Robotic Mowing of Tall Fescue at 90 mm Cutting Height: Random Trajectories vs. Systematic Trajectories

Mino Sportelli,Marco Fontanelli,Michel Pirchio,Simone Magni,Lisa Caturegli,Christian Frasconi,Marco Volterrani,Andrea Peruzzi,Michele Raffaelli

doi:10.3390/agronomy11122567

Abstract

Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) is often managed with a cutting height ranging from 70 to 100 mm in ornamental lawns. Some autonomous mowers have been specifically designed to maintain mowing height in the same range. Generally, autonomous mowers operate by following random trajectories, and substantial overlapping is needed to obtain full coverage of the working area. In the case of tall grass, this may cause lodging of grass plants, which in turn may reduce turf quality. The introduction of a navigation system based on systematic trajectories has the potential to improve the performances of autonomous mowers with respect to machine efficiency and turf quality. With the aim of determining the effects of reduced mowing frequency and systematic navigation systems on turf quality and mower performances in terms of working time, energy consumption and overlapping, the performances of two autonomous mowers working with random and systematic trajectories were tested on a mature tall fescue lawn at 90 mm cutting height. The working efficiency was approximately 80% for the systematic trajectories and approximately 35% for the random trajectories; this was mainly due to the lower overlapping associated with systematic trajectories. Turf quality was slightly higher for the mower working systematically (a score of 8 using a 1–9 score with 1 = poor, 6 = acceptable and 9 = best) compared to the one working randomly (quality of 7 and 6 on a 1–9 scale with 1 = poor and 9 = best). No appreciable lodging was observed in either case. For tall, managed lawns, systematic trajectories may improve autonomous mowers’ overall performances.

Highlights

Turfgrass is the most common and intensively managed form of vegetation in urban areas [1]
With the aim of determining the effects of reduced mowing frequency and systematic navigation systems on turf quality and mower performances in terms of working time, energy consumption and overlapping, the performances of two autonomous mowers working with random and systematic trajectories were tested on a mature tall fescue lawn at 90 mm cutting height
A systematic autonomous mower and a random autonomous mower were tested on a mature tall fescue lawn maintained at 90 mm cutting height, with the aim of determining the effects of reduced mowing frequency and systematic navigation systems on turf quality and mower performances in terms of working time, energy consumption and overlapping

Summary

Introduction

Turfgrass is the most common and intensively managed form of vegetation in urban areas [1]. Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) is the predominant turf species in Italy and in the whole Mediterranean area [3,4] for residential lawns and landscape purposes. Due to its tolerance to several abiotic stresses such as shade, salinity, warm temperatures and wear, tall fescue is often preferred over other cool-season species in the transition zone [6,7,8,9,10]. Parks and ornamental lawns, tall fescue is often managed with a tall cutting height (ranging from 70 to 100 mm) in order to achieve some benefits such as lower fertilization and irrigation requirements, reduced mowing frequency [11,12] and more efficient light penetration [13]. Dernoeden et al [14] found that tall fescue managed with a tall cutting height showed greater weed suppression compared to tall fescue mowed at lower cutting height

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