Task-based torque minimization of a 3-PṞR spherical parallel manipulator

A comprehensive dynamic modeling and actuator torque minimization of a new symmetrical three-degree-of-freedom (3-DOF) 3-PṞR spherical parallel manipulator (SPM) is presented. Three actuating systems, each of which composed of an electromotor, a gearbox and a double Rzeppa-type driveshaft, produce input torques of the manipulator. Kinematics of the 3-PṞR SPM was recently studied by the author (Zarkandi, Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci. 2020, https://doi.org/10.1177%2F0954406220938806). In this paper, a closed-form dynamic equation of the manipulator is derived with the Newton–Euler approach. Then, an optimization problem with kinematic and dynamic constraints is presented to minimize torques of the actuators for implementing a given task. The results are also verified by the SimMechanics model of the manipulator.

Torque-Angle Relationship for a 2D RRR-Type Serial Link Manipulator

This paper presents an application of Lagrange–Euler approach for dynamic analysis of three link with revolute type (RRR-type) rigid serial manipulators. MATLAB code is programmed for Lagrange– Euler approach for RRR-type serial manipulator for generating joint torque equations and plotting these joint torque values for given range of angular rotations. This study is useful for understanding the effect of combinations of link rotation on joint torque behaviour. Maximum value of required joint torques obtained can be used for selection of motors for any mechanism with serial links with revolute joints performing given task.

Real-Time Hovering Control of Unmanned Aerial Vehicles

In this paper, the design of a controller for the altitude and rotational dynamics is presented. In particular, the control problem is to maintain a desired altitude in a fixed position. The unmanned aerial vehicle dynamics are described by nonlinear equations, derived using the Newton–Euler approach. The control problem is solved imposing the stability of the error dynamics with respect to desired position and angular references. The performance and effectiveness of the proposed control are tested, first, via numerical simulations, using the Pixhawk Pilot Support Package simulator provided by Mathworks. Then, the controller is tested via a real-time implementation, using a quadrotor Aircraft F-450.

Моделирование распределения дисперсной фазы при течении в цилиндрической области методами вычислительной гидродинамики

The influence of the diameter of a cylindrical region filled with water on the structure of a bubble polydisperse flow is analyzed. Numerical simulation of the flow is based on a mathematical model that uses the Euler-Euler approach to the description of multiphase media, and includes the heterogeneous MUSIG model for the description of polydispersity, the k-ω-SST turbulence model, and interfacial momentum transfer. The bubble distributions in the sections near the sparger and near the free surface are obtained. The regimes of the bubble flow with full and partial filling of the region are identified and the transition criterion is determined.