Search

For successful push recovery in response to perturbations, a humanoid robot must select an appropriate stabilizing action. Existing approaches are limited because they are often derived from reduced-order models that ignore system-specific aspects such as swing leg dynamics or kinematic and actuation limits. In this study, the formulation of capturability for whole-body humanoid robots is introduced as a partition-based approach in the augmented center-of-mass (COM)-state space. The 1-step capturable boundary is computed from an optimization-based method that incorporates whole-body system properties with full-order nonlinear system dynamics in the sagittal plane including contact interactions with the ground and conditions for achieving a complete stop after stepping. The 1-step capturable boundary, along with the balanced state boundaries, are used to quantify the relative contributions of different strategies and contacts in maintaining or recovering balance in push recovery. The computed boundaries are also incorporated as explicit criteria into a partition-aware push recovery controller that monitors the robot’s COM state to selectively exploit the ankle, hip, or captured stepping strategies. The push recovery simulation experiments demonstrated the validity of the stability boundaries in fully exploiting a humanoid robot’s balancing capability through appropriate balancing actions in response to perturbations. Overall, the system-specific capturability with the whole-body system properties and dynamics outperformed that derived from a typical reduced-order model.

Robotic tasks often exceed the scope of steady-state or periodic behavior, which necessitates generally-applicable models of actuators intended to generate transient or aperiodic motion. However, existing electromechanical models of servomotors typically omit consideration of the switching power converter circuits required for directional, speed, or torque control. In this study, a multi-domain framework is established for switched electromechanical dynamics in servomotor systems for their analysis and control in general aperiodic tasks including transient phases. The switched electromechanical dynamics is derived from the individual models of the internal DC motor, gear train, and H-bridge circuit. The coupled models comprehensively integrate all possible distinct switching configurations of on-state, off-state, and dead time. A combination of cycle averaging with piecewise analytical solutions of the non-smooth dynamics is introduced to handle different temporal scales from high-frequency electrical to low-frequency mechanical variables. System parameters were estimated from experimental data using a dual-servomotor test platform. The model was validated for predictive accuracy against measured data in two distinct tasks—dynamic braking of a pendulum system and sinusoidal trajectory following. The model was also used to formulate the servomotor power consumption, which was implemented for optimal control demonstration and energy analysis. In particular, the servomotor power consumption model provided true optimality (minimization) when compared with the squared rotor torque and the positive rotor mechanical power that are commonly used as proxy models. While the focus of this work is on permanent-magnet, armature-controlled brushed DC servomotors, the approach is applicable to general electromechanical systems with switching-based control.

For successful push recovery control in response to unpredicted perturbations, a humanoid robot must select the appropriate stabilizing action from a wide range of available strategies. Existing approaches are restricted to a limited range of balancing motions because they are often derived from reduced-order models and ignore system-specific aspects such as swing leg dynamics or joint kinematic/actuation limits. In this work, a novel partition-aware push recovery controller is introduced that can select between the ankle, hip, and captured stepping strategies for balance by evaluating the robot’s center-of-mass (COM) state with respect to different levels of criteria. The criteria are the partition-based stability regions in the augmented COM state space, which are numerically constructed for each balancing strategy. For stepping, both free- and fixed-arm capturability regions were obtained to quantify the effect of arm momenta on balancing capability. The regions are pre-computed for control with an optimization-based method that incorporates whole-body system dynamics, contact interactions with the ground, system-specific characteristics, and requirements of the corresponding strategy. Through simulation experiments, the proposed approach was demonstrated to allow the controller to fully exploit a humanoid robot’s balancing capability and validate the use of pre-computed stability regions as explicit criteria to initiate a proper balancing motion, in contrast to the use of incomplete or implicit criteria in existing controllers.

This study examined the disagreement between an insurer’s recommendation for long-term care (LTC) services and beneficiaries’ choices and analyzed the factors associated with the disagreement. Data from the National Long-Term Care Insurance (LTCI) and the Standard Care Plan were merged to create a dataset of 43,319 LTCI beneficiaries. The dependent variable was the disagreement between beneficiaries and insurers. Predisposing, enabling, and needs factors were independent variables based on the Andersen’s Model. Disagreement between the insurer’s recommendation of home care services and the beneficiaries’ choice of institution service was 6.7% (n = 2357). The opposite disagreement occurred in 23.0% (n = 1820) of cases. A multivariate analysis showed that the OR for disagreement between insurer-recommended home care services and beneficiary-selected institution services increased with age, living with someone, having Medical Aid, living in a facility, and having high care needs, dementia, and poor subjective hearing. The OR for disagreement between insurer-recommended institution service and beneficiary-selected home care service increased for men and decreased for those 90 years or older, living with someone, having Medicaid etc, and living at institution. Korean beneficiaries of LTCI have a high preference for aging in their home, and changes in LTCI contents must be made to address the needs of this population.

Tipping is an instrumental aspect of multi-phase contact situations that arise during common tasks such as the locomotion of legged systems. Despite its importance in balance recovery, tipping is often ignored in trajectory optimization due to the lack of existing methods that are able to actively plan and optimize for unspecified contacts. Trajectory Optimization based on nonlinear programming requires a priori knowledge about anticipated contact changes, such as their order and timing, in order to generate physically feasible motions. In this paper, an optimization framework with conditional constraints is established for direct collocation in trajectory optimization for legged balancing with foot tipping allowance. The proposed approach can evaluate the timing of contact phases without preplanned contact forces or sequences of events, which is not possible with conventional methods. This optimization framework is demonstrated by computing the balanced regions of two reduced-order models of a legged system, namely, inverted-pendulum-based models without and with a flywheel, and is verified with control simulations. The contribution of tipping to balance stability is quantified and compared to prior results obtained without tipping allowance. The framework presented can also be generalized to other multi-phase contact scenarios, such as rolling and sliding, where unspecified discontinuous changes in contact occur with important consequences in the performance of legged systems.

Aim The purpose of the present study was to identify the relationship between staff mix in nursing homes and quality of care by level of case mix in Korea. Methods Data used in the present study came from Long-Term Care Insurance claims data with basic information of nursing homes with >29 beds (n = 1137) and quality evaluation reports. Staff mix was calculated as the number of nursing staff, social workers and care workers per total staff number. Results In multinomial logistic regression analyses, institutions with a higher ratio of social workers were classified as top-quality class institutes after controlling ownership, location, size and percentage of high level of care needs residents. In analyzing the higher case mix nursing homes, institutions with a high ratio of nursing staff and social workers were more likely to be classified as top-quality class than the lowest class institutions. However, there was no significant association between quality of care and ratio of staff mix in the lower case mix nursing homes. Conclusions A higher staff mix was positively related to nursing home quality of care, but the relationship was affected by case mix of residents' care demand. Therefore, the current minimum staffing standard for personnel in nursing homes should be modified considering the acuity of the residents. Geriatr Gerontol Int 2019; 19: 438-443.

To achieve walking and push recovery successfully, a biped robot must be able to determine if it can maintain its current contact configuration or transition into another one without falling. In this study, the ability of a humanoid robot to maintain single support (SS) or double support (DS) contact and to achieve a step are represented by balanced and steppable regions, respectively, as proposed partitions of an augmented center-of-mass-state space. These regions are constructed with an optimization method that incorporates full-order system dynamics, system properties such as kinematic and actuation limits, and contact interactions with the environment in the two-dimensional sagittal plane. The SS balanced, DS balanced, and steppable regions are obtained for both experimental and simulated walking trajectories of the robot with and without the swing foot velocity constraint to evaluate the contribution of the swing leg momentum. A comparative analysis against one-step capturability, the ability of a biped to come to a stop after one step, demonstrates that the computed steppable region significantly exceeds the one-step capturability of an equivalent reduced-order model. The use of balanced regions to characterize the full balance capability criteria of the system and benchmark controllers is demonstrated with three push recovery controllers. The implemented hip–knee–ankle controller resulted in improved stabilization with respect to decreased foot tipping and time required to balance, relative to an existing hip–ankle controller and a gyro balance feedback controller.

Humans play sports to improve their athletic ability. The robot, especially humanoid robot, is also able to improve its athletic performances, such as reaction speed and balancing, through robot sports. Therefore, robots have been developed through performing various robot sports events such as robot soccer, robot marathon, robot fight and so on. In this reason, The Ski Robot Challenge was held in South Korea in commemoration of the PyeongChang 2018 Winter Olympic Games. The event was an Alpine slalom skiing competition in the almost same rules to human's but on a relatively short course (80m). To participate in this ski tournament, the skiing robot DIANA has been developed. In this video, the skiing robot technologies were introduced. At first, she must be able to recognize the flags. The deep learning method was used to recognize them. Secondly, she had a motion pattern to perform the carving turn, the most difficult and fastest skiing technique. In order to improve the stability, she compensated her motion to follow reference COP, based on the measured F/T sensor data. In addition, IMU sensor was used to remove instantaneous disturbance. Using these methods, the humanoid robot, DIANA, that can perform the carved turn on a realworld slope was successfully developed.

Objectives: The purpose of this study was to investigate risk factors for chronic ADL, IADL disability. The study explored clinical and socio-demographic risk factors of functional status decline. Methods: Data from the Survey of Living Condition of Elderly 3-year panel study were analyzed. The study subjects were 5,928 community-dwelling people aged 65 years or older who were no disability in ADL and IADL at baseline. Predisposing factors, pathology, impairment, and functional limitations were regarded as risk factors. Logistic regression analysis was used. Results: During the 3-year study period, 3.9% participants developed chronic ADL disability, 9.4% participants were IADL disabled. After controlling for predisposing factor, the best predictors for ADL disability at 36 months were fall as a pathology factor, cognitive decline, disability judgement, lower limb functional limitation. Comorbidity, fall, cognitive decline, disability judgement, lower limb and upper limb functional limitation were risk factors for IADL disability. Conclusions: Health promotion program focusing elderly is essential to prevent ADL and IADL disability. Mobilizing physical activity should be included in health promotion program for elderly.Key words: function, disability, aged

This paper describes the technical approach, hardware design, and software algorithms that have been used by Team THOR in the DARPA Robotics Challenge DRC Trials 2013 competition. To overcome big hurdles such as a short development time and limited budget, we focused on forming modular components-in both hardware and software-to allow for efficient and cost-effective parallel development. The hardware of THOR-OP Tactical Hazardous Operations Robot-Open Platform consists of standardized, advanced actuators and structural components. These aspects allowed for efficient maintenance, quick reconfiguration, and most importantly, a relatively low build cost. We also pursued modularity in the software, which consisted of a hybrid locomotion engine, a hierarchical arm controller, and a platform-independent remote operator interface. These modules yielded multiple control options with different levels of autonomy to suit various situations. The flexible software architecture allowed rapid development, quick migration to hardware changes, and multiple parallel control options. These systems were validated at the DRC Trials, where THOR-OP performed well against other robots and successfully acquired finalist status.

One of the most difficult problems involving installing a rescue robot into a disaster site is maintaining constant communication. In a disaster site, it is highly probable that facilities for communication have been destroyed or rendered inoperative. Therefore, it should be assumed that nearby communication devices cannot be used, limiting communication to the equipment native to the robot itself. In this paper, we propose the operation of a segmented robot capable of multi-hop communication to overcome environments with limited communication options. As the robot that is composed of several detachable modules enters a disaster area, detaches the part equipped with a wireless router, as some lizards would shed their tail, and attempts multi-hop communication to secure reliable wireless communication when the signal strength becomes weak. In this paper, we introduce a method for multi-hop communication in segmented robots. In particular, the method by which a GUI using ROS can be constructed to operate a robot is also introduced.

Objective The injury-related disease burden in South Korea is relatively high compared to that in other nations. This study was conducted to identify the scale and causes of injury by severity, using an injury pyramid and analyzing the sex and age-dependent differences and the basic demographic characteristics. Methods Unintentional injury was estimated for each group after classifying injury-related deaths, hospitalizations, and outpatient department (OPD) visits based on their severity. The injury pyramid was calculated by classifying the injury outcomes into deaths, hospitalizations, and outpatient visits. Results The incidence of unintentional injury included 31.74 deaths, 1,715.27 hospitalizations, and 7,317.55 OPD visits per 100,000 persons. The incidence of injury was higher among males than that among females. There were more hospitalizations and OPD visits than deaths among females. The mortality and hospitalization rates due to injury per 100,000 persons were the highest among those ≥75 years old, and the OPD visit rate was the highest among preschool children aged 0 to 6 years. The injury mechanisms that caused most deaths and hospitalizations in South Korea were injuries related to traffic, falls, poisoning, and burns/fires. Conclusion The scale of unintentional injury varies based on sex, age, and injury mechanism; additionally there are differences in the incidence of injuries between males and females depending on their age and injury mechanism. The high incidence of injury in elderly people could be a factor that increases the burden of injury in South Korea; hence, it is necessary to develop an injury prevention program that targets the elderly.

Hybrid friction stir butt welding of Al6061-T6 aluminum alloy plate to Ti–6%Al–4%V titanium alloy plate with satisfactory acceptable joint strength was successfully achieved using preceding gas tungsten arc welding (GTAW) preheating heat source of the Ti alloy plate surface. Hybrid friction stir welding (HFSW) joints were welded completely without any unwelded zone resulting from smooth material flow by equally distributed temperature both in Al alloy side and Ti alloy side using GTAW assistance for preheating the Ti alloy plate unlike friction stir welding (FSW) joints. The ultimate tensile strength was approximately 91% in HFSW welds by that of the Al alloy base metal, which was 24% higher than that of FSW welds without GTAW under same welding condition. Notably, it was found that elongation in HFSW welds increased significantly compared with that of FSW welds, which resulted in improved joint strength. The ductile fracture was the main fracture mode in tensile test of HFSW welds.

Background: This study was to provide an analysis of long-term care hospitals in major foreign countries and to ultimately drive suggestions for the role of the long-term care hospital system in Korea. Methods: Services, composition of the workforce, admission criteria, and collaboration with related organization were reviewed. Japan, Canada, United States (US) and the Netherlands were selected for analysis using the case study research method. Results: Organization for Economic Co-operation and Development (OECD) defined long-term care hospital as long-term care beds in hospitals. A few OECD countries institutionalized long-term care beds in hospitals, focusing at palliative care or geriatric care. In Japan, Canada, US, and the Netherlands, all having similar long-term care hospitals as Korea, a key difference was that the hospitals in these four countries provide comprehensive post-acute and nursing care. They have clearly defined admission criteria by preadmission review and systemization of referral from other organizations. Conclusion: Based on this review of the systems in foreign countries serving as examples for Korea and considering the policy needs and the present problems raised by providers, discussions on the future role of long-term care hospitals in Korea should be conducted.

This paper describes the hardware design and motion control algorithms that have been used by Team THOR in the DARPA Robotics Challenge (DRC) Trials 2013 competition. The robotic hardware we use, the THOR-OP robot, consists of standardized and general purpose actuators and structural components, which greatly reduce the build and reconfiguration time and allows for quick field repair capability. Our software framework is also composed of fully modular function modules. This modular structure helps us to keep up easily with hardware changes and to have multiple control options to suit various situations. We validated our approach at the DRC Trials where we fared well against other robots many times more expensive and acquired the finalist status.

Impact of Nurse Staffing Level and Oral Care on Hospital Acquired Pneumonia in Long-term Care Hospitals Chae, Jung Mi · Song, Hyunjong · Kang, Gunseog · Lee, Ji Yun Health Insurance Review & Assessment Research Department Department of Health Policy and Management, Sangji University Department of Statistics and Actuarial Science, Soongsil University Department of Nursing, Kangwon National University