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This letter proposes a unified GPU-parallelizable approach for robot forward dynamics (FD) computation based on the key fact that parallelism of prevailing FD algorithms benefits from the essential band sparsity of the joint space inertia (JSI) matrix or its inverse. The existing FD algorithms are categorized into three classes: direct JSI algorithms, propagation algorithms, and constraint force algorithms...
This paper focuses on the control system design for a wearable power assist device which provides force/torque support for people who are doing physically demanding tasks. The device is actuated by the McKibben artificial muscle. The McKibben actuator is know to exhibit high nonlinearity between the supply pressure and the contractile length, and it is basically difficult to design a high performance...
The reducing of energy consumption for transportation and manipulation of industrial objects is a topical issue. The objects of manipulation are gripped with the use of industrial robot and transported from one position to another. In gripping devices, the lifting force is created on the basis of the aerodynamic effect of lifting appearing due to the use of compressed air. The efficiency of functioning...
In this paper, we propose a filter structure to satisfy velocity and acceleration limitations for arbitrary input signals. The shape of step signals is sometimes converted into trapezoidal wave in order to satisfy velocity limit in FA field. Then we can prevent an overload for the robot. In some cases, physical protection of equipments, safety and ride quality are achieved with limitation of input...
Nowadays, when designing a bird-like flapping wing robot, single-section or two-foldable-section wing type is normally adopted to mimic the flexible wing, which is hard to simulate a real bird's flapping fly or gain well aerodynamic performance. In present work, a new flexible flapping wing vehicle, of which the flexibility of the wing is more authentic, is designed firstly, then the kinematic model...
The identification procedure specially designed for an n-link inverted pendulum on a cart is presented. By the Lagrangian mechanics, the mathematical model of the n-link inverted pendulum is established initially. To fully model the system, the standard dynamic parameters which are some algebraic functions of geometric, inertial, and friction parameters are introduced. Because the dynamic model of...
A wheeled inverted pendulum cannot balance without control, and it is important to save motion in a control range. In some situations, however, to avoid a collision, the maximum acceleration and deceleration must be applied. A motion-planning method for a wheeled inverted pendulum (“body” hereafter)-which uses full performance from all attitudes under hardware constraints-was developed. The developed...
This paper presents the dynamic model and control scheme of an active variable buoyancy system (VBS) actuator for Autonomous Underwater Vehicles (AUVs). Our aim is to design an active disturbance rejection controller for the AUV maneuvering in the vertical plane with two VBS actuators. Firstly, a vertical plane mathematical model of AUV and a dynamics model of the VBS are established, and the model...
In this paper, we present a Lagrangian swarm model that shows emergent formations of multiple autonomous unmanned ground vehicles (UGVs). The Direct Method of Lyapunov is used to construct the instantaneous velocity of each individual in the swarm. The velocity controllers ensure the cohesion and therefore the stability of the swarm. Via computer simulations, we illustrate self-organizations such...
The classical nonlinear guidance algorithm for a fixed-wing flying robot has the shortcoming of the unchangeable guidance length. To improve the algorithm, a novel guidance method is proposed based on the guidance point optimized online. The kinetic equations and the classical nonlinear guidance algorithm are introduced. The effects of the guidance length to the tracking performance are analyzed....
Obtaining a dynamic model for the parallel mechanism is always regarded as a challenging process due to high complexity of the dynamic equations especially in presence of friction. In this paper the process of black-box identification of friction and rigid-body dynamics of an overconstrained 3-DOF decouple mechanism is addressed. Since the under study mechanism is an overconstrained parallel mechanism,...
Pipelines have been used to convey products such as oil, gas, chemicals and water. It means that problems with pipelines would indicate money waste and environment damages. To avoid those problems, inspections are realised periodically. The technology improvement has made possible employing robots and mobile platforms to inspect pipes. The focus of this work is to implement a strategy to acquire the...
In this article, a method for kinematic configuration estimation of a structure similar to a human finger, is presented. The method is based on the EKF and a model reflecting kinematic constraints of a finger-like structure (2-DOF metacarpophalangeal joint, and one 1-DOF proximal interphalangeal rotational joint), using 3 low cost IMUs. During tests, the IMUs were attached to a 3D-printed setup equipped...
This paper presents a method for the real-time determination of joint angles, velocities, accelerations and joint torques of a human. The proposed method is based on a constrained Extended Kalman Filter that combines stereophotogrammetric and dynamometric data. In addition to the joint variables, subject-specific segment lengths and inertial parameters are identified. Constraints are added to the...
Humanoid robots propel themselves and perform tasks by interacting with their environment through contact forces. Typically, nonuniqueness of these forces is dealt with by distributing them evenly between the contacts. In the present paper, we introduce strict prioritization in contact force distribution, to reflect situations when an application of certain contact forces should be avoided as much...
In this paper, we propose a method to estimate the disturbance information using repetitive technique based on a disturbance map. The disturbance map is shared among unmanned aerial vehicles (UAVs) during platoon flight. Shared map improves the estimated accuracy of disturbance observer via repetitive technique, referred as repetitive estimation. Using the estimated disturbance information, the disturbance...
In this article, we build dynamic models of 2D compliant links to evaluate injury level in a human-robot interaction. Safety is a premium concern for co-robotic systems. It has been studied that using compliant links in a robot can greatly reduce the injury level. Since most safety criteria are based on tolerance of acceleration of the operator's head during the impact, an efficient and yet accurate...
The dynamics research of folded-deployable suspension of a new planetary exploration robot is carried out. The first three-order natural frequency and vibration mode of planetary robot in folded and deployable states are obtained respectively by finite element simulation analysis; the robot's natural frequencies in folded and deployable states are achieved respectively through vertical and horizontal...
In this paper we propose a new method to tackle the problem of discontinuous curvature observed in the time-optimal Dubins trajectories of car-like robots. The discontinuous curvature profile renders the paths untraceable by a real robot due to the existence of infinite accelerations at the transition points. To make way for a continuous curvature profile, we relax the idealized nonholonomic constraint...
Tracking a desired trajectory in joint space has been favored in several robot manipulators and end-effector control scheme due to the simplicity and high sampling rate offered by the joint space scheme. This usually require the trajectory conversion process, of the desired position, velocity, and acceleration, from Cartesian space to joint space using conventional inverse kinematics solutions which...
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