HighlightsAn end-effector with two degrees of freedom (2R) was developed for pruning apple trees.A rational 2×2 relationship (R2 = 0.93) was found for ‘Fuji’ apple tree branch diameter and cutting force.Simulation showed that the cutter can be aligned in a wide range of orientations in a spherical workspace.The developed end-effector was able to cut branches up to 12 mm in diameter.Abstract. Robotics and automation technologies are now used extensively in agriculture, while production operations for tree fruit crops still largely depend on manual labor. Manual pruning is a labor-intensive and costly task in apple production. Robotic pruning is a potential solution, but it involves several challenges due to the unstructured work environment. This study focused on designing an end-effector prototype for pruning considering the maneuvering, spatial, mechanical, and horticultural requirements. Branch cutting force was measured with a thin force sensor to provide guidelines for the end-effector design. The test results indicated the relationship between the force required to cut different diameter branches with an R2 value of 0.93. The end-effector was developed using two rotary motors, a pneumatic cylinder, and a pair of bypass shear blades. A three-directional linear manipulator system and a control system were built for moving the end-effector to targeted locations. A mathematical model was developed for simulation of the workspace utilization and reachable points of the end-effector. The simulation results indicated that the end-effector can be aligned in a wide range of orientations of the cutter. Field tests were conducted for validation of the simulation results and performance assessment of the end-effector. The results indicated that the end-effector with the current parameter settings successfully cut branches up to 12 mm in diameter and was able to cut branches in a wide range of possible orientations in a given 3D space. The robotic end-effector developed in this study is a core component of an automated pruning system for fruit trees. In future work, an integrated manipulator system will be developed for branch accessibility with collision-free trajectories. Keywords: Malus × domestica (Borkh.), Pruning end-effector, Reachable-points simulation, Tree pruning.
The intuitionistic fuzzy entropy has been widely used in measuring the uncertainty of intuitionistic fuzzy sets. In view of some counterintuitive phenomena of the existing intuitionistic fuzzy entropies, this article proposes an improved intuitionistic fuzzy entropy based on the cotangent function, which not only considers the deviation between membership and non-membership, but also expresses the hesitancy degree of decision makers. The analyses and comparison of the data show that the improved entropy is reasonable. Then, a new IF similarity measure whose value is an IF number is proposed. The intuitionistic fuzzy entropy and similarity measure are applied to the study of the expert weight in group decision making. Based on the research of the existing expert clustering and weighting methods, we summarize an intelligent expert combination weighting scheme. Through the new intuitionistic fuzzy similarity, the decision matrix is transformed into a similarity matrix, and through the analysis of threshold change rate and the design of risk parameters, reasonable expert clustering results are obtained. On this basis, each category is weighted; the experts in the category are weighted by entropy weight theory, and the total weight of experts is determined by synthesizing the two weights. This scheme provides a new method in determining the weight of experts objectively and reasonably. Finally, the method is applied to the evaluation of railway reconstruction scheme, and an example shows the feasibility of the method.
“Probability theory and mathematical statistics” is an important public compulsory course of arithmetical foundation. MATLAB software is introduced into the teaching process to make some abstract concepts and theorems expressed in the form of graphics to achieve visualization effect. This method makes it easy for students to understand, improve their learning enthusiasm and achieve twice the result with half the effort.
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