The Influence of a User-Centred Design Focus on the Effectiveness of a User Interface for an Agricultural Machine

As agricultural machines become more complex, it is increasingly critical that special attention be directed to the design of the user interface to ensure that the operator will have an adequate understanding of the status of the machine at all times. A user-centred design focus was employed to develop two conceptual designs (UCD1 & UCD2) for a user interface for an agricultural air seeder. The two concepts were compared against an existing user interface (baseline condition) using the metrics of situation awareness (Situation Awareness Global Assessment Technique), mental workload (Integrated Workload Scale), reaction time, and subjective feedback. There were no statistically significant differences among the three user interfaces based on the metric of situation awareness;however, UCD2 was deemed to be significantly better than either UCD1 or the baseline interface on the basis of mental workload, reaction time and subjective feedback. The research has demonstrated that a user-centred design focus will generate a better user interface for an agricultural machine.

Real-world emission characteristics of carbonyl compounds from agricultural machines based on a portable emission measurement system

Emissions of carbonyl compounds from agricultural machines cannot be ignored.Carbonyl compounds can cause the formation of ozone(O3)and secondary organic aerosols,which can cause photochemical smog to form.In this study,20 agricultural machines were tested using portable emission measurement system(PEMS)under real-world tillage processes.The exhaust gases were sampled using 2,4-dinitrophenylhydrazine cartridges,and 15 carbonyl compounds were analyzed by high-performance liquid chromatography.Carbonyl compound emission factors for agricultural machines were 51.14–3315.62 mg/(kg-fuel),and were 2.58±2.05,0.86±1.07 and 0.29±0.20 g/(kg-fuel)for China 0,China II and China III emission standards,respectively.Carbonyl compound emission factor for sowing seeds of China 0 agricultural machines was 3.32±1.73 g/(kg-fuel).Formaldehyde,acetaldehyde and acrolein were the dominant carbonyl compounds emitted.Differences in emission standards and tillage processes impact ozone formation potential(OFP).The mean OFP was 20.15±16.15 g O3/(kg-fuel)for the China 0 emission standard.The OFP values decreased by 66.9% from China 0 to China II,and 67.4%from China II to China III.The mean OFP for sowing seeds of China 0 agricultural machines was 25.92±13.84 g O3/(kg-fuel).Between 1.75 and 24.22 times more ozone was found to be formed during sowing seeds than during other processes for China 0 and China II agricultural machines.Total carbonyl compound emissions from agricultural machines in China was 19.23 Gg in 2019.The results improve our understanding of carbonyl compound emissions from agricultural machines in China.

Design and experiments of 4CJ-1200 self-propelled tea plucking machine

As agricultural labor is decreasing,famous tea production is nearly hard to sustain and is getting more and more expensive in China.To improve the mechanization of tea plucking,this paper designs a self-propelled track-type tea plucking machine that integrates mechanic,hydraulic and electronics.The main parameters of chassis were optimized based on conditions of tea garden.And,three different kinds of cutter blades were designed and analyzed about vibration performance with finite element software.Also,a rigid-flex mixed motion model was established.Based on the model and plots,it is explicit that:(1)the blades move in a sine law;(2)the blades take a symmetrical deform from middle to end while moving;(3)the deformation increases along the blade from the center to sides.The single factor experiment revealed that both travel speed and speed ratio of cutting and travelling had a significant effect on quality indexes(integrity rate,unpicking rate,stubble unevenness)of plucked tea leaf.By universal rotary combination experiment of quadratic regression,the regression equations of three indexes about two experimental factors were established.And,the comprehensive optimization of three indexes was conducted with software Design expert.The optimal operating parameters of machine are as follow:travel speed is 0.41 m/s,speed ratio of cutting and travelling is 1.06;prediction of three indexes are that integrity rate could be reach to 78.26%,unpicking rate reduced to 0.82%,stubble unevenness reduced to 1.30 mm.The results of verification experiment are that:integrity rate could be reach to 77.41%,unpicking rate reduced to 0.87%,stubble unevenness reduced to 1.23 mm.These test indexes that are very close to the predicted values,all surpass the requests specified in the standard of tea plucking with machine.In all,the optimized parameter set is indeed synthetically optimal one that enables the wide use of this tea plucking machine,which can be used in the tea garden that has a lengthways slope less than 18°,a crosswise slope less than 20°,and a height of tea trees between 50-120 cm.From above,the tea plucking machine investigated in this paper provides an effective solution to present tea picking problem that is the bottleneck of tea industry.Further studies need to do for making this machine more automated and intelligent.

Design and experiment of spray and rotary tillage combined disinfection machine for soil

A spray and rotary tillage combined disinfection machine for soil was designed to solve the serious problems of plant diseases and insect pests,and it was divided into two operations which were soil disinfection and rotary tillage.The main structure and working principle of this machine were illustrated and analyzed.The reasonable structural parameters of the key parts of this machine were optimized,such as spraying disinfection system and rotary tillage land preparation system.To optimize the working performance and obtain better operation parameters,the orthogonal experiments were carried out to analyze the influences of three factors(forward speed of driving machine,rotational speed of rotary tillage,and working pressure)on the working performance.The mixing uniformity coefficient and the variation coefficient of spraying were selected for evaluating working performance.The range analysis and variance analysis were studied based on experimental data.The results showed that,the mixing uniformity coefficient of spraying was 93.95%and the variation coefficient was 6.01%with a working speed of 3 km/h,rotational speed of 2000 r/min and working pressure of 2.0 MPa.The machine can meet the agronomic requirements of disinfection and plowing,which was designed simply,compactly and strong applicability.The results can provide a guidance and technical support for preventing the plant diseases and insect pests,developing sustainable and ecological agriculture and improving the efficiency of compound cultivation.

A sliding-mode variable-structure controller based on exact feedback linearization for automatic navigation system

In order to improve the path tracking accuracy and robustness of the agricultural machinery navigation system,a sliding-mode variable-structure controller based on exact feedback linearization was presented.Firstly,based on the differential geometry theory and the affine nonlinear kinematics model,the corresponding nonlinear coordinate change matrix and nonlinear state variable feedback equations were deduced,and an exact feedback linearization model was then established.Secondly,based on the exact feedback linearization model,a sliding-mode variable-structure controller was designed by selecting suitable linear switching function and exponential reaching law.Finally,the comparative experiments were carried out.And the experimental results indicated that the proposed method had a high tracking accuracy and robustness.The maximum lateral error of the straight line tracking was less than 0.06 m,and maximum lateral error of the curve path tracking was less than 0.09 m.Experimental results show that the transplanter based on this automatic navigation system can effectively track the predefined path.