Author(s): P. SARKAR

Abstract: A broad overview of the various techniques of fruit harvesting in the field and greenhouse is presented in this paper. Fruits are harvested mechanically or by using a robotic arm which reduces labor requirement. Mechanical harvesting is not suitable for damage-prone fruits. The detachment of fruits by shaking the tree at trunk, limb, or canopy or by oscillation using air blast is considered as the mechanical harvesting system.The effect of shaking frequency and amplitude have been thoroughly discussed in this article. On the other hand, harvesting using a robotic arm is very much effective for high-value crops. The construction and working principles of various types of fruit harvesting robotic arms have been discussed along with their performance in terms of successful harvesting rate, execution time, etc. Grasping approaches for plucking fruits have been illustrated. Grippers with different mechanisms were reported with gripping efficiency. A significantly higher harvesting rate is obtained through mechanical harvesting over manual picking. The detachment of fruit by shaking mechanism has been implemented successfully with the highest fruit removal efficiency of 93.3%. The maximum picking rates of trunk shaking harvesters, canopy shakers, and manual pickers were found as 0.5 t h-1, 10 t h-1, and 25 t h-1, respectively. A higher harvesting rate was reported in the planned architecture of fruit orchards. On the other hand, well-designed robotic arms were found to be very accurate (highest 94.2% accuracy) and with very low cycle time (lowest 4-5 seconds). In the field operations, environmental factors like vibration, dust, occlusions, lighting conditions, etc., affect the performance of robotic arms. Manual harvesting process is still a better option in terms of higher harvesting rate and lower harvesting time. Hopefully, these research gaps will be fulfilled soon and the robotic arm will emerge as a suitable substitute for the manual harvesting technique.

DOI: 10.22271/09746315.2021.v17.i2.1444

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