Testing for small-delay defects (SDDs) is necessary to ensure the quality and reliability of high-performance integrated circuits fabricated with the latest technologies. These timing defects can be caused by process variations, crosstalk, and power-supply noise, as well as by physical defects such as resistive opens and shorts. Timing-aware ATPG tools have been developed for SDD detection. However, they only use static timing analysis reports for path-length calculation and neglect important parameters such as process variations, crosstalk, and power-supply noise, which can induce small delays into the circuit and impact the timing of targeted paths. In this paper, we present an efficient pattern evaluation and selection procedure for screening SDDs that are caused by physical defects and by delays added to paths by process variations and crosstalk. In this procedure, the best patterns for SDDs are selected from a large repository test set. Experimental results demonstrate that our method sensitizes more long paths and detects more SDDs with a much smaller pattern count compared with a commercial timing-aware ATPG tool.

Power supply noise may have big impacts on the design performance in the latest technologies. Accurately mapping the IR-drop effect to real delay is a challenging task, which will directly impact the accuracy of IR-drop related performance evaluation, test, and diagnosis. In this paper, we first present our previous work on setting up an IR2Delay database for addressing this issue. We then propose a flow to validate this database by comparing it with full-circuit SPICE simulation results. In this flow, mixed-signal simulation is used, which can reuse the existing digital testbench as stimuli while maintaining the accuracy of SPICE simulation.

Drag reduction is one of the important problems for the supersonic vehicles. As one of the drag reduction methods, aerospike has been used in some equipment because of its good drag reduction effect. In this paper, the numerical simulations of Carman curve bodies with different lengths of the aerospike and different radius of the flat cylindrical aerodisk in supersonic flow freestream are investigated. Based on the numerical simulations, the mechanism of drag reduction of the aerospike is discussed. The drag reduction effect influence of the parameters of the aerodisk radius and the aerospike length on the Carman curve body is analyzed. The aerodisk radius within a certain range is helpful for the drag reduction. The change of length of the aerospike has little effect on the drag of Carmen curve bodies. The drag reduction effect of the same aerospike becomes worse with the increase of the incoming Mach number.

This paper establishes a dynamic pressure-based PID parameter adjustment method, which uses the function of the ratio of the maximum dynamic pressure of the rocket to the actual dynamic pressure of the current flight to correct the rocket control parameters. Compared with the traditional time-based PID parameter gain scheduling method, the number of PID parameters to be adjusted is significantly reduced from nearly 50 to 10, and the adjustment complexity is significantly reduced. Based on the method in this paper, the PID parameter debugging of the attitude control of a model-guided rocket is completed. The six-degree-of-freedom ballistic simulation results show that the control law obtained by the method in this paper meets the requirements of the attitude control of the model-guided rocket, and is superior to the traditional time-based PID parameter gain adjustment method in terms of response rate.

The two-dimensional axisymmetric nozzle is initialized by two methods which are the hybrid initialization method of the commercial computational fluid dynamics software Fluent and the initialization program based on the one-dimensional isentropic theory. The first-order upwind format is combined with the SA model to solve the two-dimensional axisymmetric nozzle under the same boundary conditions. The convergence process is obtained in the process of numerical calculation, and the influence of two different initialization methods on the convergence process is analysed. The results show that the initialization method based on the one-dimensional isentropic theory effectively improves the convergence of the nozzle numerical model calculation process, accelerates the convergence speed and improves the calculation efficiency.

This paper focuses on the integrated guidance and autopilot design with control input saturation in the end-game phase of hypersonic flight. Firstly, uncertain nonlinear integrated guidance and autopilot model is developed with third actuator dynamics, where the control surface deflection has magnitude constraint. Secondly, neural network is implemented in extended state observer (ESO) design, which is used to estimate the complex model uncertainty, nonlinearity and state coupling. Thirdly, a command filtered back-stepping controller is designed with hybrid sliding surfaces to improve the terminal performance. In the process, different command filters are implemented to avoid the influences of disturbances and repetitive derivation, meanwhile solve the problem of unknown control direction caused by saturation. The stability of closed-loop system is proved by Lyapunov theory, and the principles abided by the controller parameters are concluded through the proof. Finally, series of 6-DOF numerical simulations are presented to show the feasibility and validity of the proposed controller.