Measurements of the horizontal sprayer boom movements by sensor data fusion

A study investigated the horizontal movements of trailed sprayer booms with the aim of distinguishing their yaw and jolt motions as well as their deformations. Two vehicles were equipped with a radar speed sensor and a three-axis dynamic measurement unit, while each boom was instrumented with ultrasonic sensors and accelerometers. Sensor fusion was used to extract yaw, jolt and deformation speeds by assuming that the motion of any point of the boom is equal to the superimposition of complementary high and low-frequency motions, delimited by a cut-off frequency, estimated on the basis of laboratory trials. Tests performed on trailed sprayers equipped with 22 and 24 m boom lengths, on different soils, indicated that yaw, jolting and deformation, respectively, occurred near 0.3, 2 and 1 Hz. Velocity variations relative to the forward speed of the vehicle were lower than 0.57 m/s and were reached at a speed of 3.5 m/s (12.7 km/h). Ground deposit, roughly estimated as proportional to the inverse of the speed, exhibited coefficients of variation between 4 and 6% for all tests. (C) 2002 Elsevier Science B.V. All rights reserved.