Design, development and control of a new generation high performance linear actuator for parallel robots and other applications

The main focus of this research is to design and develop a high performance linear actuator based on a four bar mechanism. The present work includes the detailed analysis (kinematics and dynamics), design, implementation and experimental validation of the newly designed actuator. High performance is characterized by the acceleration of the actuator end effector. The principle of the newly designed actuator is to network the four bar rhombus configuration (where some bars are extended to form an X shape) to attain high acceleration. Firstly, a detailed kinematic analysis of the actuator is presented and kinematic performance is evaluated through MATLAB simulations. A dynamic equation of the actuator is achieved by using the Lagrangian dynamic formulation. A SIMULINK control model of the actuator is developed using the dynamic equation. In addition, Bond Graph methodology is presented for the dynamic simulation. The Bond Graph model comprises individual component modeling of the actuator along with control. Required torque was simulated using the Bond Graph model. Results indicate that, high acceleration (around 20g) can be achieved with modest (3 N-m or less) torque input. A practical prototype of the actuator is designed using SOLIDWORKS and then produced to verify the proof of concept. The design goal was to achieve the peak acceleration of more than 10g at the middle point of the travel length, when the end effector travels the stroke length (around 1 m). The actuator is primarily designed to operate in standalone condition and later to use it in the 3RPR parallel robot. A DC motor is used to operate the actuator. A quadrature encoder is attached with the DC motor to control the end effector. The associated control scheme of the actuator is analyzed and integrated with the physical prototype. From standalone experimentation of the actuator, around 17g acceleration was achieved by the end effector (stroke length was 0.2m to 0.78m). Results indicate that the developed dynamic model results are in good agreement. Finally, a Design of Experiment (DOE) based statistical approach is also introduced to identify the parametric combination that yields the greatest performance. Data are collected by using the Bond Graph model. This approach is helpful in designing the actuator without much complexity.

The transition experience for registered nurses new to case management in the community

Case management is increasingly being used within today‟s healthcare system in an effort to reduce healthcare costs while meeting the complex needs of populations within the community. Registered nurses (RNs) are often recruited for the role of case managers in the community because of their specific skill set and ability to navigate the healthcare system. There is a vast amount of literature related to the client and system benefits of case management, the roles and responsibilities of RN case managers, and job satisfaction among RN case managers. However, there is a literature gap noted in relation to the transition experience for RNs new to case management in the community setting. This research study used grounded theory methodology, guided by Glaser and Strauss (1967) to explore the process of RNs transitioning to case management in the community setting. Eleven RNs new to case management in the community were interviewed using semi-structured interviews. Data analysis was carried out using the constant comparative method. Three stages of adjusting to case management in the community were identified: slugging it out, seeing the job as it is, and finding the way. By gaining an understanding of this transition experience, recommendations for nursing practice and administration, education, and research that are based on the evidence from this study can be implemented to improve the transition experience for RNs new to case management in the community setting