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Gravel roads form a significant share of the global road network, usually in sparsely populated rural areas. They are important, especially in agriculture, tourism, and forestry, connecting rural to urban areas. This systematic literature study comprises 105 reviewed publications on gravel road maintenance. Review articles on maintenance management practices, especially concerning objective condition assessment and data-driven methods (DDMs), are lacking. Therefore, this review provides a concise overview of current gravel road maintenance practices and ongoing research on objective condition assessment and DDMs for gravel road maintenance. It offers researchers in gravel road maintenance and other related fields a clear indication of where to focus their research efforts, as it suggests the direction for future research. Visual assessment methods are predominant for monitoring the condition of gravel roads, while objective methods and DDMs are not common. Research on gravel roads and their maintenance has increased in the last two decades, especially in North America and Northern Europe. Condition assessment is shifting from subjective to objective methods, utilizing knowledge from technological advancements in image processing, vibration and acoustics analysis, and so forth. There are some excellent research initiatives for objectively assessing the condition of gravel roads and DDMs, but the practical implementation is limited. Implementing objective assessment methods and DDMs generally improves the management of gravel roads with regard to decision-making, maintenance costs, safety, and the stability and comfort of the ride. Objective condition assessment and DMs have the potential to enhance maintenance practices in the maintenance of gravel roads., Sustainable maintenance of gravel road (HUG)

There is an increasing need for an effective monitoring strategy for the performance and condition of Down The Hole drilling. To achieve that, it is important to gain knowledge in the physics involved in Down The Hole drilling processes.A logical way to gain such understanding is to develop simulation models that are capable to represent the process. That requires physical understanding and thus, it is an iterative process. To capture the physics, it is essential to couple the axial impact, and the subsequent axial motion, with the rotation of the drill. The indentation into the rock due to impact and the subsequent resistance against rotation will couple the rotation to the axial motion and vice versa. The scenario is complicated due to the non-linear nature in the contacts and the varying stiffness of the rock.This paper presents a methodology that can be used to couple the axial and rotational motions of the DTH drills and explores the pros and cons of such a 3D simulation model.Keywords: DTH, 3D simulation, Condition monitoring

The key driving factors in using humans and robots in collaborativeapplications for assembly processes are to reduce assembly time, cost and toimprove the human working environment from an ergonomic viewpoint. Currently,there are limited automated procedures in assembly operations in house constructionbecause the traditional type of assembly process depends entirely on manpower.This is common in the assembly process in different industries since assembly isone of the most demanding and intense manufacturing processes, and it is difficultto automate. This paper presents a case study on the implementation of human-robotcollaboration for window assembly by way of an offline robot programmingsimulation. A self-adaptive software architecture that runs on a real-time targetmachine is also proposed for robotic window assembly. The window assemblymethod that will be used in this study is called “Click-In” and is manufactured byFixture System Sweden AB. Apart from robot simulations, detailed suggestions aregiven for building a pilot cell for robot window assembly. The case study presentedin this paper has both economical and ergonomic goals. The economic goal is toreduce the assembly time which will lead to an increase in window production. Byintroducing human-robot collaboration, operators do not need to performuncomfortable assembly operations—rather the robot will perform these unergonomic operations. The feasibility of both goals is verified with offline robotprogramming simulation.

Needs for new competences and knowledge arise as industry 4.0 evolves in increasingly digitalized production. This development entails that job transformations and future skills need attention from the perspective of industry 5.0, where human and machine find ways of working together to improve production performance. Facing this perspective, one challenge is a growing need for novel lifelong learning initiatives, to meet emerging and altering occupations for the fulfilment of future skill requirements. This challenge is addressed here by portraying a case where three Swedish universities have formed a distinctive collaboration to develop a flexible (i.e. blended) course for professionals, in the subject of Digitally-enabled production. The purpose is to develop a sustainable collaboration between the universities and create a course format on master level addressing lifelong learning for the increasingly digitalized production. The ambition is to increase the impact of the universities respective efforts by sharing resources and utilizing individual specialized expertise to develop a practical and relevant course that can reach a larger target group. The course encompasses industry 4.0 readiness on three levels of production systems; plant-, production cell-, and component level; to adopt a holistic view of digitalization in production. We followed an action research approach for continuously collecting and documenting our experiences during the course development, implementation, and dissemination of the course. Within the frame of action research, an explorative case study describes and analyzes the initiative. The results highlight challenges and opportunities for succeeding with this form of co-produced course. The joint course gives professionals possibilities to work on cases from their own companies with expert supervision from three manufacturing levels to address complex challenges in industry 4.0 implementation. To conclude, the importance of lifelong lea

The gravel road network is an important function for rural residents and entrepreneurs. Traditional maintenance of gravel roads is well-functioning but provides a relatively high maintenance cost per unit length of the road, and every maintenance action as well as extraction and transport of new gravel contributes to increased climate impact and resource depletion. Today, maintenance planning is carried out periodically based on the maintenance history, which also is reflected in the economic models and procurement methods. Current maintenance plans may be enhanced and will not be a reliable basis in the future, e.g. due to climate change. Instead, real needs and conditions must be given greater consideration. Today, appropriate maintenance management systems are lacking, e.g. in order to be able to evaluate maintenance deficiencies, prioritize objects and choose the appropriate maintenance action. Moreover, the knowledge available at specific stakeholders is not shared with other actors. In this paper, an Information and Communication Technology (ICT) system for gravel road maintenance is proposed in the form of a cloud-based system covering the information needs of stakeholders in the gravel road maintenance ecosystem. Requirement specifications are given for the sub-systems intended for the maintenance executioner and the maintenance planner. The specifications are based on workshops and interviews conducted with stakeholders, where requirements were acquired e.g. in the form of User stories., Hållbart underhåll av grusväg

Reliable simulations of the DTH drilling cycle are important in understanding the physics related todrilling, which in turn enables development of robust performance and condition monitoring methodologies. The DTH models available today model different aspects of the system like impact, hydraulics etc. separately. There are models available that incorporates hydraulics/pneumatics with onedimensional structural dynamics of the system. A common drawback of such models is that the effectof rotation is neglected. In reality rotation is an integral part of the DTH system and is interconnectedwith other parameters of drilling. This paper focuses on a simple model that combines rotation of thedrill string with the impact and hydraulic mechanics. The aim is to build upon this basic model tofacilitate the development of a more robust and accurate model that represents the condition andperformance monitoring problem.

The gravel road network is an essential function for rural residents and entrepreneurs. Traditional maintenance of gravel roads is well-functioning but provides a relatively high maintenance cost per unit length of the road. In addition, every maintenance action and extraction and transport of new gravel contribute to increased climate impact and resource depletion. Today, maintenance planning is carried out periodically based on the maintenance history, which also is reflected in the economic models and procurement methods. Current maintenance plans may be enhanced and will not be a reliable basis in the future, for instance due to climate change. Instead, real needs and conditions must be given greater consideration. Today, appropriate maintenance management systems are lacking, e.g., to be able to evaluate maintenance deficiencies, prioritize objects and choose the appropriate maintenance action. Moreover, the knowledge available at specific stakeholders is not shared with other actors. In this paper, an Information and Communication Technology (ICT) system for gravel road maintenance is proposed in the form of a cloud-based system covering the information needs of stakeholders in the gravel road maintenance ecosystem. Requirement specifications are given for the subsystems intended for the maintenance executioner and the maintenance planner. The specifications are based on workshops and interviews conducted with stakeholders, where requirements were acquired using techniques such as User stories, Use case scenarios, and mock-up prototypes. System examples corresponding to the requirements specifications are also given., Sustainable maintenance of gravel roads

The educational phenomena studied in this paper is remote-controlled physical laboratory environments and their applicability in upper secondary school physics education. In order to gain a better understanding of the situation and needs regarding laboratory activities in the upper secondary school, eight physics teachers were interviewed at six different schools. This revealed that the resources for laboratory activities vary between schools and may be inconsistent with the Swedish National Agency for Education curriculum. Furthermore, 165 upper secondary school students answered a questionnaire survey regarding subject preferences, program choices, views on technology and self-ability, and approach to technology and technology-related situations. The acquired knowledge provides a basis concerning the needs and conditions of teaching and learning within the subject of physics. This new knowledge motivates the development of the Flipped laboratory concept that is introduced in this paper, based on remote-controlled physical laboratories, for upper secondary school.

The paper suggests a remote condition monitoring and maintenance laboratory environment based on theIndustry 4.0 concept. The architecture provides a remote connection with distance students and a test rig, which permitsthem to be able to perform condition monitoring, diagnostic, prognostics, etc. on the equipment. The ICT architecturefollows standards, such as the MIMOSA CRIS and the OSA-CBM. The remote laboratory environment supportslifelong learning as well as relevant training for the modern engineer and highlights the specific requirements of amaintenance engineer. As an example, the objectives and expected learning outcomes for a course in Maintenance 4.0fundamentals are displayed. The expected results are, among others, increased maintenance competences in theindustry, and the improvements of the different maintenance services following a predictive, condition-basedmaintenance strategy.

High quality information is essential for the efficient decision making. Road condition is, together with traffic frequency, commonly used as input for classifying road status. Road condition is also a major input for the maintenance executor (vehicle operator) when deciding on maintenance actions, such as amount of gravel to replenish. With better condition related information, the maintenance execution as well as maintenance planning could be greatly improved. The current deficiencies in gravel road condition monitoring methods and technologies are described in this paper, and an approach for objective measurement of gravel road condition is proposed, including new measurement techniques and systems as well as information processing for decision making. This is realized by utilizing research findings from the area of signal processing, maintenance engineering, and information systems engineering in the specific context of gravel road monitoring, thus utilizing available technologies and methods as well as physics.

High quality information is essential for the efficient decision making. Road condition is, together with traffic frequency, commonly used as input forclassifying road status. Road condition is also a major input for the maintenance executor (vehicle operator) when deciding on maintenance actions, such asamount of gravel to replenish. With better condition related information, the maintenance execution as well as maintenance planning could be greatlyimproved. The current deficiencies in gravel road condition monitoring methods and technologies are described in this paper, and an approach for objectivemeasurement of gravel road condition is proposed, including new measurement techniques and systems as well as information processing for decision making.This is realized by utilizing research findings from the area of signal processing, maintenance engineering, and information systems engineering in the specificcontext of gravel road monitoring, thus utilizing available technologies and methods as well as physics.

Gravel road maintenance is a complex endeavour comprising physical, technical and social aspects that have to be considered, and resources to be coordinated. The maintenance requirements are affected by weather conditions, geography, and traffic frequency, but also by the physical properties of the road and the previous maintenance performance. The physical properties and maintenance requirements are area dependent; in Northern Europe, ground frost, for instance, is a problem, while flooding is a problem in East Asia. Understanding the specific context-dependent variables is therefore important when designing a maintenance information system. In this paper, the maintenance information system requirements are identified focusing on the Swedish gravel road ecosystem. The system elicitation process is crucial to be able to specify the requirements of the future system and its users, and in this paper, a stakeholders’ approach is utilized. Different stakeholders are described, including their maintenance related needs, information needs, and roles in the maintenance system. The interdependencies between different stakeholders are also illustrated in an ecosystem diagram. From these descriptions, requirements for computerized maintenance management systems are elicited, and main users are identified. User scenarios are thereafter illustrated using the User Case technique.

As more features are added to the heavy duty construction equipment, its complexity increases and early fault detection of certain components becomes more challenging due to too many fault codes generated when a failure occurs. Hence, there is a need to complement the present onboard diagnostics method with a more reliable diagnostics method for adequate condition monitoring of the heavy duty construction equipment in order to improve uptime.Major components of the driveline (such as the gearbox, torque converter, bearings and axles) are components necessary to monitor. A failure among any of these major components of the driveline may result in the machine standing still until a repair is scheduled. In this paper, vibration based condition monitoring methods are presented with the purpose to provide a diagnostic framework possible to implement onboard for monitoring of critical driveline parts in order to reduce service cost and improve uptime.For the development of this diagnostic framework, sensor data from the gearbox, torque converter, bearings and axles are considered. Further, the feature extraction of the data collected has been carried out using adequate signal processing methods, which includes: Adaptive Line Enhancer and Order Power Spectrum respectively. In addition, Bayesian learning was utilized for adaptive learning of the extracted features for deviation detection. Bayesian learning is a powerful prediction method as it combines the prior information with knowledge measured to make updates. The results indicate that the vibration properties of the gearbox, torque converter, bearings and axle are relevant for early fault detection of the driveline. Furthermore, vibration provides information about the internal features of these components for detecting deviations from normal behavior. In this way, the developed methods may be implemented onboard for the continuous monitoring of these critical driveline parts of the heavy duty construction equipment. T

At excavations of quarries, construction sites or in mining, etc. articulated haulers are commonly used for the transportation of material. Thus, articulated haulers are exposed to a diversity of different worksites that all will load them differently. With a continuously growing market and added exhaust emission regulations, the machines need to be continuously optimized to meet durability and weight (fuel efficiency) requirements. In the structural design of any given component in an articulated hauler, the assumed loads used will reflect on its design. However, it is rarely the case that the loads used in the design procedure strictly represents the dynamic loads a hauler will be subjected to. As a result, the machines are generally oversized. To address the issue of oversized components, a statistical approach for the estimation of their fatigue life may be utilized. With the aid of power spectral density estimates of a components dynamic loads in combination with a finite element model of the component its vibration response in terms of power spectral densities may be estimated. Based on the vibration response spectra the component's fatigue life may be estimated assuming that the components dynamic loads may be considered as weakly stationary stochastic processes. To investigate if the dynamic loads used for fatigue life estimation may be considered as weakly stationary stochastic processes; stationarity tests have been carried out as well as estimates of the kurtosis and the mean square value as a function of time have been produced. The results indicate that the dynamic loads may not be considered as weakly stationary stochastic processes. Furthermore, by segmenting the dynamic load time series into segments that can be considered as weakly stationary the estimated fatigue life seems to decrease slightly if compared to the case when assuming that the dynamic loads are weakly stationary.

Light road construction machinery such as manually operated reversible plate compactors or reversible vibratory plates are used for compacting sand, gravel, rock fill, soil, etc. with the aid of vibration. The purpose of the vibration excitation of the ground is to produce pressure waves that penetrate the ground layers to overcome the resisting friction between the soil particles, in order to reduce the soil porosity and permeability. During compaction, the ground is dynamically excited via a compactor's bottom plate. However, the actual spatial dynamic behaviour of a compactor's bottom plate during operation may not be known. To increase the knowledge concerning the spatial dynamic behaviour of a compactor's bottom plate during operation, a reversible plate compactor whose bottom plate has been considered as a rigid body in its design has been investigated. An increased knowledge concerning the dynamic behaviour of compactor's bottom plate during operation is likely to enable a further improvement in the design of reversible vibratory plates concerning their performance, vibration exposure of operator, etc. To acquire knowledge concerning the dynamic behaviour of the bottom plate of a reversible vibratory plate during operation, spatial measurements of its acceleration response have been carried out on it during operation on rubber mats. Operating deflection shape analyses of the bottom plate have been carried out based on both power spectral density estimates and power spectrum estimates of the recorded acceleration responses. The fact that the frequency of the vibration excitation of the reversible plate compactor varied slightly, and thus induced a frequency modulated vibration response of the plate, was considered in the ODS analysis. The analyses indicate different dynamic behaviours of the bottom plate depending on the operation of the reversible vibratory plate, i.e. if it operates in idle, reverse or forward motion.

The manufacturing industry are dependent of engineering expertise. Currently the ability to supply the industry with engineering graduates and staff that have an up-to- date and relevant competences might be considered as a challenge for the society. In this paper an education approach is presented where academia - industry - research institutes cooperate around the development and implementation of master level courses. The methods applied to reach the educational goals, concerning expert competence within remote diagnostics, have been on site and remote lectures given by engineering, medical and metrology experts. The pedagogical approach utilized has been flipped classroom. The main results show that academic courses developed in cooperation with industry requires flexibility, time and effort from the involved partners. The evaluation interviews indicate that student are satisfied with the courses and pedagogical approach but suggests more reconciliation meetings for course development. Labs early in the course was considered good, and division of labs at the system and the component level. However further long- term studies of evaluation of impact is necessary.

The drilling industry is steadily moving towards automation. To have a better control over the drilling operation and to optimize the drilling performance, it is necessary to have a good understanding of the physics involved in the process. A good simulation model of the drilling process/system would be of great value in assisting this and in enabling the development of strategies to optimize it. A representative simulation model can provide insights into various phenomena that appear during drilling for different drilling conditions. Such a model is also likely to be of assistance in preparing various measurements. Issues such as choosing the type of sensors, their positions and which quantities to measure are supported by a model. A well calibrated model in combination with information extracted from measured data are hence likely to assist in selecting control strategies for optimized drilling performance. In this paper we present a MATLAB based 1D simulation model of a Down The Hole (DTH) drill and compare it with an existing 1D model in terms of computational speed and accuracy. The emphasis is to make a 3D model of a DTH system that is computationally efficient and accurate.