A Passivity-based Decomposing Method for Operational Space Control of Kinematical Redundant Tele-operation Systems

In the passivity-based decomposing method, a bilateral tele-operation system is virtually decomposed into 2 sub-systems (shape/locked) to ensure coordination between the master and slave robots and to provide a general referenced motion of the closed-loop bilateral tele-operation along with the passivity of the master and slave robots. So far, the passivitybased decomposing methods in the literature have been studied only for the joint-space control of tele-operation systems with kinematical similar master and slave robots. In this study, a passivity-based decomposing method is proposed for operational space control of bilateral teleoperation systems with kinematic redundancy in the slave robot. The main objectives of the proposed method are to ensure operational space coordination between the robots' end-effector trajectories and to achieve a referenced general movement of the closed-loop tele-operation system. In addition, the kinematic redundancy of the slave robot, which usually complicates the control problem, is turned into an advantage, and secondary tasks are designed for the slave robot. Moreover, experiments are carried out to validate the achievement of the proposed method using a kinematical redundant tele-operation setup. © 2021. All Rights Reserved.This work was supported by TUBITAK project no. 113-E-147.113-E-14

New Dynamic Models for Planar Extensible Continuum Robot Manipulators

Abstract: In this paper, the dynamic model for planar continuum manipulators that was presented in our previous work is extended to include new terms reflecting the effects of potential energy. First the gravitational potential energy of the manipulator is derived. Then, the elastic potential energy of the manipulator is derived for both bending and extension. Finally, the effects of the total potential energy are included in the dynamic model. Numerical simulation results are presented for a planar 3-section extensible continuum robot manipulator. The results show a much stronger match to physical continuum robots than with previously available models. I

Unsuspected risk factors of frequent exacerbations requiring hospital admission in chronic obstructive pulmonary disease

PubMedID: 23758448Introduction Severe exacerbations are the leading cause of fatal events in chronic obstructive pulmonary disease (COPD). The new Global Initiative for Chronic Obstructive Lung Disease strategy included the number of exacerbations in the grading of the disease. The primary aim of this study was to evaluate the potentially modifiable precipitating factors of frequent severe exacerbations requiring hospital admission in COPD. The secondary aim was to investigate the risk factors of readmission within 2 months following an exacerbation requiring hospitalisation. Methods Data regarding the number of exacerbations in the previous year, current comorbidities, medications, and clinical and functional status of COPD patients were evaluated. Results We included 107 COPD patients (85% men). The mean number of severe exacerbations was 1.3 ± 1.7 (per patient/per year), and 37.4% of the patients had frequent severe exacerbations (? 2/year). Multivariate analysis indicated that haematocrit < 41%, angiotensin converting enzyme inhibitor or angiotensin receptor blocker use, positive gastro-oesophageal reflux disease symptoms, poor adherence to inhaled therapy/regular outpatient follow-up visits and FEV1 < 50% were independent predictors of frequent severe exacerbations. Readmission rate within 2 months after hospital discharge was 39.3%. The independent risk factors of readmission were poor adherence to inhaled therapy/regular outpatient follow-up visits, serum haematocrit < 41%, and FEV1 < 50%. Conclusion Chronic obstructive pulmonary disease patients with frequent exacerbations should be carefully assessed for modifiable confounding risk factors regardless of poor lung function to decrease exacerbation frequency and related poor prognosis. © 2013 John Wiley & Sons Ltd

Modified Limberg flap reconstruction compares favourably with primary repair for pilonidal sinus surgery

Background: The present study analyses the results of wide excision with primary closure (PC), wide excision with classical Limberg flap reconstruction (LF) and wide excision with modified Limberg flap reconstruction (MLF) in the surgical treatment of sacrococcygeal pilonidal disease. Methods: One hundred and sixty-two well-documented patients who were operated on for pilonidal disease and followed for more than 1 year were analysed retrospectively. Group 1 was composed of patients with excision plus PC (n = 78) while group 2 included those with excision plus a LF reconstruction (n = 40), and group 3 included those with excision plus a MLF reconstruction (n = 44). Results: There were no significant differences among the three groups with respect to age, sex distribution, frequency of recurrent disease, or follow-up periods (P > 0.05 for all comparisons). Significant disadvantages regarding postoperative infection rate, mobilization time, discharge from hospital, and time off work were noted for primary closure, compared with both LF and MLF reconstructions. Following a median follow-up period of 4.2 years, 14 recurrences (17.9%) developed in the PC group, three (7.5%) in the LF group, and none (0%) in the MLF group. The zero recurrence rate in the MLF group was significantly lower than that in the PC group (P = 0.003). On the other hand, the recurrence rate in the LF was not found to differ significantly from that in the PC group (P = 0.126). Comparing the LF and MLF groups, none of the surgical end points reached a statistically significant difference (P > 0.05 for all comparisons). Conclusions: For the surgical treatment of sacrococcygeal pilonidal disease, excision plus a classical or modified Limberg flap reconstruction proved to be superior to excision plus primary closure in terms of infection, mobilization time, discharge from hospital and time off work. Additionally, MLF reconstruction resulted in a statistically lower recurrence rate when compared with PC