# Robotic Button Mushroom Harvesting Systems: A Review of Design, Mechanism, and Future Directions
## 1 Introduction  
The global demand for agricultural products has rapidly increased due to a significant growth in population. By 2050, the world population will rise by 20%, posing a critical challenge to meeting agricultural and food demands [1, 2]. Compounding this issue is the declining human involvement in agriculture, driven by factors such as rising labor costs, global pandemics like COVID-19, an aging workforce, and high-paying alternative careers that make agriculture less attractive [3, 4]. In the US, the percentage of people undertaking farming as a main profession has decreased by three times in the last 60 years and has been declining by 10% every year while the population has more than doubled. Moreover, the increase in labor expenses has caused a decrease in the profitability of agricultural products [5, 6, 7]. These trends have left the agriculture industry in a vulnerable state, making it clear that reliance on human labor alone is no longer feasible [8]. To address these pressing challenges, there is a crucial need for the widespread adaptation of automation, which must be both efficient and sustainable [5, 9]. Automation systems in agriculture involve the use of control systems, computers, and information technology to operatemachinery with minimal human intervention. This can take the form of a fully automated system where machines perform all assigned tasks, either independently or in collaboration with humans and other machines. The use of machines and automation in agriculture began after the Industrial Revolution in the 19 th century. With the advent of computers and robotics in the latter half of the 20 th century, automation in agriculture rapidly expanded. In the present time, the use of machine learning and artificial intelligence (AI) has improved the performance of machines by increasing the accuracy of object detection, monitoring, quality control, and much more [10; 11]. This growth is driven by the reliability, efficiency, and long-term sustainability that automation offers. Today, various automation systems are employed in the agricultural industry, with some mechanical harvesters significantly boosting harvesting efficiency compared to manual labor [12]. Mushrooms are low in calories, fat, cholesterol, and sodium levels, yet they provide rich nutritional benefits, including high levels of dietary fiber, protein, vitamins, and essential minerals like copper, manganese, selenium, and zinc [13; 14; 15]. Both the mushroom caps and stems offer these nutritional advantages, with dried mushroom stem powder also being used as animal feed [16]. Button mushrooms, the most popular species, are known for their exceptional nutritional value, texture, and medicinal benefits, such as anti-aging effects [17], immune support [18], and potential anticancer properties [19; 20]. In 2022, button mushrooms accounted for 61.8% of the global edible mushroom production [21; 22]. The global market for button mushrooms was valued at USD 25 billion in 2023, with a 6.6% CAGR (compound annual growth rate) [23; 24]. Traditionally, the mushroom industry relies heavily on human labor for tasks from pre-treatment to harvesting. However, since the early 1990s, researchers have explored automation in mushroom harvesting [25]. Pioneers like [PERSON], [PERSON], and [PERSON] developed early robotic systems for button mushrooms [26; 27; 28; 29], and by 2024, advancements have significantly improved the design, operation, and performance of these automated harvesters. Automated harvesting of button mushrooms involves several steps, such as identifying the target mushroom's location, guiding the manipulator and end-effector to the mushroom, picking it, and transporting it to the post-harvest site. These tasks are performed by various robotic components and mechanisms aided by computer vision, sensors, and control systems (Figure 1). Due to recent technological advancements and the complexity of harvesters, many studies have focused on optimizing individual components to develop the most efficient system.