Search results

This paper presents a new method for deploying RoboCrane‐type cable robots, without the need for fixed rigid cable support points. That is, the system provides its own deployable mobile overhead support points.

This paper presents a new RoboCrane support concept based on rigid members, cable actuation, and cable suspension. It is self‐contained and provides mobility for the required six overhead cable connections, thus extending the workspace of the existing RoboCrane. The paper presents the RoboCrane support concept overview, followed by kinematics and statics analysis, plus a case study of a specific design.

Design for kinematic horizontality, workspace, and statics are competing so the designer must make tradeoffs for the best system performance according to specific design needs.

Since the support system plus RoboCrane are both cable‐suspended robots, there are limitations in the pseudostatic workspace, i.e. since the cables can only exert tension and cannot push, the motion range is limited.

Specific system design and deployment is still remaining work – practical issues such as outriggers for moment and tipping resistance, easy portability, control of the mast from the ground, and safety must be solved in the future.

Enables RoboCrane applications in many more arenas, such as automated construction, where rigid overhead cable support points are simply unavailable.

Aerostatic porous bearings are important for guide rails and spindles. It is well-known that flow restrictors made of porous materials offer major advantages over conventional restrictors in such bearings, including design and manufacturing, load-carrying capacity, stiffness, damping and dynamic stability. Thus, this work numerically investigates the effect of the arc on a new combined annular-thrust aerostatic porous bearing.

The static characteristics of an annular-thrust aerostatic porous bearing were studied using a fast finite element scheme. The pressure distribution, radial load and thrust load were analyzed as functions of the arc, permeability and eccentricity.

The results reveal that the radial load achieves maximal values at an optimal arc value between 200 and 300, and the thrust load increases monotonically with increasing arc.

This work developed a new combined annular-thrust aerostatic porous bearing to investigate the effect of arc on the annular-thrust aerostatic porous bearings to increase the load-carrying capacity.

The purpose of this paper is to use a unique, hand-collected data set of Food and Drug Administration (FDA)-approved products to understand the effect of lobbying on the product market. The authors gather total 86,462 FDA labels including drug patents, drugs, pre-market approvals and medical devices and test the relationship between lobbying and future firms’ product submissions.

Using a sample of 86,462 FDA labels including drug patents, drugs, pre-market approvals and medical devices, the authors test the effect of lobbying on a firm’s future product submissions using survival analysis, logit, difference-in-differences and propensity score matching techniques.

The authors find lobbying firms experience an increase in the number of medical products approved. However, increased number of FDA labeling comes at the cost of product failure. The authors document that lobbying increases product recalls when responsible firms are associated with higher market withdrawals.

This study contributes to both the management literature on corporate lobbying and product recalls. Additionally, the study reveals the connection between pharmaceutical lobbying and firm value.

Consumption analysis is one of the most refined branches of economic theory. Over a century of scholarly efforts in utility analysis has created an impressive body of logic that incorporates the most advanced tools of mathematics. But despite the elaborate refinements it has also become one of the least operational of economic analyses. It is so highly general that it offers little in the way of testable predictions[l].

This paper aims to present a kinematics analysis method and statics based control of the continuum robot with mortise and tenon joints to achieve better control performance of the robot.

The kinematics model is derived by the geometric analysis method under the piecewise constant curvature assumption, and the workspace and dexterity of the proposed robot are analyzed to optimize its structure parameters. Moreover, the statics model is established by the principle of virtual work, which is used to analyze the mapping relationship between the bending deformation and the applied forces/torques. To improve the control accuracy of the robot, a model-based controller is put forward.

Results of the experiments verify the feasibility of the proposed continuum structure and the correctness of the established model and the control method. The force deviation between the theoretical value and the actual value is relatively small, and the mean value of the deviation between the driving forces is only 0.46 N, which verify the established statics model and the controller.

The proposed model and motion controller can realize its accurate bending control with a few deviations, which can be used as the reference for the motion planning and dynamic model of the continuum robot.

This paper aims to investigate empirically the findings of an analytical impure public good model. The impure public good model described in this study allows for the application of different technologies generating public and private characteristics. The influence of the individual technologies on the total level of (impure) public good provision is of main concern in this study.

After the illustration of the impure public good model, the analytical results are compared to the results of a numerical approach based on climate policy in Germany.

The study shows that comparative static analyses do not always generate clear results. Therefore, the numerical approach is helpful to derive unambiguous results. The paper finds that technologies which exclusively generate private characteristics may have significant effects on total impure public good provision, since they may replace the private characteristics of the impure public good.

This paper provides useful information on the influence of the individual technologies on the total level of (impure) public good provision.

The purpose of this paper is to provide a unified theoretical framework that explains farm capital structure choice.

The framework accommodates different credit access scenarios and heterogeneous risk profiles of borrowers. It recognizes that the costs of capital are endogenously determined, reflecting the degree of credit risk and accessibility to credit markets. Based on the proposed model and the comparative statics derived thereof, the paper empirically tests the impacts of different factors on capital structure choice.

Based on the theoretical framework, the paper derived the impacts of different factors on capital structure choice using comparative statics. Results suggest that the potential determinants of capital structure have varying effects at different ranges of leverage. Empirical evidence supports the theoretical model.

Despite all of previous work on various aspects of farm capital structure choice, a framework that encompasses each of the different assumptions and scenarios is still lacking. The theoretical model integrates credit risk models and accommodates endogenous cost of capital, providing a comprehensive framework for studying farm capital structure choice and its determinants. The results provide insights that could help policy makers and lenders develop effective instruments to manage, monitor, and influence the financial leverage of farms at different quantiles of debt ratio.

This paper aims to present an innovative example of a master for teleoperation capable of moving in six degrees of freedom and of providing a force and torque feedback on the operator's hand.

After a brief overview of what the state of the art in teleoperation has to offer, the paper outlines the choice of an innovative structure in terms of both geometry and components, pointing out its main characteristics compared with traditional interfaces.

The master for teleoperation WiRo‐6.3 has been designed and constructed and is fully operative, thanks to the following theoretical analyses: positional and orientation workspace(s), forward and inverse kinematics, statics, overall control strategies. The mechanical details are also presented.

The WiRo‐6.3 is suitable to those applications in which human command is necessary but potentially harmful, and where a force‐feedback interface is preferred to obtain better control over the task to be accomplished. A possible field of interest could be the control of robot arms in dangerous environments, nuclear applications, uncomfortable climates, remote operations.

The master WiRo‐6.3 is a novel device both for its geometric structure and for the wire actuation choice; those characteristics provide very interesting results in terms of dexterity, force feedback performance and overall user‐friendliness.