科创中国

以南水北调中线SG09标石方开挖爆破施工为例,采用理论计算、数值分析和本工程实际施工相结合的方法,详细分析了爆破对周围环境的影响范围及安全控制措施,为类似工程的施工提供了参考.

结合南水北调天津干线工程建设管理具体工作实践,对南水北调中线天津干线施工控制体系构建、主要做法和成功经验进行了分析梳理总结,结果表明南水北调天津干线工程施工中的土方工程、混凝土工程,施工受季节影响以及施工工期受资源配置、施工方案的选择影响较大,在建设实施过程中通过合理安排施工,配置资源合理,优化施工方案,充分发挥整体钢模台车的整体优势,对加强工程实体质量控制等方面的实践是成功的,对进一步提高南水北调天津干线工程以及其它大型水利工程建设水平具有一定的借鉴意义.

Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation(RLSE) to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This paper constructs an adaptive robust controller which can compensate the friction force in the cylinder.

In the prediction of active vibration isolation performance,control force requirements were ignored in previous work.This may limit the realization of theoretically predicted isolation performance if control force of large magnitude cannot be supplied by actuators.The behavior of a feed-forward active isolation system subjected to actuator output constraints is investigated.Distributed parameter models are developed to analyze the system response,and to produce a transfer matrix for the design of an integrated passive-active isolation system.Cost functions comprising a combination of the vibration transmission energy and the sum of the squared control forces are proposed.The example system considered is a rigid body connected to a simply supported plate via two passive-active isolation mounts.Vertical and transverse forces as well as a rotational moment are applied at the rigid body,and resonances excited in elastic mounts and the supporting plate are analyzed.The overall isolation performance is evaluated by numerical simulation.The simulation results are then compared with those obtained using unconstrained control strategies.In addition,the effects of waves in elastic mounts are analyzed.It is shown that the control strategies which rely on unconstrained actuator outputs may give substantial power transmission reductions over a wide frequency range,but also require large control force amplitudes to control excited vibration modes of the system.Expected power transmission reductions for modified control strategies that incorporate constrained actuator outputs are considerably less than typical reductions with unconstrained actuator outputs.In the frequency range in which rigid body modes are present,the control strategies can only achieve 5–10 dB power transmission reduction,when control forces are constrained to be the same order of the magnitude as the primary vertical force.The resonances of the elastic mounts result in a notable increase of power transmission in high frequency range and cannot be attenuated by active control.The investigation provides a guideline for design and evaluation of active vibration isolation systems.

Dual mechanical port machine(DMPM), as a novel electromechanical energy conversion device, has attracted widespread attention. DMPM with spoke type permanent magnet arrangements(STPM-DMPM), which is one of several types of DMPM, has been of interest recently. The unique coupling characteristics of STPM-DMPM are beneficial to improving system performance, but these same characteristics increase the difficulties of control. Now there has been little research about the control of STPM-DMPM, and this has hindered its practical application. Based on a mathematical model of STPM-DMPM, the coupling characteristics and the merits and demerits of such devices are analyzed as applied to a hybrid system. The control strategies for improving the disadvantages and for utilizing the advantage of coupling are researched. In order to weaken the interaction effect of torque outputs in the inner motor and the outer motor that results from coupling in STPM-DMPM, a decoupling control method based on equivalent current control is proposed, and independent torque control for the inner motor and outer motor is achieved. In order to solve address the problem of adequately utilization of coupling, minimizing the overall copper loss of the inner motor and the outer motor of STPM-DMPM is taken as the optimization objective for optimal control, and the purpose of utilizing the coupling adequately and reasonably is achieved. The verification tests of the proposed decoupling control and optimal control strategies are carried out on a prototype STPM-DMPM, and the experimental results show that the interaction effect of torque outputs in the inner motor and the outer motor can be markedly weakened through use of the control method. The overall copper loss of the inner motor and the outer motor can be markedly reduced through use of the optimal control method, while the power output remains unchanged. A breakthrough in the control problem of STPM-DMPM is accomplished by combining the control methods. Good performance in the control of STPM-DMPM will enhance its practicality, particularly as applied to hybrid systems.

For the Cooperative Adaptive Cruise Control(CACC)Algorithm,existing research studies mainly focus on how inter-vehicle communication can be used to develop CACC controller,the influence of the communication delays and lags of the actuators to the string stability.However,whether the string stability can be guaranteed when inter-vehicle communication is invalid partially has hardly been considered.This paper presents an improved CACC algorithm based on the sliding mode control theory and analyses the range of CACC controller parameters to maintain string stability.A dynamic model of vehicle spacing deviation in a platoon is then established,and the string stability conditions under improved CACC are analyzed.Unlike the traditional CACC algorithms,the proposed algorithm can ensure the functionality of the CACC system even if inter-vehicle communication is partially invalid.Finally,this paper establishes a platoon of five vehicles to simulate the improved CACC algorithm in MATLAB/Simulink,and the simulation results demonstrate that the improved CACC algorithm can maintain the string stability of a CACC platoon through adjusting the controller parameters and enlarging the spacing to prevent accidents.With guaranteed string stability,the proposed CACC algorithm can prevent oscillation of vehicle spacing and reduce chain collision accidents under real-world circumstances.This research proposes an improved CACC algorithm,which can guarantee the string stability when inter-vehicle communication is invalid.

The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions-constant, linear, and quadratic-are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12–2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25.71–3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

The existing research of the active suspension system(ASS) mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.

江都站作为南水北调东线工程从长江取水的起点泵站,工程作用重要、运行十分频繁.本次按设计规划进行综合改造,涉及的工程数量多、范围广,施工对工程运行的影响较大,与运行的矛盾十分突出,为此,通过制订科学合理的总体实施方案、加强施工进度和安全管理、抓好工程调度运行管理、制订切实可行的应急措施等,妥善地处理了施工与运行的矛盾,在保证改造工程顺利实施的同时,工程效益也得到了充分发挥.

施工中土工膜的接缝试验检测有严格的质量标准,同时土工膜焊缝又是防渗的质量控制重点,施工中通过对土工膜检测设备的改进,缩短了土工膜的施工及焊接检测、验收的时间,保证了渠道工程的施工质量,加快了施工进度;达到了较理想的使用效果.