Delta robots from igus have been deployed on an interesting application in the agricultural sector, definitely a growth industry
The world’s first non-chemical robotic weeding method for cereal crops, manufactured by agri-tech start up The Small Robot Company (SRC) has successfully identified and killed weeds at a field trial in Hampshire which was witnessed by MachineBuilding.net yesterday, 28th April.
The wheeled robot features igus delta robot arms to position a 'zapper' which uses ‘lightning strikes’ of an electrical current to kill weeds. Did we say the trials were conducted in Ampshire? The Delta robot arms from igus were selected, according to a spokesman for SRC, for their precision, low-cost and lubrication-free engineering. The weed killing robot, aka 'Dick', works in concert with a monitoring robot, aka 'Tom', to identify weed patches and then home in and kill individual plants with the zapper device. SRC is already actively exploring other applications for the robot using its delta arms.
igus says that the machine is the world’s first non-chemical weed killing robot that can destroy weeds at an individual plant level, making it an exciting, low impact technology for farming. Currently the (necessary) blanket spraying of herbicides involves costly wastage, sometimes of up to 95% according to quoted industry studies, with an accompanying detrimental impact on the environment. Further, soil degradation from herbicides and soil compaction reduces crop yields.
The weed killing wheeled robot identifies individual weeds using artificial intelligence (AI) and vision technology, using an end effector supplied by Rootwave. SRC has developed three robot variants for farming applications – Tom, Dick and Harry. The igus delta robot is commonly used in industry for a multitude of pick-and-place operations, but in this case it positions the zapper into place using an integrated motor and encoder, linked to the (Dick) robot master controller. The three igus delta arms fitted to each of these mobile units can destroy weeds simultaneously.
igus points out that its Delta robots were selected for their light weight, precision and low cost: the company says that many competing Delta robots cost up to £20,000 while the igus Delta is priced at around £5,000. It was developed at this price point as part of the igus Low-Cost Automation division for R&D applications, but still offers durable and capable engineering which is suitable for commercial scale-up.
'Tom' the monitoring robot, uses proprietary Wilma artificial intelligence (AI) to scan the field for weed patches and then defines a path for 'Dick' to follow. Dick is then dispatched to “seek and destroy”. The two-robot approach demonstrates SRC’s “end-to-end service” model, using multiple robots with AI working together to scan the field on a plant level then take action. Further, SRC and igus are looking to work on different actions, where Tom and Dick might combine again for spot spraying, spot fertilizing or slug killing, for example. They'll lettuce know in due course we expect.
The igus Delta robot components and control system are said to be key to the weed killing operation, where ease of use and cost are paramount. The Delta units are made from standard drylin parts, making assembly straightforward and inexpensive: they have been thoroughly field tested to ensure they cope with wet mud and water splash.
Stepper motors are linked to controllers that help position the Delta robot directly over the weeds. The motors have encoders, which help the Delta know what position it is in, with good industrial protocols so they are easy to programme. SRC’s Dick robot sees the master controller and AI 'speak' to the igus motor controller to synchronise the robot’s position with the Delta arm, forming a closed loop monitoring system.
igus Low-Cost automation engineer Angelos Bitivelias has worked with universities and industrial companies on Delta robots for applications like fruit picking, so he brings the knowledge of how the igus delta can be best modified for the weed killing application.
“The Dick robot moves to one side, a camera takes a photo of the weed, the AI identifies it as a weed, and then AI decides where to zap it,” says Angelos. “The kinematics of the Delta makes it well suited to the end effector and the belt drive means the zapper is always parallel to the ground below.”
An essential feature of the Delta and igus components is that they are lubrication-free. Lubricated moving parts like the belt drive and bearings would potentially clog up with soil and water in a muddy field, but igus polymers and parts are designed to be dry running.
Precision is also said to be a strong feature. “The milestone we’ve hit is that we can now take action at the plant level,” says Andy Hall, head of prototyping at SRC. “Using artificial intelligence, the robots can recognise the weeds in the [camera] shot and target the robotic arm onto those weeds. At that point we can do anything we want. Our robotic platform incorporating the igus arm could have many different technologies bolted on.”
“The affordability, precision, durability and reliability of our Delta robots are well suited for this and new agricultural applications” says igus UK Managing Director Matthew Aldridge. “Because the Delta is lightweight and low-cost it has opened up new opportunities for these robots to be used in mobile applications, proving a new technology in a harsh outdoor environment. Igus is planning to work with SRC on new industrial applications where precise and low impact actions are needed on farms - and potentially in other areas too.”
“To prove the power of per-plant farming, we are focused on answering the biggest problem that farmers face at the moment, which is weeding,” comments Ben Scott-Robinson, SRC CEO and co-founder. “We’ve now proved we can deliver per plant weeding: a world first. The focus for us now is being able to move forward to deliver this repeatedly, and at scale. This will be game-changing.”
Following the successful field trials on 28 April, the next stage for Tom and Dick are efficacy trials, measuring the force required to destroy the weeds, including the comparison of different varieties, to ensure that they are destroyed and not just partially killed.