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.

This paper comprehensively investigates the dynamic modeling and simulation of the conjoined twins 3RPRS (CT-3RPRS) ROBOT, an advanced parallel spatial mechanism distinguished by its kinematic efficiency, structural rigidity, and expansive accessible workspace. The CT-3RPRS ROBOT is equipped with six actuators, comprising three prismatic and three revolute actuators, which contribute to its unique structure, enabling precise control over its constrained kinematic chains. To thoroughly analyze the ROBOT's KINEMATICS and kinetics, the Jacobian matrix and Lagrange multipliers are employed, respectively, to resolve reaction forces and moments inherent to closed-loop topologies. Motion equations are systematically derived using dual methodologies: the Euler-Lagrange formulation, which accounts for energy-based dynamics, and the principle of virtual work, which ensures equilibrium under non-conservative forces. These equations are subsequently verified to ensure their equivalence. The comprehensive modeling processes are rigorously validated through MATLAB simulations, providing a robust framework for analysis. Additionally, the results obtained from MATLAB are corroborated using SimScape, further confirming the accuracy and reliability of the dynamic models. This study highlights the dynamic features of the CT-3RPRS ROBOT as well as the effectiveness of the employed modeling techniques.

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.

Parallel ROBOTs are closed-loop mechanisms presenting very good performances in terms of accuracy, rigidity, and the ability to manipulate large loads. Inverse KINEMATICS problem for most parallel ROBOTs is straightforward, while the direct KINEMATICS is not. The latter requires the solution of the system of nonlinear coupled algebraic equations and has many solutions. Except in a limited number of these problems, there is difficulty in finding exact analytical solutions. So these nonlinear simultaneous equations should be solved using some other methods. Continuation or path-following methods are standard numerical techniques to trace the solution paths defined by the Homotopy. This paper presents the direct KINEMATICS solutions for a 3RCC parallel ROBOT by using a semi-analytical Homotopy method called Homotopy Continuation Method (HCM). The HCM has some advantages over the conventional methods and alleviates drawbacks of the traditional numerical techniques, namely; the acquirement of good initial guess values, the problem of convergence and computing time. The direct kinematic problem of the 3RCC parallel ROBOT leads to a system of nonlinear equations with 9 equations and 9 unknown parameters. The proposed method solved these nonlinear equations and extracted all the 36 solutions. Results indicate that this method is effective and reduces computation time in comparison with the Newton– Raphson method.

In this paper, efforts were made in order to use the visual system in controlling an industrial 6R ROBOT and also it is tried that the visual system, realizes the target and controls the ROBOT by taking picture from the environment and processing the picture. To test the action of ROBOT, Kinematic equation are used. In Direct KINEMATICS test, the quantities of joint angles are determined. On the basis of the given angles, the location of the end-effector is calculated by the system and via the Transition Matrix. In Inverse KINEMATICS test, the specifications of the location of the end-effector are accessible. Using Inverse KINEMATICS equations, the quantity of joint angles are distinguished and the ROBOT rotates to that quantities and on this basis, the location of the end-effector in space becomes distinct. Since the movement of each of the joints has a limited scope and junction of the joints limits their movement scope, the need for knowledge of the working space of a ROBOT seems necessary. To find Singular Points, we seem determinant of the Jacobean matrix equal zero and we determined the working space of the ROBOT by Matlab Simulink. Finally the results are tested within the ANSI-RIA R15.05-2 standard.

IntroductionROBOTs have been used for material handling for many years, and their applications have greatly expanded with the integration of intelligent technologies. While numerous researchers have proposed various ROBOTs for this field, it is crucial to design customized configurations that are suitable for agricultural farms. However, research in our country has been limited to a few mobile agricultural ROBOTs. The main focus of this paper is to design and model workspaces and analyze the KINEMATICS of manipulators in agricultural settings.Materials and MethodsThis article investigates the workspace and KINEMATICS of a ROBOT manipulator to design and manufacture a four-DOF manipulator for farming. This manipulator will be capable of performing a variety of tasks, but the goal of this project is to enable it to load and unload materials and products on the farm as an auxiliary force for the farmer.When designing and analyzing a manipulator, the first step is to determine the specific task that the ROBOTic arm will perform. For example, consider a scenario where the task involves loading or unloading forage packages from a trailer at a designated location. This task specification forms the basis for further design and analysis, ensuring that the manipulator is appropriately designed to meet the requirements of the task.An intelligent ROBOTic arm that is attached to a tractor can perform this operation in the shortest possible time without the intervention of human workers. Otherwise, a large number of laborers would be required to move boxes weighing 10 kg over distances of 3 to 4 meters and heights of 1 to 2 meters, which would require a great deal of torque.At this stage, the design of the arm KINEMATICS model, direct kinematic equations, velocity KINEMATICS, and Jacobian matrix solving were performed. The calculations were carried out using two methods: manual calculation and kinematic modeling in MATLAB software for three arm configurations in two simulation tests. The results of both methods were compared.The workspace analysis of the selected manipulator configurations, as well as the use of arm kinematic performance evaluation indices, were illustrated in graphs.Results and DiscussionThe issue of moving forage packages on the farm is described below. If a farmer were to move 48 packages of fodder weighing about 10 kg manually (using human workers) in the workspace modeled in Figure 10, each package would take an average of 30 seconds to be moved reciprocally along an unobstructed path. Hence, it would take approximately 24 minutes to move all the packages. However, the linear speed of the final operator of the ROBOT arm during the first test was found to be 1 meter per second, which is 3.7 times faster than the manual work scenario, and the total movement of the packages can be completed in about 6.5 minutes.Upon analyzing the velocity diagrams of the final performer in both tests, it becomes evident that there is not much variation in speed and acceleration due to the change in configurations. The evaluation of ROBOT workspace indicators was conducted using two methods: workspace index and structural length index. These indicators were calculated for all three configurations, and the results indicated that Configuration Type 1 was the most suitable option. Furthermore, the manipulability index of the ROBOT arm was assessed based on the obtained diagrams for all three configurations in the two tests. It was observed that Configuration Type 1 outperformed the other two types in terms of score, indicating its superior performance. This aligns with the suggestion made by Yoshigawa for the first three joints of the Puma ROBOT.Overall, the results suggest that Configuration Type 1 is one of the most favorable options, ensuring better performance for the final performer.ConclusionOne of the main considerations when using ROBOTs in agriculture is the appropriate kinematic design of joints and links for work operations. Using the example of ROBOTs assisting with moving products on the ground, it can be seen that using ROBOTs significantly reduces the time required compared to manual labor. Furthermore, in terms of energy consumption and cost within a certain period, the use of ROBOTs has economic justification.Based on the studies conducted, Configuration Type 1 passed the kinematic path in both tests with a higher manipulability index and a more suitable workspace index based on both calculated criteria. Therefore, this configuration is recommended for the design of ROBOTs for the operation of moving products on the ground.

Snake ROBOTs are hyper-redundant ROBOTs that are connected with one or two DOF joints. They offer a number of potential advantages beyond the capabilities of most wheeled and legged ROBOTs. In this paper, KINEMATICS and dynamics of a planar multi-link snake ROBOT in worm-like locomotion on an inclined surface is investigated. In this locomotion, Snake ROBOT is able to move in the vertical plane. Body shape and curvature function are used to determine the joint relative angles in accordance with the worm-like locomotion. Next, position, velocity and acceleration of each link as well as center of gravity of the snake body are calculated. Newton principle is used to derive the dynamic equations based on KINEMATICS of the snake ROBOT. Friction forces, as the only driving force is modeled using Coulomb friction. Effects of friction coefficient and angle of inclined surface on the joint torques are investigated. It is shown that by increasing these coefficients the motor torques also increase. Webots software and Lagrangian method are both used to verify the theoretical results. Additionally, KINEMATICS and dynamics equation presented in this paper may be used to generate other locomotions in vertical plane. Effect of link geometrical shape on motor torques is also investigated. Finally, FUM-Snake3 ROBOT and physical experiments are used to further validate the mathematical model.

In this paper, the forward KINEMATICS of a parallel manipulator with three revolute-prismatic-spherical (3RPS), is analyzed using a combination of a numerical method with semi-analytical Homotopy Continuation Method (HCM) that due to its fast convergence, permits to solve forward KINEMATICS of ROBOTs in real-time applications. The revolute joints of the proposed ROBOT are actuated and direct KINEMATICS equations of the manipulator leads to a system of three nonlinear equations with three unknowns that need to be solved. In this paper a fast and efficient Method, called the Ostrowski-HCM has been used to solve the direct KINEMATICS equations of this parallel manipulator. This method has some advantages over conventional numerical iteration methods. Firstly, it is the independency in choosing the initial values and secondly, it can find all solutions of equations without divergence just by changing auxiliary Homotopy functions. Numerical example and simulation that has been done to solve the direct kinematic equations of the 3-RPS parallel manipulator leads to 7 real solutions. Results indicate that this method is more effective than other conventional Homotopy Continuation Methods such as Newton-HCM and reduces computation time by 77-97 % with more accuracy in solution in comparison with the Newton-HCM. Thus, it is appropriate for real-time applications.

Analysis of the inverse KINEMATICS of redundant manipulators is one of the nesseccary tools in various ROBOTic fields such as design, motion planning and control of these systems. Since, there is not an analytical solution for the inverse KINEMATICS of several redundant manipulators, numerical approaches are needed to execute and investigate in this field. In this paper, combination of the neural networks, fuzzy systems and quadratic programming is used to obtain the joint variables. According to the proposed approach, seven neural networks are considered according to the each joint variable and by adaptation of the neural network’s weights, suitable configurations of the ROBOT is determined to track a desired trajectory in the Cartesian space. Meanwhile, initial weights of the neural networks are obtained by fuzzy systems based on the vicinity of the endeffector to desired point and feasibility of the joint variables. Obstacle avoidance scheme is performed by investigation of the conditions including choosing the joint variables that involved in the equations of the arms constraints and determination of the most critical arm. In order to establish the constraints of the problem in the quadratic programming, realization of the Kun-Tucker conditions will be used. Evaluation of the proposed approach will be carried out on the PA-10 manipulator by simulation and analysis of the results.