Changes In Motor Parameters Research Articles

Comparative Motor Pre-clinical Assessment in Parkinson's Disease Using Supervised Machine Learning Approaches.

Millions of people worldwide are affected by Parkinson's disease (PD), which significantly worsens their quality of life. Currently, the diagnosis is based on assessment of motor symptoms, but interest toward non-motor symptoms is increasing, as well. Among them, idiopathic hyposmia (IH) is associated with an increased risk of developing PD in healthy adults. In this work, a wearable inertial device, named SensFoot V2, was used to acquire motor data from 30 healthy subjects, 30 people with IH, and 30 PD patients while performing tasks from the MDS-UPDRS III for lower limb assessment. The most significant and non-correlated extracted parameters were selected in a feature array that can identify differences between the three groups of people. A comparative classification analysis was performed by applying three supervised machine learning algorithms. The system resulted able to distinguish between healthy and patients (specificity and recall equal to 0.967), and the people with IH can be identified as a separate class within a three-group classification (accuracy equal to 0.78). Thus, the system could support the clinician in objective assessment of PD. Further, identification of IH together with changes in motor parameters could be a non-invasive two-step approach to investigate the early onset of PD.

Hypothesised and Actual Changes in the General Motor Parameters of Field Hockey Players During the Training Cycle

Abstract Introduction. The aim of the study was to determine the changes in selected motor parameters of highly skilled field hockey players during the training macrocycle. It was assumed that the changes in the parameters examined in the study would correspond with the hypothesised variation related to the adaptive changes that were expected to take place. Material and methods. The study involved eleven field hockey players from the KS AZS-AWF Poznań club (age = 22.3 ± 1.1 years; height = 176.5 ± 4.0 cm; weight = 75.2 ± 6.3 kg; %FM = 12.2 ± 3.9%; VO2max = 55.4 ± 4.85 ml/kg/min). The dates of the measurements were agreed on with the trainers, who played an active role in the study, and were consistent with the cycle of planned measurements that were aimed at assessing the implementation of training/competition loads (two measurements during the preparatory period and one during the competition period). We examined the fundamental elements of motor preparation that are considered important in field hockey, that is speed endurance, running speed, and aerobic endurance. These assessments were supplemented by the measurements of lactate concentration in capillary blood as well as those of jumping ability and agility. Results. In most cases, the changes in the actual results corresponded with the hypothesised values adopted for the training. The relationships between the levels of particular parameters of the players’ motor skills were adequate to a great extent. Conclusion. The effects of the training observed both for the entire team and for individual players were generally in line with the goals of the training/ competition loads implemented. Any discrepancies that were found were identified and corrected by regulating individual exercise loads and were monitored in subsequent measurements.

The effects of interventions implemented during a rehabilitation camp on changes in motor skills parameters and body mass in patients with simple obesity

Abstract Introduction:According to the latest UNICEF report, Polish children put on weight at the highest pacein Europe. The number of overweight children has doubled in the last decade. The aim of the work was to assess the effects of kinesiotherapy implemented during a 3-week rehabilitationcamp on changes in motor skills parameters measured on the Leonardo dynamometric platform (Novotec Medical) and on body mass in patients with simple obesity. Materialand methods:The study group included 32 children and youth aged 7-16 with simple obesity who underwent an exercise programme during a 3-week rehabilitation camp. The subjects were examined twice, i.e. at the beginning and at the end of the camp. The control group consisted of 70 healthy children within the same age range who were examined once. Body mass and body height were measured and the BMI was calculated (taking into account centile charts) for all the study participants. Motor skills were assessed on the basis of avertical jump performed on the Leonardo GRFP (GroundReaction Force Platform). The following data were registered: jump velocity, maximum jump height, strength, power, power with reference to body mass and the Esslinger Fitness Index (EFI). Daily kinesiotherapy included exercises in the form of circuit training and water exercises. All the patients participated in meetings with a dietician and a clinical psychologist. Results:Statistically significant reduction in body mass after a 3-week rehabilitation camp was noted in 27 patients with simple obesity (84.1%) (p<0.05). Motor parameters did not improve significantly. Conclusions:Regular physical activity resulted in weight loss only. However, physical activity did not bring about positive changes in motor parameters.

A Study on Correcting the Nonlinearity Between Stack Length and Back Electromotive Force in Spoke Type Ferrite Magnet Motors

The accurate estimation of the performance change according to variations in stack length of motors is important in related industries. A permanent magnet (PM) motor usually represents a characteristic in which its back electromotive force (EMF) constant (K e ) is linearly proportional to stack length. It is an enormous advantage in designing and estimating the performance of PM motors. However, the linearity cannot be held in spoke-type ferrite magnet synchronous motors (SFMSM) due to the axial leakage magnetic flux that is irrelevant to the stack length. Thus, it is possible to accurately analyze the performance of SFMSM using a 3-D finite-element analysis (FEA) method but this method is very inefficient. In this paper, a new relationship formula that can consider the nonlinearity between stack length and back EMF constant in SFMSM is proposed. This formula can estimate the back EMF constant in a new stack length based on the results of 2-D-FEA and 3-D-FEA in a specific stack length. Finally, the validity of this formula is verified through analyzing its accuracy and testing it according to changes in motor parameters.

Impact of Auditory Context on Executed Motor Actions.

The auditory and motor systems are strongly coupled, as is evident in the specifically tight motor synchronization that occurs in response to regularly occurring auditory cues compared with cues of other modalities. Timing of rhythmic action is known to rely on multiple neural centers including the cerebellum and the basal-ganglia which have access to both motor cortical and spinal circuitries. To date, however, there is little information on the motor mechanisms that operate during preparation and execution of rhythmic vs. non-rhythmic movements. We measured acceleration profile and muscle activity while subjects performed tapping movements in response to auditory cues. We found that when tapping at random intervals there was a higher variability of both acceleration profile and muscle activity during motor preparation compared to rhythmic tapping. However, the specific rhythmic context (cued, self-paced, or syncopation) did not affect the motor parameters of the executed taps. Finally, during entrainment we found a gradual as opposed to episodic change in low-level motor parameters (i.e., preparatory muscle activity) that was strongly correlated with changes in high-level parameters (i.e., shift in the reaction time to negative asynchrony). These findings suggest that motor entrainment involves not only adjusting the timing of movement but also modifying parameters that are related to its production. These changes in motor output were insensitive to the specifics of the rhythmic cue: although it took subjects different times to become entrained to different types of rhythmic cues, the motor actions produced once entrainment was obtained were indistinguishable. These findings suggest that motor entrainment involves not only adjusting the timing of movement but also modifying parameters related to its production. The reduced variability of muscle activity during the preparatory period could be one mechanism used by the motor system to enhance the accuracy of motor timing.

Control Environment of Linear Induction Drive Dynamics Models

Developed dynamic models of linear induction drives allow examining various dynamic characteristics of linear induction drives according to results of simulation. Nevertheless, changes in motor windings connection way or motor parameters require recalculating and renewing set up of model parameters. The integrated control environmental of model is discussed. Developed software allows controlling model and investigating non-symmetrical modes of single phase breaking and breaking by direct current, compare obtained characteristics and examine influence of motor parameters on that. Active program window is presented, where the motor parameters, winding connection way, operation mode and desired simulation results can be set up. Algorithm of simulation program and algorithm for processing of simulation results are presented. Breaking time dependence on the resistance of the secondary element has minimum value. Presented dependence of breaking time against resistance of the secondary element and the breaking voltage allows choosing these parameters for obtaining of desirable braking time. Ill. 6, bibl. 10 (in English, summaries in English, Russian and Lithuanian).

Ski-jumpers’ performance in a laboratory setting: a 29-year longitudinal study

This study assesses the longitudinal changes in anthropometric and motor parameters of ski jumpers. Male ski jumpers (n = 329) at various competitive levels participated in this study. These competitors were divided into two groups by age (18 years and younger, and over 18 years), and then divided into seven even intervals within those groups. Basic anthropometric parameters, maximal relative isometric knee extensor force, reaction time, knee extension time, and vertical jump height were measured. The conditions, instruments, and systems of measurement were consistent throughout the study. A reduced body mass index (BMI) in the adult jumpers was significant (P < .01) in the first three (1982–1993) and in the last three (1998–2010) intervals. Adults had an increase of maximal relative isometric knee extensor force (P < .01) in the last three intervals (1998–2010). They had greater maximal relative isometric knee extensor force (with exception of the first interval, 1982–1985) and vertical jump height than younger competitors (P < .01). Both young and adult jumpers exhibited the increase of strength and power in the lower limbs and a decrease in BMI during the whole observed period.

Electrophysiological assessment of Chronic Inflammatory Demyelinating Peripheral Polyradiculoneuropathy(CIDP) in Patients with Diabetes Mellitus

Back ground: Peripheral neuropathy is a common complication of diabetes mellitus. However, patients with diabetes are more vulnerable to develop chronic inflammatory demyelinating peripheral polyradiculoneuropathy (CIDP) which is an acquired immune mediated disorder.&#x0D; Subjects and methods: Three groups of subjects of either sex involved in this study; fourty one (41) patients with diabetic CIDP, fourty six (46)patients with diabetic peripheral polyneuropathy and fourty one (41) control subjects. Sensory and motor nerve conduction study (NCS) and electromyography (EMG) of both upper and lower limbs were performed for each subjects. This study was conducted at the unit of neurophysiology in Neuroscience Hospital and Al- yarmouk Teaching Hospital, in a period from November /2012 to May /2013.&#x0D; Objectives: : Assess the role of electrophysiological study (NCS and EMG) in the diagnosis of CIDP in diabetic patients and Differentiate between diabetic CIDP and diabetic peripheral polyneuropathy(PNP).&#x0D; Results: Prolonged distal sensory latency distal (DSL), decreased sensory nerve action potential (SNAP) amplitude and slowing of sensory nerve conduction velocity (SNCV). Sensory NCS was significantly changed in both patients groups. While the presence of abnormal median-normal sural (AMNS) and abnormal radial – normal sural (ARNS) pattern of sensory involvement were detected only in diabetic CIDP patients. Concerning motor nerve conduction study, prolonged distal motor latency (DML), slowing of conduction velocity and prolonged mean F-wave latency were detected in both patients group, but these abnormalities were more in diabetic CIDP patients. Conduction block CB% and abnormal temporal dispersion TD% were observed only in diabetic patients with CIDP. Whereas needle EMG of diabetic CIDP revealed that there are mixed axonal and demyelinating neuropathy.&#x0D; Conclusion: This study conclude that the abnormal sensory and motor NCS in the lower limbs were higher when compare with that of upper limbs. However, the changes in motor parameters are more in diabetic patients with CIDP than that of diabetic PNP. In addition, the proximal nerve segments are more vulnerable to be affected by demyelinating process rather than the other segments. Moreover, most of diabetic patients with CIDP have mixed axonal and demyelinating changes in respect to those who had only demyelinating neuropathy.

Adaptive Control for Brushless DC Motor Based on Fuzzy Inference

Due to the nonlinearity of brushless direct current (BLDC) motor, it is difficult to obtain satisfied control characteristics using proportional integral derivative (PID) controller. A novel adaptive fuzzy control method based on high performance speed control is proposed in this paper, which combines an adaptive parameter adjustment mechanism with fuzzy controller to solve the problems of non-linearity, parameter variations and load excursions that occur in the BLDC motor drive system. The adaptive parameter adjustment mechanism can give better quantization and proportion factors of the fuzzy controller when there are variations in motor parameters or load, hence the fuzzy control rules are changed. The adaptive fuzzy control system is simulated in matlab with the changes of motor parameters and load, the control performance of the traditional PID controller is compared with the adaptive fuzzy controller. The comparison results indicate that the adaptive fuzzy control system has stronger robust and self-adaptive ability, faster response time, and zero overshoot and steady state error, which can satisfy the request of the BLDC motor control system. DOI : http://dx.doi.org/10.11591/telkomnika.v12i5.4950

An Adaptive Neurocontroller for Induction Motors

The paper is focused on presenting possibilities of applying artificial neural networks (ANN) at creating a speed controller of an induction motor drive. The presented method of control takes advantage of approximating properties of multi-layer feedforward networks. The availability of the proposed neurocontroller is verified through the Matlab simulation. The effectiveness of the controller is demonstrated for different operating conditions and motor parameter changes of the drive system.

Simple Hybrid Model for Efficiency Optimization of Induction Motor Drives with Its Experimental Validation

New hybrid model for efficiency optimization of induction motor drives (IMD) is presented in this paper. It combines two strategies for efficiency optimization: loss model control and search control. Search control technique is used in a steady state of drive and loss model during transient processes. As a result, power and energy losses are reduced, especially when load torque is significant less related to its rated value. Also, this hybrid method gives fast convergence to operating point of minimal power losses and shows negligible sensitivity to motor parameter changes regarding other published optimization strategies. This model is implemented in vector control induction motor drive. Simulations and experimental tests are performed. Results are presented in this paper.

Sensorless Motor Drives with Predictive Current Control

Hardware complexity of a motor drive can be reduced by estimating controls rather than measuring using sensors. In this way the corresponding sensors are eliminated and the system becomes more robust. This article is about speed control of a sensor less induction motor with predictive current controller technique. This particular speed control technique does not require direct measurements of motor speed or motor flux. The PCC is based on a closed loop observer, which is insensitive to parameter variations. This closed loop observer calculates the required state variables over wide frequency range. This technique is more reliable even at very low frequency due to its insensitive nature against changes of motor parameters. It is proved that the drive system is applicable to the high dynamic performance and wide range of rotor speed. The obtained simulation results confirm the good properties of the proposed speed sensor less induction motor drive. Keywordspredictive current control, closed loop observer, sensorless induction motor. I. Nomenclature PCC – Predictive current controller IM – Induction motor, FOC – Field oriented control, PWM – Pulse width modulation, EMF – Electromagnetic force (back EMF) SVM – Space vector modulation, αβ – Stationary frame of references, dq – Rotating frame of references, p.u. – per unit system com – Superscript denotes commanded value, pred – Superscript denotes predicted value, ^ – Denotes value calculated in the observer, bold style font denotes vector CEMF – EMF transformation matrices, C2EMF – EMF transformation matrices, e – Motor EMF, is, ir – Stator and rotor current vector, J – Inertia, k, k-1 – Instants of calculation: actual, previous, etc., kab – Observer gain, Lr – Rotor inductance, Ls – Stator inductance, Lm – Mutual inductance, Rr – Rotor resistance, Rs – Stator resistance Timp – Inverter switching period, TL – Load torque, us – Stator voltage vector, υe – Angle position of the motor EMF vector, ρψs – Angle position of the rotor flux vector, ωr – Rotor mechanical speed, ω2 – Motor slip, I

Neural network-based optimal control of a DC motor positioning system

This article describes an optimal control algorithm for a DC motor drive operating as a positioning system. The control algorithm is based on combination of artificial neural network and state space method with variable gain. The positioning system operating under proposed algorithm has demonstrated a transient process close to optimal without overshoot. It has been also shown that the control algorithm is robust to the change of the DC motor parameters and the supply voltage disturbances. An experimental setup based on TMS320F243 evaluation module has been designed and built in order to prove the simulation results. The algorithm has been verified by simulation using MATLAB/Simulink and proved by a number of practical experiments.

RBF Neural Network Approach for Identification and Control of DC Motors

In this paper, a neural network approach for the identification and control of a separately excited direct (DC) motor (SEDCM) driving a centrifugal pump load is applied. In this application, two radial basis function neural networks (RBFNN) are used: The first is a RBFNN identifier trained offline to emulate the dynamic performance of the DC motor-load system. The second is a RBFNN controller, which is trained to make the motor speed follow a selected reference signal. Two RBFNN control schemes are proposed using direct inverse and internal model control schemes. The performance of the RBFNN identifier and controller is investigated in terms of step response, sharp changes in speed trajectory, and sudden load change, as well as changes in motor parameters. The performance of RBFNN in system identification and control has been compared with the performance of the well-known back-propagation neural network (BPNN). The simulation results show that both of the BPNN and RBFNN controllers exhibit excellent dynamic response, adapt well to changes in speed trajectory and load connected to the motor, and adapt to the variations of motor parameters. Furthermore, the simulation results show that the step response of RBFNN internal model and direct inverse controllers are identical.

Speed Sensorless Control System of Mining Locomotive Drive Based on DSP

The paper presents a dual closed-loop vector control system based on dsPIC30F6010A for asynchronous motor which is a multi-variables, nonlinear, strong coupling and time-varying system and is difficult to determine precise mathematical model because of changes in motor parameters and load fluctuations in factors. Torque current differential Speed estimation method proposed and experiment results proved this method has satisfactory dynamic response, anti-interference ability and robustness.

Sensorless speed control of switched reluctance motor using brain emotional learning based intelligent controller

In this paper, a brain emotional learning based intelligent controller (BELBIC) is developed to control the switched reluctance motor (SRM) speed. Like other intelligent controllers, BELBIC is model free and is suitable to control nonlinear systems. Motor parameter changes, operating point changes, measurement noise, open circuit fault in one phase and asymmetric phases in SRM are also simulated to show the robustness and superior performance of BELBIC. To compare the BELBIC performance with other intelligent controllers, Fuzzy Logic Controller (FLC) is developed. System responses with BELBIC and FLC are compared. Furthermore, by eliminating the position sensor, a method is introduced to estimate the rotor position. This method is based on Adaptive Neuro Fuzzy Inference System (ANFIS). The estimator inputs are four phase flux linkages. Suggested rotor position estimator is simulated in different conditions. Simulation results confirm the accurate rotor position estimation in different loads and speeds.

Treadmill running protects spinal cord contusion from secondary degeneration

It is known that physical activity triggers changes in the central nervous system. Adult rats, trained on treadmills for 4 weeks, and a group of sedentary rats was submitted to contuse moderate spinal cord injury. A group of sedentary rats was submitted to a sham operation. The trained group continued running on treadmill after lesion for 4 weeks. Motor behavior evaluated by BBB score was smaller in the sedentary group compared to the trained rats by 7 days after lesion. Computerized activity monitor showed clear-cut differences in spontaneous motor parameters in trained rats only before lesion. After surgery, sedentary rats showed changes in motor parameters but not in later periods of analysis. Animals were euthanized by 28 days after surgery, and their spinal cords were processed for Nissl staining and immunohistochemistry. The number of the remaining neurons and the lesion areal and lesion volume fractions were obtained by stereological method. The number of the remaining neurons did not change after training. Lesion volume and lesion areal fraction per section were smaller in the trained group. Lesion index was more pronounced in the sedentary group. Microdensitometric image analysis demonstrated a microglial reaction, astroglial activation, and glial FGF-2 production more pronounced in the spinal cord of sedentary animals. GAP-43 was higher in caudal levels of contusion in the sedentary group. In conclusion, treadmill running may favor a better functional recovery in the acute period after spinal cord lesion and wound repair processes leading to neuroprotection.

Stator-Current-Based MRAS Estimator for a Wide Range Speed-Sensorless Induction-Motor Drive

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper deals with an analysis of the vector-controlled induction-motor (IM) drive with a novel model reference adaptive system (MRAS)-type rotor speed estimator. A stability-analysis method of this novel MRAS estimator is shown. The influence of equivalent-circuit parameter changes of the IM on the pole placement of the estimator transfer function and the stability of the whole drive system are analyzed and tested. The influence of the adaptation-algorithm coefficients of the MRAS-estimator scheme is also tested. The allowable range of motor-parameter changes is determined, which guarantees the stable operation of the sensorless field-oriented IM drive with this speed and flux estimator. Dynamical performances of the vector-control system with the current-type MRAS estimator are tested in a laboratory setup. </para>

Rotor Fault Analysis in the Sensorless Field Oriented Controlled Induction Motor Drive

In the paper an analysis of the Direct Field Control of induction motor drive with broken rotor bars is presented. A drive system with and without a mechanical speed sensor is analyzed. In the sensorless induction motor (IM) drive the rotor flux and speed is reconstructed with the use of a MRASCC estimator, where the induction motor is used as a reference model. The stator current estimator and current model of the rotor flux are used as adapted models. Most of the speed estimators used in sensorless drives are sensitive to motor parameter changes, especially to the rotor resistance changes. The proposed MRASCC estimator is very robust to all motor parameter changes, hence it should work properly in a faulty rotor. In the paper simulation and experimental results of the sensorless IM drive with broken rotor bars are presented. Characteristic frequency harmonics of the IM state variables connected with the broken rotor bars are introduced. The low speed region and the dynamic properties of the IM drive with rotor faults are tested. The range of stable work of the control system is shown.

Mislocalization of Flashed and Stationary Visual Stimuli after Adaptation of Reactive and Scanning Saccades

When we look around and register the location of visual objects, our oculomotor system continuously prepares targets for saccadic eye movements. The preparation of saccade targets may be directly involved in the perception of object location because modification of saccade amplitude by saccade adaptation leads to a distortion of the visual localization of briefly flashed spatial probes. Here, we investigated effects of adaptation on the localization of continuously visible objects. We compared adaptation-induced mislocalization of probes that were present for 20 ms during the saccade preparation period and of probes that were present for >1 s before saccade initiation. We studied the mislocalization of these probes for two different saccade types, reactive saccades to a suddenly appearing target and scanning saccades in the self-paced viewing of a stationary scene. Adaptation of reactive saccades induced mislocalization of flashed probes. Adaptation of scanning saccades induced in addition also mislocalization of stationary objects. The mislocalization occurred in the absence of visual landmarks and must therefore originate from the change in saccade motor parameters. After adaptation of one type of saccade, the saccade amplitude change and the mislocalization transferred only weakly to the other saccade type. Mislocalization of flashed and stationary probes thus followed the selectivity of saccade adaptation. Since the generation and adaptation of reactive and scanning saccades are known to involve partially different brain mechanisms, our results suggest that visual localization of objects in space is linked to saccade targeting at multiple sites in the brain.