As the road conditions are completely unknown in the design of a suspension controller, an improved linear quadratic and Gaussian distributed (LQG) controller is proposed for active suspension system ...without considering road input signals. The main purpose is to optimize the vehicle body acceleration, pitching angular acceleration, displacement of suspension system, and tire dynamic deflection comprehensively. Meanwhile, it will extend the applicability of the LQG controller. Firstly, the half-vehicle and road input mathematical models of an active suspension system are established, with the weight coefficients of each evaluating indicator optimized by using genetic algorithm (GA). Then, a simulation model is built in Matlab/Simulink environment. Finally, a comparison of simulation is conducted to illustrate that the proposed LQG controller can obtain the better comprehensive performance of vehicle suspension system and improve riding comfort and handling safety compared to the conventional one.
For attenuating the shimmy phenomenon appeared in an electric vehicle (EV) with independent suspension, this study proposes a finite-time active shimmy stability control method based on an ...uncertainty estimation observer. Firstly, a four-degree-of-freedoms shimmy model of an EV with independent suspension is constructed. Secondly, in order to deal with the uncertainties in the shimmy model, a finite-time control method via a non-linear uncertain disturbance observer is proposed. The direct Lyapunov function method is used to analyse the global stability of the closed-loop system, and the results show that the system outputs globally converge to zero. Simulation and hardware-in-the-loop simulation test results verify the built shimmy model and show the effectiveness of the designed control method compared with the sliding mode control method.
Large truck crashes have significantly declined over the last 10years, likely due, in part, to the increased use of onboard safety systems (OSS). Unfortunately, historically there is a paucity of ...data on the real-world efficacy of these devices in large trucks. The purpose of this study was to evaluate the two OSSs, lane departure warning (LDW) and roll stability control (RSC), using data collected from motor carriers.
A retrospective cohort approach was used to assess the safety benefits of these OSSs installed on Class 7 and 8 trucks as they operated during normal revenue-producing deliveries. Data were collected from 14 carriers representing small, medium, and large carriers hauling a variety of commodities. The data consisted of a total of 88,112 crash records and 151,624 truck-years that traveled 13billionmiles over the observation period.
The non-LDW cohort had an LDW-related crash rate that was 1.917 times higher than the LDW cohort (p=0.001), and the non-RSC cohort had an RSC-related crash rate that was 1.555 times higher than the RSC cohort (p<0.001).
The results across analyses indicated a strong, positive safety benefit for LDW and RSC under real-world conditions.
The results support the use of LDW and RSC in reducing the crash types associated with each OSS.
•The current study assessed the efficacy LDW and RSC using data collected directly from motor carriers.•Lane departure warning (LDW) significantly reduced a LDW-related crashes by 1.917 times.•Roll stability control (RSC) significantly reduced a RSC-related crashes by 1.555 times.
(1) Background: The standard treatment for periodontal disease, a chronic inflammatory state caused by the interaction between biofilms generated by organized oral bacteria and the local host defense ...response, consists of calculus and biofilm removal through mechanical debridement, associated with antimicrobial therapy that could be delivered either systemically or locally. The present study aimed to determine the effectiveness of a hyaluronic acid membrane matrix as a carrier for the controlled release of the active compounds of a formulation proposed as a topical treatment for periodontal disease, and the influence of pH on the complex system's stability. (2) Methods: The obtained hyaluronic acid (HA) hydrogel membrane with dispersed melatonin (MEL), metronidazole (MZ), and tetracycline (T) was completely characterized through FTIR, XRD, thermal analysis, UV-Vis and fluorescence spectroscopy, fluorescence microscopy, zeta potential and dielectric analysis. The MTT viability test was applied to check the cytotoxicity of the obtained membranes, while the microbiological assessment was performed against strains of
spp. and
spp. The spectrophotometric investigations allowed to follow up the release profile from the HA matrix for MEL, MZ, and T present in the topical treatment considered. We studied the behavior of the active compounds against the pH of the generated environment, and the release profile of the bioactive formulation based on the specific comportment towards pH variation. The controlled delivery of the bioactive compounds using HA as a supportive matrix was modeled applying Korsmeyer-Peppas, Higuchi, first-order kinetic models, and a newly proposed pseudo-first-order kinetic model. (3) Results: It was observed that MZ and T were released at higher active concentrations than MEL when the pH was increased from 6.75, specific for patients with periodontitis, to a pH of 7.10, characterizing the healthy patients. Additionally, it was shown that for MZ, there is a burst delivery up to 2.40 × 10
mol/L followed by a release decrease, while for MEL and T a short release plateau was recorded up to a concentration of 1.80 × 10
mol/L for MEL and 0.90 × 10
mol/L for T, followed by a continuous release; (4) Conclusions: The results are encouraging for the usage of the HA membrane matrix as releasing vehicle for the active components of the proposed topical treatment at a physiological pH.
This paper presents an online dynamic event location method that uses wide-area measurements. The method is based on an offline hierarchical clustering of N generators into coherent groups. The ...clustering method can be used to produce any number of groups between 1 and N. One measurement location is selected during the offline phase to represent each cluster in the online phase. Event location is formulated as finding the most likely group from which an event originates. The rotor frequencies of the representative generators are used to identify the cluster with the largest initial swing. The method is demonstrated for locating events caused by faults and generator trips on a 176-bus model. The online location accuracy is around 80% when the offline clustering is good.
The humanoid robot has the human shape and has great advantages in assisting human life and work. The ability to work, especially in a dynamic, unstructured environment, is an important prerequisite ...for humanoid robots to assist humans in their mission. Table tennis hitting involves a variety of key technologies such as visual inspection, trajectory planning, and artificial intelligence. It is an important research example that can reflect the ability of humanoid robots. First, according to the requirements of humanoid robots in the human living environment and the requirements of coordinating table tennis batting movements throughout the body, a method of establishing a humanoid robot model was analyzed, and a control system was designed to meet the needs of rapid table tennis batting. Second, a motion model construction and optimization algorithm based on intelligent learning training is proposed. Based on the parameter knowledge base established by the multiple trajectories of table tennis, a kind of electromagnetic mechanism and D-optimality regularized orthogonal minima are introduced. Design a two-pass method (regularized orthogonal least squares method + D-optimality) to learn the two-level learning method, which is used to learn the key parameters of the table tennis model. Third, for human-like robotic table tennis fast-moving, it is necessary to satisfy both the task and the stability requirements and to propose a stability-optimized whole-system coordinated trajectory planning method. The effectiveness of the proposed humanoid robot table tennis hitting motion planning and stability control method is verified by experiments.
With the purpose of overcoming the defect that unmanned air vehicles (UAVs) are easily disturbed by air current and tend to be unstable, an augmented-stability controller was developed for a certain ...UAV’s longitudinal motion. According to requirements of short-period damping ratio and control anticipation parameter (CAP) in flight quality specifications of GJB185-86 and C*, linear quadratic regulator (LQR) theory was used in the augmented-stability controller’s design. The simulation results show that the augmented-stability controller not only improves the UAV’s stability and dynamic characteristics but also enhances the UAV’s robustness.
Conventional robotic wheelchairs (three or four-wheeled) which are statically stable are poor in mobility. Though a two-wheeled robotic wheelchair has better mobility, it is not statically stable and ...needs an active stability controller. In addition to mobility and stability, velocity control is also important for the operation of a wheelchair. Conventional stability and velocity controllers rely on the motion of the wheels and require high driving torque and power. In this paper, this problem is tackled by adding a compact pendulum-like movable mechanism whose main function is for stability control. Its motion and those of the wheels are controlled through a quasi-sliding mode control approach to achieve a simultaneous velocity and stability control with much less driving torque and power. Simulation results are presented to show the effectiveness of the proposed controller.
The paper proposes new method for assessment of power system stability. New method based on advancing approach to determination of stability limits. The paper represents more accurate and reliable ...ways to determine limits for power transmission through the grid. Nowadays, the static stability limits formed by using special software which solves nonlinear equations of the electrical system. Power systems control power flows through the power lines for avoiding black outs by using automated control systems. Automation thresholds depend on the maximum power transmitted through the line or section, and the maximum transmitted power is calculated using the iterative methods. But the calculations in this way are not sufficiently accurate and flexible, since the calculations are done for the entire system, and not for each section individually. And it means the limits on certain sections and lines can vary. The proposed method differs from the existing one in a way it determines the limits using the angle shift between the voltage phasors in the nodes in real time. It makes possible to more deeply and adaptively manage. Also proposed new control algorithms which determines stability boundaries in advance. Algorithm was verified through experimental studies on physical model of the power system.
A self-balancing platform is constructed on a robot smart car, and its navigation parameters are investigated by running the car outdoors on a straight surface with structured bumps of 3and 5 mm in ...height. A ball-and-socket joint are supported at the centre of the platform, which is to be freely rotated with the lateral and longitudinal movement of the platform and in each axis, is controlled by three servomotors. Which move according to the recorded data movements from a gyro-accelerometer sensor which controlled by an Arduino UNO. The SimMechanics Matlab simulation helps to give the initial values of all parameters and the additional unexpected signals due to the influence of bumps on the vibration signals, with the proportional-integral-derivative (PID) controller, used to control the relationship of the rapid simulation of the robot smart car and mathematical model between platform and car shock absorber system with respect to the servomotor's rotation angle. These bump is more effective on the pitch and roll angle values when compared to other parameters, with more than 815 degrees and error up to 35 degrees due to vibration signals, and the time required for stabilization increases due to the bump height and the navigation parameters, roll angle from 2 to 6 in mean change value 2, yaw angle from 43 to 59 in mean change value 8 and pitch angle from 1 to 2 in mean change value 0.5, which indicates that yaw, roll and pitch angle have variation changing in Mission Planner software
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