Position Sensor Research Articles

Typical faults and safety analysis of brake controller for AC locomotive

PurposeThe brake controller is a key component of the locomotive brake system. It is essential to study its safety.Design/methodology/approachThis paper summarizes and analyzes typical faults of the brake controller, and proposes four categories of faults: position sensor faults, microswitch faults, mechanical faults and communication faults. Suggestions and methods for improving the safety of the brake controller are also presented.FindingsIn this paper, a self-judgment and self-learning dynamic calibration method is proposed, which integrates the linear error of the sensor and the manufacturing and assembly errors of the brake controller to solve the output drift. This paper also proposes a logic for diagnosing and handling microswitch faults. Suggestions are proposed for other faults of brake controller.Originality/valueThe methods proposed in this paper can greatly improve the usability of the brake controller and reduce the failure rate.

Sensorless HSPMSM Control of an Improved SMC and EKF Based on Immune PSO

Here, for controlling a high-speed flywheel permanent magnet synchronous motor (HSPMSM), a position sensorless control method for estimation of motor rotor position and speed is proposed to address the problems faced by mechanical position sensors of high cost, large size, and poor interference immunity. The extended Kalman filter (EKF) has difficulty obtaining the optimal covariance matrix when performing state estimation. Therefore, the particle swarm algorithm (PSO) with an immune mechanism is used to optimize the covariance matrix of the EKF. However, the EKF algorithm makes the system less robust due to its delay effect. Based on the traditional sliding mode control rate, the exponential convergence law is improved, and the continuous function sat(s) is used instead of the symbolic function sgn(s). This improves the convergence law and proves the asymptotic stability of the designed sliding mode variable structure controller based on Lyapunov’s stability theorem. Then, the novel control law is applied to the sliding mode surface (SMS). An ordinary sliding mode controller (OSMC) using a linear sliding mode controller (LSMC), a global sliding mode controller (GSMC) using a global sliding mode surface (GSMS), and an integral sliding mode controller (ISMC) using an integral sliding mode surface (ISMS) are designed for improving control. Joint simulation in MATLAB and Simulink verifies that the optimized EKF based on the immune PSO can improve precision and accuracy for controlling the electronic rotor position and speed. Comparing the new sliding mode controller with a traditional PI controller reveals that the proposed system has stronger resistance to load disturbance and better robustness.

Lasing Emission from Soft Photonic Crystals for Pressure and Position Sensing.

In this report, we introduce a 1D photonic crystal (PhC) nanocavity with waveguide-like strain amplifiers within a soft polydimethylsiloxane substrate, presenting it as a potential candidate for highly sensitive pressure and position optical sensors. Due to its substantial optical wavelength response to uniform pressure, laser emission from this nanocavity enables the detection of a minimum applied uniform pressure of 1.6‱ in experiments. Based on this feature, we further studied and elucidated the distinct behaviors in wavelength shifts when applying localized pressure at various positions relative to the PhC nanocavity. In experiments, by mapping wavelength shifts of the PhC nanolaser under localized pressure applied using a micro-tip at different positions, we demonstrate the nanocavity's capability to detect minute position differences, with position-dependent minimum resolutions ranging from tens to hundreds of micrometers. Furthermore, we also propose and validate the feasibility of employing the strain amplifier as an effective waveguide for extracting the sensing signal from the nanocavity. This approach achieves a 64% unidirectional coupling efficiency for leading out the sensing signal to a specific strain amplifier. We believe these findings pave the way for creating a highly sensitive position-sensing module that can accurately identify localized pressure in a planar space.

PWM Controlled Servomechanism

Precise control of aircraft flight control surfaces by the pilot is critical to flight safety. The joystick and control surface positions must be detected accurately and quickly, and the motion mechanism must be operated in such a way as to ensure synchronization between them. The analogue voltage value taken from the potentiometer, which is used as a position sensor in many small aircraft, can be used directly or by converting to digital. 
 In this applied study, the analogue position knowledge received from the potentiometer on the joystick was converted into a PWM signal with an oscillator circuit. The PWM position signal applied to the IR (InfraRed) LED in the transmitter unit is sent as infrared light. The PWM position knowledge detected by the photodiode in the receiver unit was passed through the LPF (Low Pass Filter) and the voltage value of the joystick potentiometer was obtained again. With the mechanism controlled according to the difference between the potentiometer values of the joystick and the control surface, the synchronization between the joystick and the control surface is ensured. In this study, a wireless and stable servomechanism connection is obtained by transmitting PWM position knowledge as IR.

Analysis of torque controlling strategies of interior permanent magnet synchronous machine in hybrid electric vehicle

Significance of this research is based on torque controlling strategies in hybrid electric vehicle. The traction motor of a hybrid electric commercial vehicle must have a high power density-to-weight ratio and excellent torque at extremely low speeds. A proportional-integral controller estimates the high-resolution rotor position based on the difference between actual as well as reference output power. This technique can correct for hall position sensor installation error and also accurately estimate rotor position. In this study, a current proportional integral controller is also used to determine the permanent magnetic flux linkage. Experiments are used to test other key metrics such as d-axis and q-axis inductances, stator resistance, and energy loss. The measured parameters are kept in lookup tables that span the whole operating range at various current levels. A maximum torque per ampere control methodology, paired with the feed forward parameter iteration method, may be used to produce accurate and efficient torque control based on these precise parameters. The standard driving cycle performance requirements of the modelled Federal Test Procedure vehicle is analysed in the article for understanding the real model requirements of the vehicle. The efficacy of the proposed methodology using Matlab/Simulink environment is analysed. Both modelling and experimental findings validate the efficacy, torque ripple, stator and rotor flux, sensitivity of the vehicle parameter as well as the computational complexity of the proposed methodology.

Validity and Reliability of a Linear Position Transducer to Measure Velocity, Duration, and Displacement in the Barbell Back Squat

The purpose of this investigation was to determine the validity and reliability of the Humac360 linear position transducer (LPT) as compared to Tendo Weightlifting Analyzer. Seventeen recreationally active men and women completed three visits. Visit one included maximal strength assessments via one-repetition maximum (1RM) for the barbell back squat. On visits two and three, participants completed two sets of three repetitions at 30-, 50-, 60-, and 70% 1RM. Mean Concentric Velocity (MCV), Peak Velocity (PV), Displacement (D), and Duration (T) were collected. Repetition data agreement was assessed with Intraclass Correlation Coefficients (ICCs) and were categorized as poor (<0.50), moderate (0.50 – 0.75), good (0.75 – 0.90), and excellent (>0.90). Significance was accepted at an alpha (p) value < 0.05. Repetition-to-repetition comparisons between devices demonstrate varying degrees of agreement, with significant differences between devices across all intensities and all measurements (p < 0.001). Inter-set reliability was excellent for MCV, PV, D, and T with the exceptions of MCV and PV at 70% 1RM (ICC2,k = 0.548 and 0.816). Inter-session reliability data demonstrated reduced agreeableness in an intensity-dependent manner, with ICCs decreasing and SEMs increasing with increases in intensity. The Humac360 LPT does not appear to be valid when compared to the criterion reference, though we contend it maintains construct validity. Coaches may use the Humac360 LPT as a tool to monitor fatigue, and the associated changes in trainee movement velocity on an inter-set and inter-session basis.

Safety, usability, and performance of a wireless left atrial pressure monitoring system in patients with heart failure: the VECTOR-HF trial (final results)

Abstract Background In heart failure (HF), implantable hemodynamic monitoring devices have been shown to optimize therapy, anticipating clinical decompensation and preventing hospitalization. Direct left-sided hemodynamic sensors offer theoretical benefits beyond pulmonary artery pressure (PAP) monitoring systems. Aims We evaluated the safety, usability, and performance of a novel left atrial pressure (LAP) monitoring system in HF patients (V-LAP). Methods and Results The VECTOR-HF study was a first-in-human, prospective, multicenter, single-arm, clinical trial enrolling 30 patients with HF. The device consisted of an interatrial positioned leadless sensor, able to transmit LAP data wirelessly. After three months, a right heart catheterization (RHC) was performed to correlate mean pulmonary capillary wedge pressure (PCWP) with simultaneous mean LAP obtained from the device. Remote LAP measurements were then used to guide patient management. The miniaturized device was successfully implanted in all 30 patients, without acute Major Adverse Cardiac and Neurological Events (MACNE). At 3 months, freedom from short-term MACNE was 97%. Agreement between sensor-calculated LAP and PCWP was consistent, with a mean difference of -0.22±4.92mmHg, the correlation coefficient and the Lin’s Concordance Correlation Coefficient values were equal to 0.79 (P<0.0001) and 0.776 (95%CI=0.582-0.886), respectively. Preliminary experience with VLAP-based HF management was associated with significant improvements in NYHA functional class (32% of patients reached NYHA II class at 6 months, P<0.005; 60% of patients at 12 months, P<0.005) and 6-minute walk-test distance (from 244.59±119.59m at baseline to 311.78±129.88m after 6 months, P<0.05, and 343.95±146.15m after 12 months, P<0.05). Conclusion The V-LAP™ monitoring system proved to be safe and provided a good correlation with invasive PCWP. Initial evidence also suggests possible improvement in HF clinical symptoms that could be associated to a better outcome. Further studies are needed to test the efficacy of the device in heart failure patients.

A learning observer-based control strategy for PMSM with position sensor fault in railway

In this paper, control strategy for PMSM with position sensor fault in railway is investigated. Conventional control approaches rely on accurate measurement feedback signal by position sensor. However, position sensor of PMSM in trains is prone to failure. To solve such a problem, a learning observer-based control strategy is proposed. Firstly, a novel learning observer is proposed in order to achieve high-precision estimation of electromotive force. Secondly, a combined PD-SMC controller is designed to accelerate speed response. Estimation of position and speed can be deduced from EMFs estimation, the estimated speed information can be employed by proposed PD-SMC controller. The effectiveness and validity of proposed learning observer and PD-SMC controller are verified by simulations and experiments.

FACTORS INFLUENCING THE EFFICIENCY OF MODERN ELECTRO-EROSION PROCESSING

The article describes the factors of increasing the efficiency of processing products on EDM equipment. due to the use of linear drives with high dynamic accuracy. Also, the inter-electrode gap in the processing zone, its influence on optimal energy regimes and maximum material removal was investigated in the work. The electrode is fed into the spark formation zone 5-10 times more often, the relative duration is several times longer than in machines with KGP drives. Sludge removal due to the pumping effect from rapid movements of the electrode instead of pumping. The use of linear motors, servo drives, precision linear position sensors, devices for automatic wire feeding, hole search, wire breakage prevention - will increase the productivity of wire-cutting processing by 40-100%.A comparative analysis of the performance of parts processing on equipment with the use of linear and KGP (ball-screw pairs) drives was carried out.

A Novel Speed-Sensorless Wireless Universal Motor With Bidirectional Movement

This paper proposes a novel wireless universal motor. By eliminating the motor controller and position sensor, the secondary side is very simple and robust. Besides, bidirectional movement can be achieved. The key is to employ a self-driving circuit at the secondary side. Also, the advantages of the small size and large starting torque of universal motors can be retained. Hence, the proposed wireless universal motor is very suitable to be sealed and employed in isolated environments, such as pipeline pigging. A series of simulations and experiments have been conducted, which confirms that the secondary side can be self-driven, and the motor speed can be detected at the primary side.

Online Adaptive Gain for Passivity-Based Control for Sensorless BLDC Motor Coupled With DC Motor for EV Application

Passivity based control (PBC) is an energy based control inwhich total energy is an algebraic sum of stored and dissipated energy. The energy equations are analysed using Hamiltonian operator. Exact Tracking Error Dynamics Passive Output Feedback (ETEDPOF) method is used to drive a BLDC motor coupled with DC motor. The controller is a linear controller which adapts precise variation by means of sensing output current as well as position of motor for varying speed reference. The system is made sensorless by eliminating both position and speed sensors to reduce cost of implementation using back EMF method. The back EMF of each winding is sensed and using zero crossing detectors, the initial position is found for starting the motor. The speed is observed from back EMF and also the gate signals are sent to inverter. The inverter is powered from single phase AC supply through DC filter and boost converter. In order to verify features of proposed control scheme, PBC is compared with widely used PI controller and Sliding Mode Control (SMC) for boost converter and inverter, simulated in MATLAB and results are observed with constant load torque and speed conditions.

Feasibility Investigation on Sinusoidal-Reluctance Rotor Contour in Variable Reluctance Resolver

Variable reluctance (VR) resolvers are universally employed as the absolute position sensor in motor control systems. In this paper, a 4-pole 16-tooth VR resolver is proposed with the novel sinusoidal-reluctance rotor contour, and its operation feasibility is evaluated via the analytical investigation and finite element (FE) analysis. Considering the slot and air-gap flux leakage, the original third-order harmonic from the sinusoidal-reluctance rotor contour can be compensated to suppress the total harmonic distortion (THD) in the envelope. And the magnitude of the compensation third-order harmonic can be regulated by adjusting the tooth width. Under 4 mm tooth width, the THD of the cosine envelope with the proposed rotor contour can be limited to only 0.54%, and the angle error can also be restricted to only 0.012 degree (0.72 arc min).

Low-Latency Beaming Display: Implementation of Wearable, 133 $\mu$s Motion-to-Photon Latency Near-eye Display.

This paper presents a low-latency Beaming Display system with 133 μs motion-to-photon (M2P) latency, the latency from head motion to the corresponding image motion. Beaming Display is a recent near-eye display paradigm consisting of a steerable remote projector and a passive wearable headset that aims to overcome the typical trade-offs of OST-HMDs such as weight and computational resources. However, because Beaming Display projects a small image onto a distant moving viewpoint, M2P latency has a significant effect on displacement. To reduce M2P latency, we propose a low-latency Beaming-Display system that can be modularized without expensive high-speed devices. In our system, a 2D position sensor, which is placed coaxially on the projector, detects the light from the IR-LED on the headset and generates a differential signal for tracking. Analog closed-loop control of the steering mirror based on this signal keeps projecting images onto the headset. We implement a proof-of-concept prototype, evaluate the latency and augmented reality experience through a user-perspective camera, and discuss the limitations and improvements of the prototype.

Fault Tolerant Brushless DC Motor Drive for Aerospace Applications

This article brings out a Fault-tolerant BLDC motor drive for aerospace applications using the redundancy concept. In a way, it brings out a fault-tolerant strategy that can be used to continue the regular operation of a BLDC motor drive even after the occurrence of faults. As BLDC motors are used in critical and dangerous control areas like military services and space vehicles, a fault-tolerant drive is essential to maintain drive operation and provide desirable output. This article compares fault simulation results in the software model of a BLDC motor drive to those of fault simulation results in hardware for three main types of faults. Fault simulation is carried out for three types of faults, viz. inverter device open circuit fault, motor winding open circuit fault, and rotor position sensor (hall sensor) open-circuited fault. Fault tolerance is ensured by introducing a redundant drive (drive-2), which operates the complete drive at the advent of any of the faults mentioned above in the main (healthy) drive-1. A fault-tolerant (redundant) hardware comprising dual stator BLDC motor and redundant controllers is realized and operationalized. Fault simulation is carried out in this hardware, and these results are validated with the results of fault simulation in the MATLAB SIMULINK model. Software and hardware results are comparable and form a basis for developing fault-tolerant electro-mechanical actuation systems for high-reliability, high-cost applications, mainly aerospace.

A commercial fluorine membrane-based triboelectric nanogenerators for self-powered attitude sensors

A commercial fluorine membrane-based triboelectric nanogenerators for self-powered attitude sensors

Cyber-Physical Multi-Robot Formation: Virtual Agents Approach and Low-Cost Experiments

A cyber-physical formation includes all the strategies to coordinate mobile robots moving in different physical workspaces sharing information through internet and the cloud. This work addresses a formation scheme of robots moving in two different workspaces. The control strategy is based on virtual agents used like ”avatars” which must converge to the position of the robots in the opposite workspace. The control approach is designed for robots modeled as single integrators and extended to the case of unicycle-type robots. Results of numerical simulations and real experiments are shown using a low-cost cyber-physical micro-robot platform based on a camera as position and orientation sensor.

Permanent Magnet with Direct Drive Synchronous Wind Turbine Generator System

This postulation illustrated a control framework for an immediate drive permanent magnet coordinated generator wind turbine system, with the goal of maximising the efficiency of this framework and capturing the maximum amount of wind energy. Additionally, in order to decrease the electric speed sensor installed on the rotor shaft of the PMSG (Permanent Magnet), as well as to reduce the complexity of the framework equipment and increase the stability of the framework, a sliding mode eyewitness-based PM rotor position and speed sensor less control calculation is shown here.The wind turbine and the permanent magnet combination machine with PMSG simulation models are first built in this proposal, and then largest force control calculations for this framework are presented. The best tip speed percentage based on the highest force point after control is used to achieve the strongest catch for the framework.

A novel data acquisition approach for valves in industrial refrigeration

In this paper, a novel method is introduced for the acquisition and transmission of critical parameters from valves used in industrial refrigeration. The parameter sensing provides local intelligence to the valve, which can be later used as a feedback signal for the controller. The hardware design includes ICS (Industrial Control Servo) valve with modifications to connect a Linear Variable Transformer (LVT) position sensor, pressure and temperature sensors. Also, a circuit board carrying the phase shift oscillator, Root Mean Square (RMS) to Direct Current (DC) converter, power supply and a dedicated Bluetooth Low Energy (BLE) module for transmitting the collected data is designed. The transmitted data can be received in a mobile phone android application and used for a secondary data calculation, alarm notification and alerting service technician. The sensor integration along with BLE connectivity creates a novel platform for data acquisition in Industrial Refrigeration (IR). The proposed method tested in real time to regulate the Helium gas flow rate and measured valve parameters is monitored by the dedicated mobile application.

Development and Testing of a Soft Exoskeleton Robotic Hand Training Device.

Hand-function recovery is often a goal for stroke survivors undergoing therapy. This work aimed to design, build, and verify a pneumatic hand training device for its eventual use in post-stroke rehabilitation. The system was built considering prior research in the field of robotic hand rehabilitation as well as specifications and design constraints developed with physiotherapists. The system contained pneumatic airbag actuators for the fingers and thumb of the hand, a set of flex, pressure, and flow sensors, and software and hardware controls. An experiment with the system was carried out on 30 healthy individuals. The sensor readings were analyzed for repeatability and reliability. Position sensors and an approximate biomechanical model of the index finger were used to estimate joint angles during operation. A survey was also issued to the users to evaluate their comfort levels with the device. It was found that the system was safe and comfortable when moving the fingers of the hand into an extension.

Hybrid trust-based secure routing protocol for detection of routing attacks in environment monitoring over MANETs

Maintaining a healthy environment requires constant vigilance. Keeping constant tabs on environmental factors might be a useful tool in the fight against and recovery from environmental degradation. It is possible to send environmental data from strategically positioned sensors that monitor the surrounding circumstances. Environmentalists are the first to arrive at a disaster site, assess the situation, and take corrective measures. To get information from the sensors, they must coordinate with one another. Remote environmental sensing, the tracking from several physical systems, as well as risk assessment and management, have all seen significant improvements as a result of the use of these networks, which are comprised of many dispersed devices, each of which includes sensing, processing, and wireless technology capabilities. To facilitate communication between sensors and ecologists, the authors of this research suggest the usage of MANETs. To address these issues, a hybrid trust-based secure routing protocol is designed. Firstly, nodes are clustered using the Skill Optimization Technique. The Direct and Indirect (Hybrid) trust is computed using the Deep Q-Learning technique and then Routing is established using Diffusion Convolutional Neural Networks. With these methods, routing attacks such as Black Hole, Gray hole, and Wormhole attacks are identified and compared with the traditional security protocols using network simulation tools.