排序方式: 共有10条查询结果,搜索用时 15 毫秒
1
1.
袁德虎 《内蒙古广播与电视技术》2013,(1):95-97
天线系统的好坏对通信质量的影响不可忽视,定期维护是非常必要的。文章较详细的介绍了天线的输入阻抗、天线的极化方式和天线增益对传输效果的影响,所以,定期维护是非常必要的。 相似文献
2.
基于NTG(Nonlinear Trajectory Generation)软件包提出了一种机器人yoyo运动实时最优轨迹生成的通用方法,即数值解法,该方法也可以应用于其他类似周期性动态系统的轨迹规划问题。对于这类系统的实时最优控制来说,一个最为关键的问题就是如何实现快速求解最优轨迹,以满足实时性要求。而传统的数值求解方法都很费时。通过把最优问题映射一个较低维的空间进行求解,并且利用多线程编程技术,大大减少了计算所用的时间。仿真结果显示所求得的数值解与解析解完全相同,这也验证了该方法的正确性。单循环yoyo仿真的计算时间为10 ms左右,这表明该方法完全可以应用于实时控制。 相似文献
3.
依据ISO19973-4:2007设计了一种减压阀可靠性试验平台,并介绍了其气动回路、电气控制回路以及测控软件系统。利用该平台可方便地进行减压阀的可靠性试验,可获得减压阀自开始试验到出现故障为止的全部有效试验数据,并自动绘制压力波形。长期的试验结果证明,该试验平台稳定性好、精度高、具有明显的节能优势。 相似文献
4.
5.
A general approach for controlling of periodical dynamic systems was presented by taking robotic yoyo as an example. The height
of the robot arm when the yoyo arrives at the bottom was chosen as virtual control. The initial amplitude of yoyo could be
mapped to the desired final amplitude by adjusting the virtual control. First, the yoyo motion was formulated into a nonlinear
optimal control problem which contained the virtual control. The reference trajectory of robot could be obtained by solving
the optimal problem with analytic method or more general numerical approach. Then, both PI and deadbeat control methods were
used to control the yoyo system. The simulation results show that the analytic solution of the reference trajectory is identical
to the numerical solution, which mutually validates the correctness of the two solution methods. In simulation, the initial
amplitude of yoyo is set to be 0.22 m which is 10% higher than the desired final amplitude of 0.2 m. It can be seen that the
amplitude achieves the desired value asymptotically in about five periods when using PI control, while it needs only one period
with deadbeat control. The reference trajectory of robot is generated by optimizing a certain performance index; therefore,
it is globally optimal. This is essentially different from those traditional control methods, in which the reference trajectories
are empirically imposed on robot. What’s more, by choosing the height of the robot arm when the yoyo arrives at the bottom
as the virtual control, the motion of the robot arm may not be out of its stroke limitation. The proposed approach may also
be used in the control of other similar periodical dynamic systems. 相似文献
6.
7.
8.
本文介绍了通过改换天馈线系统的扩大接收范围,提高了辐射的最大范围,从而保证了电视节目播出的不间断、高质量. 相似文献
9.
10.
1