Shared human–robot path following control of an unmanned ground vehicle

This paper considers the shared path following control of an unmanned ground vehicle by a single person. A passive measure of human intent is used to blend the human and machine inputs in a mixed initiative approach. The blending law is combined with saturated super-twisting sliding mode speed and heading controllers, so that exogenous disturbances can be counteracted via equivalent control. It is proven that when the proposed blending law is used, the combined control signals from both the human and automatic controller respect the actuator magnitude constraints of the machine. To demonstrate the approach, shared control experiments are performed using an unmanned ground vehicle, which follows a lawn mower pattern shaped path.     

Trajectory-Shaping Guidance with final speed and load factor constraints

This paper describes the design of a guidance law used for guiding a hypersonic gliding vehicle against a ground target from a near-vertical orientation with a specified final speed and a near-zero final load factor. The guidance law consists of two terms: one is Trajectory-Shaping Guidance (TSG) used for steering the vehicle to the target from the specified orientation; the other is Final-Speed-Control Scheme (FSCS) used for controlling the vehicle to perform lateral maneuver to adjust the final speed. Further, the generalized closed form solutions of TSG are obtained from a more general linearized engagement model, where the speed of the vehicle can be an arbitrary positive function of time. By analyzing these solutions, the stability domain of the guidance coefficients is obtained such that the final load factor is zero. This domain is not affected by the change rate of the speed. Thus, according to this analysis, the proposed guidance law can achieve a near zero final load factor by properly selecting the guidance coefficients in the stability domain.     

Human–machine shared control for lane departure assistance based on hybrid system theory

To improve the human–machine cooperation of lane departure assistance system (LDAS), a human–machine shared control strategy based on hybrid system theory was proposed. By considering vehicle’s discrete and continuous states and time-varying longitudinal speed, the hybrid system was formalized as hybrid automaton, and the shared control strategy was built to govern the human–machine interaction. Robust gain-scheduling energy-to-peak method was adopted to design the assistance system controller. The D-stability of the system was also studied and guaranteed by solving the linear matrix inequality (LMI). The proposed human–machine shared control method was evaluated via the co-simulation of CarSim/Simulink and the hardware-in-loop (HIL) experiment. The results showed that the proposed approach can effectively keep the vehicle in lane and a good human–machine coordination was demonstrated.     

台头焦煤7202运输顺槽弱胶结围岩支护技术研究

台头焦煤7202运输顺槽进过程中存在弱胶结膨胀软岩地层,支护难度大。为解决该问题,进行耦合模拟研究,结果表明,普通锚杆支护在90 d左右时会出现巷道垮塌现象,结合顶板离层仪观测数据,表明模拟结果真实可靠。对巷道支护优化方案,采用工字钢结合管棚锚喷技术,实施完成进行效果考察,考察结果显示优化方案有效解决了弱胶结软岩支护难度大的问题。     

共用直流母线的电梯节能控制系统

电梯是使用频度较高的交通工具,每年消耗的电能是巨大的.电梯在一个上下行的运行周期中,有几乎一半的时间电梯的电机处于发电状态,这时电梯不但不需要消耗电能,而且会发出电能,传统电梯是将这部分电能经电阻白白消耗掉,从而造成了能源的浪费.为了更好地利用电机发出的电能,通过对电梯运行中能量转换过程的分析,提出了二台或多台电梯共用直流母线的节能新方式,为电梯节能控制系统的设计提供了一个选择方案.     

West 8:大众文化图景下的当代景观

West8通过他们的设计观念及作品表明．面对商业主义消费社会大众文化的平庸化侵蚀，当代景观的塑造需要一种乐观主义精神以及对于建筑、规划景观、工业设计等多学科领域的充分整合。     

Constructions and Properties of General (k,n) Block‐Based Progressive Visual Cryptography

Recently, Hou and others introduced a (2, n) block‐based progressive visual cryptographic scheme (BPVCS) in which image blocks can be gradually recovered step by step. In Hou and others’ (2, n)‐BPVCS, a secret image is subdivided into n non‐overlapping image blocks. When participants stack their shadow images, all the image blocks associated with these t participants will be recovered. However, Hou and others’ scheme is only a simple 2‐out‐of‐n case. In this paper, we discuss a general (k, n)‐BPVCS for any k and n. Our main contribution is to give two constructions (Construction 1 and Construction 2) of this general (k, n)‐BPVCS. Also, we theoretically prove that both constructions satisfy a threshold property and progressive recovery of the proposed (k, n)‐BPVCS. For , Construction 1 is reduced to Hou and others’ (2, n)‐BPVCS.]