Development of a Round Bale Weighing System for Spring-Loaded Bale Ramps

Knowledge of individual hay bale weights can be beneficial to both the hay producer and the consumer. A weighing system that utilizes a pressure transducer has been developed for round balers that are equipped with a hydraulic kicker plate; however, a large amount of round hay balers on the market are manufactured with a spring-loaded bale ramp. The weighing system developed here tested two different sensors (accelerometer and gyroscope) mounted in three different locations of a model spring-loaded ramp to predict the weight of various cylinders (PVC pipe filled with concrete) as they were dropped on to the ramp. The sensor device was mounted at the end of the ramp furthest from the pivot point, in the middle of the ramp, and directly in front of the pivot point. Of the two sensors tested, a gyroscope was found to be the sensor with the lowest prediction error when correlating a peak response of the sensor to the weight of a cylinder. Accuracy of the sensor response was improved from an absolute error of 31.4% to 15.4% when the sensor was mounted directly in front of the pivot point of the ramp. The accuracy of the gyroscope was further improved to an absolute error of 3.6% by correlating a single axis response to cylinder weight for a particular diameter of cylinders. Repeatability of the test in a lab setting suggested that the use of a ramp-mounted gyroscope might be suitable to predict the weight of a bale as it is ejected from a round baler onto a spring-loaded bale ramp. In this configuration, the bale weight is estimated as a function of the peak angular rate of change of the ramp as it is forced to the ground. On-baler field data from a gyroscope mounted in front of the pivot point on a spring-loaded bale ramp showed promising results, but additional research is needed before conclusions can be made about the accuracy of a gyroscope under field conditions.