Neural Network Based Adaptive Tracking Control for a Class of Pure Feedback Nonlinear Systems With Input Saturation

In this paper, an adaptive neural networks(NNs)tracking controller is proposed for a class of single-input/singleoutput(SISO) non-affine pure-feedback non-linear systems with input saturation. In the proposed approach, the original input saturated nonlinear system is augmented by a low pass filter.Then, new system states are introduced to implement states transformation of the augmented model. The resulting new model in affine Brunovsky form permits direct and simpler controller design by avoiding back-stepping technique and its complexity growing as done in existing methods in the literature.In controller design of the proposed approach, a state observer,based on the strictly positive real(SPR) theory, is introduced and designed to estimate the new system states, and only two neural networks are used to approximate the uncertain nonlinearities and compensate for the saturation nonlinearity of actuator. The proposed approach can not only provide a simple and effective way for construction of the controller in adaptive neural networks control of non-affine systems with input saturation, but also guarantee the tracking performance and the boundedness of all the signals in the closed-loop system. The stability of the control system is investigated by using the Lyapunov theory. Simulation examples are presented to show the effectiveness of the proposed controller.

Dimensions of the Internationalization-Performance Relationship： Applied to Euronext 1 O0 Multinationals

In spite of the extensive literature regarding the relationship between corporate internationalization and performance, questions still remain due to conflicting empirical results. Is this due to the diversity of the conceptualization of international profile？ The results of statistical non-parametric tests obtained from a sample of 68 Euronext 100 companies over the period 2005-2009 point to a different relationship, between internationalization and performance, depending on whether the extent of international activities or their dispersion is considered.

The Influence of Insole with Metatarsal Retro-Capital on Posture, Plantar Pressure and Body Segments Positions in Runners

Objectives. The aim of this study was to investigate the effects of orthopaedic soles on the body posture. Methods. Forty-eight runners (21 men and 28 women) maintained a standing-up position on both feet with bare feet with neutral soles and orthopedic soles which contained bilaterally a podiatrist element of 3 mm height behind the metatarsal heads (Metatarsal Retro Capital Bar, MRCB). Stabilometric, plantar pressure and kinematic data in the sagittal plane on both sides were measured at 40 and 60 Hz, respectively. The position of the center of pressure on the anteroposterior axis (YCoP), the forefoot plantar pressure (FPP) and the anteroposterior position of the knee (Yk), the hip (YH), the shoulder (YS) and the ears (YE) with respect to the vertical axis passing through the joint of the ankle were determined for each experimental condition. Findings. The addition of a MRCB orthopedic element induced in backward displacement of CoP, hip, shoulder and ears (p CoP and FPP changes were significantly correlated with YH, YS and YE changes (p Conclusion. These results suggest that the addition of an orthopedic element located behind the metatarsal heads influences the overall position of the body and can help podiatrist in the care of their patients.

Thermal comfort of Frail People under dynamic and non-uniform thermal environments using a thermal manikin with thermoregulatory control:An experimental study

The thermal comfort of frail people has to be considered carefully,mainly because of the high thermal sensitivity of this population and the negative influences that unsatisfactory thermal conditions have on their health.Most existing thermal comfort works have been conducted under steady-state,uniform thermal environments,with far fewer being performed in dynamic and non-uniform thermal environments,and even less for frail people.This study aimed at assessing the thermal responses of frail people under transient and non-uniform thermal environments,using a thermal manikin and a climatic test cell.Thermal responses were investigated and discussed in both genders.The analysis of variance showed a significant difference in thermal comfort and thermal sensation between females and males over time,under hot exposure.Under cold exposure,results showed a significant difference in thermal sensation between females and males over time,but no significant difference was observed in term of thermal comfort.Analysis revealed also significant differences in the dynamic thermal sensation between the sexes under cold exposure,while results confirmed that there is no significant difference in the dynamic thermal sensation between sexes under hot exposure.

Adaptive Type-2 Fuzzy Sliding Mode Controller for SISO Nonlinear Systems Subject to Actuator Faults

In this paper, an adaptive type-2 fuzzy sliding mode control to tolerate actuator faults of unknown nonlinear systems with external disturbances is presented. Based on a redundant actuation structure, a novel type-2 adaptive fuzzy fault tolerant control scheme is proposed using sliding mode control. Two adaptive type-2 fuzzy logic systems are used to approximate the unknown functions, whose adaptation laws are deduced from the stability analysis. The proposed approach allows to ensure good tracking performance despite the presence of actuator failures and external disturbances, as illustrated through a simulation example.