Design of Improved and Semi-Automated Red Raspberry Cane Bundling and Taping Machine Based on Field Evaluation

Abstract

Abstract. Canopy management activities such as bundling, tying, and pruning are labor-intensive operations in red raspberry production. These activities are responsible for about 50% of the total production cost, the majority of which is spent on bundling and tying canes. In a previous study, a cane bundling and tying mechanism was developed to bundle red raspberry primocanes and wrap adhesive tape around them in an experimental red raspberry plot, with an overall success rate of 83%. The prototype was fabricated primarily for functionality evaluation, which was limited by size and precision issues. Based on the findings from that study with the first prototype, an improved mechanism with novel components was designed and fabricated to increase the accuracy and efficiency of operation in the field. The bundling and taping process was automated using a machine vision system for cane detection and localization. The time required for the mechanism to complete the bundling and taping process was decreased from 3 min to 30 s. The improved system achieved an overall success rate of 90% when tested in a red raspberry plot. The durability of two types of adhesive tape (used in the taping mechanism) in holding the bundled canes together was also evaluated. Forty-five red raspberry plants were randomly selected and tied with type I tape (tensile strength of 316 N m-1) and type II tape (tensile strength of 27 N m-1). The bundles were evaluated six months after tying. The failure of the tape to keep the cane bundles intact was significantly lower with type I tape (higher adhesive and tensile strength; two failures out of 39 tapings) compared to type II tape (seven failures out of 39 tapings). For yield comparison, manual tying was performed with baling twine (~5 mm diameter) on another 45 randomly selected plants. The mean fruit yield between machine taped and manually tied raspberry plants showed no significant difference (two-sample t-test, df = 88, p = 0.67) at 5% significance. All these results showed good potential for the development of a high-speed automated red raspberry cane bundling and taping mechanism. Keywords: Agricultural machinery, Automation, Cane bundling, Cane tying, Machine vision.