ABSTRACT
In order to solve the tracking accuracy problem of the redundant manipulator, a PI control method with Henry gas solubility optimization parameter regulator (PI-HGSO) is proposed in this paper. This method consists of the controller and the parameter regulator. The characteristic is that the position deviation of a manipulator is equivalent to a specific function; namely, the proportional-integral (PI) controller is used to adjust the deviation input. The error can be better corrected by the processing of the PI controller so that the inverse kinematics solution of the minimum error can be realized. At the same time, the parameter selection of PI controllers has always been a difficulty in controller design. To address the problem, Henry gas solubility optimization (HGSO) is selected as a parameter regulator to optimize the parameters and obtain the optimal controller, thereby achieving high-precision trajectory tracking. Experiments on 9-DOF redundant manipulator show that our method achieves competitive tracking accuracy in contrast with others. Meanwhile, the efficiency and accuracy of the PI controller are greatly guaranteed by using HGSO to automatically optimize controller parameters instead of making approximate adjustments through infinite manual trial and error. Therefore, the feasibility and competitive superiority of PI-HGSO is fully proved in trajectory planning of redundant manipulators.
Subject(s)
Solubility , Biomechanical PhenomenaABSTRACT
The coherence time is the time over which the channel-gain-values correlation coefficient drops below a predefined threshold. The coherence time is typically used to quantify the pace of appreciable channel changes and is important, for example, for determining handoff and resource allocation time constraints. The goal of this work is to experimentally measure the coherence time of indoor optical wireless communication (OWC) channels under various mobile scenarios. The amount of movement was quantified by mobile sensor measurements. The experiments show that it is reasonable to assume that the channel varies slowly for a time period of ~100 milliseconds for most mobile scenarios.
ABSTRACT
Accurately quantifying animal activity and movements is of fundamental importance in a broad range of disciplines, from biomedical research to behavioral ecology. In many instances, it is desirable to measure natural movements in controlled sensory environments in which the animals are not physically or chemically restrained, but their movements are nevertheless constrained to occur within a fixed volume. Here, we describe a novel device to quantify the movements of small animals in response to sensory stimulation. The device consists of an Arduino controlled inertial measurement unit that senses angular velocity (along three axes) of a suspended mesh enclosure that temporarily houses the animal subject. We validated the device by measuring the phonotaxis behavior of gravid female frogs in response to acoustic broadcasts of male mating calls. The system, as designed, proved effective at measuring natural movements made in response to acoustic stimulation.