-1), and vertical seat vibration transmissibility was highest between 4 and 8 Hz at the 345 kPa tyre pressure setting. The recorded values of WBV were significantly reduced by a reduction in tyre inflation pressure which may therefore be used to moderate the magnitude of WBV on wheeled timber harvesters.

Comparative Performance Evaluation of Tele-Operated Pipe Laying

Excavation, in particular, trenching, presents a hazardous working environment for workers. Many deadly accidents still occur even though the Occupational Safety and Health Administration has increased its training for safe trenching. The work presented in this paper originated with the belief that the best approach to remedy this problem is technology. Its premise is the need to remove the workers from this deadly trap and replace them with a mechanical device capable of doing the work necessary to lay pipes accurately. Presented is the result of a comparative field evaluation designed to prove that such a technology is not only technically feasible, but also cost-effective. For this purpose, a tele-operated pipe manipulator was built, capable of being easily attached to an excavator bucket and controllable from the safety of an operator cabin. The new technology was subsequently evaluated during field tests using both qualitative and quantitative performance criteria. Data from the study clearly demonstrate that this technological intervention not only works as intended, but also promises to reduce the cost of installing pipes, especially with increasing trench depths.

Inhalation of radionuclides during agricultural work in areas contaminated as a result of the Chernobyl reactor accident

Radionuclide concentrations have been determined inside and outside the cabs of tractors operated on soils that are typical of the 30 km exclusion zone around the Chernobyl nuclear power plant. It was found that when the total plutonium deposit exceeded 3.7 kBq m − and the 137Cs deposit exceeded 7.4 MBq m −2, the levels of these radionuclides in the operator's cabin could exceed the maximum permissible air concentrations. However, due to the seasonal nature of work, the quantities of these radionuclides inhaled would not exceed the annual limit on intake. Dose to the lungs caused by the inhalation of hot particles has been addressed by either including or neglecting spatial dose distribution. The levels of risk of carcinogenic changes in cells of lung tissue calculated according to each of the two approaches have been shown to be of the same order of magnitude.

Human Operator Efficiency in Monotonous Transport Operations. Effects on Safety

The increasing automation of the operator's cabin as well as the longer distances travelled constitute factors likely to provoke lowered vigilance during critical periods in transport operations. The aim of this laboratory research is to study the capacity of the security system of French trains to detect decreases in vigilance. This system is based on the safety deadman circuit. In order to identify a relationship between motor behavior (activation of the pedal) and variations in vigilance (EEG, eyes blink frequency) a simplified monotonous driving task was used. Main results have shown that during periods of lowered vigilance some perturbations of motor behavior appeared. Futhermore, a degradation of performance in term of increased reaction time and omission of signals was observed during these phases. Main perspectives concern the use of such a system in the detection of decreases in vigilance on the field.

Health and safety measures for working in extremely hot environments

Studies have been made on the effects of exposure to extremely hot environments on health, and control measures were carried out both in laboratory and in industrial environments. The results showed that the characteristics of the workplace in extremely hot environments, such as soaking pit crane operator cabin, first-aid repair for smelting furnace, were high temperature (above 40°C), and high radiant heat (5–15 cal/cm2/min). Workmen suffered from a very severe physiological strain, even heat stroke. The measures, such as heat resistant clothing, drink for heat resistance and air conditioning, which may efficiently reduce or even eliminate the physiological strain, and raise labor efficiency during over-exposure to extremely hot environments.