Design and experiment on mechanized batch harvesting of Shiitake mushrooms

Shiitake mushroom must be harvested in time or its commercial value will be reduced. At present, manual harvesting is time-consuming and labor-intensive, and the robotic selective harvesting is far from mature and marketable. Based on the analysis of manual harvesting, a mechanized batch-based harvesting method for the stick cultivation of shiitake mushrooms is proposed as an alternative harvest method in the scenario of large-scale factory production. The feasibility of the simplified picking method was verified by a data acquisition system with integrated force sensor and inertial measurement unit, and the picking force and picking action during manual picking were measured. A mechanized harvesting scheme by picking rings with forward forces to the mushroom stalk was proposed, and its finite element analysis concluded that the mushroom could be picked without damaging the mushroom by using a 5/10 size latex tube. A new mushroom Batch Harvesting Picker (BHP) was designed, including a pushing mechanism, a guiding mechanism, and a harvesting mechanism. By analyzing the causes of harvesting failure and mushroom damage, the stick surface profiling unit were improved by multi-body dynamics simulation. The simulation results show that when the preload force of the reset spring of the harvesting mechanism is set to 30 N, the least pressure on the mushroom stick is 8.97 N, and the picking ring working closer along the surface of stick. The experiment of BHP showed that the harvesting success rate is 98.93 %, the harvesting damage rate is 3.31 %, and the average harvesting time of a single mushroom stick is 9.8 s, which improved the harvesting efficiency of single stick by 2.2-6.6 times compared with the manual harvesting process, which proved the feasibility and efficiency of this batch harvesting scheme in large-scale factory production of shiitake mushrooms.