Robust Control of Automotive Active Seat-Suspension System Subject to Actuator Saturation

This paper deals with the problem of robust sampled-data control for an automotive seatsuspension system subject to control input saturation. By using the nature of the sector nonlinearity, a sampled-data based control input saturation in the control design is studied. A passenger dynamic behavior is considered in the modeling of seat-suspension system, which makes the model more precisely and brings about uncertainties as well in the developed model. Robust output feedback control strategy is adopted since some state variables, such as, body acceleration and body deflection, are unavailable. The desired controller can be achieved by solving the corresponding linear matrix inequalities (LMIs). Finally, a design example has been given to demonstrate the effectiveness and advantages of the proposed controller design approach

Nondestructive defect detection in castings by using spatial attention bilinear convolutional neural network

X-ray images of castings are widely used in manufacturing for quality assurance. This article investigates the X-ray-image-based defective detection. The main contributions in this article are twofold: first, a new full-image method is proposed to classify defective castings and nondefective ones; and second, by combining two technologies, spatial attention mechanism and bilinear pooling used in deep convolutional neural networks (CNNs), a new spatial attention bilinear CNN is proposed to enhance the representation power of CNN. To validate the above initiatives, extensive experimental studies have been carried out to show the advantages of the new method over a number of existing ones

Analysis and synthesis of randomly switched systems with known sojourn probabilities

In this paper, a new approach is proposed and investigated for the stability analysis and stabilizing controller design of randomly switched linear discrete systems. The approach is based on sojourn probabilities and it is assumed that these probabilities are known a prior. A new Lyapunov functional is constructed and two main theorems are proved in this paper. Theorem 1 gives a sufficient condition for a switched system with known sojourn probabilities to be mean square stable. Theorem 2 gives a sufficient condition for the design of a stabilizing controller. The applications of these theorems and the corresponding corollary and lemma are demonstrated by three numerical examples. Finally, some future research is proposed

Improved delay-dependent robust stabilization conditions of uncertain T-S fuzzy systems with time-varying delay

This paper aims to develop simplified yet improved delay-dependent robust control for uncertain T-S fuzzy systems with time-varying delay. This is achieved through constructing new Lyapunov-Krasovskii functionals and improving Jensen's inequality. Unlike existing work in this area, the approach developed in this paper employs neither free weighing matrices nor model transformations. As a result, simplified yet improved stability conditions are obtained for T-S fuzzy systems with norm-bounded-type uncertainties. For controller synthesis of the fuzzy systems, the stabilization problem with memoryless state feedback control is solved via utilizing a cone complementarity minimization algorithm. Numerical examples are given to demonstrate the effectiveness of the proposed approach

Event-Based H

In order to save network resources and network bandwidth, this paper proposed an event triggered mechanism based on sampled-data information, which has some advantages over existing ones. Considering the missing sensor measurements and the network-induced delay in the transmission, we construct a new event-based H∞ filtering by taking the effect of sensor faults with different failure rates. By using the Lyapunov stability theory and the stochastic analysis theory, sufficient criteria are derived for the existence of a solution to the algorithm of the event-based filter design. Finally, an example is exploited to illustrate the effectiveness of the proposed method

Fault-Distribution Dependent Reliable Control for T-S Fuzzy Time-Delayed Systems

The problem of reliable control for T-S fuzzy time-delayed systems is investigated in this paper. A more practical and general actuator-fault-model is proposed by assuming that actuators fault obeys a certain probabilistic distribution. In order to get less conservative results, the state-delay is segmentalized into several continuous equivalent subintervals in constructing the Lyapunov function and stochastic fault information is also introduced in deriving the results. Sufficient conditions for the existence of reliable controller are expressed by a set of linear matrix inequalities. Illustrative examples are exploited to show the effectiveness of the proposed design procedures

A delay system method for designing event-triggered controllers of networked control systems

This note is concerned with event-triggered H∞ controller design for networked control systems. A novel event-triggering scheme is proposed, which has some advantages over some existing schemes. A delay system model for the analysis is firstly constructed by investigating the effect of the network transmission delay. Then, based on this model, criteria for stability with an H∞ norm bound and criteria for co-designing both the feedback gain and the trigger parameters are derived. These criteria are formulated in terms of linear matrix inequalities. Simulation results have shown that the proposed event-triggering scheme is superior to some existing event-triggering schemes in the literature

Modified minimally invasive laparoscopic peritoneal dialysis catheter insertion with internal fixation

AbstractBackground Laparoscopic technique is widely used in peritoneal dialysis (PD) catheter placement. We developed a modified minimally invasive laparoscopic PD catheter (PDC) insertion with internal fixation and evaluated the early results by observing the intraoperative and postoperative conditions of the novel technique with those of conventional open surgery.Methods Retrospective research was performed on 59 patients who underwent PDC insertion from June 2019 to January 2022, including 23 patients who received open surgery and 36 patients who received modified minimally invasive laparoscopic surgery. Information such as preoperative conditions, operation time, incision length, incidence of intraoperative complications, time from operation to starting PD, time from operation to discharge, and incidence of catheter-related complications were collected and analyzed.Results The incision length, intraoperative blood loss, catheter migration rates and the total incidence of complications 6 months after operation in the laparoscopic group were lower than those in the conventional group. There were no statistically significant differences between the two groups in operation time, time from operation to starting PD, time from operation to discharge and the incidence of catheter blockage, leakage, exit-site infection, peritoneal dialysis associated peritonitis and hernia.Conclusions Modified minimally invasive laparoscopic PDC insertion and internal fixation method achieved direct vision and reliable fixation of the catheter, significantly reduced incision length and blood loss. The incidence of catheter migration was significantly lower than that of open surgery. Our primary findings reveal that modified minimally invasive laparoscopic PDC insertion with internal fixation is safe, effective and beneficial for PD patients