Path planning algorithm in wheeled mobile manipulators based on motion of arms

M. H. Korayem,R. Abbasi Esfeden,S. R. Nekoo 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

This work proposes an algorithm besides output feedback linearization method for controlling a wheeled mobile robot with two manipulators. To control such a mobile robot, three desired trajectories (or fixed points for regulation) are needed: two for the arms and onefor the base. Improper choice in base path leads to singularity, low performance and failure. To prevent singularities and to attain asmooth motion, an algorithm is introduced as a local path planning process for the base. It consists of two parts which helps the robot tomaintain the desired configuration. The first part of the algorithm mainly focuses on the position and orientation of the base in future timebased on the arms configuration, and the second part adjusts the movement of the arms for obtaining a consistent motion. This maintenancereduces and preserves the norm of applied torques, which consequently leads to an increase in the performance of the robot and itsdynamic load carrying capacity (DLCC). Also, it is no longer required to define a trajectory or an end point for the base movement sincethey will be calculated automatically by the algorithm.

Sensitivity Analysis in 3D Manipulation of Biological Nanoparticles

Korayem, M. H.,Hoshiar, A. K.,Kim, M. O.,Yoon, J. American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.8

<P>Computer simulations to predict the motion of nanoparticles had been developed for Atomic Force Microscopy (AFM) based robots. The proposed model includes a system of coupled nonlinear equations which determine the system dynamics. As biological nanoparticles are fragile by nature, it is important to apply the exact amount of pressure during manipulation process. Therefore, the sensitivity analysis simulation has been performed to study the effects of inflectional parameters. Using derivative sensitivity analysis, the effects of geometrical (particle and cantilever shapes), process (user defined) and environmental parameters have been investigated and the most influential parameters have been introduced. The simulations provide a real-time platform and make the biological nanoparticles positioning more practical.</P>

Finite time SDRE control design for mobile robots with differential wheels

M. H. Korayem,S. R. Nekoo,A. H. Korayem 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

The State-dependent differential Riccati equation (SDDRE) control design for mobile robots with differential wheels is introduced for the first time, considering holonomic and non-holonomic constraints. Differential constraints of wheels put the SDDRE or even conventional State-dependent Riccati equation (SDRE) controller into uncontrollability condition. Since the actuators of wheels are not directly related to coordinates of the base, a proper kinematic transformation in design provided that relation; as a result, controllability of the controller over mobile robot was obtained. Moreover, finite time structure of the SDDRE resulted in terminal time control. Simulation data confirmed the accuracy and capability of the proposed design in nonlinear optimal control domain for both regulation and trajectory tracking cases. Time analysis of the controller was presented to assess the effectiveness of the SDDRE design for the final boundary condition. The SDRE was compared with output feedback linearization control to verify the proposed structure and to show the performance of design.

Determining load carrying capacity of a manipulator by game theory: Closed-loop nonzero-sum differential game approach

M. H. Korayem,H. Esfandiar,R. Dargahi 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11

The aim of this study is to determine the load capacity of a manipulator in closed-loop form and specified path. In open-loop mode, due to the lack of controller in the system, end effector accuracy constraint is considered as the main constraint in load carrying capacity and the motors are not able to use their maximum capacity for carrying larger load. In this study, for increasing the load carrying capacity of the robots and the use of saturation limit of the motors, the design of the controller is proposed based on game theory. The controller design is aroused as a problem of nonzero-sum differential game. In the method proposed, the motors driven are considered as the players and the track of specific path for end effector with a maximum load are regarded as objective function of the players. The players' optimal strategy is calculated based on Nash equilibrium strategy. By using iterative algorithm according to Riccati equations, optimal values of the control inputs are represented. In general, optimal strategy of the manipulator means to determine the best torques applied by the motors for carrying maximum load. To evaluate the effectiveness of the method proposed, the simulation is performed for Scout mobile robot and a manipulator with flexible joints. The results represent that differential game method when dealing with elastic deformation of the joints has a better performance and efficiency compared with LQR method.

Hybrid IPSO-automata algorithm for path planning of micro-nanoparticles through random environmental obstacles, based on AFM

M. H. Korayem,S. Nosoudi,S. Khazaei Far,A. K. Hoshiar 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.2

Nanomanipulation plays a significant role in nanotechnology research. The process of Atomic force microscopy (AFM) based manipulation is complex and time-consuming, which can be improved using a path-planning algorithm to reduce its manipulation time and time complexity. Due to real-time monitoring limitation in AFM based manipulations, Virtual reality (VR) environments have been developed. One such developed VR environment, however, is limited to point to point manipulation and lacks any path information. Therefore, we propose using a hybrid Improved particle swarm optimization (IPSO), a cellular automata-based algorithm for path planning during manipulation of micro/nanoparticles. In this technique, the critical time-force diagram, representing the AFM based manipulation dynamic is considered as a constraint, and is subsequently used to find the best path. The main path is divided into several segments and is optimized. Used as an algorithm for manipulation, this technique provides a more precise path in the AFM-based manipulation. Finally, the ability of this technique was compared to the other path planner algorithms based on its efficiency in reducing time-complexity parameters.

Vibration suppression of atomic-force microscopy cantilevers covered by a piezoelectric layer with tensile force

M. H. Korayem,A. Alipour,D. Younesian 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

In this paper, vibration suppression of a micro-beam covered by a piezoelectric layer is studied. The micro-beam is modeled with the specific attention to its application in AFM. The AFM micro-beam is a cantilever one which is stimulated close to its natural frequency by applying a harmonic voltage to the piezoelectric layer. The beam is an Euler-Bernoulli beam which abbeys Kelvin-Voigt model. Using such model supplies the comparison between elastic and viscoelastic beams; and one of the most important properties of viscoelastic materials, damping effect can readily be investigated. The pump provides an axial load with the result that it suppresses the vibrations. First, the vibration equations are extracted using Lagrangian and extended Hamiltonian method in vertical, longitudinal, as well as torsional directions and are discretized by exploiting the Galerkin mode summation approach. The discretized time-domain equations are solved by the aid of the Runge-Kutta method. The viscoelastic beam is compared with the elastic one, and the effects of damping ratio on vibration responses are presented. Additionally, the effects of micro-pump load, excitation voltage, and initial twist angle are investigated on the amplitude of vibration and natural frequency of system. It is observed that viscoelasticity of beam and axial load of the pump reduce vibrations and provide uniform time-domain responses without beatings.

Design and simulation of a magnetohydrodynamic micro-pump to provide time varying tensile force for vibration suppression in viscoelastic micro-beams

A. Alipour,M. H. Korayem,D. Younesian 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.5

In this paper, a new strategy for providing tensile force to suppress the transverse vibration of a micro-beam is introduced. This axial tensile force is supplied by a specific fluid flow called "magnetohydrodynamics" (MHD), which flows in a micro-pump, and then the fluid enters the micro-beam. The micro-beam is vibrated by an oscillating external force acting at its base. Therefore, a fluid structure interaction problem arises. The pressure of the fluid is increased due to the Lorentz force appears in the micro pump, and is directed by the channel towards the micro-beam and suppress the vibration of the micro-beam. It was observed that when the magnetic field rises from 0.25 Tesla to 0.5 Tesla, the amplitude of the micro-beam fluctuations will decrease from 13 6 10 m - ´ to 13 3 10 m - ´ . Assuming a laminar and incompressible flow, the finite volume method (FVM) is used to solve the governing equations. In the design of the micropump, the parameters studied are the value of the magnetic field, the amount of voltage applied to the micro-pump, the external force oscillation amplitude and the Reynolds number, and the effect of each parameter on the fluid and micro-beam behavior. The results show that with increasing fluid pressure in the micro-pump, the micro-beam vibration is suppressed. In addition, the pressure of the fluid along the micro-beam remains constant at 0.1 percent.