Status and scope of Robotics in Agriculture

Automation of agricultural operations is demand of the time to improve the productivity with the help of tools and technology. In recent years, the development of autonomous vehicles in agriculture has experienced increased interest. In the field of agricultural autonomous vehicles, a concept was adopted to use multiple small efficient autonomous machines in place of traditional large tractors . Moreover, such a system may have a less environmental impact as it can reduce over-application of chemicals and high usages of energy and inputs by the control that is better matched to stochastic requirements. Most of the researcher are working for autonomous vehicle design for precision agricultural mobile robots . The design works on implementing three different verticals namely 1. Mobile robot navigation 2. Implements (Framework & Applications) 3.sensor modules. Different countries like the USA, European Unions, Denmark, Australia, Finland, India etc are designing mobile robots under these verticals which are mainly to procure agriculture farming over commercial industries.

In the scientific literature , studies show that to adapt agricultural machinery for agricultural platforms (autonomous vehicles or mobile robots) leads to the development of autonomous navigation for agricultural machine should be designed with higher safety. Excellent research carried out in Canada, Japan, Europe, Australia, the USA and initiated in India development of agricultural autonomous vehicles .
Most agricultural autonomous robotics research has been performed in controlled environments such as robotic picking of cherry tomatoes , cucumbers , mushrooms and other fruits . In horticulture, robots have been applied to citrus and apples .
However, the development of these platforms presents two challenges :

•  to develop a physical structure suitable for the agricultural environment, and
•  to develop an electronic architecture to integrate the various electronic devices. An electronic architecture must be robust and reliable, provide quick and ease maintenance and have modularity and flexibility to allow future expansions and connection of new equipment. As more autonomous applications for agriculture will be operating in upcoming years, it gives an idea applying robotics in agriculture may be technically difficult compared to industrial robots.  

Curent sceanarios of Agriculture system in India and Factors Affecting

The projected world's population to grow to more than 9.15 billion by 2050 [25]. Therefore, the challenge for the next decades will be to supply the needs of the expanding world population by developing a highly productive agriculture management, whilst at the same time preserving the quality of the environment [37]. Most of the developing countries including India facing agricultural labor shortage problem. A major portion of youths from village shifting to urban for led better life. As a result, agriculture operation gets delayed during its peak seasons due to a labor shortage.

• Human, animal, and Mechanical power source are utilized in agricultural operation in terms of seed bed preparation, tillage, seeding or transplanting, fertilizer and chemical application, intercultural operation and harvesting. Average power availability on Indian farm is about 2.02 kW/ha. Human, animal, and Mechanical power operated agricultural machinery fail to optimize the operational cost, time and all other inputs. The tractor is the main machine power source on which most of the farm mechanization depends. Most of the farm operation is done by using the tractor as a prime mower with attaching different implements on it. Although the traditional animal operated country plow gives low output and requires a higher number of field operations are still being used by the majority of the farmers. Zero tillseed drill, inclined plate planter is used for seeding operation which is tractor power operated.
• High precision and input required during intercultural and plant protection operation. Placement of seed at optimum depth for better germination rate required precession applicator. At present intercultural operation mainly carried out by using manually operated implements such as Wheel hoe and Conoweeder are very popular for horticultural crops and paddy field. Both the implements are manually drawn.
• Nutrient management is the important operation for augmenting agricultural production and retain its sustainability. Most of the farmers in developing country apply nutrients manually without simulating the already availability of the nutrient in the field and application of nutrient is uncontrolled throwing by the hand. some instrumental setup has been designed for delivering fertilizer which facilitates for delivering fertilizer uniformly.

CURRENT STATUS OF AGRICULTURAL ROBOTS

MF-Scamp Robots Designed by Blackmore

MF-Scamp robots are designed for scouting, weeding and harvesting . It is designed either four wheel or six wheel drive weed seeking robot to perform weed removing or destroy the weed. Generally the crops are grown in rows and column which can remove weeds when running hoe tools between the crops row and column.

• This intelligent hoe tools uses vision sensor to locate and identify the crops in rows and column and steers itself accurately, to a larger extend reducing the usage of herbicides.
• It also uses colorsensor to identity weeds between the crops by producing weed maps identifying plans. This robot designed not only reduce the labor time but also the economic feasible with slight reductions in prices of navigation systems.
• This kind of design not only reduce the cost of spraying but also decrease the usage of tractor. The negative effects of the robot is the higher costs for small farmers and additional costs used for electronics devices like GPS-system

  Autonomous Plant Inspection (API) Research Platform designed by Danish institute of Agricultural science (DIAS)

The API Platform was initially developed by Madsen and Jakobsen in the year 2001. Further it was developed by Aalborg University in Denmark. It is third generation autonomous research platform for precision farming prototype designed having four wheel- drive, four wheel steering with two motors per wheel.
Advantage

• This enables weed mapping system to produce weed maps for the robot and will be helpful for precise patch spraying with right mixture of herbicides.
•  Reduce the usage of herbicides which might vary from 30% to 75%.

Sub canopy robot ISAAC 2 from Hohenheim University, Germany

This prototype is designed to collect timely and accurate information in the crop carrying range of sensors to assess crop health and status. This high clearance platform carries instruments above the crop canopy and utilize GPS.

• The portal robot used to provide automated crop survey as well as to measure crop nutrient status and multispectral responses (stress), visible images (pan Chromatic), weedspecies and weed density.
• Using machine vision the position and density (biomass) of different weed species are recorded in the form of weed mapping.

BoniRob farming robot developed by Deepfield robotics funded by Bosch, Germany

BoniRob is a multi-purpose robotic platform for applications in agriculture. It has four independently steerable drive wheels that has the ability to adjust its track width and makes it highly maneuverable . The robot run purely on batteries or connected to a generator to extend its range and usage time. It can be retrofitted and upgraded with exchangeable application modules (tools)

• The robot can navigate autonomously along plant rows (e.g. dams) in the field, carrying the application module (plantation) as it goes. It has environmental sensors like Lidar, inertialsensors, wheel odometry,satellite and GPS for row detection and navigation.
• This robot is designed for application like chemically weed control or uses a rod device to crush the weeds, to combat volunteer potatoes from the previous year, to measure soil compaction and manage plant breeding. Testing of the robot in carrot fields have proved that it is over 90% effective in removing weeds and preserving crop plants..

Lettuce Bot, California

Lettuce Bot also known as Rambo of weeds was designed by Heraud and the Bot’s co- creator, Lee Redden at standford University as shown in fig.2.6. The bot design is more of robotics, computer vision and machine learning algorithm to advance the growing fields.

• The Bot has a database of more than a million images that it uses to identify the plants. It looks for a weed or a lettuce plant that are grown too close to plant or crops. Once it identifies the weed, it releases a strong spray of fertilizer disintegrating the weeds around the plant and fertilizing the lettuce around it.
•  This bot application can also be used in organic farming, one of the areas where weeds are the biggest problem.since there’s no practical way of eliminating weeds in an organic field other than pulling them by hand one by one which is not sustainable and also fertilizer used are not organic so not allowed in organic fields. The bot is designed for lettuce fields not for other fields as lettuce is the second largest crop grown in California.

CROPS, European union

The CROPS research project, “Clever Robots for Crops”, which is sponsored by the EU Commission, could provide a solution for an automated harvesting procedure. The aim is a configurable, modular and intelligent robot platform, which reliably recognizes both the fruit as well as obstacles and other objects. In this way it can navigate and harvest on its own on plantations and in greenhouses.

• The robot platform is also intended to be able to treat selected areas with pesticides. For the development of the right gripping and cutting device, the researchers are concentrating on the harvesting of apples and peppers .
• The CROPS robotic platform is used for selective harvesting of fruits which detects the fruit, determines its ripeness, then moves towards the ripen fruit, grasps it and detach itsoftly, also it is capable of determining site specific spraying for targets spray towards foliage.

HortiBot, Denmark

Hortibot is a commercially produced and robust tool carrier designed for high tech plant nursing for e.g. organic grown vegetables as shown in fig.2.8. The steering of the bot is operated using computer vision based guidance system. The main function is to control weed, enable an automatic execution of one-sided repetitive weeding for outdoor gardening .

• The major advantage of this prototype is that it did not take much time for labor training and reduces the labor cost, doing repetitive tasks like cultivating and other form of mechanical weeding also efficient use of herbicides thus reducing herbicides cost.

Agribot, India

Many countries in Asia including India are agrarian economies and most of their rural populations depend on agriculture to earn their livelihood. Agribot is an agricultural robot designed by BIT Hyderabad students, India.

•  It is designed to increase the productivity, speed, application accuracy of the work and minimizing the labor of farmers. Its major area of function involved in farming     i.e.   harvesting, spraying, seeding and removing the weeds. This robot is designed to execute the basic functions required to be carried out in farms.
•  The major design of the robot is based on image processing and relay controls the motor of the robot. A vision based row-guidance method is used to guide robot        platform driven along the crops planted in row. The system is having a camera equipped to give a live vision of the field, also for large farms a GPS based module can be installed depending on the map specific land can be fixed for harvesting.
•  After harvesting, it can pick up crops and place it in a vessel, also spraying system can be designed on the robot which will spray the pesticides on the crops. The main obstacle to this kind of robot farm is that farms are a part of nature and nature is not uniform.

SCOPE OF AUTONOMOUS FARMING

Data scouting at different stage of crop growth

Yield in a given field may vary in space depending on a combination of factors such as nutrient availability, soil moisture, rooting depth, pest pressure, weed density, crop maturity and others. Good agricultural practice needs an application of optimum input at appropriate timeseries. Continue monitoring and data collecting related to crop NDVI, Biomass, Leaf area index, crop growth rate, water stress are an important parameter for optimizing the variable input parameters in different stages of crop growth and also crop health. Crop physical status monitoring would be less expensive and timelier if an automated system could remain within the crop canopy for continual monitoring .

• Real-time management of inputs like fertilizers, herbicides, at variable rate could be achieved by sensing the different parameters of the crop measured in the field by and processing it for further application part using microprocessor or microcontroller. As the robotic vehicle continuously monitor the crop canopy it is easy to identify crop diseases and pest attack at an early stage in patches or selectively. Also, it can monitor weed density, water stress at a different stage of crop growing periods.

Intercultural operation

Weed competes with the crop for sunlight, space, and nutrients. To control weed species, a large number of herbicides and chemicals are used in agricultural fields, which results in drinking water contaminated and environmental pollution. Currently, the excessive use of herbicides damages the health of people, animal etc. According to the weed science research,about 33% of the total losses by agricultural pests are caused by weeds only[2]. Therefore it is important to identify the weeds from the crop and selectively spray herbicides to optimize the chemical application.

• There are various techniques developed all over the word for distinguishing weed from the crop.In the conventional weed control system, the herbicide is sprayed uniformly over the field which may damage crop condition. Machine vision systems present a great potential to be used on data collection for precision agriculture, where images would be used to extract information. The autonomous agricultural robot can accomplish intercultural operation using the machine vision based technique. It can be achieved by mapping the weeds in selectively or in patches by image processing method, in row crop, the patch identification in between the row can help to distinguish the weed. There is specific shape reorganization method are applicable for classifying the weeds by its shape this method is more accurate in weed identification method.
• Another method is color segmentation for identifying weeds. Based on all these technique weed maps is generated. Detecting weeds selectively from a field with the application of proper methods of image segmentation technique and post processing the segmented data finally, optimize the application part of chemicals in the field.Based on the map generated appropriate weeding technique is considered for weeding. There are different operational methods for removing the weeds like mechanical chemical application. Identifying the actual position of the weeds mechanical weeder can be incorporated in removing weeds by partial tillage operation at 2 to 4 cm depth. Removing of weeds from between the row is easy as compared to removing weeds from intra-row which required high- speed sensing device and high- speed mechanisms to push rotary blades or chemical spray for intra row application.

Fertilizer

Crop nutrient is a basic and important component ofsunlight, water for its growth and increasing productivity. The rational use of fertilizers and fertilizer technology has a significant effect on the development of agricultural . Among the various nutrients, soil nitrogen is one of the important parts of agricultural production, Nitrogen has been perceived as a critical nutrient for productivity of crops but it also has important factors of environmental contamination
A major portion of the input fertilizer is lost by leaching, and contaminates freshwater, marine ecosystems when high rates of N fertilizers are applied to agricultural fields .

• There are variations of nutrient in quantity within the small area of the field. Traditional measurements of soil nitrogen are very difficult and laboratory method by which nutrient map is generated. Which helps in pre-assessment of the actual requirements of fertilizer in the field. That involve in the uniform rate of application of fertilizer over an entire field. This map used as asite-specific management tool that allows the producer to vary the rate of application of crop input across a given area.
• Variable-rate technology has a potential to optimize the input that further enhance the benefits of operator and maintain soil environmental health. Most of the Variable rate technology are GPS base few are available on control system based on reckoning up track distance for a variable rate fertilizer applicator without GPS. Nitrogen variability in an area is defined by grid area mapped by GPS latitude and longitude. According to a position of pre-defined grid area nitrogen output is fixed in controlling unit. While during the time of final fertilizer application controlling unit have control over the motor rpm which directly responsible for opening are of metering unit or its rpm that is calibrated with the input amount of fertilizer requirement at that particular grid.

Harvesting

Bulk harvesting is the common trend of harvesting in India. This process of harvesting suitable for few selective crops, so far some crops like cotton where the maturity of cotton ball achieves at the different time period in a single plant , therefore in this case selective harvesting of a cotton ball is important. Other than the cotton cereal pulses crop are get matured in patches selectively. Harvesting immature crop effects its quality. Therefore selection of mature crop for harvesting needs certain threshold parameter to define the range of maturity level for defining crop as mature.

• selective harvesting needs sensing technology for collecting information of crop which needs to be processed through microprocessor or microcontroller and finally define thestatus according to which decision support system supply command to the mechanical mechanism to harvest of defined crops.
• Broadly there is two part of work first is to sense the crop status and according to that harvesting of a selective crop is done which is the second part of this complete process. Harvesting with the agricultural robot can be done at real-time data sensing and the processing unit or feeding the processed data map on robotic vehicle harvesting could be done.such kind of precision monitoring and harvesting with the help of agri-robot could help to get ride off the ever decreasing labor scarcity load and increasing labor charge and also can maintain a quality of food at the end of the harvesting.  The Bots uses GPS, Vision processes, Lidar etc. for navigation in the field. It calculates the waypoints of the field and accordingly robots move across and perform the given operation.
• The basic principle for the agricultural robot is thestability factor while moving in the field are controlled by the speed & rpm of the motor, obstacle detection as well controlling the angular and linear movement of the robot. The main source for power is fromsolar and battery. This factors leads to field operation like optimum seed placement, weed control,spraying, harvesting, crop monitoring etc.
  4. CONCLUSIONS
  The autonomous robot have potential to work on precision agriculture having continuous monitoring by using different sensing technology, which provides different crop status parameter like, micro nutrient availability, bio mass index,status of pest and disease, waterstress, thermalstress etc. for better remedies of crops. As ever increasing of world population and decreasing of agricultural workers created constraint to farming system. Agricultural robot has potential to take off the load of labor shortage and increasing the productivity. Various technology like machine vision, image processing, and mechatronics can be assembled in asingle platform named agricultural robot which can give optimal solution for autonomous agricultural operations.

By: Dr.Dharminder Singh