Boom Movements Research Articles

Spray Boom Motions and Spray Distribution: Part 1, Derivation of a Mathematical Relation

Undesired vertical and rolling rigid body motions and excessive horizontal movements of the spray boom are some of the main sources of an irregular spray pattern. The algorithm presented in this paper, relates unevenness in spray deposition with these spray boom motions. The method is computationally attractive since no advanced mathematics are involved. The three dimensional static spray distribution model of a nozzle which can be measured quite easily under laboratory conditions is used to calculate the spray deposit distribution generated by the same type of nozzle mounted on a moving spray boom.

A modelling procedure for linearized motions of tree structured multibodies—2: Design of an active spray boom suspension on a spraying-machine

In part 1 of the paper, the linearized equations of motion of a multibody system have been established. In this part, the method is used to compute the equations of motion of a spraying-machine consisting of 10 bodies. Tyres are represented by the tyre model of Crolla. The contact length tyre-ground which determines the low-pass filtering quality for the tyres, is also taken into account. Through a smaller nominal model that has been derived directly from the multibody model, an active spray boom suspension is designed with the aid of the linear quadratic Gaussian method with loop transfer recovery. A hydraulic actuator counteracts undesired rolling of the tractor by rotating the spray boom in the opposite direction, such that the distance between the spray nozzles and the field crops remains within an acceptable range. In the simulations, compensated and uncompensated spray boom motions are generated by driving the machine over some incompressible standardized tracks and corresponding spray deposit distributions are generated.

Evaluation of the quality of spray distribution from boom sprayers in practical conditions1

The quality of distribution from field sprayers involves many parameters. Distribution is affected by environmental conditions. It also depends on static parameters concerning the boom at rest, and dynamic parameters involving boom movements. Field measurements at the Biologische Bundesanstalt (BBA) have shown the importance of the dynamic criteria. To avoid the effect of environmental parameters. one solution is to use a track simulator. A method has been developed at Cemagref (FR) to simulate distribution on soil from measurements of boom movements on the track simulator. Other evaluation methods have been dcvcloped by other laboratories. Two EU research programmes are now under way to develop test methods for field sprayer booms. The aim of the first is to compare the methods used to show the effect of boom movements. The second concerns the development of a test method for inspecting sprayers on firms. The results of these two projects will be used for the elaboration of an IS0 standard.

Comparison of Two Methods for Judging Distances Near Overhead Power Lines.

Sixteen certified crane operators performed several series of boom movements toward a segment of a typical power line using a 100-ton lifting capacity crane equipped with an 18-m boom, a single lifting cable, and a hard ball hook. The operators were instructed to stop the crane movement when the lifting cable reached the edge of the danger zone located 3 m from the power line. To achieve each maneuver, they evaluated the distance between the nearest wire and their crane using two methods: free sighting and the use of highly visible markers delineating the edge of the danger zone. The dependent measure was the distance between the lifting cable and the edge of the danger zone. Results showed that operators were generally unreliable when judging the distance between their crane and the power line when sighting the power line directly, but the use of markers proved to be much more precise and reliable in targeting the edge of the danger zone.

Vibrations of the Low Power Atmospheric Compensation Experiment satellite

The Low Power Atmospheric Compensation (LACE) satellite dynamics experiment has measured vibrations of an orbiting satellite from a ground site and has observed the excitation of satellite vibrations by a sequence of boom movements. The preprogrammed boom movements were initiated by commands from a ground control site and observed by the Massachusetts Institute of Technology Lincoln Laboratory Firepond laser radar facility located in Westford, Massachusetts. In the tests, a narrow-band heterodyne COi laser radar, operating at a wavelength of 10.6 /Ltm, detected vibration-induced differential Doppler signatures of the LACE satellite. Augmentation of vibration amplitudes was achieved through timing of repeated boom movements. Evidence of open-loop vibration damping by this method of repeated boom movements was also obtained, although the data were not conclusive since only a single attempt at open-loop damping was observed. The tests have demonstrated the feasibility and advantages of using relatively low cost ground-based observation techniques for vibration measurements and health monitoring of orbiting structures and for improving the accuracy of mathematical models for the structural dynamics of light, flexible space structures.

A Model for Measuring the Effect of Tire Pressure and Driving Speed on Horizontal Sprayer Boom Movements and Spray Pattern

There are a number of reasons for incorrect spray distributions but horizontal boom vibrations, effected by soil unevenness, are a major cause of irregular spray patterns. A modal model of a flexible sprayer boom was developed, based on experimental measurements and modal analysis techniques to investigate horizontal boom vibrations and the related spray pattern. Field input forces were simulated with a tractor and mounted sprayer driven over a standardized bumpy road. The modal model and the input force were combined in a forced response technique to simulate the boom movement by which the spray deposit distribution was computed. A comparison of the spray patterns with different tire pressures and driving speeds gave an optimal range of use for the tested sprayer, tractor, and tires. This method allows rapid testing of new sprayer designs.

Study and Development of a Test Method for Spray Boom Suspensions

Spray booms are equipped with suspensions to reduce the influence of boom movements and so minimize the non-uniformity of spray distributions on crops. The quality of suspensions can be estimated in terms of distribution regularity. Spray systems were tested on a track simulator which is able to reproduce ground irregularities under the wheels of a self-propelled vehicle. Boom positions were observed with an infra-red sensor and related to the simulated ground. Distribution patterns under a boom equipped with flat fan nozzles were investigated by measurements on a patternator. The effect of boom position was studied for height above the crop and boom tilt angle in the vertical plane. Heterogeneity of sprays from the same manufacturing series are an important factor in causing variations. Spray overlap was shown to modify the distribution pattern. A program was developed from these observations to compute a theoretical spray distribution pattern on soil. A map of volume distribution is drawn depending on boom movements, on tractor velocity and on spray parameters. Statistics and image analysis provide interpretation tools. Variations caused by boom movements are very important when compared with those caused by the nozzles themselves. The use of this set of tools for boom suspension testing is discussed.

Distribution of dye deposits from a small-plot track sprayer on biological and artificial targets

The design and operation of a portable track sprayer for small-plot deposition evaluations are described. Boom movement was regulated through an electrostatic clutch that provided rapid acceleration then constant speed. The drive mechanism together with a fixed boom path provided consistent deposits over a defined 6.4 m 2 sampling area. When nozzles were orientated downward and operated at selected pressures or heights, volumes of deposits on wheat heads were 37–45% of those on paper strips. Total variability in deposits was higher on wheat heads [coefficient of variation (CV) 36.4–39.3] than on paper strips (CV 11.3–13.8). Heterogeneity indices, derived from variance components, identified important sources of variation. Random variation and across-boom variation were ≈ 15–20% higher on wheat heads than on paper strips. Volumes of deposits on both target surfaces fluctuated in a cyclic pattern between ( d b) and below d n) nozzles. Fluctuations were more pronounced on wheat heads ( d b/ d n = 1.5−1.9) than on paper strips ( d b/ d n = 1.1−1.2) when nozzles were orientated downward. When nozzles were orientated forward rather than downward, volume and uniformity of deposits on paper strips declined by 3% and 9%, respectively. In contrast, volumes of deposits on wheat heads increased by 51–57%, CV values declined by 9–23% and across-boom variation declined by 17–28%. Fluctuations in deposits were reduced markedly ( d b/ d n = 0.9−1.1). Deposits were most uniform at 200 kPa and 0.40 m spray path. These conditions also would reduce potential drift. Findings indicated that droplet trajectories were the most important factor influencing deposits on wheat heads, especially those positioned directly below nozzles.

The design and performance of a gimbal-type mounting for sprayer booms 2. Optimization model and validation

An empirical approach had already indicated that the gimbal-type mounting is effective in reducing movement of a sprayer boom. This mounting involves springs and viscous dampers and it was concluded that the effects of these would more readily be optimized by calculation than by further experiments. An analysis was made of the dynamics of the gimbal mounting and a computer model developed by means of which the value of viscous damping could be optimized for a spring stiffness by searching for the minimum value of an output function integrated over a range of components of an input power spectrum. Power spectra for roll and yaw were calculated from data recorded at three speeds over the standard bumpy test track. The polar moment of inertia of the boom was determined by bifilar suspension. Optimum values of damping were computed for ranges of natural frequencies. The experimental gimbal mounting was rebuilt to facilitate tests at ranges of polar spring stiffness and polar damping coefficient. The conditions giving minima in the response obtained were found to agree well with the values predicted by the computer model.

The design and performance of a gimbal-type mounting for sprayer booms 1. Development procedure

A spray boom suspension comprising horizontal and vertical pivots through the centre of gravity of the boom was developed. With this pair of mutually-perpendicular pivots—a gimbal-type of mounting—the boom was restrained in both planes by tension springs and movements were restricted by viscous dampers. Measurements were made of its effectiveness in reducing undesirable spray boom movements. Comparability of test conditions was ensured by making runs over a standard bumpy test track. The horizontal pivot considerably reduced vertical boom tip movements and the vertical pivot reduced the yawing movement of the boom. It was recognized that the values of spring stiffness, damping coefficient and boom inertia profoundly affected behaviour and that optimum values of each would more effectively be determined by analytical than by empirical methods. The trial arrangement of the gimbal mounting was more effective in reducing transmission to the boom of the rolling and yawing movements of the sprayer frame than both a commercial, vertically-sprung suspension and a simple, experimental, pendulum arrangement.

Comparison of helmet-mounted visual displays for flight simulation

The objective was to determine if there are performance differences among pilots accomplishing simulated aerial refuelling using five different visual display configurations. The displays were all used in the A-10 cockpit of the Advanced Simulator for Pilot Training (ASPT). The configurations were (a) a helmet-mounted binocular display, (b) lead lanthanum zirconate titamate (PLZT) goggles (binocular) used with one channel of the ASPT display, (c) a helmet-mounted biocular display, (d) the ASPT 300° field-of-view (FOV) dodecahedron display, and (e) the ASPT display masked to present an FOV equal to that of the helmet-mounted displays. Forty subjects participated in this effort: eight per display condition. After an initial practice period, the subject's first task was to estimate distances behind the refuelling tanker while the A-10 was flown automatically to the contact position. The pilots then flew the refuelling task three times. Dependent variables measures were the oscillation of the A-10 receiver receptacle around the centre point of the acceptable refuelling boom movement envelope in three dimensions. The results show that the subject's ability to estimate distance does not differ significantly among the display configurations. Although performance measures were recorded during both the approach and contact phase of the refuelling task, a computer malfunction negated the value of the approach measures. Measures obtained during the contact phase clearly indicate the value of a wide FOV and of stereoscopic depth cues. Optics in front of the eyes were shown not to be detrimental, and the helmet-mounted stereoscopic display proved superior to the PLZT goggles.

The dynamic behaviour of field sprayer booms

The wide variations in spray deposit which were found in an earlier survey to occur in field spraying operations were mainly ascribed as an effect of the errant behaviour of sprayer booms. It was suggested that vertical and horizontal boom tip movements resulted from rotational motions of the sprayer. Measurements were taken of the movement of the booms and sprayer frames of a representative sample of sprayer types and sizes operating in typical cereal spraying conditions. It was concluded that whilst there are some features which would be best avoided in boom design and construction the main cause of boom movements was the transmission to the boom of the rapid rolling motion of the sprayer. For better stability booms should be constructed as stiff beams and attached through suspensions which isolate them as much as possible from the rolling motion.

The effect of spray-boom movement on the liquid distribution of field crop sprayers

Vibrations of the spray-boom of field crop sprayers affect liquid distribution in a negative way. In field studies the intensity and character of the vibrations of boom-ends of four tractormounted field crop sprayers were studied in the horizontal and vertical planes. Based on the results of power spectral density functions and the results of filmed boom movements, the effects of vibration of well-known amplitude, frequency and direction on liquid distribution of hollow and full cone nozzles and flat-fan nozzles were studied under laboratory conditions.

A fluorescent tracer technique for determination of the liquid distribution of field crop sprayers

A fluorescent tracer technique is described for the examination of evenness of liquid distribution by moving field crop sprayers and the sensitivity of different types of nozzles to the movement of a spray boom.

The Located Factors of Sericultural Area in Iwate Prefecture

In this research and investigation, by using labour force as indication, the author analysed the located factors of sericultural industry in Iwate Prefecture, situated in north-eastern Japan.1) Research of the region has been classified into three areal groups: (A) Northern dry-field farming area, where extensive agriculture is carried on, and spring cocoon crops are the main production. (B) Southern dry-field farming area, where intensive agriculture is carried on and spring cocoon crops are the main production. (C) Paddy-field farming area of Kitakami Basin, where the ratio of sericulturists is rather low and summer-autumn cocoon crops occupy more than half of the whole year cocoon production.2) The common characteristic in the each area of sericultural industry, classified into three group types, showed that most of the inhabitants in these areas can still get a decent livelihood from their own silkworm raising income, though cash income has fairly decreased compared with prewar days.3) On the position of management: there are a few dominant differences in these three areas, in respect to the basis and structure of productions.As the inhabitants keep on with the management, acting self-sufficiently, in the northern dry-field farming areas, there is no relation of competition that comes into existence between the sericultural industry and the cropped rotation of cereals (the order cropped cereals) and seasonal distribution of labour forces.The sericultural management, in the southern dry-field farming area, Iwate Prefecture, has been formed parallel with the commercial crops, ensuring a direct profit to the inhabitants and the rice-culture as a countermeasure in preparation for industrial fluctuation. A downward movement of the postwar boom, however, brought a change in the position of sericultural management. By the connection between arable land and labour force; on the other hand, the introduction of new efficient management is not easy. So, traditional silkworm raising is compelled to be carried on between the former, and a newly risen management methods, for the sake of increasing the cash income in the family budget.The sericultural management, in the paddy-field farming area, Kitakami Basin, is kept by the surplus labour of rice-culture. Because introduction of a new management method is difficult, in this area, with the exception of the normal rice-culture. This is a far cry from the pattern of dry-field farming areas.