A Study on a New Independent Metering Valve for Hydraulic Boom Excavator

Nowadays, hydraulic excavators are an indispensable part of the construction industry; however, conventional hydraulic excavators consume a great deal of fossil fuel and release a large amount of pollution emissions into the environment. This causes many unwanted costs, therefore, effective solutions are required to solve the above-mentioned problems. In this paper, a new independent metering system is proposed to improve energy-saving and reduce costs of a conventional system. In detail, a directional valve is used to control movement and three electro-hydraulic poppet valves are integrated to adjust the flow rate at the inlet and outlet ports of the boom cylinder. In addition, a control strategy based on the coordination between the speed of the pump and the opening area of the spool valve is designed to improve the performance of the system. Specifically, the valves are controlled based on the strategy that the meter-in valve is opened fully to reduce throttling losses and that the meter-out valve is controlled to reduce leakage. The speed of the pump is adjusted according to the feedback position signal. To demonstrate the effectiveness of the new configuration, a real test bench of the boom system was built under laboratory conditions. From the experimental results, the new independent metering valve system not only works with a high tracking precision, but it also reduces energy consumption. Compared with a conventional independent metering system, the fuel economy of the proposed structure can achieve a reduction of approximately 6.5%.

P028 The Nox A1 ambulatory system is reliable when self-applied

Background Home Sleep Apnea Tests (HSAT) increases access to SDB diagnostic testing (Safadi, 2014). A previous study defined a reliable HSAT if: ≥4hours total recording time, an intelligible position signal and respiratory effort, airflow and oximetry for at least 80% of the night were recorded, however, admits no standardized criteria in the literature (Domingo, 2010). Aim To test the reliability of a self-applied HSAT using the Nox-A1 ambulatory system (NOX Medical, Iceland). Method Patients self-applied the HSAT guided by industry produced video and written instructions. Signals for the HSAT included; two electro-occulagrams (EOG), two sub-mental electromyograms (EMG), a single modified frontal encephalogram (EEG), a lead I ECG, single leg anterior tibialis EMG, chest and abdominal inductance respiratory effort, nasal pressure airflow, WristOx 2 3150 SpO2 (Nonin Medical, Inc., USA) and 3-D accelerometer and body position sensor. Analysed with ProFusion PSG 4 (Compumedics Limited, Australia) after importing data into Nexus. 33 consecutive studies were recorded during lock-down. Recording satisfactory if SpO2 signal and EEG present >80% of study, it was considered a failure if doctor requested test repeat. Results 33 subjects, age 43.1 ± 13.7 years, BMI 27.4 ± 6.0 kg/m2, 66.6% male. 81.8% of studies satisfactory. 6% of studies needed a repeat in-lab PSG due to 1) loss of oximetry & EEG and 2) loss of EEG Discussion 6% doctor request repeat in-lab PSG is comparable to a study (Lloberes, 2001) of partially self-applied HSAT. Demonstrated good reliability with this self-applied COVID-safe method of HSAT.

Sensor fusion approach for shape estimation of a base-excited cantilever beam

In smart structures, achieving a reliable set of measurement signals to monitor the system’s performance is critical. Also, the essence of using the optimum batch of sensors and an efficient algorithm to process these signals is significant for active vibration control of these structures. This paper primarily introduces a method of sensor fusion using the Kalman filter as an observer to gain the proper position signal from both an accelerometer and an ultrasonic sensor mounted on the tip of a cantilever beam. The main goal of this procedure is to eliminate both sensors’ shortcomings. Also, we present a novel approach to estimate the overall shape of the beam, using only the tip position signal. To this end, a high-speed camera is used to capture the motion of three markers on the beam under different excitation frequencies. Then, three long short-term memory networks are trained by deep learning methods, using a finite sequence of beam tip position, to act as observers for estimating the shape of the beam. The proposed methods are simulated and then validated by experiments.

Fault Tolerant and Nano Displacement Drive Control Method of Photoelectric Motor for Battery Electric Vehicle

The low-resolution photoelectric position sensor is used, that is, Hall position sensor replaces the traditional photoelectric encoder and other high-resolution position sensors to monitor the rotor position. However, because the three-phase Hall position sensor can only output six position signals, a hardware circuit design of low-resolution position sensor monitoring rotor position signal is proposed. Meanwhile, nanotechnology has been introduced in the study of micro drive of battery electric vehicle (BEV). BEV driver has some disadvantages such as hysteresis, creep and nonlinearity, which seriously affects its application in nano environment. A nano displacement sensor is designed for the characteristics of BEV driver. The nonlinear problem of micro driver is solved through the closed-loop control of position feedback. In the test, through the verification of rotor position and current waveform, it can be proved that the method based on photoelectric position sensor and rotor position signal monitoring can ensure the low deviation of rotor position calculation and correct output signal of three-phase photoelectric position sensor. The decoupling performance of vector control is verified by 3/2 transformation. In the displacement detection of micro driver, the designed nano displacement sensor has higher resolution and its performance is better than that of the previous three generations of displacement sensors.

A method to solve the problem of low precision of micro stabilized platform caused by frame coupling - Based on Fuzzy PID

Aiming at the problem of low control efficiency of small stable platform due to frame coupling, an intelligent control algorithm (fuzzy-PID) combining fuzzy controller with traditional PID is designed. The fuzzy PID controller is added to the position closed loop of the stable platform control system, and the motor position signal is collected and analyzed. Compared with the traditional PID control algorithm, the fuzzy PID control algorithm has the advantages of small overshoot, high control precision and strong anti-interference ability. The simulation test in Simulink environment shows that the overshoot of the system is reduced under the algorithm σ, which can be controlled within 1% and the adjusting time t is controlled within 0.5s, which can realize the stable control of the yaw angle, pitch angle and roll angle of the stabilized platform.

Implementation of Singular Spectrum Analysis in Industrial Robot to Detect Weak Position Fluctuations

A fault or mechanical flaw causes several feeble swings in the position signal. Identification of such swings by encoders can help to identify machine performance and health status and provide a convenient alternative to a vibration-based monitoring system. In operations, the trend is usually several orders higher than the interested magnitude swings, thus increasing the difficulty of identifying feeble swings without signal deformity. Moreover, the swings can be intricate, and the amplitude can be changed under a nonstationary operating condition. Singular spectrum analysis (SSA) for detecting feeble position swings from the rotary encoder signal is suggested in this paper to address this issue. It allows the complex signal of the encoder to be reduced to a variety of explainable noise-containing components, a collection of periodic oscillations, and a trend. The numerical simulation reveals the achievement of the technique. It demonstrates that the SSA is superior to the empirical mode decomposition in terms of accuracy and ability. In addition, rotary encoder signals from the robot arm are evaluated to identify the causes of oscillation at junctions during industrial robot movements. The proposed route for the robotic arm is proven to be feasible and reliable.

Uniform robust exact differentiator-based output feedback adaptive robust control for DC motor drive systems

This paper studies a high-accuracy motion control method named output feedback adaptive robust control for a dc motor with uncertain nonlinearities and parametric uncertainties, which always exist in physical servo systems and deteriorate their tracking performance. As only position signal is measurable, a uniform robust exact differentiator (URED) for the unmeasurable states and adaptive control for the parametric uncertainties are integrated in the model compensation term; and the robust control is applied to handle uncertain nonlinearities and stabilize the system. Then, the stability of the closed-loop system is proved theoretically. Finally, simulation and experimental results are studied for a dc motor system to prove the control performance of the proposed control method.