Employing machine tools with more than three degrees of freedom, is one of the effective methods for increasing the flexibility and accuracy of the machining parts. The milling machines with parallel mechanisms and higher degrees of freedom, have great stiffness and flexibility and also have great capability in the machining of the complicated parts. The calibration of this type of device, allows for increasing the accuracy and repeatability of the produced parts. In this article, a 4DOF milling machine with a parallel mechanism is introduced and necessary tests are performed to detect the movement errors of its rails. Again, the movement errors of the device have been measured by means of a dial indicator on a fixed part of the device using a magnetic base for positioning and linear movement of the device, and the measurement of errors after calibration has shown that the errors of the device have been significantly reduced. And it has increased the accuracy of the movement axes of the milling machine. Furthermore, the straightness of the axes is measured using a dial indicator and the error compensations are done. It is shown that the straightness of each axis with the adjustment of limit switches are improved very well.

Fused deposition modeling (FDM) is one of the most common 3D printings technologies. Low cost and the ability to produce models using wide range of thermoplastic polymers, makes this process suitable for rapid prototyping and manufacturing some commercial parts. The manufacturing complicated parts and increasing their qualities are possible, using more than three degrees of freedom printers. In this paper, a 5-DOF 3D printer is introduced. The mechanism of this printer is 4-DOF parallel mechanism with one additional degree of freedom resulting from rotation of printer bed about Z-axis. In order to generate tool path for 5-DOF printer, a CAM software was developed with python. For controlling the printer, control software was designed based on open-source Repetier framework. Since original framework only supports 3-axis printers, source code needed to be changed such as extending source code to support 5-axis and adding mechanism inverse kinematics. By using this 5-Dof mechanism, the prints of complicated parts without using the support are possible.

parallel kinematic machines, are closed loop structures which have more accuracy, stiffness and ability to withstand high loads. In this paper the vibration equations of the new parallel mechanism, that has higher stiffness because of parallelogram system and fixed length pods, have been derived by analytical approach. Whereas the proposed mechanism is applied as a machine tools, its vibrational behavior investigation has key impact factor. All the kinematic chains of the mechanism have been taken into consideration to achieve the coupled system of equations. To extract mechanism natural frequencies, modal analysis is carried out using three methods including analytical, finite element (FEM) and experimental method on parallel mechanism which has four degrees of freedom including three linear motion along the x, y and z axes and a rotary motion about x axis. Finally the natural frequencies and mode shapes obtained from analytical, experimental and FEM were compared. It is worth noting that all the frequencies obtained from three methods had little differences.

parallel kinematic machines, are closed loop structures which have more accuracy, stiffness and ability to withstand high loads. Kinematic of these mechanisms is complicated due to their closed–loop structure, parallel pods, joint constraints and movement constraints. This paper proposes a new parallel mechanism that has four degrees of freedom. In workspace analysis algorithm, conversion of inverse kinematics after providing the moving platform position (position and orientation) from search algorithm, provides basis position for testing the physical limitations of machine. Workspace of the mechanism is obtained by extracting analytical relations and consequently computational programs are written in MATLAB software. Sweep operations is started by dividing the workspace into x – y planes or horizontal sections with fixed spaces of z, then after sweeping all points of the plane, sweep operations of the next plane begins. Constraints and physical limitations considered in this mechanism includes moving restriction of saddle, collision of basis to rails, joint angles and collision of basis to moving platform. If any of these limits are violated, considered point would not be considered in the workspace. Then, to evaluate the correctness of the obtained results of workspace analysis, a suggested mechanism is simulated in Solid Works software and obtained workspace is validated in this study. Also position kinematic and workspace analysis results are verified experimentally.

parallel kinematic machines are closed-chain mechanisms with high accuracy and stiffness. Kinematics and dynamics of these manipulators are complicated due to the closed-loop structure and the constraints that exist for these manipulators. These mechanisms have some limitations like having erratic workspace, singular points in the workspace and complexity of control systems. These limitations should be studied for suitable usage of parallel mechanisms. This paper presents a novel 4-DOF parallel manipulator with 3 different linear motions and one rotational motion around x direction. Inverse and forward kinematic models of 2-PR(Pa)U-2-PR(Pa)R parallel machine tool mechanism are developed and also simulated by the code written in MATLAB. The results obtained by the mathematical model for the kinematics of the mechanism are verified using motion analysis under Solid Works. Workspace and singularity analysis are done by solving the kinematic relations and using Matlab software. To investigate the results of workspace analysis the structure has been modeled in Solidworks software and the obtained workspace have been validated using the simulation Finally the Newton-Euler method for inverse dynamic analysis of the proposed robot has been used. Therefore, moving path of the end effector, considering the various loads on it can be determined. By defining the path of platform with the specified velocity profile, inverse dynamic model simulated by the code written in MATLAB and diagram of actuator forces obtained and analyzed.

The Stewart platform is primarily used for generating arbitrary motions in three-dimensional space. However, it can also be utilized for measuring the three-dimensional position of an object attached to the moving platform. In this configuration, the Stewart platform functions as a sensory system. One challenge of this application is the high computational cost associated with determining the position of the moving platform relative to the fixed reference platform using data from six-length sensors. In this study, the sensory capabilities of the Stewart platform are investigated by introducing a high-performance and numerically agile approach. This approach involves developing an extended set of nonlinear algebraic equations that are well-suited for real-time applications. By applying this procedure to derive the Cartesian coordinates of three points on the moving platform and comparing the results with those obtained from computer-aided design software, a strong correlation is observed. To further evaluate the effectiveness of the approach, its performance is analyzed when subjected to harmonic time histories from six length sensors and when the legs' base positions are arranged regularly or non-regular on the fixed platform. The results demonstrate that the present method, particularly by updating initial conditions at every time increment, exhibits high computational efficiency.

This paper presents the dynamic modeling and design of micro motion compliant parallel mechanism with flexible intermediate links and rigid moving platform. Modeling of mechanism is described with closed kinematic loops and the dynamic equations are derived using Lagrange multipliers and Kane's methods. Euler-Bernoulli beam theory is considered for modeling the intermediate flexible link. Based on the Assumed Mode Method theory, the governing differential equations of motion are derived and solved using both Runge-Kutta-Fehlberg4, 5th and Perturbation methods. The mode shapes and natural frequencies are calculated under clamped-clamped boundary conditions. Comparing perturbation method with Runge-Kutta-Fehlberg4, 5th leads to same results. The mode frequency and the effects of geometry of flexure hinges on intermediate links vibration are investigated and the mode frequency, calculated using Fast Fourier Transform and the results are discussed.

The main objective of this paper is to model and optimize the parallel and relatively complex FuzzyP+FuzzyI+FuzzyD (FP+FI+FD) controller for simultaneous control of the voltage and frequency of a micro-grid in the islanded mode. The FP+FI+FD controller has three parallel branches, each of which has a specific task. Finally, as its name suggests, the final output of the controller is derived from the algebraic summation of the outputs of these three branches. Combining the basic features of a simple PID controller with fuzzy logic that leads to an adaptive control mechanism, is an inherent characteristic of the FP+FI+FD controller. This paper attempts to determine the optimal control gains and Fuzzy membership functions of the FP+FI+FD controller using an improved Salp swarm algorithm (ISSA) to achieve its optimal dynamic response. The time-domain simulations are carried out in order to prove the superb dynamic response of the proposed FP+FI+FD controller compared to the PID control methods. In addition, a multi-input-multi-output (MIMO) stability analysis is performed to ensure the robust control characteristic of the proposed parallel fuzzy controller.