Search results
1 – 10 of over 7000Jiaqi Zhang, Ming Cong, Dong Liu, Yu Du and Hongjiang Ma
The purpose of this paper is to use a simple method to enhance the ability of lower limb exoskeletons to restore balance under large interference conditions and to solve the…
Abstract
Purpose
The purpose of this paper is to use a simple method to enhance the ability of lower limb exoskeletons to restore balance under large interference conditions and to solve the problem that biped robot stability criterion cannot be fully applied to the underactuated lower limb exoskeletons.
Design/methodology/approach
The method used in this paper is to construct an underactuated lower extremity exoskeleton ankle joint with a torsion spring. Based on the constructed exoskeleton, the linear inverted torsion spring pendulum model is proposed, and the traditional capture point (CP) concept is optimized.
Findings
The underactuated exoskeleton ankle joint with torsion springs, combined with the improved CP concept, can effectively reduce the forward stepping distance under the same interference condition, which is equivalent to enhancing the balance ability of the lower extremity exoskeleton.
Originality/value
The contribution of this paper is to enhance the balance ability of the exoskeleton of the lower limbs under large interference conditions. The torsion spring is used as the exoskeleton ankle joint, and the traditional CP concept is optimized according to the constructed exoskeleton.
Details
Keywords
Petrus Sutyasadi and Manukid Parnichkun
The purpose of this paper is to introduce a quadruped robot strategy to avoid tipping down because of side impact disturbance and a control algorithm that guarantees the strategy…
Abstract
Purpose
The purpose of this paper is to introduce a quadruped robot strategy to avoid tipping down because of side impact disturbance and a control algorithm that guarantees the strategy can be controlled stably even in the presence of disturbances or model uncertainties.
Design/methodology/approach
A quadruped robot was developed. Trot gait is applied so the quadruped can be modelled as a compass biped model. The algorithm to find a correct stepping position after an impact was developed. A particle swarm optimization-based structure-specified mixed sensitivity (H2/H∞) robust is applied to reach the stepping position.
Findings
By measuring the angle and speed of the side tipping after an impact disturbance, a point location for the robot to step or the foothold recovery point (FRP) was successfully generated. The proposed particle swarm optimization-based structure-specified mixed sensitivity H2/H∞ robust control also successfully brought the legs to the desired point.
Practical implications
A traditional H∞ controller synthesis usually results in a very high order of controller. This makes implementation on an embedded controller very difficult. The proposed controller is just a second-order controller but it can handle the uncertainties and disturbances that arise and guarantee that FRP can be reached.
Originality/value
The first contribution is the proposed low-order robust H2/H∞ controller so it is easy to be programmed on a small embedded system. The second is FRP, a stepping point for a quadruped robot after receiving side impact disturbance so the robot will not fall.
Details
Keywords
ShunXiang Wei, Haibo Wu, Liang Liu, YiXiao Zhang, Jiang Chen and Quanfeng Li
To achieve stable gait planning and enhance the motion performance of quadruped robot, this paper aims to propose a motion control strategy based on central pattern generator…
Abstract
Purpose
To achieve stable gait planning and enhance the motion performance of quadruped robot, this paper aims to propose a motion control strategy based on central pattern generator (CPG) and back-propagation neural network (BPNN).
Design/methodology/approach
First, the Kuramoto phase oscillator is used to construct the CPG network model, and a piecewise continuous phase difference matrix is designed to optimize the duty cycle of walk gait, so as to realize the gait planning and smooth switching. Second, the mapper between CPG output and joint drive is established based on BP neural network, so that the quadruped robot based on CPG control has better foot trajectory to enhance the motion performance. Finally, to obtain better mapping effect, an evaluation function is resigned to evaluate the proximity between the actual foot trajectory and the ideal foot trajectory. Genetic algorithm and particle swarm optimization are used to optimize the initial weights and thresholds of BPNN to obtain more accurate foot trajectory.
Findings
The method provides a solution for the smooth gait switching and foot trajectory of the robot. The quintic polynomial trajectory is selected to testify the validity and practicability of the method through simulation and prototype experiment.
Originality/value
The paper solved the incorrect duty cycle under the walk gait of CPG network constructed by Kuramoto phase oscillator, and made the robot have a better foot trajectory by mapper to enhance its motion performance.
Details
Keywords
Allison S. Gabriel, David F. Arena, Charles Calderwood, Joanna Tochman Campbell, Nitya Chawla, Emily S. Corwin, Maira E. Ezerins, Kristen P. Jones, Anthony C. Klotz, Jeffrey D. Larson, Angelica Leigh, Rebecca L. MacGowan, Christina M. Moran, Devalina Nag, Kristie M. Rogers, Christopher C. Rosen, Katina B. Sawyer, Kristen M. Shockley, Lauren S. Simon and Kate P. Zipay
Organizational researchers studying well-being – as well as organizations themselves – often place much of the burden on employees to manage and preserve their own well-being…
Abstract
Organizational researchers studying well-being – as well as organizations themselves – often place much of the burden on employees to manage and preserve their own well-being. Missing from this discussion is how – from a human resources management (HRM) perspective – organizations and managers can directly and positively shape the well-being of their employees. The authors use this review to paint a picture of what organizations could be like if they valued people holistically and embraced the full experience of employees’ lives to promote well-being at work. In so doing, the authors tackle five challenges that managers may have to help their employees navigate, but to date have received more limited empirical and theoretical attention from an HRM perspective: (1) recovery at work; (2) women’s health; (3) concealable stigmas; (4) caregiving; and (5) coping with socio-environmental jolts. In each section, the authors highlight how past research has treated managerial or organizational support on these topics, and pave the way for where research needs to advance from an HRM perspective. The authors conclude with ideas for tackling these issues methodologically and analytically, highlighting ways to recruit and support more vulnerable samples that are encapsulated within these topics, as well as analytic approaches to study employee experiences more holistically. In sum, this review represents a call for organizations to now – more than ever – build thriving organizations.
Details
Keywords
This study aims to incorporate theory on effort-recovery and stressor-detachment models to examine the roles of relaxation, mastery and types of control on the relationship…
Abstract
Purpose
This study aims to incorporate theory on effort-recovery and stressor-detachment models to examine the roles of relaxation, mastery and types of control on the relationship between psychological detachment from work and boundary violations at home.
Design/methodology/approach
This study analyzes data from two time points using a sample of 348 working mothers recruited from Prolific.
Findings
Working moms who psychologically detach from work have less work boundary violations at home. There are mixed findings on whether and when the other types of recovery experiences moderate the relationship between psychological detachment and boundary violations at home. Relaxation, control after work and job autonomy do not moderate the effect while mastery and boundary control do. Specifically, psychological detachment is more effective as reducing boundary violations at home for working moms who have (1) low levels of mastery and (2) high levels of boundary control.
Practical implications
Working mothers juggle multiple roles and often have increased stress and less time to manage the two domains. The findings of this study illustrate whether and when psychological detachment from work acts as a key to recovery from work-based stressors.
Originality/value
Much of the research on recovery experiences is based on employees without consideration of motherhood status. Further, scholars have not examined the combinative potential of recovery experiences. Finally, examining control over both domains (vs. one domain) adds precision to the literature.
Details
Keywords
Charles Hubert Blouin-Delisle, Renee Drolet, Serge Gagnon, Stephane Turcotte, Sylvie Boutet, Martin Coulombe and Eric Daneau
The purpose of this paper is to increase efficiency in ORs without affecting quality of care by improving the workflow processes. Administrative processes independent of the…
Abstract
Purpose
The purpose of this paper is to increase efficiency in ORs without affecting quality of care by improving the workflow processes. Administrative processes independent of the surgical act can be challenging and may lead to clinical impacts such as increasing delays. The authors hypothesized that a Lean project could improve efficiency of surgical processes by reducing the length of stays in the recovery ward.
Design/methodology/approach
Two similar Lean projects were performed in the surgery departments of two hospitals of the Centre Hospitalier Universitaire de Québec: Hôtel Dieu de Quebec (HDQ) and Hôpital de l'Enfant Jesus (HEJ). The HDQ project designed around a Define, Measure, Analyse, Improve and Control process revision and a Kaizen workshop focused on patients who were hospitalized in a specific care unit after surgery and the HEJ project targeted patients in a post-operative ambulatory context. The recovery ward output delay was measured retrospectively before and after project.
Findings
For the HDQ Lean project, wasted time in the recovery ward was reduced by 62 minutes (68 percent reduction) between the two groups. The authors also observed an increase of about 25 percent of all admissions made in the daytime after the project compared to the time period before the project. For the HEJ Lean project, time passed in the recovery ward was reduced by 6 min (29 percent reduction).
Originality/value
These projects produced an improvement in the flow of the OR without targeting clinical practices in the OR itself. They demonstrated that change in administrative processes can have a great impact on the flow of clinical pathways and highlight the need for comprehensive and precise monitoring of every step of the elective surgery patient trajectory.
Details
Keywords
In this chapter, I develop an analysis of the institutional logics which have shaped the organizational field of public sector mental health and which provide a framework for…
Abstract
Purpose
In this chapter, I develop an analysis of the institutional logics which have shaped the organizational field of public sector mental health and which provide a framework for understanding the complexities facing policy makers, providers, researchers, and community mental health advocates.
Approach
I first assess the current state of public sector mental health care. I then describe institutional theory, which focuses our attention on the wider social values and priorities (i.e., institutional logics) which shape mental health care. In the current post-deinstitutionalization era, there are three competing institutional logics: recovery and community integration, cost containment and commodification, and increased social control over those with severe mental disorders. Each of these logics, and the conflict between them, is explicated and analyzed. I then develop a theoretical framework for understanding how conflicting institutional logics are resolved. In the concluding section of this chapter, I offer some guidance to both researchers and advocates seeking meaningful system level reform.
Research implications
Researchers studying mental health policy need to understand how competing institutional logics work to shape the political climate, economic priorities, and types of services available.
Social implications
Advocacy is critical for meaningful reform, and a fourth institutional logic – that of social justice – needs to be developed by which to evaluate policy reforms and service offerings.
Details
Keywords
This chapter investigates the nature of the transformation of macroeconomics by focusing on the impact of the Great Depression on economic doctrines. There is no doubt that the…
Abstract
This chapter investigates the nature of the transformation of macroeconomics by focusing on the impact of the Great Depression on economic doctrines. There is no doubt that the Great Depression exerted an enormous influence on economic thought, but the exact nature of its impact should be examined more carefully. In this chapter, I examine the transformation from a perspective which emphasizes the interaction between economic ideas and economic events, and the interaction between theory and policy rather than the development of economic theory. More specifically, I examine the evolution of what became known as macroeconomics after the Depression in terms of an ongoing debate among the “stabilizers” and their critics. I further suggest using four perspectives, or schools of thought, as measures to locate the evolution and transformation; the gold standard mentality, liquidationism, the Treasury view, and the real-bills doctrine. By highlighting these four economic ideas, I argue that what happened during the Great Depression was the retreat of the gold standard mentality, the complete demise of liquidationism and the Treasury view, and the strange survival of the real-bills doctrine. Each of those transformations happened not in response to internal debates in the discipline, but in response to government policies and real-world events.
Details
Keywords
Qinan Luo and Haibin Duan
Artificial bee colony (ABC) algorithm is a relatively new optimization method inspired by the herd behavior of honey bees, which shows quite intelligence. The purpose of this…
Abstract
Purpose
Artificial bee colony (ABC) algorithm is a relatively new optimization method inspired by the herd behavior of honey bees, which shows quite intelligence. The purpose of this paper is to propose an improved ABC optimization algorithm based on chaos theory for solving the push recovery problem of a quadruped robot, which can tune the controller parameters based on its search mechanism. ADAMS simulation environment is adopted to implement the proposed scheme for the quadruped robot.
Design/methodology/approach
Maintaining balance is a rather complicated global optimum problem for a quadruped robot which is about seeking a foot contact point prevents itself from falling down. To ensure the stability of the intelligent robot control system, the intelligent optimization method is employed. The proposed chaotic artificial bee colony (CABC) algorithm is based on basic ABC, and a chaotic mechanism is used to help the algorithm to jump out of the local optimum as well as finding the optimal parameters. The implementation procedure of our proposed chaotic ABC approach is described in detail.
Findings
The proposed CABC method is applied to a quadruped robot in ADAMS simulator. Using the CABC to implement, the quadruped robot can work smoothly under the interference. A comparison among the basic ABC and CABC is made. Experimental results verify a better trajectory tracking response can be achieved by the proposed CABC method after control parameters training.
Practical implications
The proposed CABC algorithm can be easily applied to practice and can steer the robot during walking, which will considerably increase the autonomy of the robot.
Originality/value
The proposed CABC approach is interesting for the optimization of a control scheme for quadruped robot. A parameter training methodology, using the presented intelligent algorithm is proposed to increase the learning capability. The experimental results verify the system stabilization, favorable performance and no chattering phenomena can be achieved by using the proposed CABC algorithm. And, the proposed CABC methodology can be easily extended to other applications.
Details