A modified measure for the Parallel cable driven Robots is presented in this paper. These Robots have additional advantages compared to other Robots and even the Parallel structures, but they are readily exposed to disturbances. The presence of external wrench (Force-Moment) may be the cause of violation against the motion constraint. The stability measure proposes a number between zero and one that could be the criterion for the evaluation of the Robot's ability while returning to its original equilibrium which was influenced by external disturbances. To offer a stability measure, Gibbs-Appell equations and acceleration energy are used. Robot kinematic and dynamic modeling based on Newton-Euler’s method calculates the measure. To illustrate the capabilities of the proposed measure, a 6 DOF cable Robot with six cables is simulated. The results of the two simulations are presented and analyzed. The stability measure is depended to kinematic parameters and also to kinetics parameters as cables tension at the beginning of motion. Therefore using the proposed measure one can better evaluate the stability within the wider range of Parallel cable Robots.

In this study, a couple of 3PRR Parallel Robot is used for the rehabilitation process of a patient to eliminate a walking disability and leads to his treatment. The 3PRR Robot has three degrees of freedom, provided by three prismatic actuators. Also using a couple of them, can quickly rehabilitate and provide the rehabilitation movements of a patient in the walking process. In this study, the extraction of kinematic and dynamic Equations of the Robot was investigated, and a fuzzy-logicbased controller is performed. This controller has the ability to repel unwanted disturbances to follow the desired path. All modelling was simulated by MATLAB software. The simulation results show that using the mathematical model and controller, it is easy to go any desired path in the workspace, and this controller will be able to repel environmental disturbances like the sudden movement of patients.

Parallel Robots are widely used in many industrial and medical applications. Reconfigurable Parallel Robots could be defined as a group of Parallel Robots that can have different geometries, thus obtaining different degrees of freedom derived from the basic structure. These Robots have some disadvantages like having erratic workspace and singular points in the workspace. These limitations should be studied for proper usage of Parallel manipulators. This paper presents the kinematics and workspace analysis of a 3DOF Parallel reconfigurable Robot. This Robot has two different configurations. The first configuration is a Tricept Robot (3UPS-PU) and the second is a fully Spherical Robot (3UPS-S). The kinematic equations are derived based on the geometry of the system and then Jacobian matrices are determined via velocity loop closure analysis. The kinematic model is verified by the results obtained from Robot simulation in ADAMS software. Then, the workspace of the Robot is determined by considering the kinematic constraints.

Accommodation of mechanism with human being’s physical characteristics creates the possibility of safe and efficient interaction between human being and Robot. Regarding the fact that amputation of a limb in human beings causes several mental, economical and social difficulties and problems, need to a substitute limb which has the most efficiency for the person after amputation is a vital need. The cable Robots are the kinds of Robots that the cable is used instead of rigid link. The cable Robots have a simple appearance that some cables connect the motors to the final organ. In this research a Robot with cable mover is designed and modeled as a tool in the case of creating movement with the most accordance for an artificial organ below the knee. In addition, in this mechanism some advantages are also considered including creating movement in two axes, its cheapness and lightness. In this research at first a primary design of the artificial organ is presented. The forward and inverse kinematic relations which are dominant on system are explained, in fact you can find different features with kinematic Robots like dexterity, global condition, local condition, etc, and finally we study the available workspace for the system. Workspace in cable Robots is different from other Parallel Robots, in this paper, first description about some methods for finding workspace in cable-driven-Robots and then use of force-closure workspace to find workspace for this system are presented.

Musculoskeletal disorders caused by heavy workloads are very common in workers, which negatively affects workers' health and productivity. In this regard, the idea of designing an exoskeleton Robot is proposed. This Robot is similar to a dress which worn on the user's body and Parallels the body, accompanying and helping the person. In this paper, the Parallel distributed compensation control method is proposed to be applied to a four degrees of freedom exoskeleton waist Robot. Initially, the dynamical equations governing the system are extracted. According to the nonlinear nature of the system, the Parallel distributed compensator controller is designed with a Takagi-Sugeno linearization approach. The closed loop system response of this controller is investigated in the Simulink environment of the MATLAB software. The results show that the Takagi-Sugeno linearization approach accurately estimates the nonlinear system, and also the proposed controller perfectly intercepts the optimal closed loop response.

Parallel mechanisms are more utilized, because of their extra precision and stiffness in comparison with serial mechanisms. Measuring position and orientation (pose) of Parallel Robot end effector and performing kinematic calibration, is a guaranty for, moving precision of these Robots. Through different measurement devices, machine vision has advantages such as low cost, simplicity in use and rather appropriate precision. In this research, in order to measure pose of end effector of a 4-DOF (degree of freedom) Parallel Robot, a vision-based measurement system, is designed and implemented in Matlab software. The laboratory device is a stereo camera. Camera calibration is carried out in Matlab. A triangular shape is used as feature on the Robot end effector. By processing the images acquired from pose of end effector, in designed measurement system, rotation matrix and translation vector are obtained and the exact position of the end effector is revealed. For investigating precision and accuracy of proposed measurement system, a conventional measurement method with the help of gauge block and indicator, is used. According to the nature of machine vision, the results achieved in this examination, are acceptable; although better precision can be attained by improving devices used in this research.

This paper presents an analytical inverse kinematic simulation method to define the kinematics aspect of a 6-degree-of-freedom (DOF) Hexa Parallel Robot. The Robot was designed using six independent links, each constructed of upper and lower links. Every link has three joints with a 6-RSS configuration. This configuration is aimed to enhance motion flexibility. In this study, the orientation of the end effector is adjusted based on its position to larger the reach and workspace. The proposed method was implemented to create a computer program in MATLAB, which was used to calculate the motors' motion during a complex path. The results indicate that the developed algorithm can determine the rotation motion of all the motors, which are used to place the end of the arm tool to the target position and orientation. Another verification test was conducted to assess the applicability of the proposed algorithm to a physical Robot. The results demonstrated that the proposed approach could perform complex tasks accurately. Moreover, the comparison test proved that the proposed method is more efficient regarding computational time than the Jacobian method. It is the main advantage of the method compared to numerical based method.

In this paper, a new optimal method for modelling of a 3PRS Robot is proposed according to NOC algorithm. An optimal method of selecting the generalized coordinate is presented and a new algorithm of extracting the null space of over and under constrained Robots is proposed through which a lower amount of mathematical calculations is required. In this method, using the principal of derivatives of implicit functions, the null space of constraint matrix will be extracted. Afterwards the null space matrix is calculated with orthogonal columns. The proposed method is implemented on a 3PRS Robot which is an under constrained Robot. This Robot is a kind of Parallel spatial Robot with 6 DOFs which can be controlled using 3 active prismatic joints and 3 passive rotary ones. This Robot similar to other Parallel Robots has heavy, complicated and nonlinear model which needs heavy and time consuming mathematical calculations. The proposed strategy of extracting the null space of the Robot, extremely and heavily decreases the volume of required mathematical calculations for modelling the Robot and consequently decreases the inevitable consumed time of processing and numerical errors and increases the accuracy of simulations.

Wheeled Robots have various applications in industrial, laboratory, art, and filming environments. The choice of wheel and platform type in these Robots depends on the motion and the degrees of freedom expected from the Robot. With an appropriate choice of the wheel and platform, the degrees of freedom of 3 (known as holonomic Robots) can be achieved in which the Robot can move in both x and y directions and also rotate about the z axis in the general coordinate system. If the wheeled Robot is designed to carry objects, it is necessary to consider a platform on top of the Robot for this purpose. In this paper, a 3-DOF Stewart platform is used such that it provides rotation about x and y axes as well as motion in direction of z axis. The goal of this research is to develop a wheeled Robot equipped with the 3-DOF Stewart platform to carry objects with ability of orientation control within the path. With integrating these two Robots, the resultant Robot will have 6 degrees of freedom, three of which are provided by the Stewart platform (α , β , Δ z) and the other three are provided by the wheeled platform (Δ x, Δ y, γ ). Therefore, the Robot, with 6 degrees of freedom, can be controlled via the six parameters of Δ x, Δ y, Δ z, α , β , γ .