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A total of 27 test profiles from the IEC 61400-1 design load cases were tested using a 7.5-MW wind turbine drivetrain test bench and two multi-megawatt wind turbine drivetrains. Each test profile consisted of simultaneous vertical, lateral, and longitudinal forces, yawing and nodding bending moment, and rotational speed. These test-bench inputs were compared with the forces, bending moments, and speed that were applied to the wind turbine drivetrains to quantify the test-bench tracking error. This tracking error was quantified for a range of ramp-rate limits of the yawing and nodding bending moments. The experimental results were compared with predictions from an evaluation method for the capability of wind turbine drivetrain test benches to replicate dynamic loads. The method’s predictive capability was found to be sufficient for the goal of early screening and its formulation is applicable to any wind turbine drivetrain test bench and drivetrain design.

Tradespace analysis capabilities are critical for organizations either selecting large programmatic efforts or those engaged in providing solutions to major program opportunities. The ability of an organization to effectively use the tradespace in their decision-making process had a substantial impact upon programmatic success. Poorly bounded tradespaces may lead to prototype vehicles (or any other system to be designed) that are ultimately unacceptable due to performance, cost, or technical risk issues. Tradespaces that are over-constrained can unduly limit design options and lead to stagnant designs that are unable to incorporate technical innovations. Most organizations find that tradespace analysis presents numerous challenges, so this research aims to address the evaluation of strengths, weaknesses, and opportunities for improvement within an organization. In this study, we explain how an interview-based process was used to perform this analysis and make recommendations for opportunities for process improvement within an organization (Ground Vehicle Systems Center or GVSC). Similar approaches could be applied to other organizations to facilitate the development of an organizational self-assessment that can aid in the identification of internal strengths, weaknesses, and opportunities for improvement within organizations performing tradespace activities.

A 7.5-MW wind turbine drivetrain test bench has been used to apply dynamic loads from IEC 61400-1 design load cases to a multi-MW wind turbine drivetrain. A total of 15 test profiles were tested with each test profile demanding the simultaneous application of vertical, lateral, and longitudinal forces, yawing and nodding bending moments, and rotational speed. These inputs to the test bench were compared with the forces, bending moments, and speed that were applied to the wind turbine drivetrain to quantify the tracking error of the test bench and cross-coupling between forces and bending moments. The effect of the tracking error and cross-coupling on the dynamic response of the test article was quantified using multibody simulation. The tracking error was found not to significantly change the dynamic response of the drivetrain. The experimental and simulation results are used to recommend acceptance criteria for the tracking error when replicating dynamic loads.

Despite the rise of development in continuum manipulator technology and application, a model-based feedback closed-loop control appropriate for continuum robot designs has remained a significant challenge. Complicated by the soft and flexible nature of the manipulator body, control of continuum structures with infinite dimensions proves to be difficult due to their complex dynamics. In this article, a novel strategy is designed for trajectory control of a multisection continuum robot in three-dimensional space to achieve accurate orientation, curvature, and section length tracking. The formulation connects the continuum manipulator dynamic behavior to a virtual discrete-jointed robot whose degrees of freedom are directly mapped to those of a continuum robot section under the hypothesis of constant curvature. Based on this connection, a computed torque control architecture is developed for the virtual robot, for which kinematics and dynamic equations are constructed and exploited, with appropriate transformations developed for implementation on the continuum robot. The control algorithm is implemented on a six degree-of-freedom two-section OctArm continuum manipulator. Experiments show that the proposed method could manage simultaneous extension/contraction, bending, and torsion actions on multisection continuum robots with decent performance (arc length and curvature error of ±4 mm and ±0.35 m–1). The designed dynamic controller can reduce the curvature tracking error and rise time by up to 48.1% and 94.8% compared to the traditional proportional-integral-derivative controller during two-section maneuvers.

Enhanced battery pack cooling remains an open thermal management challenge in hybrid electric vehicle applications. A robust cooling system should maintain the battery pack core temperature within a prescribed operating range to improve system performance, durability, and reliability while minimizing power consumption. This paper proposes a smart battery thermal management system utilizing heat pipes as a thermal bus to efficiently remove heat. The system couples a standard air conditioning system with traditional ambient air ventilation. The two loops can run independently or in tandem to achieve the desired control. A nonlinear model predictive controller was developed to maintain the battery core temperature within a designated range using the compressor and fan speeds as the control inputs. A mathematical battery thermal model was developed to estimate the core and surface temperatures. The system performance and power requirements were evaluated for various driving cycles and ambient conditions. Numerical results showed that the proposed cooling system can regulate the battery core temperature within the desired temperature range (maximum tracking error of 2.1°C) while compensating for ambient temperature conditions using a suitable cooling strategy. The simulation results showed the ability to remove up to 1135 kJ of heat. The simulation also presents the power consumed by system components under varying modes and ambient conditions.

Compared to mobile devices of the past decade, current devices provide desktop computer-level processing power in a palm-sized package. However, battery life of such devices has not made the same stride, forcing the user to rely on portable battery packs for backup power. Portable energy harvesting methods could provide a possible solution to reduce the user's dependence on the power grid. In this regard, a mobile energy harvester powered by human arm motion during walking or running activities is developed and tested. The device consists of a pendulum connected to a DC generator through a planetary gear train. An electronic module filters the output and supplies power to a load. A mathematical model of the human arm-harvester system is derived and simulated based on the triple pendulum system. The power output of the harvester for two output modes are recorded for a constant running pace by the user, and the results are compared with the simulation. The model predicted an energy output of 1.72 mJ and testing resulted in 1.39 mJ and 1.16 mJ for a period of 5 s of running activity. This successfully demonstrates the energy harvester's potential as a mobile power supply for charging portable consumer electronics.

Background Limb amputation may be recommended in domestic cats following a severe injury or disease. The purpose of the study was to report the signalment, the complications, recovery outcome, owner satisfaction and expectations of domestic cats following limb amputation. Results Medical records of 3 specialty hospitals were reviewed for cats that received a single limb amputation in a 10 year period (2007–2017). These cat owners were contacted, and 59 owners completed surveys, comprising the study population. The most common reasons for limb amputation were neoplasia (54.2%, 32/59), traumatic injury (40.7%, 24/59), bone or joint infection (3.4%, 2/59), and thromboembolism (1.7%, 1/59). Thirty-four cats (57.6%) had postoperative complications. Of the fifty-nine surveys, 52.5% reported minor complications and 5.1% reported major complications. There were no differences in postoperative complication rates for thoracic versus pelvic limb amputations. All owners reported either excellent (77.9%, 46/59), good (20.3% 12/59), or fair (1.7%, 1/59) satisfaction with the procedure. Based on their previous experiences, 84.7% (50/59) of owners would elect limb amputation if medically warranted for another pet. The remaining 15.3% of owners who would not elect limb amputation again had experienced death of their pet with a median survival time of 183 days. Conclusion Owners reported a positive satisfaction when considering complications, recovery outcome, and expectations. This study can be used by veterinarians to guide cat owners in the decision making process of limb amputation.

This chapter will introduce the single port robotic system. Topics include an introduction to the robotic single site port, the trocars, and the single site instruments. Step-by-step instruction is provided on how to create the umbilical incision and properly insert the single site port and trocars. The advantages and disadvantages of single port robotic surgery compared to multiple port robotic surgery and laparoscopic single site surgery are reviewed. Surgical tips and tricks are provided throughout each section to maximize efficiency, minimize complications, and overcome inherent limitations of the robotic single site system. The utility of the robotic single site platform for performing minor gynecologic surgery is discussed. Finally, a simple method for umbilical closure is described.

Hybrid electric vehicle motors offer propulsion while accelerating and charge the battery pack when braking or decelerating. Though electric motors have high operating efficiency, considerable heat is generated based on required operating torque and speed. Thus, an efficient motor cooling system is needed to maintain the temperature within a prescribed range. The traditional motor liquid cooling system is effective but consumes energy to run the coolant pump and radiator fan. This paper examines the performance of a hybrid cooling system, combining heat pipes with conventional liquid cooling in a compact thermal cradle. This innovative design allows heat removal via an integrated thermal pathway by regulating various actuators (e.g., centrifugal fans, radiator pump, and fan) to minimize energy consumption. A reduced order thermal model predicts the motor's internal temperatures. Cooling performance is evaluated based on the Urban Assault driving cycle for different conditions. Numerical results show that the electric motor temperature is maintained at approximately the target value of 70 °C. Additionally, up to approximately 370 kJ of energy is saved as compared to a conventional liquid cooling system for a specific 85 kW e-motor within 1500 s run time.