In this paper we present a controller that achieves global input-to-state stability for a linear system of arbitrary relative degree, subjected to matched and unmatched disturbances. This controller combines the prope...
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ISBN:
(纸本)9781467371605
In this paper we present a controller that achieves global input-to-state stability for a linear system of arbitrary relative degree, subjected to matched and unmatched disturbances. This controller combines the properties of a discontinuous term, and a linear one, enforcing a conventional sliding mode using only partial state information. A direct and simple way of choosing the gains for this controller is also provided.
Spinal cord injury is damage to the spinal cord that results in loss of functions, causes muscle, joint and bone deficits, moreover it increases the muscle tone level. FEScycling is an alternative rehabilitation proce...
Spinal cord injury is damage to the spinal cord that results in loss of functions, causes muscle, joint and bone deficits, moreover it increases the muscle tone level. FEScycling is an alternative rehabilitation process to conserve the musculoskeletal system affected by the injury in the functional state. The aim of this study is to get the legs bilaterally synchronized by FES and compare MMG signal responses. The preliminary protocol consists of five consecutive contractions. The first and the last contractions were discarded and the three intermediate contractions were analyzed. A ratio between MMG values of muscle responses during propulsion and return of pedalling phases was calculated for each cycle and each leg. The applied FES profile consisted of pulse and burst on time of 250 us and 5 ms and frequencies of 1000 Hz and 20 Hz, respectively. Results showed that greater MMG RMS values tend to occur during the propulsion phase than in the return phase. MMG Z axis of RLL and MMG X axis of LLL were the axes that presented the greatest ratios. The MMG RMS signal showed that greater values tend to occur during the propulsion phase than in the return phase of the same thigh.
Correct discrimination of essential tremor from Parkinson's tremor is a major problem in clinical neurology as minor differences in the tremor patterns are hard to distinguish. Mathematical analysis of tremor sign...
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Correct discrimination of essential tremor from Parkinson's tremor is a major problem in clinical neurology as minor differences in the tremor patterns are hard to distinguish. Mathematical analysis of tremor signals recorded non-invasively has been widely accepted for tremor differentiation. However, classification of tremor signals collected from electromyograph or accelerometer, based on time and frequency domain techniques has limited accuracy because of overlapping frequency range and non-stationary nature of those signals. This paper describes a simple, non-invasive decision making logic method for discrimination of tremor. Wavelet transform based feature extraction technique in combination with feed forward type artificial neural network is proposed. Fractal dimensions of wavelet features of the decomposed detailed coefficients are used as the feature matrix. The neural network classified the tremor sEMG signals with 91.66% accuracy and 100% in case of accelerometer signals. Although, the classification accuracy of sEMG signal is comparable to that of accelerometer but the localized involuntary vibratory nature of tremor at the extremities of human body puts accelerometer as a better option in cases where tremor fails to excite the muscle. This proposed classification algorithm adds strength to the non-invasive signal detection methods at reduced cost and higher sensitivity.
With the increasing grid penetration levels of wind power, there is a large need for the energy reserves for grid support during under-frequency conditions. Such energy reserves are created by operating the wind farm ...
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engineering graduates who enter the work environment after finishing their studies are faced with completely different setting compared to the safe academy environment that they are used to. Main differences at the wo...
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Today, Mexico is one of the leading countries of the Latin American region in receiving foreign direct investment, with expected GDP growth for the coming years between 4% and 6% per annum, according to estimates publ...
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Today, Mexico is one of the leading countries of the Latin American region in receiving foreign direct investment, with expected GDP growth for the coming years between 4% and 6% per annum, according to estimates published by the OECD and other international organizations. Sustaining such growth demands the strengthening of one of the main pillars of economic development, the National Electricity Sector. To accomplish this growth in the electricity sector will require an energy portfolio that allows for three basic conditions in the sector's planning: reliability, economy and sustainability. To ensure the sustainability of the National Electric Sector, the optimal energy portfolio must meet the CO 2 eq emission reduction that the country has adopted based on international commitments. Sources of electricity generation with low water consumption as well as reduced pollutant discharge are needed, given the great importance of water efficiency in energy production. This paper determines an optimal energy portfolio involving conventional technologies, clean technologies and alternative and intermittent renewable technologies, based on a simple optimization model and using variables such as future electricity demand, CO 2 eq emissions by source, and taking into account data from several studies of life cycle assessment of the electricity sector, such as energy payback rate and water pollution. The research presented assumes two scenarios of growth in electricity demand of about 350 and 1,150 TW-hours in 2050.
A general transformation that takes linear systems into their regular form, for any relative degree is introduced. A sliding surface where unmatched unknown inputs are attenuated via a reduced order H_∞ control is de...
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ISBN:
(纸本)9781467357159
A general transformation that takes linear systems into their regular form, for any relative degree is introduced. A sliding surface where unmatched unknown inputs are attenuated via a reduced order H_∞ control is designed, for the case of relative degree two. By a discontinuous control action, the surface is reached exactly in finite time, guaranteeing the minimization of the unmatched disturbance. Complete state measurements are not necessary.
With the increasing grid penetration levels of wind power, there is an increasing need to study both the power control systems and the regulatory aspects associated with frequency control capabilities of wind power pl...
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ISBN:
(纸本)9781467344456
With the increasing grid penetration levels of wind power, there is an increasing need to study both the power control systems and the regulatory aspects associated with frequency control capabilities of wind power plants at various levels (turbine, wind farm and power system levels). This is especially very important in the United States with a goal of achieving 20% nation's electricity from wind energy by 2030. This paper provides observations and challenges identified with wind energy integration with respect to active power control strategies used in implementing frequency regulation at various levels. This paper also discusses the current and future aspects of market regulation of frequency responsive services offered by converter based variable generation technologies and the need for an appropriate utility market structure in order to provide settlements for these capabilities.
The fault detection and isolation problem is studied for a class of nonlinear systems. Under structural conditions, a bank of High-Order Sliding-Mode observers is proposed. The value of the equivalent output injection...
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The fault detection and isolation problem is studied for a class of nonlinear systems. Under structural conditions, a bank of High-Order Sliding-Mode observers is proposed. The value of the equivalent output injection is used for detecting and isolating particular faults in the system. The proposed method provides finite-time isolation of actuator and plant faults. Simulation results support the proposed approach.
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