Weapons release at supersonic speeds from an internal weapons bay is a highly desirable capability. To ensure a successful release at multiple Mach numbers, the aerodynamic environment must be well-understood and repeatable, with a robust system for safe testing of store separation. For this reason, experimental methods were used to investigate the characteristics of a scaled WICS bay with a length-to-depth ratio of 4.5 at multiple Mach numbers and stagnation pressures. Three new nozzles were designed, manufactured, and characterized for the AFIT small supersonic tunnel, yielding freestream Mach numbers of 2.22, 1.84, and 1.43. In addition, a control valve was recon gured to achieve stagnation pressures as low as 1.0 psia. These nozzles were then used in conjunction with piezosresistive pressure transducers and high-speed Schlieren photography to capture the time-varying pressure signal and spectra of the cavity. Resonant frequencies from these tests matched very well with analytically predicted results for the Mach 2.3 and Mach 1.9 nozzles. The Mach 1.5 nozzle posed some di culties for the con guration tested due to shocks re ecting into the cavity. The Mach 2.3 nozzle was utilized in freedrop testing of a 1:20 scaled sphere and compared to computational simulations. The computational solution was obtained using the OVERFLOW solver with incorporated 6DOF motion and the DDES/SST hybrid turbulence model. Analysis of the Schlieren video generated by the experimental tests allowed direct comparison of computational and experimental trajectories. Measured trajectories compared closely to computational trajectories, especially for the lowest stagnation pressure settings, where heavy Mach scaling yielded operationally relevant results, despite the small scale of the tests.

关键词：压力传感器；谐振频率；罗斯特模式

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在柴油机润滑油中分别加入不同比例的硬脂酸甲酯、油酸甲酯和亚油酸甲酯,通过高温氧化试验对柴油机润滑油的氧化过程进行了模拟。采用旋转氧弹法和傅里叶红外光谱对柴油机润滑油的氧化诱导期和氧化衰变产物结构组成进行了试验分析。结果表明,不饱和脂肪酸甲酯的存在加速了柴油机润滑油的氧化,且不同质量等级的脂肪酸甲酯对柴油机润滑油氧化速率影响程度不同,其由大到小顺序依次为CD 15W/40+亚油酸甲酯,CD 15W/40+油酸甲酯,CD 15W/40+硬脂酸甲酯,CD 15W/40。

关键词：不饱和脂肪酸甲酯；柴油机油；氧化衰变；模拟试验

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本文提出一种基于多目标优化的纯电动车动力系统的参数匹配方法。该方法以最高车速、加速时间和100km电耗等多个整车性能指标作为优化目标,以传动比为优化变量建立参数匹配优化模型;再以该车型的最基本性能指标作为约束条件得到传动比的可行域,在可行域中采用多目标遗传算法对优化问题进行求解;求出固定传动比变速器和两挡变速器两种情况下的Pareto最优解集,作为备选方案集;综合对比不同电机的备选方案集,确定最终的参数匹配方案,并进行样车的开发。转鼓试验结果表明,所开发车辆达到设计的性能指标,验证了所提出的参数匹配方法的有效性。

关键词：纯电动车；Pareto最优解集；参数匹配；多目标优化；遗传算法

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本文中提出一种变逻辑门限值的车辆稳定性控制策略,并重点对动态逻辑门限值的确定方法进行了深入的研究,以改善不同工况下车辆的稳定性。由于逻辑门限值受到行驶环境和运动状态的影响,因此利用模糊推理的方法分别确定横摆角速度偏差和质心侧偏角变化率的门限值;然后利用逻辑门限PI控制方法计算出附加横摆力矩;最后在电控液压制动(EHB)系统中实现了附加横摆力矩。仿真结果表明,当车辆失稳时,所提出的控制策略能及时对车辆进行稳定校正控制,提高了车辆行驶的安全性。

关键词：车辆稳定性；动态逻辑门限值；模糊控制器；电控液压制动系统

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In this research effort, a Microelectromechanical system (MEMS) cantilever pressure sensor was designed, modeled, and fabricated to investigate the photoacoustic (PA) response of gases to terahertz (THz) radiation under low vacuum conditions. Previous efforts in this project were improved upon, to include lowering resting out-of-plane curvature to improve sensitivity of devices. Dimensional analysis is taken into consideration and altered dimensions also serve to boost sensitivity while improving fragility of devices. All devices were fabricated on silicon-on-insulator (SOI) wafers and tested in a custom designed THz vacuum chamber. Fabricated devices have a minimum normalized noise equivalent absorption (NNEA) coefficient of 4.28x10(- 10), an improvement of 69% on prior 10micro devices.

关键词：吸收；加速阶段；悬臂；化学检测；化学传感器

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为提高ISG混合动力汽车的燃油经济性,开展控制规则优化与转矩分配策略研究,以保证发动机工作在高效区域。从控制发动机输出负荷角度出发,综合考虑ISG效率特性和电池组充放电特性,对发动机、ISG、电池组稳态工作区域进行划分。以混合动力系统工作模式分析为基础,提出各模式下能量管理策略,并根据车辆行驶过程中工作模式动态切换的需要,制定了模式切换策略。以IVECO并联混合动力汽车为例,按照ECE+EUDC工况进行了基于优化规则的转矩分配策略硬件在环仿真,结果表明采用基地规则的转矩分配策略能有效地协调转矩在发动机和ISG之间的分配,综合油耗比原车降低20%。

关键词：混合动力汽车；ISG；规则优化；转矩分配策略

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Impedance/admittance control algorithms are considered as key technologies in human-robot interaction and other fields of advanced robotics where complex physical interaction plays role. In this chapter, we utilize a Tensor Product (TP) Model Transformation based method to derive the delay and stiffness dependent polytopic LPV representation of the impedance controlled physical interaction. The applied transformation method is feasible with bounded delay that is the non-linear function of the environmental stiffness. Thus, the ideal transformation space is non-rectangular that makes it improper for the TP model transformation. We propose a dimensionless parametrisation to define a rectangular grid upon witch the transformation is viable. The resulted model form is promptly appropriate for the modern multi-objective LMI based control design techniques.

关键词：互动机器人；LPV/ qLPV造型；阻抗控制

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This paper proposes a method of motor-position acquisition from hall sensors installed on the mover of linear synchronous motor. The sensors are combined to Dual-rate sampling observer to estimate motor speed and position. Then this paper describes a design method of speed and position controllers for smooth transition between alternating speed and position control. And the parameters of speed controller are variable with motor speed.

关键词：直线同步电机；双速率采样观测；位置和速度控制器；霍尔传感器

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The Morpheus vertical test vehicle is an autonomous robotic lander being developed at Johnson Space Center (JSC) to test hazard detection technology. Because the initial ground contact simulation model was not very realistic, it was decided to improve the model without making it too computationally expensive. The first development cycle added capability to define vehicle attachment points (AP) and to keep track of their states in the lander reference frame (LFRAME). These states are used with a spring damper model to compute an AP contact force. The lateral force is then overwritten, if necessary, by the Coulomb static or kinetic friction force. The second development cycle added capability to use the PolySurface class as the contact surface. The class can load CAD data in STL (Stereo Lithography) format, and use the data to compute line of sight (LOS) intercepts. A polygon frame (PFRAME) is computed from the facet intercept normal and used to convert the AP state to PFRAME. Three flat plane tests validate the transitions from kinetic to static, static to kinetic, and vertical impact. The hazardous terrain test will be used to test for visual reasonableness. The improved model is numerically inexpensive, robust, and produces results that are reasonable.

关键词：荷载（部队）；多边形；机器人技术；模拟

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This study proposes a novel sliding mode control with self-turning law for nonlinear systems with time-delay and external disturbances possessing uncertain parameters. The adjustable control gain and a bipolar sigmoid function are online tuned to force the tracking error to approach zero. The proposed control scheme provides good transient and steady-state performance. Moreover as the proposed controller, the chatting phenomenon can be avoided and the problem of time-delay and external disturbances are solved for a class of nonlinear systems. The closed-loop control system stability is proved to use the Lyapunov method. Steady-state system performance and chattering are considerably improved. Numerical simulation results are given to illustrate the effectiveness of the proposed procedure.

关键词：滑模控制；自适应控制；李雅普诺夫方法；边界层

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