Mobile Machinery Research Articles

Energy-optimization design and management strategy for hybrid electric non-road mobile machinery: A case study of snowblower

Reduced reliance on fossil fuels is a critical issue, and electrification of agricultural machinery is a solution for lowering greenhouse gas emissions in non-road transportation. By separating the load and drive from the engine, electrification the implement allows the engine to operate at higher efficiency. This study suggests a series hybrid design that combines a snow blower with battery support and a tractor with a reduced engine size to meet the fuel consumption reduction target while maintaining its performance. Accordingly, the Particle Swarm Optimization (PSO) algorithm is employed to size the battery that meets the constraints. Additionally, the motors of actuators are designed based on efficiency maps. Moreover, the rule-based energy management strategy is also proposed to assess the solution. This suggestion is analyzed using simulation and compared to a traditional tractor as a benchmark. The simulation results demonstrate the effectiveness of the strategy in lowering emissions from non-road machinery. Furthermore, this approach can be applied to various different types of implements attached to the tractor.

Research on an Intelligent Agricultural Machinery Unmanned Driving System

Intelligent agricultural machinery refers to machinery that can independently complete tasks in the field, which has great significance for the transformation of agricultural modernization. However, most of the existing research on intelligent agricultural machinery is limited to unilateral research on positioning, planning, and control, and has not organically combined the three to form a fully functional intelligent agricultural machinery system. Based on this, this article has developed an intelligent agricultural machinery system that integrates positioning, planning, and control. In response to the problem of large positioning errors in the large range of plane anchoring longitude and latitude, this article integrates geographic factors such as ellipsoid ratio, long and short axis radius, and altitude into coordinate transformation, and combines RTK/INS integrated inertial navigation to achieve precise positioning of the entire vehicle over a large range. In response to the problem that existing full-coverage path planning algorithms only focus on job coverage as the optimization objective and cannot achieve path optimization, this paper proposes a multi-objective function-coupled full-coverage path planning algorithm that integrates three optimization objectives: job coverage, job path length, and job path quantity. This algorithm achieves optimal path planning while ensuring job coverage. As the existing pure pursuit algorithm is not suitable for the motion control of tracked mobile machinery, this paper reconstructs the existing pure pursuit algorithm based on the Kinematics characteristics of tracked mobile machinery, and adds a linear interpolation module, so that the actual tracking path points of motion control are always ideal tracking path points, effectively improving the motion control accuracy and control stability. Finally, the feasibility of the intelligent agricultural machinery system was demonstrated through corresponding simulation and actual vehicle experiments. This intelligent agricultural machinery system can cooperate with various operating tools and independently complete the vast majority of agricultural production activities.

Simulation-Based Digital Twins Enabling Smart Services for Machine Operations: An Industry 5.0 Approach

The Industry 5.0 initiative seeks the sustainability and resilience of production systems through digital technologies. Derived from such an initiative, the Operator 5.0 concept surged to place the operator as the main value-creation contributor of sustainable and resilient human-machine systems. Smart service systems are data-driven services that provide intelligent capabilities to support decision-making in business processes. Despite previous research on smart services driven by multiple technologies in different contexts, further studies approaching Digital Twins as enablers of smart services in machine use phases are yet to be explored. Digital Twin, an Industry 5.0 enabler, is a technology that virtually represents physical assets that collect and analyze data from actual operations to make predictions for decision-making. Simulation-based Digital Twins generate simulation models that are continuously upgraded with asset data in real time, improving the accuracy of predictions. This paper aims to investigate how the Simulation-based Digital Twins (SDT) can enable the development of smart services in the Operator 5.0 context. We build on a multiple case study of 13 interviews from nine heavy mobile machinery manufacturers. We capture our results in categorizing SDT-enabled smart services for the use phases of the machine lifecycle. The categorization identifies the capabilities of each smart service for decision-making support and value co-creation.

Temporal and Spatial Variations of Potentially Toxic Elements in PM10 Collected in Jeddah City, Saudi Arabia.

Air pollution causes environmental and health problems around the world. In this study, ambient particulate matter with an aerodynamic diameter equal to or less than 10 microns (PM10) has been collected at three different locations in Jeddah city, Saudi Arabia. The locations are characterized by differences in terms of traffic, residential intensity, industrial, and non-road mobile machinery activities. The monthly and annual mass concentration of the PM10 exceeds the recommended annual limit of the World Health Organization (15 µg/m3) and the European air quality standard (40 µg/m3) at the three locations. The collected PM10 samples as well as a certified reference material of atmospheric particulates (NIST 1678a) were digested in aqua regia using microwave digestion. The quantitative elemental analysis was carried out using inductively coupled plasma mass spectrometry. The variations of the elemental concentration in terms of workdays, weekends, seasons, and annual were determined at the three locations. The spatial and temporal elemental variations were found to be different between the three sites, pointing to local influences that should be further evaluated. The concentration of Cd was found to be high and may cause health problems.

Use of biodiesel in non-road mobile machineries for low-carbon construction: Policy review and lifecycle analysis

Carbon reduction is nowadays part of the sustainable development initiative worldwide, and promoting the use of biodiesel as a substitute for conventional diesel in non-road mobile machineries (NRMMs) used in the construction sector is a direct and effective way to reduce carbon emissions in this energy-intensive industry from a lifecycle perspective. In addition, the production and use of biodiesel made from waste cooking oil provide a solution to environmental issues and waste management, achieving a circular economy. Nevertheless, biodiesel usage in NRMMs in Hong Kong is largely limited to public works and the current biodiesel promotion and regulation measures are inadequate. This study aims to review and analyse biodiesel policies and promote the use of biodiesel in Hong Kong for low-carbon construction. Incentive and mandatory policies applicable to NRMMs are reviewed and analysed for two stages: biodiesel production and supply, and biodiesel consumption. Recommendations on biodiesel policies for the construction industry in Hong Kong are made accordingly, including expanding biodiesel production through incentives, and encouraging contractors to use biodiesel in private projects. A lifecycle analysis is then conducted to quantify the carbon reduction capability of using biodiesel. It is estimated that a lifecycle reduction of 3.2 × 104 tCO2e, i.e., a 4.5% decrease could be achieved by using B5 waste cooking oil biodiesel instead of diesel in the construction industry of Hong Kong. This study reviews and analyses biodiesel policies clearly and critically, paving the way for the establishment of feasible and effective regulations for promoting biodiesel use for low-carbon construction.

Characterization of particulate matter emissions from internal combustion engines using δ13C values: Impact of engine operation conditions and fuel type on PM10 isotopic composition

Stable carbon isotope ratio of particulate emissions from internal combustion engines (ICEs) is an important characteristic in atmospheric carbonaceous PM source studies. Long-term measurements (2009–2020) of δ13C values of commercial fuels in Lithuania were conducted to evaluate the current isotopic composition of the fuel due to the changing share of renewable energy sources (RES). In this work, we present experimental results on stable carbon isotope ratio (δ13C) in PM10 emitted by different types of ICEs (two-stroke and four-stroke), including on-road transport and non-road mobile machinery. Different driving scenarios were simulated on a test bench (idling, NEDC, different torque, and speed). At idle, the average δ13C(PM10) values of different fuel types were determined: −27.80‰ for gasoline, −28.97‰ for diesel, − 27.89‰ for biofuel-C3, and −16.95‰ for biofuel-C4. Isotopic fractionation during combustion in ICEs depended on fuel type. The magnitude of Δ13C was 3‰ for gasoline, 2‰ for diesel, 1.5‰ for biofuel-C3, and 0.6‰ for biofuel-C4. The δ13C values of ICEs-generated PM10 were found to be dependent on the amount biobased components such as hydrotreated vegetable oil (HVO) to the fuel. However, insubstantial differences were found between the δ13C of PM derived from pure diesel and from an ethanol/diesel blend (E40).

Constrained Motion Control of an Independent Metering System with Uncertain Loads

Independent metering systems (IMSs) have been applied and researched in mobile machinery due to their advantages of reduced throttling energy losses and remarkable advances under negative load through decoupling actuator throttling control. Although IMSs have the control flexibility to deal with negative workloads, the control performance of the IMSs is challenged by uncertain loads in mobile operations, limiting the control accuracy. In addition, if the motion reference is improperly specified and exceeds the constraints, the pressure of the actuator may oscillate significantly and potentially result in control instability. In this study, a constrained adaptive robust control strategy is proposed for an IMS. An adaptive robust control strategy is designed for the meter-in and meter-out throttling to achieve precision motion control despite the nonlinearities and uncertainties of the electro-hydraulic IMS. The value of the uncertain workload is estimated in real-time and utilized in the model-based controller to improve control accuracy. In addition, a constrained trajectory planning approach is presented to handle out-of-constraint references and ensure motion tracking performance. This effectively prevents pressure fluctuations caused by the inappropriate reference.

Design and Experimental Validation of a Scaled Test Bench for the Emulation of a Hybrid Fuel Cell Powertrain for Agricultural Tractors

Hybrid fuel cell powertrains are a promising strategy to reduce the environmental impact of vehicles and non-road mobile machinery. To preserve the state-of-health of fuel cells, an energy storage system with sufficient power capacity, such as ultra-capacitors or batteries, should be introduced in the system to help the fuel cell during sudden and abrupt changes in power demands. However, the presence of two or more energy sources necessitates the development of an energy management strategy. The energy management strategy should properly split the power request between the different energy sources. In this paper, the design and the experimental validation of a scaled test bench for the emulation of a fuel cell/battery powertrain for a vehicular application is presented. The fuel cell is emulated through an analogically controlled DC power source that reproduces its real voltage–current curve. To split the power between the emulated fuel cell and the batteries, controlled DC-DC is used and a simple energy management strategy based on a proportional-integral controller is developed. The external load is reproduced using a load unit composed of a programmable electronic load and a power supply. Experimental tests are performed to evaluate the system behaviour and to characterize its main components. The experimental results show that the system successfully emulates the powertrain in accordance with the proposed energy management strategy.

Tyre pyrolytic oil blends in a state-of-the-art compression ignition engine: Towards fuel-optimised combustion

The end-to-end efficiency and environmental impact of tyre pyrolysis oil (TPO) are currently high on the agenda of worldwide research. However, most knowledge regarding combustion and emissions of TPO fuels comes from legacy (pre-Euro standard) engine platforms, operating in non-optimal combustion conditions. The few tests on modern automotive engines have used factory, diesel-optimised calibration maps and focus on only small TPO admixtures to diesel fuel (DF). The present work aspires to tackle these knowledge gaps by testing higher TPO admixture diesel blends in a state-of-the-art research engine realising low nitrogen oxides (NOX), partially premixed compression ignition. Measurement campaigns focus on accuracy in establishing fuel-to-fuel differences in emissions, also with consideration of unlegislated species. A combination of thorough combustion analysis and accurate fuel property characterisation allows evaluation of a calibration strategy that harnesses multi-pulse injection and a fully controlled air-path to mitigate emissions. This strategy enables an engine fuelled with a 40% TPO blend to realise low-temperature combustion in a wider area of the calibration map than is possible with DF. The most favourable NOX/particulate matter (PM) mode is extended towards high exhaust gas recirculation and early injection regimes. Adopting this dedicated engine control for TPO allows best-point NOX/PM emissions of 1.22 g/kWh and 0.18 g/kWh respectively, while maintaining the baseline indicated thermal efficiency target of 42%. Carbon monoxide and hydrocarbons emissions are elevated, but in terms of current EU Non-road Mobile Machinery Stage V limits, differences between TPO and DF are insignificant. However, regardless of calibration, TPO's chemical make-up causes increased emissions of sulphur oxides and aromatic hydrocarbons.

Distribution of benzene and formaldehyde in tractor cabin: Effects of components, ventilation conditions, and vent positions

Tractor cabin is a relatively closed microenvironment in which operator is exposed to various pollutants that can adversely affect human health. In this study, the distribution of benzene and formaldehyde inside tractor cabin was investigated using computational fluid dynamics (CFD) method and verifying its effectiveness with field measurements. The effects of pollution source, ventilation, and vent position on the distribution of pollutants were discussed by using the validated CFD model. The results indicated that the areas with high concentration of pollutants are mostly distributed in the corners, and the ceiling contributes the most to its emission. The concentration difference of benzene and formaldehyde in the driver’s breathing area can reach a maximum of 20% by adjusting the air supply angle. It can also be reduced by 3.9% and 4.3% for every 1 m s−1 increase in air supply speed when the airflow angle emitted from the vent was 90°. In the common vent locations, the vent arranged on the front ceiling has the best pollutant reduction effect. This study provided a reliable CFD simulation method for benzene and formaldehyde distribution, offered a theoretical basis for the selection of ventilation conditions and the design of internal layout in tractor cabins for improving air quality. It also suggested that then environment and air quality of non-road mobile machinery cabs should be paid more attention in the future.

Practical adaptive robust tracking control of the dual-valve parallel electro-hydraulic servo system with reduced-order model

To meet the increasing demand for trajectory tracking accuracy and high-efficiency requirements in modern mobile machinery, this paper proposes a practical adaptive robust control method based on the dual-valve parallel electro-hydraulic servo system. Existing tracking control strategies for such servo systems rely on a backstepping method and assume that full states are known, which is stringent in practice. To cope with the problem, we reduce the mathematical model order of the studied system using singular perturbation theory in this paper, and only the position feedback is required for the control implementation. Then, to achieve high accuracy tracking control, a direct adaptive robust control scheme combing with a dynamic flow allocation layer is adopted to synthesize the controller. With this method, parameter uncertainties and load disturbance are rejected, and valve characteristics are considered in the dynamic flow allocation layer to solve the flow redundancy problem, respectively. Convergence of the simplified system tracking results is proved theoretically. Extensive co-simulations and experimental tests are carried out to illustrate the effectiveness of the proposed strategy, both tracking precision and flow distribution can be achieved efficiently by simple parameter adjustments in the field.

Study of Mobile Source Pollutants Based on Multi-Source Data Fusion: A Case Study of Zibo City, China

The primary pollutants emitted from mobile sources have become one of the main sources of urban air pollution. In this study, the primary pollutants CO, HC, NOx and PM from mobile sources in Zibo city, China are studied. Firstly, the localized mobile-source pollutant emission factors are corrected using vehicle emission experiments; secondly, multi-source data fusion is performed using road network data, road traffic data, air quality and meteorological data; then, the corrected pollutant emission factors and multi-source data are used to construct a localized emission measurement model and dispersion simulation model, visualize the emission distribution and propose residual concentration correction to accurately obtain the pollutant sharing rate. The results show that the pollutant emission trends are highly coupled with the distribution of urban residents’ working hours. Based on the localized dispersion model used to analyze the pollutant traceability at air monitoring stations, the emission sharing rate of NOx is the largest, and according to the analysis of the changing trend of mobile-source emission sharing rate, the mobile source pollutants in Zibo are mainly influenced by pollutant emissions from road motor vehicles. This study provides data support and a theoretical basis for the management of the transportation industry to carry out exhaust gas control of motor vehicles and non-road mobile machinery and to make decisions related to improving the air environment (delineating the scope of low emission zones).

Investigating the potential for reduced emissions from non-road mobile machinery in construction activities through disruptive innovation

The construction industry relies heavily on non-road mobile machinery (NRMM) for transportation and earthmoving operations, and it is therefore important, from a sustainable perspective, to reduce emissions from NRMM in construction activities. This paper analyses the European emission inventory to find out if technological development has lowered the environmental impact of NRMM over time, with a focus on local, regional and global air emissions. The findings suggest that current regulations have been successful in reducing local and regional emissions (PM2.5 and NOX) by sequentially imposing more stringent requirements, which has promoted incremental innovations in existing technology. However, global emissions in terms of greenhouse gases have not been reduced due to the present regulations. The results are analysed and interpreted using Christensen’s theory of disruptive innovations for technological change to assess whether the development appears to progress incrementally or if the data point towards a required technology shift. Currently, the signal of a broad technology shift towards zero-emission solutions is not evident, but at the niche level activities are progressing with new technology. This paper proposes that a shift will require not only a technical transition, but also a sociotechnical change, involving stakeholders acting in symbiosis.

An exploratory study of software engineering in heavy-duty mobile machine automation

As the amount and complexity of software for automating heavy-duty mobile machinery is increasing, software engineering in this domain is becoming more important. To characterize the industry’s current state of software engineering and its issues to guide future research, we performed an empirical exploratory study. We interviewed 16 software engineering professionals from 13 different companies conducting business in heavy-duty mobile machines and their automation. The interviews were analyzed qualitatively, and quantification of the analysis results is presented. We first create an overview of software engineering in the heavy-duty mobile machinery industry. We then identify problem areas affecting software development and discuss some of the possible solutions found in literature. Our findings indicate that the major problem areas faced in the industry that require more research are its digital transformation, autonomous machine functional safety, low availability of workforce for developing software for robotic mobile machines and the lack of established software standards.

Direct synthesis of high silica SSZ-16 zeolite with extraordinarily superior performance in NH3-SCR reaction

The development of Cu ion-exchanged small-pore zeolites with excellent performance and high hydrothermal stability in NH3-SCR reaction is of great importance. However, many frameworks of the small-pore zeolites are Al-rich, for instance, Cu-SSZ-16 zeolite with Si/Al ratio always no more than 5, showing relatively low hydrothermal stability. In this work, inspired by theoretical calculation for the interaction between organic structural directing agents (OSDAs) and zeolite framework, high silica SSZ-16 zeolite with Si/Al ratio at 6.7 was directly synthesized using an economical diquaternary alkylammonium cation as an OSDA. After exchanged with Cu ion, the Cu-SSZ-16 catalyst shows extraordinarily superior performance in NH3-SCR reaction even after hydrothermal aging at 900 °C. The designed synthesis combined with excellent performance as well as high hydrothermal stability of the high silica SSZ-16 zeolite might provide an attractive alternative candidate for NH3-SCR catalyst on diesel vehicles and non-road mobile machinery in the future.

A Multi-mode Electronic Load Sensing Control Scheme with Power Limitation and Pressure Cut-off for Mobile Machinery

In mobile machinery, hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level, but diversified control functions (e.g., power limitation and pressure cut-off) are integrated into the electronic controller only from the pump level, leading to the potential instability of the overall system. To solve this problem, a multi-mode electrohydraulic load sensing (MELS) control scheme is proposed especially considering the switching stability from the system level, which includes four working modes of flow control, load sensing, power limitation, and pressure control. Depending on the actual working requirements, the switching rules for the different modes and the switching direction (i.e., the modes can be switched bilaterally or unilaterally) are defined. The priority of different modes is also defined, from high to low: pressure control, power limitation, load sensing, and flow control. When multiple switching rules are satisfied at the same time, the system switches to the control mode with the highest priority. In addition, the switching stability between flow control and pressure control modes is analyzed, and the controller parameters that guarantee the switching stability are obtained. A comparative study is carried out based on a test rig with a 2-ton hydraulic excavator. The results show that the MELS controller can achieve the control functions of proper flow supplement, power limitation, and pressure cut-off, which has good stability performance when switching between different control modes. This research proposes the MELS control method that realizes the stability of multi-mode switching of the hydraulic system of mobile machinery under different working conditions.

Calculation of emissions into the air of non-road mobile machinery from the landfill

Waste disposal is just one of the segments in solid municipal waste management system. During the entire life cycle of waste, starting from waste generation, through storage, collection, transport, recycling, treatment and disposal, several different pollutants are emitted. By disposing solid waste, non-road mobile machinery (NRMM) emits various pollutants into the air such as CO2, CO, NMVOC, PM, PAHs, heavy metals, etc. These substances can pose certain problems for human health and the environment. The subject of this study is the calculation of air emissions of CO2, CH4, N2O, NMVOC, PM10, CO, Cd, Cr and PAHs (chrysene and benz[a]anthracene) from NRMM which are included in the activities of receiving and disposing of waste at the Banja Luka landfill. The study evaluates the emission of pollutants using the EEA guidelines for the assessment of the emission of pollutants into the air, based on the consumption of diesel fuel during the year. This study, which is based on the calculation of NRMM emissions at the Banja Luka landfill, should serve as an example not only to other landfills but also to sectors that use NRMM on the importance of keeping track of pollutant emissions. The goal is to look at these emissions and introduce changes and improvements in this sector by replacing old NRMMs with new ones, optimizing operation, using diesel of satisfactory quality, etc.

Correction: Differently shaped Al2O3-based Pd catalysts loaded catalytic converter for novel non-road mobile machinery exhaust systems

Correction: Differently shaped Al2O3-based Pd catalysts loaded catalytic converter for novel non-road mobile machinery exhaust systems

Multi-Chamber Actuator Using Digital Pump for Position and Velocity Control Applied in Aircraft

This paper presents a multi-chamber hydraulic actuator controlled by digital pumps and on/off valves, in order to improve the efficiency of hydraulic systems applied in aircraft for flight control. Hydraulic positioning systems are used in many different applications, such as mobile machinery, industry and aerospace. In aircraft, the hydraulic actuators are used at flight control surfaces, cargo doors, steering, landing gear and so one. However, the massive use of resistive control techniques, which throttles the passages of the hydraulic fluid, associated with internal leakage of the hydraulic components, make these systems low energy efficient. In order to improve their energy efficiency, digital hydraulics emerges as a promising solution mainly for mobile applications. In this paper a hydraulic positioning system for aircraft control surfaces using a multi-chamber actuator controlled by on/off valves and a digital pump is proposed. The use of a digital pump with three fixed displacement pumps can provide eight different volumetric displacement outputs. The multi-chamber actuator with four areas can operate in two different modes, normal or regenerative, resulting in six different equivalent areas. The regenerative mode allows the actuator to achieve higher actuation velocity values with smaller pumps. These equivalent areas combined with the different supplied flow rates can deliver 43 different discrete output velocity values for the actuator, in steady-state. For the system dynamic analyses, three mathematical simulation models were developed using MATLAB/Simulink and Hopsan, one for the digital system, and two for the conventional solutions applied in aircraft (Servo Hydraulic Actuators (SHA) and Electro Hydrostatic Actuator (EHA)). The simulation results demonstrate that the digital actuator can achieve, for position control, a maximum position error, in a steady-state, of 0.7 mm. From the energy consumption point of view, the digital circuit consumes 31 times less energy when compared with the SHA and 1.7 when compared to the EHA, resulting in an energy efficiency of 54%.

Analysis of Frequency Adjustable Control of Permanent Magnet Synchronous Motor for Pump-controlled Actuators

Recently the pump-controlled system has actively been proposed as a replacement for conventional valve-controlled systems, to improve the energy efficiency in non-road mobile machinery. Earlier research demonstrated that a pump-controlled hydraulic system combines the best properties of traditional hydraulics and electric intelligence. This pump-controlled system can be realized via direct control of hydraulic pimp/motor by varying speed of electric motor without complex servo valves. Nowadays, a wide range of different electric motors is known and available with efficiency higher than 95% One of the most attractive option of electric motor is Permanent Magnet Synchronous Motor (PMSM) due to its size, power, and high efficiency.
 However, control of electric motors in pump-controlled systems has are not yet considered and not well researched.
 In this paper, the main objective of this investigation is determination of control values for the pump-controlled actuator and analysis of system’s behavior in different applications.
 Therefore, model of PMSM drive with pump-emulated load is proposed. Field Oriented Control (FOC) gives wide range of the speed regulation and smooth characteristics, but tuning of controllers is challenging.
 Case of the steering-modeled load represented that such operations need more power than other modes. More complex frequency converters allow to reach higher level of accuracy and decrease torque ripples, but complexity of such systems increases rapidly.