摘要：An attitude and heading reference system (AHRS) is a nonlinear state estimator unit for computing orientation in 3D space. This paper designs an AH RS using three approaches: an in variant observer, an invaria nt exte nded Kalman filter (IEKF), and a conventional extended Kalman filter (EKF). The three designs are validated in experiment versus a ground truth, dem on strati ng the practical interest of the invariant observer methodology and the advantage of the IEKF over the EKF under model uncertainty.

摘要：This paper presents a nonlinear robust control design method for a generic rotorcraft unmanned aerial vehicle(RUAV). The control objective is to let the RUAV track some pre-defined time-varying position and heading trajectories. The proposed controller employs feedback linearization process to realize the dynamic decoupling control and applies adaptive sliding mode control to compensate for the parametric uncertainties and external disturbances. The global asymptotical stability is proved via stability analysis. Compared with the cascaded controller, the proposed controller demonstrates a superior tracking performance and robustness through numerical simulation in the presence of parametric uncertainties and unknown disturbances.

摘要：This study evaluates the seismic response of an existing two stories RC building using non-linear analysis. The original model was resized and there were obtained two buildings designed under two different methodologies to fulfill the Venezuelan codes requirements for a high seismic hazard. An elastic analysis was applied to the original building in order to verify interstory drifts;the resizing building it was designed under requirements of strong column-wake beam condition. A third building was modeled according to the seismic displacement design procedure. It were performed non-linear static analysis and 2D and 3D dynamic analyses, obtaining capacity curves, structural ductility, structural performance point, global and interstory drifts for each building. Torsional effects for the resizing building were also computed from 3D analysis. In the original building it was obtained a weak seismic behavior, while resized buildings presented good seismic performance under the Limits States evaluated in this study.

摘要：This paper proposes a Genetic Programming based algorithm that can be used to design optimal controllers. The proposed algorithm will be named a Multiple Basis Function Genetic Programming (MBFGP). Herein, the main ideas concerning the initial population, the tree structure, genetic operations, and other proposed non-genetic operations are discussed in details. An optimization algorithm called numeric constant mutation is embedded to strengthen the search for the optimal solutions. The results of solving the optimal control for linear as well as nonlinear systems show the feasibility and effectiveness of the proposed MBFGP as compared to the optimal solutions which are based on numerical methods. Furthermore, this algorithm enriches the set of suboptimal state feedback controllers to include controllers that have product time-state terms.

摘要：To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this *** spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its *** can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical *** a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is *** results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure *** spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.

摘要：Based on the feedback linearization technique, we present a systematic design method for the General Integral Control and a new integral control strategy along with a class of fire-new integrator. By using the linear system theory and Lyapunov method along with LaSalle’s invariance principle, the conditions on the control gains to ensure regionally as well as semi-globally asymptotic stability are provided. Theoretical analysis and simulation results demonstrated that: by using this design method, General Integral Control can deal with nonlinearity and uncertainties of dynamics more effectively;the optimum response can be achieved in the whole control domain, even under uncertain payload and varying-time disturbances. This means that General Integral Control has strong robustness, fast convergence, good flexibility, and then makes the engineers design a high performance controller more easily.

摘要：This paper proposes a systematic method to design general integral control with the generic integrator and integral control action. No longer resorting to an ordinary control along with a known Lyapunov function, but synthesizing singular perturbation technique, mean value theorem, stability theorem of interval matrix and Lyapunov method, a universal theorem to ensure regionally as well as semi-globally asymptotic stability is established in terms of some bounded information. Its highlight point is that the error of integrator output can be used to stabilize the system, just like the system state, such that it does not need to take an extra and special effort to deal with the integral dynamic. Theoretical analysis and simulation results demonstrated that: general integral controller, which is tuned by this design method, has super strong robustness and can deal with nonlinearity and uncertainties of dynamics more forcefully.

摘要：Electronic throttle control (ETC) system has worked its way to becoming a standard subsystem in most of the current automobiles as it has contributed much to the improvement of fuel economy, emissions, drivability and safety. Precision control of the subsystem, which consists of a dc motor driving a throttle plate, a pre-loaded return spring and a set of gear train to regulate airflow into the engine, seems rather straightforward and yet complex. The difficulties lie in the unknown system parameters, hard nonlinearity of the pre-loaded spring that pulls the throttle plate to its default position, and friction, among others. In this paper, we extend our previous results obtained for the modeling, unknown system parameters identification and control of a commercially available Bosch’s DV-E5 ETC system. Details of modeling and parameters identification based on laboratory experiments, data analysis, and knowledge of the system are provided. The parameters identification results were verified and validated by a real-time PID control implemented with an xPC Target. A nonlinear control design was then proposed utilizing the input-output feedback linearization approach and technique. In view of a recent massive auto recalls due to the controversial uncontrollable engine accelerations, the results of this paper may inspire further research interest on the drive-by-wire technology.

摘要：There are large errors of linear measurement when the thermocouple measure temperature as temperature *** order to improve the measurement precision,the sensor cold junction compensation and nonlinear compensation are usually *** the circumstances that the cold junction’s temperature is determinate,there is biggish nonlinear between thermoelectric power and temperature signals of the thermocouple sensor’s *** order to solve the problem,this paper proposed a practical method of linear compensation,introduced the principle of linear compensation and gave the corresponding compensation circuit and circuit *** circuit has the characteristic of simpleness,high reliability,small linear error and so on.