Abstract:A snake changes its gait to adapt to different environments. A snake-like robot that is able to perform as many or more gaits than a real-life snake has the potential to successfully adapt to a range of environments, similar to a real-life snake. However, only a few mechanisms in the current snake-like framework can perform common gaits. In this paper, a novel snake-like robot is developed to resolve this problem. A multi-gait is established and used as a reference for the articulation design. A non-snake-like mechanism with linear articulation is combined with the classical swing joint. A prototype is designed and constructed for verification and analysis. Two basic main gaits, namely, serpentine and rectilinear locomotion, are fused, and a novel obstacle-aided locomotion based on rectilinear motion is developed. The experiment demonstrates that the robot can generate all of the expected gaits with high movement efficiency.
The aims of this paper are to present a new model to calculate the maximum equilibrium road network capacity and obtain the associated optimal origin-destination (i.e. OD) flow pattern for a general road network with given network topology and link attributes. First, the Static Congested Traffic Assignment (SCTA) is introduced to describe the network where all used routes are in a congested state. Congested Equilibrium Travel Times (CETTs) between OD pairs obtained by the SCTA model are regarded as the corresponding upper limits of actual equilibrium travel times which are called Uncongested Equilibrium Travel Times (UETTs) and derived from the traditional Static Uncongested Traffic Assignment (SUTA) model. The main idea of modeling is that the total OD flows can be maximized by flexibly scaling and adjusting OD flows of each individual OD pairs to make the UETTs of all OD pairs reach their upper limits (i.e. CETTs). Next, a novel equilibrium road network capacity model is built by combining the SUTA and the SCTA models. Then, the equivalency condition and the solution uniqueness of the proposed model are proved. The paper moves on to provide two solution algorithms together with an analysis of the model characteristics. Finally, through three numerical examples, it is demonstrated that the proposed model can obtain the unique equilibrium network capacity with the given network topology and associated link attributes. The optimal OD flow pattern, which leads to the maximum total OD flows, is thus obtained. The findings in the paper can help to improve the utilization of road networks and contribute to land development planning and control.INDEX TERMS Transportation, equilibrium road network capacity, optimal origin-destination flow pattern, traffic assignment.
Gathering real-time tracking for Charge-discharge voltage and temperature values of lithium iron phosphate battery.We can take full advantage of the charge-discharge characteristics of the battery to optimize battery usage, and ultimately improve the efficiency of the battery. The battery performance test system designed in this paper is based on STC12C5A60S2 microcontroller as the microprocessor, connecting the two pieces of AD7888 chip to achieve A/D acquisition and conversion, temperature measurement is connected to the temperature sensor through analog switches CD4051, collection of data via USB bus communications chips CH340T transferred to the host computer. The internal resistance of the battery can be calculated according to the difference between the former DC discharge and post-discharge voltage, obtaining the battery capacity by using the chargedischarge current and the time, the results show: the charge and discharge of the current and voltage difference caused by its internal resistance cannot be ignored and need to real-time correction; if need fast charging, select the constant current mode; when batteries are being stored for a long time, the battery voltage should be remained in the most stable discharge interval to ensure stable performance of the battery.
To measure viscosity of magnetic fluids (MFs) in adjustable magnetic field, this paper presented a novel method using a double tube and a torque measuring motor. The inner tube was fixed and the outer tube was driven by a motor. Mathematical analysis indicated that the viscosity of MFs in the gap between the two tubes could be determined by the rotational speed. A magnetic circuit constructed by some permanent magnets and yokes provided the magnetic field for the MFs in the gap. Changing the number of the magnets could adjust the magnetic density easily. Taking the temperature's influence on the viscosity into account, an extrapolation method was adopted to measure and control the MFs' temperature precisely. This method was calibrated by the standard liquid with the known viscosity, which showed that the mean error was less than 0.82%. This method was used to measure the viscosity of MFs composed of MnZnFeO 4 nanoparticles, oleic acid surfactants and lubricant carrier liquid in variable magnetic field at the different temperatures.
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