The Somerset based Fruit Harvesting division of SFM Technology Limited, is widely recognised as one of the world’s leading designers and manufacturers of advanced fruit harvesting machines. Its SFM Samurai is a self-propelled apple harvester that harvests fallen fruit and is widely used in the cider production industry. With its 800 mm pick-up head, the multi-operational machine clears a passage between rows of apple trees and scoops up the fruit which is cleaned and stored in an integral 3 tonne capacity hopper whilst a powerful blower cleans the row by propelling any missed fruit to the next row. With the capacity to harvest up to 100 tonnes of apples each day, the machine is designed for optimal navigation through the narrowest of orchard rows thanks to its SFM developed four-wheel steering system that uses Novotechnik RFC4800 series angle sensors, supplied by Variohm EuroSensor, to monitor each axle position to ensure complete front and rear wheel synchronisation.
Image: The SFM Samurai with steering system shown in inset – Variohm supplied NovoTechnik RFC4800 angle sensors
Novotechnik’s RFC4800 series ‘touchless technology’ non-contacting angle sensors are well proven for steering position feedback on agricultural machinery and other mobile machinery applications. Its widespread use also extends to cost effective rotary position feedback tasks in construction equipment, industrial and automation technology and medical engineering. The robust and durable sensor features a 12-bit resolution (0.09 degrees) in a compact two-part design comprising a position marker in the form of an encapsulated magnet that is typically attached to a rotating shaft component and a physically separate and fixed sensor electronics encased in an environmentally sealed housing. The wear-free and completely ‘touchless’ sensor offer a practically unlimited operational life and with no bearings required and no need mechanical couplings, installation is straightforward. The RFC4800’s compact dimensions suit space restricted areas and the separate magnet and sensor arrangement is less sensitive to axial and radial alignment tolerances and can also operate through non-magnetic materials if required – allowing uncomplicated mechanical interfacing. Furthermore, with the sensor’s absolute position output signal and the permanently fixed alignment between magnet and sensor, there is no need for elaborate calibration on set-up or a need to reset the steering position on start-up or when restoring power to the vehicle.
The RFC4800 series is available in single channel or multichannel versions with dual redundant output. Nominal sensor electronics housing dimensions are around 48 mm diameter x 14 mm thickness with 38 mm PCD mounting, whilst a choice of optional encapsulated magnet housings are nominally 28 mm diameter and 15 mm thick. Other magnet options include bolts, separate magnets and shaft adaptors.
A wide choice of output signal options include voltage, current and ratiometric as well as fieldbus interfaces for CAN and SAEJ1939, IO-Link, SSI and SPI. Environmental sealing can be specified for IP67 or IP69 and the sensors generous operational temperature extends to -40 °C to +105 °C.
With its longstanding distribution partnership and wide application experience Variohm EuroSensor delivers complete sales and service across Novotechnik’s comprehensive range of sensor technologies and can assist with specifying standard or customised sensor solutions. With distribution partnerships with other sensor component manufacturers and as a manufacturer with its own its own design and assembly expertise, Variohm offers complete sales and application support across a comprehensive range of position, force, pressure, load, and temperature sensor technologies for demanding measurement application solutions in industry, construction, agriculture, motorsports, research and more.