RESUMO
In robotics, the ability of quadruped robots to perform tasks in industrial, mining, and disaster environments has already been demonstrated. To ensure the safe execution of tasks by the robot, meticulous planning of its foot placements and precise leg control are crucial. Traditional motion planning and control methods for quadruped robots often rely on complex models of both the robot itself and its surrounding environment. Establishing these models can be challenging due to their nonlinear nature, often entailing significant computational resources. However, a more simplified approach exists that focuses on the kinematic model of the robot's floating base for motion planning. This streamlined method is easier to implement but also adaptable to simpler hardware configurations. Moreover, integrating impedance control into the leg movements proves advantageous, particularly when traversing uneven terrain. This article presents a novel approach in which a quadruped robot employs impedance control for each leg. It utilizes sixth-degree Bézier curves to generate reference trajectories derived from leg velocities within a planar kinematic model for body control. This scheme effectively guides the robot along predefined paths. The proposed control strategy is implemented using the Robot Operating System (ROS) and is validated through simulations and physical experiments on the Go1 robot. The results of these tests demonstrate the effectiveness of the control strategy, enabling the robot to track reference trajectories while showing stable walking and trotting gaits.
RESUMO
The construction of transfer functions in theoretical neuroscience plays an important role in determining the spiking rate behavior of neurons in networks. These functions can be obtained through various fitting methods, but the biological relevance of the parameters is not always clear. However, for stationary inputs, such functions can be obtained without the adjustment of free parameters by using mean-field methods. In this work, we expand current Fokker-Planck approaches to account for the concurrent influence of colored and multiplicative noise terms on generic conductance-based integrate-and-fire neurons. We reduce the resulting stochastic system through the application of the diffusion approximation to a one-dimensional Langevin equation. An effective Fokker-Planck is then constructed using Fox Theory, which is solved numerically using a newly developed double integration procedure to obtain the transfer function and the membrane potential distribution. The solution is capable of reproducing the transfer function and the stationary voltage distribution of simulated neurons across a wide range of parameters. The method can also be easily extended to account for different sources of noise with various multiplicative terms, and it can be used in other types of problems in principle.
Assuntos
Modelos Neurológicos , Neurônios , Neurônios/fisiologia , Potenciais da Membrana , Potenciais de Ação/fisiologiaRESUMO
Ticks are parasites of wild animals, affecting diverse and several species. The present study reveals the presence of Amblyomma aureolatum parasitizing the margay cat (Leopardus wiedii) in the city of Uruguaiana. This is the first report of the presence of this tick specie in this city, situated in west (29° 45' 18" S 57° 05' 16" W) of the state of Rio Grande do Sul, Brazil, indicating a wide host diversity.
Carrapatos podem ser parasitos de animais selvagens, afetando diversas espécies. O presente trabalho relata a presença de Amblyomma aureolatum parasitando o gato-maracajá (Leopardus wiedii) na região de Uruguaiana, esse é o primeiro relato da presença desta espécie de ixodídeo nesta cidade (29° 45' 18" S 57° 05' 16" W), situada na região oeste do estado do Rio Grande do Sul, Brasil, indicando que diversos hospedeiros silvestres podem ser acometidos pelo parasito.