Towards a Unified Taxonomy of Agricultural Harvesting Technologies: Linking Physical Interaction, Automation, and Selectivity
Organizations: Embrapa Agricultura Digital, Research Group on Scientific Computing, Information Engineering, and Automation, Campinas, Brazil · Embrapa, Information Technology Departament, Federal District, Brazill · University of Brasilia, Computational Linguistics, Federal District, Brazil
Abstract
Harvesting technologies have evolved from conventional mechanized systems based on bulk mechanical interaction toward increasingly automated and robotic systems capable of perception, decision-making, and localized actuation. This evolution has also created a classification problem, as harvesting systems are commonly described according to crop type, mechanical removal principle, sensing technology, robotic architecture, or degree of automation, making direct comparison difficult. This paper proposes a unified taxonomy for agricultural harvesting technologies based on two primary classification axes: the physical principle governing plant-machine interaction and the level of automation incorporated into the harvesting process. Selectivity is treated as an emergent functional attribute that expresses the biological and spatial scale at which perception and decision-making influence physical actuation. Conventional mechanized methods, including cutting, pulling, vibration, impact, brushing, pneumatic action, and combined systems, are analyzed together with semi-automated and robotic harvesting approaches. The analysis shows that increasing automation does not necessarily result in greater selectivity. A qualitative transition occurs when perception and decision-making directly influence product-level actuation, shifting harvesting from distributed or bulk interaction toward localized and selective manipulation. The proposed framework provides a common conceptual basis for positioning and comparing mechanized, automated, and robotic harvesting technologies. By separating the physical mechanism of product removal from the automation level and resulting selectivity, the taxonomy clarifies technological boundaries, identifies intermediate configurations, and supports the analysis and development of future harvesting systems.
Figures & tables
| Reference | Physical interaction | Perception/robotics | Automation | Selectivity | Unified cross-domain taxonomy |
|---|---|---|---|---|---|
| Droukas et al. [ 7 ] | Partial | Strong | Strong | Partial | – |
| Kootstra et al. [ 24 ] | Partial | Strong | Strong | Strong | – |
| Pu [ 34 ] | Strong | Partial | Partial | Partial | – |
| Rajendran et al. [ 35 ] | Partial | Strong | Strong | Strong | – |
| Zhang [ 43 ] | Partial | Strong | Strong | Strong | – |
| Present framework | Strong | Strong | Strong | Explicit attribute | ✓ |
| Requirement | Representative range or condition reported in the literature | References |
|---|---|---|
| Terrain slope | Lower than approximately 12–15%, supporting machine stability and operational safety | [ 1 , 8 , 22 , 29 , 30 , 32 , 42 ] |
| Row spacing | Crop-dependent spacing allowing adequate machine traffic and harvesting operation | [ 4 , 9 , 22 ] |
| Plant spacing | Approximately 0.5–0.7 m in reported applications requiring compatibility between plant size and mechanized systems; not a general limitation for grain and seed harvesting | [ 12 , 22 , 39 ] |
| Obstacles between rows | Removal or management of stones, stumps, crop residues, and other obstacles that may interfere with machine displacement | [ 13 , 22 , 23 , 39 , 40 ] |
| Planting row length | Long rows are generally advantageous because they reduce turning maneuvers and improve operational efficiency | [ 22 , 23 , 39 ] |
| Headland width | Approximately 6.0 m in reported cases to allow machine maneuvering | [ 9 , 22 , 23 , 39 ] |
| Method | Physical principle | Typical crops | References |
|---|---|---|---|
| Cutting | Product separation by mechanical shearing of the stem or entire plant | Grains and seeds (wheat, rice), sugarcane, forage crops | [ 22 , 37 , 39 ] |
| Pulling | Product removal by tensile force between plant and soil | Roots and tubers (potato, carrot, beetroot) | [ 39 ] |
| Vibration | Mechanical excitation used to detach the product from the plant | Woody crops (coffee), fruit crops (citrus, olive) | [ 8 , 10 , 34 ] |
| Impact | Transfer of kinetic energy through repeated impacts | Woody and industrial fruit crops (coffee, olive) | [ 10 , 22 , 34 ] |
| Brushing | Continuous mechanical contact using flexible elements | Fruit and woody crops under specific production systems | [ 8 , 10 , 15 ] |
| Pneumatic | Pressure differentials and airflow used for capture or transport | Seeds, lightweight fruits, auxiliary harvesting systems | [ 22 , 34 , 39 ] |
| Method | Physical principle and automation function | Typical crops | References |
|---|---|---|---|
| Selective grasping | Controlled mechanical force applied by robotic manipulators based on perception of the target product | Apple, orange, strawberry, tomato, bell pepper | [ 4 , 19 , 43 ] |
| Selective cutting | Localized cutting of the peduncle using automated blades or actuators | Lettuce, broccoli, high-value fruit crops | [ 34 , 43 ] |
| Assisted suction | Pressure differentials used for capture and transport, combined with visual perception | Strawberry, seeds, seedlings, light products | [ 34 , 43 ] |
| Semi-automated vibration | Mechanical excitation whose parameters are adjusted automatically using sensors and control algorithms | Citrus, olive, woody crops | [ 8 , 34 ] |
| Human–robot collaboration | Physical and cognitive interaction with task sharing between human operators and automated systems | Horticultural and fruit crops | [ 4 , 15 , 36 ] |
| Automated harvesting platforms | Automated navigation and operator assistance integrated with harvesting operations | Horticultural and fruit crops | [ 4 , 20 , 34 , 44 ] |
| Class | Description | Typical selectivity | References |
|---|---|---|---|
| Mechanization (no automation) | Harvesting execution based on mechanical energy; perception, decision-making, and control performed by the operator | Low | [ 12 , 22 , 39 ] |
| Automated navigation | Automation limited mainly to machine guidance and displacement while the underlying harvesting method remains mechanized | Low | [ 9 , 22 , 33 ] |
| Automated control | Automatic adjustment of harvesting parameters such as height, speed, or vibration without individual product selection | Low to medium | [ 9 , 11 , 39 ] |
| Semi-automated harvesting | Partial product selection based on automated perception with human intervention in decision-making or execution | Medium | [ 4 , 36 , 34 ] |
| Autonomous robotic harvesting | Integration of perception, decision-making, planning, and actuation in an automated harvesting system | High | [ 4 , 16 , 26 , 38 , 41 , 43 ] |
| Human–robot collaborative harvesting | Dynamic task sharing between human operators and automated or robotic systems | Variable | [ 4 , 15 , 36 ] |
| Physical interaction | Mechanized | Auto. nav./control | Semi-auto. | Autonomous | Typical selectivity | Representative refs. |
|---|---|---|---|---|---|---|
| Cutting | Low–high | [ 22 , 34 , 43 ] | ||||
| Pulling | – | – | Low–medium | [ 39 ] | ||
| Vibration | – | Low–medium | [ 8 , 10 , 34 ] | |||
| Impact | – | – | Low | [ 10 , 22 , 34 ] | ||
| Brushing | – | – | Low–medium | [ 8 , 10 , 15 ] | ||
| Pneumatic/suction | Low–high | [ 22 , 34 , 43 ] |