Inverse kinematics for cooperative mobile manipulators based on self-adaptive differential evolution.

This article presents an approach to solve the inverse kinematics of cooperative mobile manipulators for coordinate manipulation tasks. A self-adaptive differential evolution algorithm is used to solve the inverse kinematics as a global constrained optimization problem. A kinematics model of the cooperative mobile manipulators system is proposed, considering a system with two omnidirectional platform manipulators with n DOF. An objective function is formulated based on the forward kinematics equations. Consequently, the proposed approach does not suffer from singularities because it does not require the inversion of any Jacobian matrix. The design of the objective function also contains penalty functions to handle the joint limits constraints. Simulation experiments are performed to test the proposed approach for solving coordinate path tracking tasks. The solutions of the inverse kinematics show precise and accurate results. The experimental setup considers two mobile manipulators based on the KUKA Youbot system to demonstrate the applicability of the proposed approach.

Emotional system in complex cognitive activities of working memory: A literature review of its role.

Cognitive processing is needed to elicit emotional responses. At the same time, emotional responses modulate and guide cognition to enable adaptive responses to the environment. However, most empirical studies and theoretical models of cognitive functions have been investigated without taking into account emotion, which is considered interference that is counterproductive to the correct functioning of the cognitive system. To understand how complex behaviors are carried out in the brain, an understanding of the interactions between emotion and cognition may be indispensable. Given the enormous scope of this topic for both cognition and emotion, these concepts will not be further defined here; instead, this review will be relatively narrow in scope and will emphasize several brain systems involved in the interactions between emotion and working memory because an important dimension of cognition involves working memory function. In attempting to understand the relationship between emotion and working memory, we will describe the projections of a set of brain structures that support our emotional life and the neuromodulator dopamine (which is also involved in emotion processing and incentive motivational behavior) in the prefrontal cortex. According to the literature, working memory engages the cortical regions. Thus, the prefrontal cortex, particularly the dorsolateral prefrontal cortex (DLPFC), although commonly viewed as a purely cognitive area, provides a test for the hypothesis that working memory and emotion are strongly integrated in the brain. In this review, we provide an overview of neuropsychological, neuroanatomical and molecular evidence, with the aim of establishing the extent to which working memory and emotion are related.

Visual Servoing for an Autonomous Hexarotor Using a Neural Network Based PID Controller.

In recent years, unmanned aerial vehicles (UAVs) have gained significant attention. However, we face two major drawbacks when working with UAVs: high nonlinearities and unknown position in 3D space since it is not provided with on-board sensors that can measure its position with respect to a global coordinate system. In this paper, we present a real-time implementation of a servo control, integrating vision sensors, with a neural proportional integral derivative (PID), in order to develop an hexarotor image based visual servo control (IBVS) that knows the position of the robot by using a velocity vector as a reference to control the hexarotor position. This integration requires a tight coordination between control algorithms, models of the system to be controlled, sensors, hardware and software platforms and well-defined interfaces, to allow the real-time implementation, as well as the design of different processing stages with their respective communication architecture. All of these issues and others provoke the idea that real-time implementations can be considered as a difficult task. For the purpose of showing the effectiveness of the sensor integration and control algorithm to address these issues on a high nonlinear system with noisy sensors as cameras, experiments were performed on the Asctec Firefly on-board computer, including both simulation and experimenta results.