The paper describes the simulation software for preview of the motion of humanoid robot: either graphical in 3D environment or on the real robot (KHR-1 HV was used). Such software enable synthesis ...(both, online and offline) and execution of humanoid movements. Execution can be performed either on the 3D model or on the real robot. Such software brings two major advantages. First, to avoid self collision and to verify movement shape all synthesized movements can be previewed before executing on the real robot. Second, such system can be used for early stages of testing different sub-systems, for example, visual system, cognitive algorithms etc.
This paper introduces an approach to linguistic encoding of temporal relations in robotic system scenarios. The underlying idea is that a dialogue system that manages the interaction between the user ...and the external robotic system should be able (i) to understand and adopt a scenario defined in natural language, and (ii) to express a scenario, stored in a computationally appropriate form, in natural language. The paper proposes a language-independent notion of temporal structure, reports a corpus-based study on the role of temporal prepositions in signaling temporal relations in the Serbian language, and discusses the implementation of the prototype dialogue system.
Adaptive multimodal interaction with industrial robot Gnjatovic, M.; Tasevski, J.; Nikolic, M. ...
2012 IEEE 10th Jubilee International Symposium on Intelligent Systems and Informatics,
2012-Sept.
Conference Proceeding
This paper reports a spoken natural language dialogue system that manages the interaction between the user and the industrial robot ABB IRB 140. To the extent that the dialogue system is multimodal, ...it uses three communication modalities: (i) spoken language (automatic speech recognition and text-to-speech synthesis), (ii) visual recognition of the figures and determination of their positions, and (iii) typed text. To the extent that the dialogue system is adaptive, it takes the verbal and spatial contexts into account in order to adapt its dialogue behavior and to process spontaneously formulated user commands of different syntactic forms without explicit syntactic expectations. The industrial robot is slightly modified and enabled to manipulate over graphical figures, following the instructions of the dialogue system.
Acyclovir is the drug of choice for the treatment of herpes simplex virus (HSV) infections. Acyclovir-resistant HSV strains may emerge, especially during long-term drug use, and subsequently cause ...difficult-to-treat exacerbations. Previously, we set up a novel treatment approach, based on enzymatically synthesized pools of siRNAs, or siRNA swarms. These swarms can cover kilobases-long target sequences, reducing the likelihood of resistance to treatment. Swarms targeting the
essential gene of HSV-1 have demonstrated high efficacy against HSV-1 in vitro and in vivo. Here, we assessed the antiviral potential of a UL29 siRNA swarm against circulating strains of HSV-1, in comparison with acyclovir. All circulating strains were sensitive to both antivirals, with the half-maximal inhibitory concentrations (IC
) in the range of 350-1911 nM for acyclovir and 0.5-3 nM for the UL29 siRNA swarm. Additionally, we showed that an acyclovir-resistant HSV-1, devoid of thymidine kinase, is highly sensitive to UL29 siRNA treatment (IC
1.0 nM; I
97%). Moreover, the detected minor variations in the RNAi target of the HSV strains had no effect on the potency or efficacy of UL29 siRNA swarm treatment. Our findings support the development of siRNA swarms for the treatment of HSV-1 infections, in order to circumvent any potential acyclovir resistance.
Buckets are a vital substructure of all digging machines, and are intended for the realisation of the fundamental machine function - soil excavation. This paper presents the results of the ...experimental-numerical investigation of the cause of the bucket wheel excavator SRs 470 buckets failure. The chemical composition and mechanical properties, the impact toughness, hardness, tendency to cracks and the microstructure were determined using appropriate tests. Experimental examinations of working and residual stresses were performed using strain gauges. The superposition of the experimentally determined working and residual stresses and the calculation of the total principal stresses were conducted using the originally developed procedure presented in this paper. The bucket working stress state was calculated by applying the linear finite element method. Conclusions based on the investigation results show that the main reasons for the buckets failure were the ‘design-in defects’ - oversights made during the procedures of geometrical shaping and material selection. Furthermore, high values of residual stresses, as well as the cold cracking observed on the welded joint of the knife and the bucket body, suggest that the ‘manufacturing-in defects’ also played a significant role in the failure. The superposition of influences of the ‘design-in defects’ and the ‘manufacturing-in defects’ has conditioned the appearance and propagation of long-term fatigue cracks, leading to the total destruction of the buckets. The fact that buckets' failure appeared due to oversights made during geometrical shaping, material selection and manufacturing further points to the importance of the critical approach implementation during the design phase of the earthmoving machines working devices.
•We analysed the causes of buckets fractures.•Results of experimental and numerical investigations are discussed.•Superposition method of experimentally determined stresses is developed.•The ‘design-in’ as well as ‘manufacturing-in’ defects are dominant fracture causes.
•A method of selection and validation of the total number of buckets was developed.•The method used for the research is based on the dynamic response analysis.•Limiting accelerations were used as cut ...off criteria.
An original method for validation of the number of buckets on the working device of a bucket wheel excavator based on the dynamic response of its slewing superstructure (SS) is presented. A set of 16 seemingly acceptable solutions which satisfied the rigid design restrictions, based on the preservation of the existing (a) bucket wheel drivetrain, (b) theoretical capacity, (c) characteristics of the excavated soil and (d) position of the superstructure centre of gravity (CoG), was analysed. Already on the basis of the limiting vertical and lateral accelerations of the bucket wheel centre, which represents a well-grounded indicator of its dynamic behaviour prescribed by the code DIN 22261-2, 14 out of 16 analysed design variants have been discarded, reducing the set of possible solutions to only two – the originally-designed variant (with 17 buckets), and the variant with 20 buckets. Conclusions on the validity of these two design variants were derived on the basis of the dynamic response analysis of the referent points of the SS. The analysis of the impact of soiling on the dynamic response of the SS has shown that negative dynamic effects, observed in the preceding analysis of the originally-designed solution, increase with the amount of the adhered material. Although the redesigned variant with 20 buckets has proven as the only suitable solution from the standpoint of dynamic behaviour of the SS, the results have to be assessed carefully due to the fact that the reduction of the mass of the bucket wheel steel structure by more than 14% leads to the appearance of unfavourable dynamic effects, even though the SS CoG position is preserved.
In this paper are presented results of tests and analyses of complex dynamic loads carried out on the bucket-wheel excavator SchRs 650/5 × 24 Krupp, as well as assessment of service life of vital ...welded structures of a bucket-wheel excavator boom subjected to cyclic loading with a variable amplitude through the use of experimental tests carried out in order to determine operational strength and growth of a fatigue crack for one structural part. Bucket-wheel excavator was built by “Thyssen Krupp” company, Germany. Outer loads, or in other words digging forces for the overburden and coal have been calculated on the basis of measured values of actual current intensity of the bucket-wheel drive and recorded output values of changeable loads. Correlations between the power of the bucket-wheel drive system and adequate hourly production, depending on the overall digging resistance which affects the stress condition of the bucket-wheel, were also determined. Results of the theoretical and experimental analysis of natural and forced oscillations of the support structure for various exploitation conditions are presented in first part of the paper. Deformations εi determined by tensometric measurements on the rotating shaft of the bucket-wheel were converted into tangential stresses through the introduction of the modulus of elasticity and Poisson's ratio, which, along with the polar moment of inertia of the cross-section, define the moment of rotation on the bucket-wheel shaft. Through the use of the load - strength comparison method (maximization of the ratio of load and strength indicators) the application factor of the gear with the largest number of turns KA has been determined.
In the second part of the paper methodological approach for the assessment of service life of vital welded structures of a bucket-wheel excavator boom was presented. Assessment was done in order to determine operational strength and growth of a fatigue crack, through the use of experimental tests. Realized researches and results presented in this paper offer great possibilities for the analyses of behaviour of vital welded structures of the bucket-wheel boom. By the application of the measurement device with 8 channels for registration and processing of electric signals HBM Spider 8 and measurement tapes HBM 6/350 × XY31 deformations were measured at vital welded structures of the boom in the area of the bucket-wheel. The objective of the test is to determine if there is a possibility of occurrence of plastic deformations or initial cracks due to fatigue at vital welded structures and to obtain data which define crack growth.
•Specific digging resistances per knife at highest loads are 20% higher than the average value for overall measurements.•Hourly production N(Qe) show that the bucket-wheel excavator during operation cannot reach the designed capacity of Qt=4212 m3/h.•Determined application factor KA=1.6 is smaller than the one prescribed in standards for the gearbox of the excavator drive (KA=1.75-2.0).•In exploitation there is a possibility of the occurence of resonance due to their matching, and therefore of the occurence of damaging of critical cross-sections.•Fracture mechanics parameters have shown that the service life of the welded structure if a new edge crack occuris 4.55 years.
•Slope failure was the cause of a severe accident of the bucket wheel excavator.•The technology of the excavator’s rescue and balancing are presented.•The redesign solution enabled repair and ...reconstruction in field conditions.•The redesigned slewing platform meets the strength criterion, unlike the original.•During two years of exploitation since the revitalization, no damages were observed.
A slope failure was the cause of a severe accident of bucket wheel excavator (BWE) Takraf SRs 1200. This paper is dedicated to the engineering challenges that accompanied the process of returning the BWE from its after accident state to the state of full exploitation readiness. After the accident, temporary stabilization of the superstructure was carried out as well as cutting off of severely damaged parts of the bucket wheel boom (BWB) with excavating device. Successful completion of the very delicate BWE rescue and balancing operation was followed by the reconstruction of the heavily damaged slewing platform. The integrity of the slewing platform structure was preserved by removing structural parts which were seriously damaged during long-term exploitation and breakdown, and installing the newly designed elements in critical zones. The redesign of the slewing platform structure produced favorable loads and stiffness distribution while eliminating geometrical stress concentrators. Comparative analyses of the stress states pointed out that the redesigned slewing platform structure meets the strength criterion, unlike the original structure. The redesign solution enabled reconstruction in field conditions. This way the time of the reconstruction realization was drastically cut and losses due to the downtime of the machine were reduced several times over. After completing the slewing platform reconstruction, the newly manufactured BWB structural elements as well as the newly manufactured bucket wheel with drive were installed i.e. a partial revitalization of the BWE was done and by that the BWE’s life was essentially prolonged.
•Tie-rods are vital parts of the bucket wheel excavator slewing superstructure.•Experimental and numerical investigations are carried out on the eyebar model.•Plastification occurs across the full ...width of the cross-section near the hole.•DIN yields the results much lower than the actual stress values around the opening.•Nevertheless, DIN criterion is sufficient for the preservation of the eye integrity.
Tie-rods of the bucket wheel and counterweight booms are vital parts of the bucket wheel excavator slewing superstructure. This paper is dedicated to the problem of identifying the stress state of the critical cross-section ('net section') of the eye plates on these tie-rods. It presents the results of the experimental and numerical investigations carried out on the eyebar model. The results show the appearance of a plastic deformation in the zone near the contour of the hole even when the eye is subjected to the loads within the range of the permissible loads prescribed by the standard DIN 22261-2. Plastification in the eye net section occurs across the full thickness of the plate, but it does not jeopardize the integrity of the structure. The stress value in the eye net section, calculated in accordance with the standard DIN 22261-2, is significantly lower than the actual stress values around the hole and serves only as a comparative value for the static strength proof for the eye.
Service FMECA of a bucket wheel excavator Pantelić, Milorad P.; Bošnjak, Srđan M.; Misita, Mirjana Z. ...
Engineering failure analysis,
January 2020, 2020-01-00, Letnik:
108
Journal Article
Recenzirano
•We presented a consistent approach to the quantification of risk for BWE.•Results of experimental and numerical investigations are discussed.•Corrective actions for reducing risk levels are ...provided.
Surface mining systems (SMSs) are among the most significant 20th century achievements in mining industry, whose significance to miners is comparable to the invention of dynamite in the 19th century. However, problems of SMS risk assessment are very scarce in relevant literature. For this reason, this paper aims to establish a consistent risk quantification approach for bucket wheel excavators (BWEs), the backbones of these systems. Based on the original structural scheme of a BWE, the risk parameters assessing criteria stemming from multidecadal experience and the database of recorded standstills (in the considered case, one hour of SMS downtime generates indirect financial losses of ≈15000€), a study was conducted applying the Service FMECA technique to the BWE SRs2000 (one of the best-selling models from “Takraf”), with the following conclusions: (a) the material conveying subsystem is the highest contributor in the total number of mechanical and electrical failures, as well as in total downtime; (b) during the monitoring period, there were no extreme risk level failures. Besides, corrective actions for reducing risk levels of the most critical mechanical and electrical failure modes are given in the paper. The presented approach for risk quantification for a BWE can be successfully applied to other SMS subsystems, notably spreaders.
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