Recent Advances in Intelligent Manufacturing

With the emergence of capable and low cost sensing hardware simulations may be driven from real time production data. Such simulation could be used to predict future system performance. However for effective decision making knowledge of system level behaviour beyond production e.g. financial metrics would also be required. The generation of standard accounting data from simulation models has received little attention in the literature. Herein a modelling approach is demonstrated to generate production and accounting data streams from a Discrete Event Simulation for an idealised production business. The paper demonstrates an approach to assess the influence of production variables (labour arrangement) on system cash flow.

Smart factory is the foundation of intelligent manufacturing. Intelligent devices are applied to monitor and adjust factory production process and optimize production performance. Aiming at the problem that traditional decision system in die casting factory ignores the value of manufacturing data, the data driven die casting smart factory solution is developed. The key technology of intelligent factory is reviewed, and a new “Data + Prediction + Decision Support” mode of operation analysis and decision system based on data driven is put forward. Combined with the key technology of die casting and the application of data driven new mode, the “Physics + Information + Decision” three layers of cyber-physical system is designed. This solution digs the value of manufacturing data, and promote the efficient production of die casting smart factory.

In order to maintain the topological relations for the elements of casting process model and rebuild the casting process correctly when process parameters is changed, the topological entities naming method is used in this paper. Firstly, topological entities naming method, including naming rule for entity ID, Geometry_Name, and Process_Name, is proposed, and the mapping strategy between topological entity name and process information is established. Then, the geometry modeling method for casting process is studied in three steps: (1) process parameter setting method for gating and riser system; (2) parametric modeling procedure for gating and riser system; (3) the 3D process dimension design procedure for gating and riser system. Thirdly, the reconstruction method for parametric casting process model based on topological entity identification is given. A prototype of 3D casting process planning system is developed, and the reconstruction method is tested by an example part.

Tunnel shaped parts with truncated pyramidal shapes were formed using Single Point Incremental Forming (SPIF) on a Stewart platform. The accuracy behavior of these parts was characterized by an error prediction response surface generated using Multivariate Adaptive Regression Splines (MARS). This response surface predicted over forming for low wall angle parts and under forming for higher wall angle parts. It is based on geometrical parameters associated with features on the part geometry and was used to compensate for inaccuracies in the part geometry. Feature detection was found to work well for tunnel shaped parts using similar thresholds as container shaped parts, while the maximum deviations were found to be lower at a wall angle of 60° compared to a part with wall angle 40°.

A classification model is proposed to allocate, search and match services in cloud environment for Service Composition and Optimal Selection (SCOS). Unlike cloud computing, the services in cloud manufacturing (CMfg) include real time manufacturing resources besides computing services, which makes CMfg environment complicated for allocation of services to the respective tasks. Thus, problem is not having adequate tools for the fast and effective searching and allocation of services for implementation of SCOS. The method described in this paper is to achieve SCOS by organizing the services by an approach named pedigree. For this method to be applied, calculation of semantic cosine distance along with analyzing relationship between different services are required to support the collaboration for managing and matching services in pedigree. Examples are done for service registration along with searching and selecting the services which shows this method to be effective for service composition and optimal selection.

Since CNC machine tool is a typical complicated electromechanical product with thousands of parts, it is very hard to design and control the whole machine’s quality characteristics because of the intricate coupling relationships among them. In this paper, a method of quality characteristic decoupling based on meta-action unit for CNC machine tool was proposed. Besides dozens of meta-action units’ own quality, it only needs to control the coupling relationships among different meta-action units’ quality characteristics to guarantee the whole machine’s quality. Firstly, the definition of “meta-action unit” and “Function—Motion—Action (FMA)” were introduced. Secondly, the coupling constraint models based on meta-action unit were established. Thirdly, the decoupling method using design structure matrix and domain mapping matrix was proposed, while the decoupling models were built and the decoupling planning flow chart was established. Finally, APC rotary motion of CNC machine tool was taken as an example to illustrate the effectiveness.

The optimization of an individual component usually happens in isolation of the components it will interface with or be surrounded by in an assembly. This means that when the optimized components are assembled together fit issues can occur. This paper presents a CAD-based optimization framework, which uses constraints imposed by the adjacent or surrounding components in the CAD model product assembly, to define the limits of the packaging space for the component being optimized. This is important in industrial workflows, where unwanted interference is costly to resolve. The gradient-based optimization framework presented uses the parameters defining the features in a feature-based CAD model as design variables. The two main benefits of this framework are: (1) the optimized geometry is available as a CAD model and can be easily used in the manufacturing stages, and (2) the resulting manufactured object should be able to be assembled with other components during the assembly process. The framework is demonstrated for the optimization of 2D and 3D parametric models created in CATIA V5.

This paper presents the design and optimization aspect of a reaction sphere. Firstly, a novel reaction sphere actuator is proposed, which is composed of 12 curved stators, 6 electromagnets and a spherical rotor. Secondly, the relation between output torque and design parameters are discussed through finite element method (FEM) modeling. Thirdly, due to the difficulty of building a purely analytical model that takes all effects into account as design parameters, a optimization method based on Support Vector Machine (SVM) is studied, where the torque model is built through SVM and the optimized structure parameters are calculated by using genetic algorithm based on the developed SVM torque model. Finally, FEM simulation results validate the effectiveness of the proposed optimization method, showing that the proposed reaction sphere with optimized structure could increase the torque density by 68% as compared to the original prototype.

Thanks to the “one belt one road” initiative, the international logistics of Western China has made a huge development. However, the shortage of top international logistics talents prevents its further progress. This paper induces the demand types of talents and analyzes it by using the gray forecast model respectively from the qualitative and quantitative aspect. Aiming at the demand, a double-three-spiral talent training model is built, which include school-government optimizing schooling resources; joint practice platforms of school-enterprise; government-enterprise perfecting the mechanism. With perfecting three-year graduate education system, internalizing knowledge, externalizing capability, and improving themselves, the quality of talents training is finally improved.

Due to the vast distances between aerospace supply chain (SC) members, the logistical implications of outsourcing decisions must be considered, including the uncertainty in transportation costs (TC) caused by fluctuating fuel prices. Analytical models often model the impact of fuel prices without capturing the dynamic behavior of SC networks. Discrete event simulation (DES) can capture such behavior and correlate it with financial performance to support decision making. This paper uses DES to model the impact of fuel prices on TC and inventory holding costs (IHC) in a three-tier SC scenario where suppliers deliver products via land/sea- or air freight. The results show the transportation decisions can be used to mitigate the influence of fuel prices on the TC. The value, weight and size of products transported throughout the SC also influence in whether TCs or IHCs drive total SC costs. Future work could apply the methodology to larger and more complex SCs.

In the Lean Intelligent Manufacturing Environment, Improving the level of workshop process layout is the foundation and key for rail transportation equipment manufacturing to improve efficiency and reduce costs. So, it is very important to establish a scientific and reasonable process layout evaluation system. Combining with the process layout features of rail vehicle assembly workshop, an evaluation indicator system including 4 first-level indicators, 13 second-level indicators and 26 third-level indicators is constructed. Group AHP and entropy weight method are used to calculate weights. Grey relational analysis is used to calculate gray correlation between the current state and the ideal level of each indicator, so as to achieve a quantitative evaluation. Three typical urban rail vehicle assembly workshops of CRRC are evaluated, and the evaluation results are consistent with the actual situation.

The rapid development of online shopping offers new opportunities to the express delivery industry, but also brings enormous challenges due to its characteristics of multi-frequency and small-batch distribution. And the lack of cooperation among express companies in the urban distribution has resulted in uneconomical distribution. In the context of the sharing economy, this paper attempts to solve this problem by implementing joint distribution strategy with sharing the network resources. Based on the customer’s time window of receipt, a two-tier vehicle routing optimization model of urban joint distribution considering transfer stations’ sharing is established, and a hybrid heuristic algorithm has been designed accordingly. The results of a case study show significant optimization effect by comparing the independent distribution and joint distribution as well as robustness of the designed algorithm.

Based on logistics security, this paper analysis that people as one of the most important roles affect logistics security, and the games among different hierarchies will lead to different results of logistics security. By constructing a tripartite game model of participating groups, including government, managers and executors, in logistics security, the income matrix of tripartite game can be listed, and then we can find the game equilibrium points through evolutionary game theory. Through using the game model simulation by placing the value which makes the characteristic roots of the Jacobian matrix less than zero, we can get expected game equilibrium point which is $$\{$$ supervising, strengthening, executing $$\}$$ . Meanwhile changing some of the initial values under the government’s macro-regulatory effect, such as increasing the cost of punishment and rewards for managers and executors or reducing the input cost and the opportunity cost of doing other inputs appropriately and so on, can promote the three participants to build a stable and safe logistics transportation environment.

To improve the product quality and customer satisfaction, Chinese domestic automobile industries tend to perform continuous quality improvement procedure (CQIP). In this paper, an integrated VIKOR-DMAIC approach is developed to boom quality improvement practice. Firstly, the critical quality issue is chosen as the pilot program using VIKOR steps. Then, the Six Sigma method including DMAIC operations is performed to scrutinize the cause of quality issue and regulate strategic proposal. A practical case is presented to validate the integrated approach, and the pilot program improvement sets an example for other quality items.

On the issues of that the cost of the milk-run logistics mode with multi-level suppliers is hard to reduce, a mixed milk-run logistics mode involved second level suppliers is proposed in this paper. Based on the cost model in the traditional milk-run logistics mode, the transportation cost influenced by second level suppliers is taken into consideration in the new milk-run logistics mode. An improved genetic algorithm is applied to solve the new milk-run optimization problem. The preliminary comparison results indicate that the proposed mixed mode could provide a more practical method to significantly reduce the cost of logistics for the whole supply chain.

This paper proposes a logistics vehicle routing problem model based on the sustainable development theory, and develops a multi-objective planning model that includes social indicators, economic indicators and environmental indicators. Minimum total cost as a goal,that includes social costs, fixed costs, fuel costs, delay costs, CO2 emission costs and PM emissions costs. The particle swarm optimization was proposed to solve the case. The impact of different carbon dioxide prices on economic costs and environmental costs were discussed. The results show that increasing carbon dioxide prices can reduce pollutant emissions and lower operating costs. Finally the limitations and future research directions of this study are discussed.

The cold chain logistics has become an important part of national economy as the plans which the government announced these year, such like 《Development plan of cold chain logistics of agricultural products》. But also the city, Chongqing, paid more attention on its improvement that issued some files like 《The implementation of Municipal People’s government to speed up the development of agricultural Cold Chain in Chongqing, and 《Development plan of cold chain logistics in Chongqing》. This paper aimed to help fresh enterprise predicting the sales volume and profit by using Grey Model, which can grasp the trend of the market and developing direction. This paper set an example as TY Co., Ltd in Chongqing to show the operation process then get the answers. The figures of outcome past the consistency test that can prove this method’s accuracy and reliability.

Cloud manufacturing integrates supply chain resources across the country or even around the world, then virtualizes and services them to cloud platform. This allows users to access and use the services which are safe, reliable, high-quality and low-cost through the Internet at any time. The supply chain in cloud manufacturing (hereinafter referred to as the “cloud supply chain”) has a mess of resources and complex transaction status, so it will be disorderly and ill-organized without the support of system management and holistic technology. Therefore, this paper analyzes the characteristics of cloud supply chain, proposes the business model and system hierarchical structure of cloud supply chain, establishes the technical system of cloud supply chain implementation. This lays the theoretical foundation for the further development and implementation of the cloud supply chain.

To reduce the cost of logistics, optimize logistics warehousing layout and logistics distribution efficiency, logistics network of the integrated location-routing-inventory was studied. In this paper, we present a model of integrated Location-Routing and Inventory problem (ILRIP) that considers the selection of warehouses location, the inventory of products, and vehicle routing. Aiming at the characteristics of proposed model, a two-stage optimization problem is designed, and two main objective functions are established to minimize the expected total cost of inventory and location selection and distribution costs with time windows. Considering multiple constraints, the multi-objective optimization problems is designed. We solve the developed mathematical model by genetic algorithm (GA), then we code in MATLAB, a case study is proposed to prove industrial practicality of the model.

In this paper, electrical and dielectric properties of multiwall carbon nanotubes (MWCNTs)/insulating polyaniline (PANI) composites were studied. A mixture of MWCNTs and insulating polyaniline was dispersed in an ethanol solution by ultrasonic process, subsequently dried, and was hot-pressed at 200 °C under 30 MPa. Electrical and dielectric properties of the composites were measured. The experimental results show that the DC conductivities of the composites exhibit a typical percolation behavior with a low percolation threshold of 5.85 wt.% MWCNTs content. The dielectric constant of the composites increases remarkably with the increasing MWCNTs concentration, when the MWCNTs concentration was close to percolation threshold. This may be attributed to the critical behavior of the dielectric constant near the percolation threshold as well as to the polarization effects between the clusters inside the composites.

Stretch blow moulding in manufacturing bioresorbable vascular scaffold (BVS) from poly (l-lactic acid) (PLLA) provides a biaxial deformation process of raw materials to enhance the mechanical performance. Current knowledge on the mechanical behaviour of PLLA materials in this deformation process is still lacked and trial-and-error tests are relied to develop a successful operation, causing significant waste of material and cost. Motivated by this circumstance, mechanical properties of PLLA materials were investigated by biaxial stretching test at designed strain history mimicking the stretch blow moulding process. A nonlinear viscoelastic material model, i.e. Glass-rubber model was calibrated based on the experimental data from equal biaxial (EB) and constant-width (CW) stretching tests. Material anisotropy was implemented into the original model by introducing the initial orientation factor from the extrusion process. Biaxial deformation process of PLLA materials under variable strain history was modelled by the calibrated and modified model. Modelling results exhibited good agreement with the experimental data, highlighting the potential application of material modelling in improving the understanding on stretch blow moulding of PLLA materials in the industrial manufacture.

Rotational moulding is a polymer forming process used to create hollow, stress-free products using both heat and rotation. The basic principles behind the machines which execute the process of rotational moulding have not changed significantly over the last 60 years. A factor restricting the growth of the rotational moulding industry is the limited wall thickness uniformity that can be achieved using the current machines which have limited motion control. Improved flexibility of motion control over the mould is now available and will be investigated with the aim of providing a more efficient process and higher quality products. Using a mathematical ‘sphere filling’ curve approach, a rotational path can be designed which allows every area of a spherical mould to spend a more uniform time period in contact with the powder pool (Wall thickness uniformity is affected by the powder-wall contact time). This paper proposes a new approach to mould motion control optimisation and provides validation using Discrete Element Method (DEM) simulations. This method has been found to increase the uniformity of powder-wall contact time by up to 19%.

Machining technology is developed with increasing flexibility to adapt to the rapid changes of the market. Parallel kinematic machines (PKMs) have demonstrated great flexibility to suit the demands, but it is still not possible to achieve as high accuracy as the traditional NC machines (TNCMs). This paper presents a general review on the structure-based errors of PKMs in comparison with TNCMs to reveal the root causes of the errors and their relevance to the machining uncertainty. The geometric/kinematic, gravitational, and thermal aspects in both TNCMs and PKMs are identified as structure-based error sources. Errors in each aspect are comparatively analyzed, and inherent differences are found to bring new challenges to the accuracy of PKMs. Finally, perspectives in each aspect are highlighted for accuracy improvement of PKMs.

A vane Magnetorheological (MR) damper for the purpose of suspension system was designed, manufactured and tested. The working methodology of the designed rotary damper was outlined and its theoretical model was also defined in the article. The magnetic field working as well as design was modelled on ANSYS. It is clearly defined in the results that damping ability of the designed damper is more than enough to be used for automotive suspension system. The manufactured damper was tested on MTS 858 table top system and performance of damper was analyzed at different currents and frequencies. Extra ordinary results proved that proposed vane type MR damper has high torque density and compact structure.

With reference to imminent emissions regulation, the temperature is presumed to elevate in engines exhaust manifolds. To consider the present material in the manifolds, it’s necessary to study the performance of the material in the working temperature. In designing part for increase life, important material characteristics to be noted, as like creep, corrosion by oxidation and fatigue resistance. Alloys are considered for improving these material properties in exhaust gases at high temperature. In this present study, analysis of D5S is observed experimentally which is used for evaluating the damage mechanism of exhaust manifolds at variant temperature and strain amplitude. Mechanical properties are examined physically by optimizing the method of uniaxial stress-strain testing and low-cycle fatigue testing with different temperature range from 300 °C to 800 °C. Behavior of the material, experimentally analyze with these cyclic softening and cyclic hardening properties. Concisely, life cycle of material D5S confers during fatigue testing. Ni-resist D5S at high temperature, reduction in fatigue life is observed during transition from elastic part to plastic part under strain dominance. In addition, the results are achieved from low-cycle fatigue experiments lead towards the selection of rank material for these applying conditions.

With the great development of cloud manufacturing (CMfg), currently accurate prediction about quality-of-service (QoS) has become a hot issue. However, as task diversity increases, most existing QoS prediction methods mainly focus on the similarity measure between users and services, and thus ignore the impact of task characteristics in CMfg. Therefore, to solve above problem, a task-driven QoS prediction model with the case library is established to predict unknown QoS value. First, we present a similarity measure method in the case library including service similarity and task similarity, to search similar services and corresponding historical tasks. Then, QoS prediction model is established considering task similarity and the time decay function as well as service similarity. According to the experiments, our model outperforms current methods with respect to prediction accuracy, and the key parameters have also been studied.

The stability and reliability of meta-action unit is the basis for ensuring the reliability of the whole machine. Based on the analysis of the structure of meta-action units,a fishbone diagram of influencing factors of meta-action unit reliability is established. Then, the GO method is used to analyze the reliability of the meta action unit, and the universal GO diagram model and probabilistic model of the unit action reliability are established. Taking the reliability analysis of spindle rotation element motion as an example, the application of the proposed method is verified.

The sustainable production has received extensive attention. With the aim, reducing the energy consumption in the manufacturing stage is particularly important. This paper presents a new mixed-integer linear programming (MILP) model for the complex production scheduling of remanufacturing job shop. This model is suitable for the job shop that batch processing machines and non-batch processing machines exist at the same time. According to the time-of-use (TOU) electricity pricing, dispatch reasonably to optimize the makespan and the electricity cost. Reach the target of increasing production efficiency and reducing environmental impact, promoting sustainable production.

As traditional flow shop scheduling model is usually designed for deterministic production environment and under single optimization objective, this paper considers a permutation flow shop scheduling problem with uncertain processing time so as to overcome the deficiency. Moreover, a multi-objective robust scheduling model is constructed to minimize the tardiness and total completion time under min-max regret criterion. Directed graph is used to analyze the scenario of the maximum regret value scenario (i.e. the worst-case scenario). Finally, genetic algorithm is applied to solve this robust scheduling model. Through the experimental simulation results, the proposed model shows its efficiency and effectiveness.

Deteriorated stencil is the main cause of product quality failure for solder paste printing. Frequent stencil cleaning helps to reduce the quality loss, but usually results in an increased cost of downtime. In this paper, an approach for controlling the stencil cleaning is proposed and the optimal decision which balances the quality losses and the downtime losses is obtained based on renewal reward theorem. The degradation of the stencil printing capability is modelled by a Markov chain, and the product quality loss is estimated.

Stencil cleaning is a necessary operation step in solder paste printing process. Frequent cleaning operation usually leads to an excessive waste of cleaning agency and increased standby time. This paper proposes an approach for controlling the cleaning operation through variable stencil cleaning threshold sequences. A downtime ratio model is established to obtain the sequences, and a case study is given to show how to acquire the threshold sequences and makes decisions of stencil cleaning.

This paper empirically investigates how consumers’ preference towards remanufactured products is determined with consideration of their greenness, price and green attributes. A mixed between and within-subject experiment was conducted to test four hypotheses of the correlations between consumers’ preferences for remanufactured products and the level of consumer greenness, the level of price discount and green attributes of the products respectively. By analyzing data results of the experiment, the paper reveals how consumers’ preferences and utility towards remanufactured products was determined, thus providing remanufacturers with new understanding of consumers’ demand and insights into pricing strategy.

This paper presents a critical review of some existing modelling, control and optimization techniques for energy saving, carbon emission reduction in manufacturing processes. The study on various production issues reveals different levels of intelligent manufacturing approaches. Then methods and strategies to tackle the sustainability issues in manufacturing are summarized. Modelling tools such as discrete (dynamic) event system (DES/DEDS) and agent-based modelling/simulation (ABS) approaches are reviewed from the production planning and control prospective. These approaches will provide some guidelines for the development of advanced factory modelling, resource flow analysis and assisting the identification of improvement potentials, in order to achieve more sustainable manufacturing.

Blisk is one of the most important parts in advanced aero-engine, its surface processing quality directly affects the performance of aero-engine. However, it is difficult to polish the blisk at once, because of deep and narrow space, free-form surfaces, easy deformation and interference, poor reach ability, difficult-to-cut materials, and so on, so, it is difficult to guarantee the surface quality for compliance with strict industrial standards to blisk. For this aims, two different polishing methods, called six-axis linkage belt polishing and robot wire-wheel polishing, are used in this paper. The experimental results show that the surface quality meets the manufacturing requirements when different methods are used for different areas of the blisk. It is proved that this method could be integrated to enable automated polishing of blisk full-area surfaces.

Aiming at the speed regulation problems of the constant torque load such as adjustable speed asynchronous magnetic coupling (ASAMC) matching belt conveyors, based on the analysis of the magnetic field characteristics of the coupling, its slip speed-air gap-torque equation is obtained, which matches the load start characteristics. The variation of the acceleration under the matching condition of the air gap at the start of the belt conveyor is quantified. On this basis, a soft start control strategy for the matching of ASAMC and the belt conveyor is established. A 125 kW ASAMC experimental platform was set up and experiments were conducted. The experimental results and field applications verified the reliability of the algorithm.

The reliability of IMSS is an important factor that influences the lifecycle cost of the systems. However, there is little existing research that investigates relationships between the reliability of systems and their cost in the whole lifecycle. This paper reviews these costs, and proposes a method of estimating business losses due to the failure of an individual component/subsystem. When compared with the reliability and maintenance of manufacturing systems, IMSS exhibit specific, differing characteristics. The present paper also compares IMSS with other systems on three factors: operating mode, usage intensity, and preventive maintenance, which have effect on maintenance costs.

For wire and arc additive manufacturing (WAAM) technology, the instable formation and the quality of the weld bead is still a problem. In welding technology, the weave bead welding can improve welding efficiency and welding quality. Besides, the weaving arc can reduce the presence of defects in the weld seam. This paper explores the application of weave bead welding in WAAM to improve forming stability and quality of the weld bead. In single-layer experiments, different parameters of weave length and weave amplitude are investigated to analyze their influences to the weld bead geometry. The forming stability of welding beads with weaving and without weaving are compared in multi-layer experiments. A large component is manufactured using the weave bead method, showing that the application of weave bead welding is a good way to improve forming stability in fabricating large scale parts.

Milling is inevitable for CFRP components to remove excess material in manufacturing industries. Multi-flute sawtooth milling tool was widely used because of its cutting stability and high machining quality. However, obvious damage was observed on the machined surface of the CFRPs when fiber orientation is larger than 90°. Therefore, it is important to optimize the process parameters regarding the surface quality in case of multi-flute sawtooth milling tool. To this aim, the experiment of slotting of the CFRPs was conducted by the multi-flute sawtooth milling tool in this paper. The pit depth was proposed as the criterion to quantify the quality of the machined surface. The milling forces for different parameters and the relationship between the forces and the machined surface quality were researched. Based on the experimental results, it can be obtained that low cutting speed and high feed rate are the optimal cutting conditions for the good machined surface quality and high material removal rate when the up milling surface is the mating surface of CFRP components.

The milling process of carbon fiber reinforced polymer (CFRP) is prone to damages like burr and tear. The fiber cutting angle is generally recognized as an important factor in damage formation. In this study, through up milling and down milling experiments with unidirectional CFRP laminates at four typical orientations, the influence of the dynamic change of fiber cutting angle on surface damage was clarified by burr height, burr morphology and tear degree. The research shows that the dynamic change of fiber cutting angle is the basis of CFRP surface damage formation. Damage accumulates gradually in damage-prone zone, which ultimately determines burr height. When the variation range coincides 90°–135° partially or completely, a significant subsurface tear occurs. If it covers both acute and obtuse areas, the tear degree and burr morphology are determined by the order of the two regions.

Ti/CFRP stacks are widely used in the aviation field. However, the life of existing Ti/CFRP drilling tool is extremely low. This paper analyzes the wear process of chisel edge and cutting edge of the carbide step drill to reveal the wear mechanism. Based on the microscopic observations and the variation of cutting edge rounding, it is found that tool wear is affected by the carbon fiber/Ti-adhesion interaction. This interaction makes the rake face more susceptible to occur adhesive wear, and slows down the flank wear. It also reveals the secondary sharpening effect of the rake wear and flank wear on cutting edge. In addition, the relationship between thrust force and tool wear is investigated. Results indicate that the variation of thrust force is related to the flank wear width and the degree of Ti-adhesion attached to chisel edge, but not to the cutting edge rounding.

Different tolerances causes multiple values of machine capability index(Cmk) in the traditional evaluation method of machine capability. On the basis of normal distribution, a new evaluation method of machine capability, the sigma level evaluation method, is applied to solve the problems above. Combined with the six sigma quality management method, the compensation coefficient $$ \Delta_{\mu } $$ and negative stability coefficient $$ \Delta_{S} $$ of the machining process are defined. Multivariate statistical analysis methods are used to analyze the dimensional accuracy dispersion of multi-characteristics parts processing. The subjective and objective combination weighting method is used to evaluate the machine capability of multi-characteristics parts. Taking the transmission housing processing as an example, the feasibility and superiority of the sigma level evaluation method are proved.

For hypoid gears manufactured by hypoid generated modified-(HGM), according to gear cutting process and the mutual movement of tools, machine tool and wheel blank, the equations of tooth flank and fillet are derived by the gear meshing theory and gear cutting theory, and the accurate mathematical model for the hypoid gear tooth profile is built. The data of tooth surface are collected and calculated in MATLAB according to the machining parameters of a pair of gears. Imageware software and UG software are used at the same time to establish A hypoid gear solid model with a transition surface. The model with fillet can be used in the digital manufacturing and finite element analysis of hypoid gears.

This work develops a torsional vibration model with lumped-parameter method and uses it to investigate the torsional vibration characteristics of double planetary transmission system. The natural frequency of torsional vibration and corresponding modes of the transmission system are obtained by solving the vibration differential equation. And then influence of rotational inertia and torsional stiffness on the natural characteristics of torsional vibration of the system is studied. The results show that the natural frequencies of torsional vibration can be improved effectively by increasing the torsional stiffness and reducing the rotational inertia of system under the condition that the total transmission ratio and the dimensional parameters of the gear pairs are constant at all levels.

Cranes often work under conditions of large power, high torque, and impact loading. Due to the harsh working environment, it is necessary to have reliability analysis for the reducer. Taking the reducer as study object, its parametric model and the reliability analysis model are established by ANSYS software. The constrained modal analysis was done to obtain the natural frequency of gear system. Considering random variation in parameters such as rib thickness, thickness and width of the U-shaped support frame, material elastic modulus and Poisson ratio, the proximity of system natural frequency and excitation frequency will be different. Then, the rules were explored by means of response surface methodology. On this basis, the reliability and sensitivity of the gear system are achieved statistically by Monte Carlo method, which has important engineering significance for improving the reliability of crane.

Aiming at the one planetary stage and two parallel-axes wind power gear transmission system, the dynamic equation of the gearbox transmission system was established by lumping parameters method, the variable-length Runge-Kutta method was used to solve the system dynamic differential equations, the dynamic transmission errors of gear pair was obtained before and after gear profile modification. The dynamics model of the rigid-flexible coupling of the gearbox was established in LMS software, the transmission errors was imported into it. The modal superposition method was used to obtain the bearing reaction force of the gearbox, then it was used as the boundary condition of the acoustic-vibration coupling model. Acoustic finite element method was adopted to estimate vibration and noise of gearbox and research the influence of gear profile modification on the vibration and howling noise of gearbox. The research results show that there have some improvements on vibration and howling noise of gearbox with gear profile modification.

Due to the compatibility with accurate geometry of contact surface, finite element analysis (FEA) is an efficient method for tooth contact analysis of gear pair with profile deviation. However, it usually requires a dense grid along the height of the tooth in order to simulate the elliptically distributed contact pressure. In consideration of reducing the node number, the grid model of spur gear pair with profile deviation is firstly established based on the realistic tooth flank equation and then locally refined at the vicinity of theoretic contact point. With the refined grid model, global linear deformation and local nonlinear contact deformation of tooth can be accurately calculated, and mesh stiffness of gear pair with different profile deviation and load are obtained correspondingly. According to the results, the influence of each profile deviation on mesh stiffness, the coupling effect of different profile deviation, and the nonlinear relevance between load and mesh stiffness are analyzed and can be used to provide reference for further dynamic analysis of gear pair.

In this paper, the dynamic model of an 8-degree-of-freedom hypoid gear pair model with time-varying stiffness, comprehensive gear error and the nonlinearity backlash is established. The numerical integration method is applied to solve the dynamic responses. With help of bifurcation diagrams, time history, phase plane, frequency spectrum and Poincaré maps, the effects exaction frequency, load coefficient and support damping are investigated by using the numerical integration method. The results reveal that system exhibits a diverse range of one-period responses, multi-periodic responses, bifurcation and chaotic responses when the parameters are changed. Some results presented in this study provide some useful reference to dynamic design and vibration control of the gear transmission system.

In this paper, a quill shaft coupling is built and analyzed. The quill shaft coupling is a solid and thin shaft with two flexural elements on the both ends of the shaft. The flexural element is represented by an angular stiffness and a radial stiffness. The equation of motion of the quill shaft coupling is derived by the finite element method. Three groups of the quill shaft coupling are analyzed. They are a stiff coupling, a radial stiff but an angular flexible coupling, and a coupling flexibly in both the radial and angular directions. The effects of the stiffness of the flexural element and the length of the quill shaft on the first bending critical speed are studied. The results show that these two parameters could be used to raise the first bending critical speed of the quill shaft coupling above the operating speed of the system.

Spherical mobile robot (spherical robot in short) has remarkable stability, flexible motion as well as significant advantages in the exploration of unmanned environments when compared with traditional mobile robots. However, as a special under-actuated nonholonomic system spherical robot cannot be transformed to the classic chained form and is difficult to control. At present, there has not been a kinematics based trajectory tracking controller which could track both the position states and the attitude states of spherical robot simultaneously. This paper deduced a three states (two position states and one attitude state) trajectory tracking controller using sliding-mode control method and based on the kinematic model of a spherical mobile robot BHQ-1. The jittering on the sliding surface was reduced under the effect of a saturation function in the controller. The effectiveness of the proposed trajectory tracking controller were verified through MATLAB simulations for both a linear trajectory and a circular trajectory.

Omni-directional robot has the ability of 0–360° motions are received much attention in recent years. They have locomotive advantages and are widely deployed in larger range of application fields especially in constrained narrow space. This paper introduce a novel omni-directional robot with four powered caster wheels, each caster wheel has two degree of freedom (DOF) and made by two outer rotor motors connected mechanically. The kinematics of the system are analyzed, the prototype has been developed. The developed omni-directional robot is able to realize the moving motions along x and y axis and rotate about z-axis. All of the software are implemented on Robot Operation Systems (ROS) and the velocity trajectory planner is employed and embedded in the software. The squared position curve is given and tested by using lase tracker, the result is analyzed, and it shown that the following error of the system is about 2.5 cm while the width of the square is 70 cm.

The impedance control of most flexible joints generally has a cascaded structure with both inner torque feedback and outer position feedback loops. The torque control accuracy and bandwidth have great effects on their impedance control performance. But in practical applications, the improvement of the torque control performance are limited by many factors, such as the high noise level of torque sensor and the model uncertainty and nonlinearity. This paper proposes a dual-loop torque control structure with a dual-frequency control in the inner loop and a disturbance observer in the outer loop. The dual-frequency control uses a frequency-separated controller design method that employs two controllers in low and high frequency, respectively. The high frequency controller with relatively conservative gains is designed to ensure the system stability. Thus, the low frequency controller can focus on improving the torque control accuracy, without experiencing the limitations of system stability and torque sensor noise. Moreover, the disturbance observer is introduced to compensate the model uncertainty and nonlinearity. Simulations are conducted to verify the effectiveness of the proposed dual-loop dual-frequency torque controller.

This paper presents the design, analysis and fabrication of a quadruped wallclimbing robot. The robot can stick on the wall surface based on a novel negative pressure adsorption technology named as vibration suction mechanism. By combining the unique properties of vibration suction mechanism and the bionic gait design of the gecko, the robot has advantages of light weight, low energy consumption, flexible movement and high adaptability to different wall surfaces. Climbing experiments on the surface of a high-rise glass window are demonstrated, and the robot can climb vertically at the highest speed of 13.75 mm/s.