Increased autonomy for mobile working machines:

mechatronic systems, sensors and cameras are smoothing the way for assistance systems in the off-highway sector

Experts assume that, from 2025 onwards, autonomous or semi-autonomous agricultural vehicles and holistically networked machines will increasingly dominate the field work landscape – entirely in keeping with assisted farming, the guiding theme of this year's SYSTEMS & COMPONENTS. With this, the international B2B platform for the entire off-highway sector will be highlighting assistance systems for agricultural machines – and therefore the digital technologies that lead to more targeted sowing, fertilisation and irrigation on fields. The solutions shown in Hanover not only enable the combination of agricultural machines to form a single unit by means of radio and satellite navigation, but the exhibiting technology providers are also increasingly equipping heavy-duty construction vehicles such as excavators, wheel loaders and bulldozers with assistance systems which perform tasks previously restricted to the driver in rough working conditions. All of this is made possible through the combination of sensor systems, global navigation satellite systems (GNSS), plug-in technologies and steering computers on board the machines.

Maximum precision when lining up

For many drivers, GNSS-supported steering systems are now indispensable helpers in their daily farming work. Part-width control or precise individual seed sowing even at night would be unthinkable without automatic steering. Thanks to Real Time Kinematics (RTK), intervention is no longer required when the driver has to line up his tractor or other self-propelled machines such as sprayers, choppers and combine harvesters with the next track with an accuracy of two to three centimetres.

The underlying principle is that satellites transmit a signal which is received by both the mobile machine and a stationary reference station. The latter generates a second, farm-specific correction signal which is transmitted to any number of machines that are in operation within a radius of up to 20 kilometres. Taking the machine's orientation, the steering angle and the current speed into consideration, the RTK system identifies the best possible parallel track and automatically steers the machine into it, in any weather and any visibility conditions. The top-class steering systems can automatically steer up to 32 sections or rows and control the variable spreading of up to eight items. Interrupted operations can be stored and continued at any time.

Choice of steering accuracy

In the factory, manufacturers are already preparing a rapidly growing number of machines for the uncomplicated installation of various assistance systems and machine control systems. In Hanover, developers and engineers can compile individual systems with the accuracy required for the specific application – or they can start with a WAAS/EGNOS-capable entry-level solution that can be flexibly extended with RTK radio options as required. The modular all-in-one designs of the presented GNSS solutions encompass an aerial, receiving and steering computer in one single component and offer a number of upgrade options. Irrespective of manufacturer, older tractors and self-propelled vehicles can also be retrofitted with an automatic steering system in this way with no need to interfere with the machine's hydraulics. The machine's steering wheel is simply replaced by a steering wheel with an electric motor.

This pinpoint precision during operation both on the field and on grassland can only be guaranteed by networking the electro-hydraulic steering components with the navigation controller and the multifunction display in the cockpit via CAN or ISOBUS. Modern gyroscopes as well as inclination and angle sensors pave the way to achieving this as well as additionally providing data on the position of the vehicle.

Sensor system for optimised crop protection

This alone is not sufficient. When cultivating arable land, the height and position of the implements must also be adhered to precisely despite the varying crop height. Vehicle speed regulation, power take-off switching and implement lifting and slewing movements at precisely the right point and time are required to accomplish this. Row, vision or laser sensors additionally support the mobile working machines during on-field operation. Front-mounted cameras for detecting plants keep the field sprayer's wheels in the centre of the track and minimise yield-reducing crop damage regardless of potential sowing machine track deviations. Another example is optoelectronic sensors that detect swath and use light pulses to scan the edge between the harvested and unharvested field – and automatically guide the combine harvester along the edge of the crop. Crop sprayers are a typical application area for ultrasonic sensors. They prevent boom collisions on irregular terrain and ensure that liquid fertilisers or crop protection agents are spread evenly.

The latest innovations in the area of assisted farming include optical sensors which measure the light reflected by the plants while driving through crops. At SYSTEMS & COMPONENTS, they will enable manufacturers and OEMs to find the right tool for optimised spreading of fertiliser or crop protection agent. Sensor heads can be mounted on a fertiliser spreader or sprayer boom.

The future: intelligently networked off-highway vehicles

Looking ahead to SYSTEMS & COMPONENTS shows that, in technical terms, the path to automated driving is being smoothed by assistance systems and sensor technology. For instance, it is already possible to adjust a second machine to the first machine's track – this scenario, in which several machines process the field in a network, is called platooning.

However, various legal and technical obstacles must still be overcome before such technologies can be used universally. With their cameras, lidar and radar sensors, the machines must be able to obtain a 360-degree 'image' of their environments in a fraction of a second in order to pinpoint sources of danger. This also applies to construction machines, whereby the aspect of safety plays an even more important role here. Engineers and scientists are currently working on reliable human recognition by means of deep learning-capable control platforms. The trend towards automated driving functions in mobile working machines will also be reflected at AGRITECHNICA, which will be taking place at the same time as SYSTEMS & COMPONENTS at the trade fair grounds in Hanover. There, around 2,300 exhibitors will be demonstrating everything that tractors and implements can already do today – and what they will do in the future.