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The industrial robot has high repeatability but low accuracy. With the industrial robot being widely used in complicated tasks, e.g. arc welding, offline programming and surgery, accuracy of the robot is more and more important. Robot calibration is an efficient way to improve the accuracy. Previous methods such as using coordinate measurement machines, laser trackers or cameras are limited by the cost, complex operation or the resolution. The purpose of this paper is to propose an approach and calibration equipment to address these issues.

The proposed method relies mainly upon a laser pointer attached on the end‐effector and single position‐sensitive devices (PSD) arbitrarily located on the workcell. The automated calibration procedure (about three minutes) involves aiming the laser lines loaded by the robot towards the center of the PSD surface from various robot positions and orientations. The localization is guaranteed by precise PSD feedback servoing control, which means physically the intersections of each pair of laser lines (virtual lines) are on the same point. Based on the untouched single‐point constraint, the robot joint offset calibration is implemented. Using the authors' proposed approach, a portable, low‐cost, battery‐powered, wireless and automated calibration system was implemented. Error analysis was conducted on the system.

The localization error of the developed calibration system is within 2 μm. The errors in joint space are magnified in PSD plane, and consequently the resolution in the joint space is improved. The standard deviation of the identified parameters was small (10‐2), indicating the stability of the calibration method. Both simulation and experimental results verify the feasibility of the proposed method and demonstrate the developed calibration system can identify joint offset with uncalibrated laser tool parameters.

The paper shows how a portable calibration system for joint offset of industrial robots was developed and how the goal of fast, automated, low‐cost, portable, and high precision calibration methods for joint offset was achieved.

The purpose of this paper is to introduce an approach to generating a basic bodice based on human body structure. The trimmed non‐uniform rational B‐spline (NURBS) method is applied to develop computer‐aided tailoring and styling capabilities in 3D fashion design.

Based on the body structure of the scanned subject, a parameterized method to intuitively generate adaptable bodices is proposed. NURBS surfaces are applied to provide an interactive styling design based on the preset bodice. To mimic dress shearing for any specific requirement, trimmed curves are applied to the NURBS‐based clothes. A simple periodic function is introduced to develop a wave‐like style garment.

Newly‐styled apparel designed in the third dimension is much more intuitive than conceptual drawings on paper. In order to create wearable garments using the computer‐aided apparel design tools, the expertise of pattern makers is necessary.

Interactive free form surface creation and its associated techniques, by means of trimmed NURBS, are applied to computer‐assisted garment design in three dimensions. The technique provides the designers with a more freely expressive means of creativity.

The purpose of this study is to propose a model of competition between a formal lender (bank) and an informal lender (moneylender) with informational asymmetry between these two lenders. Further, the authors introduce capacity constraint on the lending capacity of the moneylender and assume that borrowers differ in risk and wealth.

The solution concept of Nash equilibrium has been used to derive the optimal strategies of the lenders.

The equilibrium strategies in most of the results depend on the difference between the expected returns from risky and safe projects where the risky project has higher expected returns. The credit market is segmented in terms of risk and wealth levels. Rationing of poor safe borrowers from the credit market is inevitable when the moneylender's capacity is sufficiently small, suggesting a low-income trap for them. Further, when moneylender has capacity constraint of some form, a zero-profit outcome is never a Nash equilibrium outcome.

There is a possibility of collusion between the lenders. However, the authors do not derive all possible outcomes under capacity constraint

When the informal lender has limited capacity, competition between formal and informal lenders may not alleviate credit rationing, instead aggravate the problem. Thus, the government should devise policies to ensure credit availability to resource poor households

While the literature models strategic interaction between lenders under the assumption of zero-profit (Bertrand Paradox) condition, this study shows that zero profit is not the only outcome under such a set-up. Also, in presence of capacity constraint of the moneylender, a zero-profit outcome is never a Nash equilibrium outcome for the lenders. There is an optimal contract at which the lenders differentiate in terms of repayment and collateral and earn positive profits under certain conditions.

This paper presents a new finite element (FE) approach to modeling edge effects in beam sandwich structures. The approach is based on a mixed 2D and beam formulation conjuncted by means of a penalty function method. Several results from analysis of sandwich beams and frames bending with different boundary conditions and laminate properties are solved in order to demonstrate the accuracy of the algorithms and software developed. The influence of the penalty factor on the spectral condition number of the stiffness matrix and on the residual norm of the solution is also investigated for different isotropic and sandwich structures. The FE analysis of complex sandwich beam joint is subsequently presented. Results of this analysis show the advantages of the developed approach for large problems.

While traders of agricultural products are known to often exercise market power, this power has rarely been quantified for developing countries. The paper aims to discuss this issue.

In order to derive a measure, the authors estimate the traders’ revenue functions and calculate the marginal value products directly from them. The authors subsequently find the determinants affecting their individual market power.

Results show that market power at the traders’ level exists and is substantial. This market power is amplified in situations of extreme remoteness, and weakens with increasing market size.

An exceptional data set with detailed information on the business practices of rubber traders in Jambi, Indonesia is employed with an innovative methodology to directly estimate revenue functions.

Frontier environments – such as battlefields, hostile territories, remote locations, or outer space – drive the need for lightweight, deployable structures that can be stored in a compact configuration and deployed quickly and easily in the field. This paper seeks to introduce the concept of lattice skins is introduced to enable the design, solid freeform fabrication (SFF), and deployment of customizable structures with nearly arbitrary surface profile and lightweight multi‐functionality.

Using Duraform^® FLEX material in a selective laser sintering machine, large deployable structures are fabricated in a nominal build chamber by decomposing them into smaller parts. Before fabrication, lattice sub‐skins are added strategically beneath the surface of the part. The lattices provide elastic energy for folding and deploying the structure or constrain expansion upon application of internal air pressure. Nearly, arbitrary surface profiles are achievable and internal space is preserved for subsequent usage.

A set of virtual and physical prototypes are presented, along with the computational modeling approach used to design them. The prototypes provide proof of concept for lattice skins as a deployment mechanism in SFF and demonstrate the effect of lattice structures on deployed shape.

The research findings demonstrate not only the feasibility of a new deployment mechanism‐based on lattice skins – for deploying freeform structures, but also the potential utility of SFF techniques for fabricating customized deployable structures.

A new lattice skin mechanism is introduced for deploying structures with nearly arbitrary surface profiles and open, usable, internal space. Virtual and physical prototypes are introduced for proof of concept, along with an optimization approach for automated design of these structures.

Nondestructive testing based on cooperative twin-robot technology is a significant issue for curved-surface inspection. To achieve this purpose, this paper aims to present a kinematic constraint relation method relative to two cooperative robots.

The transformation relation of the twin-robot base frame can be determined by driving the two robots for a series of handclasp operations on three points that are noncollinear in space. The transformation relation is used to solve the cooperative motion problem of the twin-robot system. Cooperative motions are divided into coupled and combined synchronous motions on the basis of the testing tasks. The position and orientation constraints for the two motion modes are also explored.

Representative experiments between two industrial robots are conducted to validate the theoretical developments in kinematic constraint analysis. Artificial defects are clearly visible in the C-scan results, thereby verifying the validity and the effectiveness of the proposed method.

The transformation relation of the twin-robot base frame is built under a series of handclasp operations. The position and orientation constraints for the coupled and combined synchronous motions are explored. Theoretical foundations of trajectory planning method for the transmitting and receiving transducers of the cooperative twin-robot system are presented.

Laser sintering of polyamide lattice-based lightweight fairing components for subsequent racetrack testing requires a high quality and a reliable design. Hence, the purpose of this study was to develop a design methodology for such additively manufactured prototypes, considering efficient generation and structural simulation of boundary conformal non-periodic lattices, optimization of production parameters as well as experimental validation.

Multi-curved, sandwich structure-based demonstrators were designed, simulated and experimentally tested with boundary conformal lattice cells. The demonstrator’s non-periodic lattice cells were simplified by forward homogenization processes. To represent the stiffness of the top and bottom face sheet, constant isotropic and mapped transversely isotropic simulation approaches were compared. The dimensional accuracy of lattice cells and demonstrators were measured with a gauge caliper and a three-dimensional scanning system. The optimized process parameters for lattice structures were transferred onto a large volume laser sintering system. The stiffness of each finite element analysis was verified by an experimental test setup including a digital image correlation system.

The stiffness prediction of the mapped was superior to the constant approach and underestimated the test results with −6.5%. Using a full scale fairing the applicability of the development process was successfully demonstrated.

The design approach elaborated in this research covers aspects from efficient geometry generation over structural simulation to experimental testing of produced parts. This methodology is not only relevant in the context of motor sports but is transferrable for all additively manufactured large scale components featuring a complex lattice sub-structure and is, therefore, relevant across industries.

The purpose of this paper is to investigate the applicability of the LS-DYNA software using a Lagrangian formulation in the jet formation, flight and penetration of improvised explosively formed projectiles (EFPs). Numerical results dealing with different properties of the EFPs have been validated with a significant number of field tests.

2D and 3D Lagrangian models, using different material definition, are developed to reproduce the field-measured characteristics of copper- and steel-made EFPs: projectile size and velocity. After validation, the model has been extended to analyse the penetration features. Two different plasticity models have been used to describe the steel target, Plastic-Kinematic and Johnson–Cook.

Despite the difficulty in characterizing a non-industrial artefact, the results show that both Lagrangian models (2D and 3D) are able to simulate the projectile size, velocity and penetration capability with errors less than 10 per cent when using the Johnson–Cook material model for both liner and target.

These data can be used to test the penetration ability of improvised EFP’s against different targets, i.e. light armoured vehicles.

There are no references that address the application of the Lagrangian simulation of non-industrial EFPs and its validation with field tests, including penetration assessment.

A large‐strain/high‐deformation rate model for clay‐free sand recently proposed and validated in our work [1,2], has been extended to sand containing relatively small (< 15vol.%) of clay and having various levels of saturation with water. The model includes an equation of state which represents the material response under hydrostatic pressure, a strength model which captures material behavior under elastic‐plastic conditions and a failure model which defines conditions and laws for the initiation and evolution of damage/failure in the material. The model was validated by comparing the computational results associated with detonation of a landmine in clayey sand (at different levels of saturation with water) with their computational counterparts.