Modeling and Analyses of the N-link PenduBot
As the foundation of the multi-link PenduBot control, the mathematical model should be established first. Based on the method of kinematics and dynamics, the N-link PenduBot mathematical models are established in this paper, including the nonlinear model, the linear model and the generalized model which considers the motor characteristic. The natural characteristic of the system is analyzed. By using the condition number of the controllability matrix, the control difficulty for the higher order systems is compared. From the comparison result, the control law of the different links PenduBot is obtained. Increasing with the count of PenduBot links, the control difficulty is growing dramatically. Only a strong control measure can make it stable. So, further study on multi-link PenduBot can be carried on.
Research on Control Problem of PenduBot Based on PSO Algorithm
PenduBot is a new experiment object in the control theory and a typical representation in the underactuated robot, so it is the research focus of control and robot domain. It is known for its strongly nonlinear and naturally unstable properties. To stabilize the PenduBot and verify the control abilities of the algorithm on strongly nonlinear and naturally unstable properties, the thesis presents the purpose that the state-feedback matrixes can be optimized by new bionics algorithm PSO. Based on the introduction of standard PSO algorithm, how to select the position and velocity evolution equations parameters and fitness function became a great emphasis. Next, the simulations were done on the linearized PenduBot model in MATLAB environment by PSO and LQR algorithm separately, and the results were compared. Finally, the comparison results proved the PSO advantages. The expected goal was achieved.
Recent progress in engineering near-infrared persistent luminescence nanoprobes for time-resolved biosensing/bioimaging
Persistent luminescence nanoprobes (PLNPs) can remain luminescent after ceasing excitation. Due to the ultra-long decay time of persistent luminescence (PersL), autofluorescence interference can be efficiently eliminated by collecting PersL signal after autofluorescence decays completely, thus the imaging contrast and sensing sensitivity can be significantly improved. Since near-infrared (NIR) light shows reduced scattering and absorption coefficient in penetrating biological organs or tissues, near-infrared persistent luminescence nanoprobes (NIR PLNPs) possess deep tissue penetration and offer a bright prospect in the areas of in vivo biosensing/bioimaging. In this review, we firstly summarize the design of different types of NIR PLNPs for biosensing/bioimaging, such as transition metal ions-doped NIR PLNPs, lanthanide ions-doped NIR PLNPs, organic molecules-based NIR PLNPs, and semiconducting polymer self-assembled NIR PLNPs. Notably, organic molecules-based NIR PLNPs and semiconductor self-assembled NIR PLNPs, for the first time, were introduced to the review of PLNPs. Secondly, the effects of different types of charge carriers on NIR PersL and luminescence decay of NIR PLNPs are significantly emphasized so as to build up an in-depth understanding of their luminescence mechanism. It includes the regulation of valence band and conduction band of different host materials, alteration of defect types, depth and concentration changes caused by ion doping, effective radiation transitions and energy transfer generated by different luminescence centers. Given the design and potential of NIR PLNPs as long-lived luminescent materials, the current challenges and future perspective in this rapidly growing field are also discussed.