This paper aims to design a compact manipulator system consisting of a 6 degree-of-freedom (dof) manipulator and a 1-dof rotary table. It proposes a new compactness measure that considers manipulator swept volume or the space occupied by the system while executing task. Swept volume is crucial because a manipulator has a small footprint but can occupy a substantial space due to its large workspace. Moreover, since compactness can negatively impact manipulator motion, the compact design problem is formulated with motion time or temporal constraint. A best-effort search method is proposed to minimize the swept volume and reduce the motion time to the level of temporal constraint setting. It is carried out by a proposed spatial motion coordination (SMC) for minimizing swept volume and temporal motion coordination (TMC) for reducing motion time. The two schemes are integrated with the base placement optimization, tool attachment optimization and goal rearrangement and are evaluated under various temporal constraint settings. A cross-breed algorithm called STMC utilizing SMC and TMC is then proposed to deal with the limitation. Several optimization frameworks including SMC, TMC and STMC are compared with robot motion simulations. It is found that the ability of SMC and TMC is limited by certain range of the constraint values and STMC is better than the others.

This paper discusses a fabrication process of high aspect ratio (AR) silicon micro-/nano-pore structures and modification of their surfaces to improve the function of liquid-infused-type self-cleaning surfaces. The structure and its hydrophobic surface play an important role to hold a special liquid (a lubricant) on the surface tight to produce an intermediate lubricant layer and any liquid drops, including low surface tension liquids such as oil, can slide easily on it. The nanopore structure with an AR as high as 30 was fabricated by etching in a solution of hydrofluoric acid and hydrogen peroxide. This process based on a catalyst reaction of an array of Au islands that was deposited on a silicon substrate through a particle mask. This original hydrophilic surface was changed to hydrophobic one by depositing self-assembled monolayer of octadecyltrichlorosilane to modify the energy balance at the interface of the solid structure, the lubricant, another liquid, and air. Then the lubricant could be well retained. The functional lifetime was evaluated by measuring the liquid residue on the surface after number of liquid dash. It was confirmed that longer lifetime was obtained with higher AR nanopore structure.

Ribbed stiffened machined structures are commonly used in the aerospace and automotive applications. This study presents a comprehensive approach to develop the lightweight configurations of such machined structures under axial loading. The optimized topologies (material layout) were studied by employing the Abaqus topology optimization (ATOM) module. Data was analyzed to establish the optimum values of the dependent (optimized volume, strain energy, mechanical stress, and maximum deformation) and independent parameters (axial force, initial design domain, targeted volume, and number of nodes) through the evolutionary genetic algorithm (GA). GA fitness functions were developed through the best regression models that attained through a statistical appraisal of optimal topological configurations. GA predicted results were compared with the data of topological optimized evolutions. Structural performance of the optimized configurations was also evaluated by comparing with the available experimental results. The optimized configurations showed a better strength to stiffness performance under stipulated design constraints.

Sustainable design aims at the creation of physical objects, environment and services that complies to optimize social, economic, and ecological impact. QFD is able to assess the product design by the choice and definition of parameters that can be qualitatively discussed. The purpose of design is to meet a need in new ways and in innovative ways. In this context, the QFD aims at evaluating the quality of a design process. TRIZ is a design method that aim at defining and overcome some critical issue that can affect the development of a product, by means of potential innovative solutions. In this paper QDF and TRIZ analysis have been adopted in order to validate a design method for direct open moulds, by a new strategy: hybrid manufacturing can reduce the production time, the use of material, the energy and the waste consumption, employing subtractive and addictive techniques efficiently combined.

In this paper, performance behavior of seals under compression and various hydraulic pressures were investigated. Two approaches (experimental and numerical) have been used. It was found that significant improvements in seal performance can be achieved by carefully combining rectangular and circular profiles into one seal. The folding mechanism at the step of the seal with H₁/H₂ =2.5 was found to contribute the seal's best performance. Further, for each loading condition, contact stresses were greater than the applied hydraulic pressures. This important sealing criterion confirmed that the new seal geometry has good sealing capability. Contrary to previous studies, contact stresses were found to possess a non Hertzian profile. By measuring contact lengths using a video microscope, the seal with new geometry recorded higher contact lengths compared with seals having circular profile. The fringe patterns and deformation behavior from numerical models showed remarkable similarity with experimental results.

Most models for computer aided tolerancing proposed by researchers and used in industry do not fully conform with standards. Moreover, most of them make severe assumptions on observable geometric deviations and can therefore hardly handle all kinds of 3D tolerances. These lacks inspired the idea and the development of a discrete geometry framework that is capable of considering geometric deviations of different stages of the product life cycle and is versatile regarding current and future tolerancing standards. This work uses a point cloud-based geometry representation scheme to implement the pattern left on the surfaces by a manufacturing process; then this scheme has been inserted in a four approaches for tolerance analysis: jacobian, torsor, variational and vector-loop. Moreover, gravity and friction among the parts to assemble have been simulated too. In this way a new Computer Aided Tolerancing (CAT) simulation tool has been developed; it approaches reality more than existing software packages do. To verify the effectiveness of the new CAT simulation tool, it has been applied to a case study. The obtained results have been compared with those due to a geometrical model that has been developed by simulating what happens among the parts in the actual assembly. The obtained results show how the new CAT simulation tool gives results nearer to reality than literature models do.

This paper aims to describe an in-plane detaching resistance of a white-coated paperboard subjected to a peeling deformation. Since the paperboard is composed of fibrous plies, its detaching mechanism seems to be different from a crack propagation of a fragile material. In this work, an internal breaking criteria and transient de-lamination of a weak-bonded layer of paperboard was experimentally investigated through a peel cohesion test (PCT), and its detaching resistance was estimated with a fluffing model using a finite element method (FEM) code to characterize the peeling deformation of the weak-bonded layer. A white-coated paperboard of 0.45 mm thickness (basis weight of 350 g·m^-2) was chosen for conducting a PCT and z-directional (out-of-plane) tensile test (ZDTT). The relationship between the pulling force and curvature of delaminated upper layer of the paperboard were discussed; moreover, the anaphase yielding resistance of detaching was analyzed through ZDTT. The peeled deformation of PCT was analyzed using the isotropic elasticity FEM model, which was developed through the ring crush test. The results were as follows: (1) The in-plane detaching resistance of whitecoated paperboard by PCT is experimentally characterized for observing with the maximum peak at early stage and the stationary line force. These line forces are almost independent of the paper-making direction. (2) A fluffing profile of the de-laminated layer and the thickness of the peeled upper layer experimentally depend on the pulling velocity. (3) Regarding the detaching resistance of peeled layer, a fluffing model was proposed in the developed simulation model. Equivalent fibers based fluffing model that were derived from a ZDTT experiment (approximated as discretely distributed nonlinear springs) well explains the existence of the peak point of peeling force and saturated peel resistance.

In this paper, we consider the production planning problem for a single manufacturer with the investment to improve the market impact under demand uncertainty. In the mathematical model, the average demand increases if the investment of market impact is increased for each product. The objective is to maximize the total profit with a piecewise linear investment cost and a budget constraint. The problem is formulated as a mixed integer nonlinear programming problem. A solution procedure based on Lagrangian relaxation is developed to solve the problem efficiently. In the proposed method, an analytical solution of the newsboy problem is effectively used to derive the lower and upper bounds. The condition of the concavity of the profit function is derived. The effectiveness of the proposed method is confirmed through computational experiments.

In this paper, we explore the equilibrium problem of cloud manufacturing system (CMfgS) with cost uncertainty. We propose a CMfgS supernetwork model in which decision-makers (resource service providers (RSPs), the agent and resource service demanders (RSDs)) seek to determine their optimal behavior in an environment with cost uncertainty. The cost uncertainty is represented by random variables and the decision-makers' risk aversion attitude is modeled by adopting mean-variance utility. The equilibrium conditions governing the supernetwork model are proposed based on variational inequalities. To investigate the impacts of decision-makers' risk aversion attitude and the degree of cost uncertainty on equilibrium of CMfgS, we conduct a numerical analysis in this study. The results indicate that a risk averse RSP (or agent) tends to raise selling price to mitigate risk, and a risk averse RSD is willing to pay more for the needed services . We also show that a risk neutral RSP could sell more services when the variance of cost distribution is relative large but the opposite occurs for risk averse RSPs.

Among current approaches to tolerance analysis in three-dimensional space, the Matrix method based on rigid body kinematics is widely used. However, this method ignores the impact a tolerance feature (TF) may get from the variations of TFs before it, therefore showing its demerits when applied to long and complex dimension chains. For this reason, this paper puts forward a new tolerance analysis model where two local coordinate systems are built at each TF: a nominal one based on the datum of current TF and a tracking one based on the variations of the prior TFs. Then the variations of all TFs along the dimension chain are accumulated. Compared with the Matrix method, the new approach generates results with more accuracy and higher efficiency.

In a robot grinding system, the change of the robot's pose affects the overall stiffness of the whole machining system, which indirectly leads to the irregularity of the grinding surface. For this purpose, we propose a method to enhance the stiffness of the robot. The robot grinding system layout is usually based on the experience of the designer without any quantitative selection criteria. With the introduction of the stiffness performance evaluation index, we decouple the stiffness-couple relationship between the robot pose and layout of the robot system and calculate the value of the stiffness index for evaluating the performance of each layout point as a quantization selection basis. Using Rayleigh quotient as the stiffness performance evaluation index for the manipulator, we obtain a relationship between the stiffness performance and the installation position of the grinding tool. Based on the chosen layout point, we proposed the length of the semi axis along the direction of the grinding force in the stiffness ellipsoid as the optimization objective and obtain the optimal configuration in the entire processing workspace through a genetic algorithm method. Theoretical and numerical simulation is presented to demonstrate the effectiveness of the proposed approach. The results demonstrate that the optimization improves the stiffness performance significantly.

Motion generation systems are becoming increasingly important in certain Virtual Reality (VR) applications, such as vehicle simulators. This paper deals with the analysis of the Inverse Kinematics (IK) and the reachable workspace of a three-degrees-of-freedom (3-DOF) parallel manipulator, proposing different transformations and optimizations in order to simplify its use with Motion Cueing Algorithms (MCA) for self-motion generation in VR simulators. The proposed analysis and improvements are performed on a 3-DOF heave-pitch-roll manipulator with rotational motors, commonly used for low-cost motion-based commercial simulators. The analysis has been empirically validated against a real 3-DOF parallel manipulator in our labs using an optical tracking system. The described approach can be applied to any kind of 3-DOF parallel manipulator, or even to 6-DOF parallel manipulators. Moreover, the analysis includes objective measures (safe zones) on the workspace volume that can provide a simple but efficient way of comparing the kinematic capabilities of different kinds of motion platforms for this particular application.

A novel worm gear named cylindrical roller enveloping end-face internal engagement worm gear is originally proposed for the first time in this study. Also, the meshing functions including induced normal curvature and lubrication angle are derived based on the gearing meshing theory and differential geometry. Furthermore, numerical analysis is performed to screen the potential optimal design parameters. The finite element analysis is conducted to minimize the contact stress and assessment the performance of the cylindrical roller enveloping end-face internal engagement worm gear. The theoretical calculation confirms that the novel worm gear has good meshing and lubrication characteristic; also, the study indicates that the worm-wheel rotational deflection angle β that is bigger than 43° has difficulty satisfying the meshing condition. The working surface of the cylindrical roller increases with the increase in β, which means that choosing a relatively large β results in even stress on the tooth of the worm gear, thus prolonging the service life. This study aims to provide a new drive to replace some complex gear combinations.

In this paper, a variant of 0-1 knapsack problems in graph structures is considered. Given a directed bipartite structure with a set of items and a set of players, the problem asks to find an arc reversing strategy of the players which collects items with a budget constraint so that the total weighted profit of the collected items is maximized. More players than one are associated with an item by their directed arcs, and in order to win the weighted profit, it is indispensable for the players to make their arcs with respect to the item in the same direction. The situation of the same direction of associated arcs with an item is regarded as a cooperation of the associated players with the item, and the problem is called CIC (cooperative item collecting) for short. Problem CIC is viewed as a generalization of an integrated circuit design problem, in which a certain type of the cost of changes from an initial design is newly considered. A cooperation of associated players with an item is generally adverse to another item, and problem CIC is also seen as a compromising model in conflictive states. In this paper, some complexity results of problem CIC including the NP-hardness are discussed, and greedy heuristic algorithms are designed. Numerical experiments are conducted to demonstrate the performance of the greedy heuristic algorithms, and the results are reported.

In previous study it was confirmed that changing of grip position counteracts drivers' maintenance of appropriate steering angle. Therefore, we developed the bar type steering system with low steering gear ratio. In high-speed driving, the range of steering angles used is smaller than in low-speed driving. with a steering system with a low gear ratio, further delicate steering is required. Human operation resolving ability is insufficient for such operation, it is expected that high-speed driving at a low gear ratio will become difficult. Motorcycles enable high-speed driving even at a low gear ratio. In motorcycles, a sufficiently large torque occurs during high-speed driving. Referring to this, we developed a steering system that enables easy high-speed operation at a low gear ratio from the viewpoint of vehicle behavior including both steering angle and steering torque. As the result, the difficulty of steering operation with low steering gear ratio at high speed was improved by adjusting steering reaction torque of bar type steering. Furthermore, the dynamic characteristics from the steering torque to the vehicle was examined. As result, where a large steering torque is required, the driver drives mainly based on the steering torque. Therefore, the ease of driving does not change if the phase of steering torque is delayed from the steering angle. On the other hand, the experiment confirmed that driving becomes difficult if the yaw rate is delayed from the steering torque that the driver relies on. We designed reactive torque control system to improve maneuverability and verify performance of the system by using driving simulator. Here, we report the maneuverability of bar type steering in high speed range.

To improve positioning accuracy of a magnetic head in hard disk drives (HDDs), a triple-stage-actuator system was developed with a thermal-positioning actuator for a magnetic-head-positioning system. This positioning system has three types of actuators: a voice coil motor (VCM), piezoelectric (PZT) actuators, and the thermal-positioning actuator. In this system, a magnetic head has a heater located in a horizontal direction of read/write elements as the thermal positioning actuator. By using this structure, the control system can move the position of read/write elements of the magnetic head in a horizontal direction with thermal expansion induced by the heater with an electric current. The thermal-positioning actuator is good for control in high frequency range because it has little adverse effect caused by mechanical resonances. As a result, the triple-stage-actuator system enable us to improve the positioning accuracy during a track-following control from conventional dual-actuator systems. However, the thermal-positioning actuator causes flying-height fluctuations of the magnetic head that may lead to worsening of magnetic recording performances. In HDDs, the magnetic head has another heater located in a vertical direction of read/write elements in order to control flying height of the read/write elements. This control system is called thermal flying-height control system. To compensate for the flying-height fluctuations of the magnetic heads caused by the thermal-positioning actuator, this paper presents a magnetic-head-positioning system that employs a feedforward control scheme on the thermal flying-height control system. Simulation results showed that the proposed method was able to compensate for the flying-height fluctuations during the track-following control by about 90 %.

To overcome the problem that the risk of remanufacturing telescopic boom structure system is difficult to be determined under potential multi-failure mode correlation caused by multiple coupled defects, the probability grid estimation method of second-order moment improved by firefly algorithm (PGE-ISM-FA) and the fireflies neural network structure system risk prediction method (FANN-SSRP) are proposed. The risk analysis model and prediction model of jib system with multiple coupled defects are established. Furthermore, the risk prediction system of remanufacturing telescopic boom structure is developed. With original and defect features parameters of measuring points being as the basis, random variables of performance functions are determined. Then, performance functions corresponding to failure modes are derived in accordance with the failure criterion. PGE-ISM-FA is applied to obtain the most probable failure point in the failure domain of measuring points, so as to getting representative failure model of measuring points. Thus, the risk degree of measuring points can be calculated. According to the weakest link method, the risk degree of jib structure system and the most dangerous testing point are confirmed. Based on this and combined with FANN-SSRP, the mapping relation of characteristic parameters and risk degree is built. In addition, the risk prediction system of remanufacturing telescopic boom structure is compiled, thus realized the rapid and real-time risk prediction of telescopic jib structure system in service. Finally, the effectiveness and adaptability of above methods and prediction system are verified by the example of telescopic jib structure system of QY130t mobile crane.

We propose an edge filter for road white-line detection. Many methods for white-line detection have been proposed for standardized roads. These methods are composed of two stages of processing, i.e., edge detection on an image taken with a camera and then extraction of edge clusters of white-line contours by model fitting. It is difficult to apply these methods to non-standardized roads of for which modeling are difficult. To expand the scope of white-line detection to common roads in the future, it is necessary to achieve processing through clustering without models. However, while clustering can apply to diverse contour lines, there is concern about degrading noise reduction that has so far been done by model fitting. In this study, for the first-stage processing, we developed an edge filter that utilizes the characteristics of white-line contours and detects noise correctly. This filter uses brightness-gradient approximation by discrete values, for which we obtained an idea for a non-linear filter that approximates a low-pass filter plus differential calculus. By applying the method to the images taken by on-board camera, we demonstrate that white-line detection that can apply to diverse road environments but is hardly affected by noise can be realized through combination with model-less clustering.

Applying Minimum Quantity Lubrication (MQL) for machining processes such as drilling can obtain process performance improvement comparing with completely dry situations, and reduce the use of machining fluids considerably comparing with flood cooling. Although many researches have been reported on the comparison of temperature, tool wear, surface roughness and chip patterns between dry and MQL cutting, relatively fewer literatures about the cutting forces and their features can be found. In this paper, first dry and MQL drilling of cast iron, S45C, SUS304 and Ti alloy were conducted, and then life term of dry, air cooling and MQL drilling of SUS304 were carried out. TiCN coated HSS drill bits with double inner coolant holes were applied to produce air cooling and MQL internally. The thrust force and torque were monitored by a dynamometer and, time, frequency, and time-frequency domain features of them are extracted and compared. Especially there are some newly generated features derived from transforming the thrust force and torque to two orthogonal forces and further being analyzed in a rectangular coordinate. Experiment results show that, for different workpiece materials MQL affects different force features in different ways and for SUS304 tool life is greatly lengthened, friction is suppressed, chip jamming is alleviated and both the static and dynamic components of cutting forces reduce when air cooling and MQL are applied. Moreover, it is revealed that the differences of features between dry and other two conditions are quite obvious but those between air cooling and MQL are inconspicuous.

Biodegradable microspheres have been gathering attention as a promising controlled release drug delivery system (DDS), since they can administrate with one injection, dissolve in a body, release drugs over time, and do not need to remove after use. To produce microspheres with high throughput and high uniformity, flow-focusing microfluidic devices have been widely employed. Although softlithography technology is a simply way to replicate flow-focusing microfluidic devices, there has yet to be reported organic-solvent resistant, flow-focusing microfluidic devices mainly due to lack of organic-solvent resistant elastomers. Here, we establish a method to fabricate flow-focusing microfluidic device using fluoroelastomer, SIFEL. We stacked a vinyl silicone end group rich layer and a silicone hybrid end group rich layer to seal SIFEL microfluidic devices by using hydrosilylation between two layers. Then, by flowing chloroform, we experimentally verified that SIFEL microfluidic devices did not swell, whereas polydimethylsiloxane (PDMS) microfluidic device showed swelling. When we flowed polyvinyl alcohol (PVA) 1% aqueous solution flow in continuous phase and 1% poly lactic-co-glycolic acid (PLGA) in chloroform flow in discontinuous phase, we obtained PGLA microspheres with diameter of 67.0±1.6 μm. Therefore, we envision that the SIFEL device can be a powerful tool for development of controlled-release DDS for water insoluble drugs.

In this paper, a new approach for the forward kinematics of nearly general Stewart platform (i.e., both the fixed base and moving platform are restricted to planar platforms) with an extra sensor is presented. Fifteen compatible algebra equations which express the coupling relationships between the position and orientation variables of the moving platform are obtained. Because the magnitude of the position vector is measured by the extra sensor, the fifteen compatible algebra equations can be transformed into a set of linear algebraic equations with two unknown variables with the help of elimination by substitution, from which a unique solution can be obtained. In the end, a numerical example is presented to verify the correctness of the proposed approach. The proposed approach is simple and does not need any iteration, is expected to be used in real time applications.