基于改进势场法的可变形机器人路径规划研究

采用传统的势场法对机器人进行路径规划时,如果目标位置处在障碍物产生的斥力影响范围内,由于斥力大于引力机器人很难到达目标,为此本文提出了一种改进的势场法。该算法通过机器人向着合势能最小的方向运动完成路径规划。并对目标产生的引力做了进一步的改进,解决了目标不可达问题。同时改进的方法不会增加计算量,保证了算法的实时性。仿真实验证明了机器人能够避开障碍顺利到达目标,验证了改进算法的有效性。

蛇形机器人水下蜿蜒运动的仿真研究

该文对中国科学院沈阳自动化所研制的水陆两栖蛇形机器人的水下蜿蜒运动进行受力分析并用ADAMS做了动力学仿真。从关节角函数的幅值、频率和体内形成波的个数三个方面对蛇形机器人前进速度的影响进行了仿真,得出以下结论:存在一个最优关节角函数幅值,使得蛇形机器人前进速度达到最大;增加频率和在满足形成蛇形曲线的体内形成波个数的情况下减少形成波的个数会使机器人前进的速度增加。

基于加速度反馈的柔性关节机械臂接触力控制

针对柔性关节机械臂从自由空间运动控制过渡到约束空间力控制的过程中,存在冲击、震荡甚至不稳定等问题,利用加速度传感器反馈控制,为柔性关节机械臂的接触力控制在较宽的带宽内提供阻尼,克服了利用单纯速度反馈控制带宽窄的局限。对柔性关节机械臂的接触力控制进行建模和基于加速度反馈的控制策略分析,并在柔性关节机械臂上进行了接触力控制的试验研究。结果表明,这种方法有效。

地幔压力下CaSiO3 Perovskite状态方程和弹性常数的第一性原理研究

In the past decade density functional theory (DFT) has made its way from a peripheral position in quantum chemistry to center. Of course the often excellent accuracy of the DFT based methods has provided the primary driving force of this development. This dissertation is devoted to the study of physical and chemical properties of planetary materials by first-principle calculation. The concerned properties include the geometry, elastic constants and anisotropy. In the first chapter, we give a systematic introduction to theoretical background and review its progress. Development of quantum chemistry promotes the establishment of DFT. Theorem of Hohenberg-Kohn is the fundament of DFT and is developed to Kohn-Sham equation, which can be used to perform real calculations. Now, new corrections and extensions, together with developed exchange-correlation, have made DFT more accurate and suitable for larger systems. In the second chapter, we focus on the calculational methods and technical aspects of DFT. Although it is important to develop methods and program, external package are still often used. At the end of this chapter, we briefly some widely used simulation package and the application of DFT. In the third chapter, we begin to focus on properties of real materials by first principles calculation. We study a kind of minerals named Ca perovskite, investigate its possible structure and anisotropy at Earth’s mental condition. By understanding and predicting geo-physically important materials properties at extreme conditions, we can get the most accurate information to interpret seismic data in the context of likely geophysical processes.