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.

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 .

Regarding the progress in technology and increase in the capabilities of the ROBOTs, one of the main challenges in the field of ROBOTics is the problem of real-time and collision-free path planning of ROBOTs. This paper focuses on the problem of path planning of 3-DOF decoupled PARALLEL ROBOT called Tripteron in the presence of obstacles. The proposed algorithm is synergy-based algorithm of convex optimization, disjunctive programming and model predictive control. This algorithm has many advantages compared to previous methods reported in the literature including not getting stuck in the local optimums and finding the global optimum and high computational speeds. Finally, the algorithm will be implemented on model of the real ROBOT. It should be mentioned that this algorithm has been implemented using Gurobi optimization package with C++ programming language in Qt Creator environment and the simulation of the PARALLEL mechanism is performed by the CAD2MAT package for MATLAB. Obtained results reveal that the maximum computational time at each step is less than one second which, for this particular application, could be regarded as real-time algorithm.

In this paper, dynamic modeling and control of a three-degrees-of-freedom PARALLEL ROBOT with pure translational motion is performed. Constraint equations are derived based on the kinematic model of the ROBOT and Lagrange method is applied to derive the dynamic equations. In order to control the ROBOT position on planned reference trajectories, in presence of uncertainties of the dynamic model a sliding mode controller is designed which is robust against the uncertainties and induced noises. Performance of the designed controller is simulated and evaluated in different conditions including the presence of noise and parameters variation. In this regard, a comparison has been made between the response of the proposed sliding mode controller and response of a feedback linearization controller, indicating their capabilities in noise rejection and compensation of parameters variation. Also, the effect of defining different sliding surfaces on the performance of the sliding mode controller, and using the integral of error instead of the error itself, have been studied and examined. Results show that the proposed sliding mode controller has a desirable performance in tracking the reference trajectories in presence of the model uncertainties and noise for this kind of PARALLEL mechanism.

This article investigated design and construction of a 4-DOF delta PARALLEL ROBOT’ s components and additionally inverse kinematics and kinematics control of the ROBOT. The initial and final version of the ROBOT based on existing needs, the addition of gearboxes due to the low torque of motors, and flange transformations to connect the gearbox to the ROBOT’ s base were also discussed. In the following, by simulating the ROBOT in MATLAB software, the integrity of the inverse kinematic equation of the ROBOT was investigated. In the other part, the design of the kinematic control in the joint space was discussed and the results were plotted in the graphs for a z-direction. By designing a suitable ROBOT controller, tracing the desired path and comparing its results with other controllers become possible. By designing a conveyor for the ROBOT and equipping it with a camera, detecting the objects that the ROBOT moves them become possible with image processing. For the purpose of picking and placing the objects, the ROBOT’ s end effector is equipped with a controlled suction. The results, through which the paths crossed, showed the designed PID controller for the ROBOT was working correctly and the desired path was followed with small error.

Simulation of the four degree of freedom PARALLEL ROBOT (Quattrotaar) is subjective of this paper. The mathematical model of the PARALLEL ROBOT is obtained too. The workspace is optimized for Non-singular kinematic type-2. Artificial Bees Colony algorithm and Particle Swarm Optimization algorithm as overall exploring algorithms are implemented and the results are compared to each other. In spite of any intrinsic complexity of the optimization problems, the result shows the capability of both methods for this ROBOT parameters design. Comparison of the results indicates the Particle Swarm Optimization algorithm runs faster than Artificial Bees Colony algorithm. The exploring volume consists of a plan with 500 mm x 500 mm dimension which move in a vertical direction from 500 mm to 1000 mm. One of the important hints of the paper is a 90-degree rotation of end effector around vertical axis Z. This rotation is caused more flexibility and dexterity for the ROBOT. A 3-D model of Quattrotaar PARALLEL ROBOT is created by Computer Aided Design software and finally Quattrotaar is fabricated in Human and ROBOT Interaction Laboratory (Taarlab).

This paper discussed nonlinear adaptive control of a 6 DOF biped ROBOT. The studied ROBOT was divided to three part, fix leg, moving leg and a torso and all the joints were considered rotational. Generally, for calculations, ROBOTs are considered as a whole which makes the related calculations complex. For balance calculations, the zero moment point (ZMP) was either considered as a fix point on the ground or a moving point on the foot plate. In the presented ROBOT in this study with priority of movements, first, the calculations were carried out on the moving foot, then the effect of the motion on the foot was inspected and a pendulum was used to balance the ROBOT. To check the balance, ZMP in the simulation in MATLAB software was considered as a fix point While in Adams software simulation, ZMP was considered moving along the bottom of the sole. All the charts active with both software met each other. In the presented study the inverse kinematics was calculated by trigonometric method and inverse dynamics of each leg was investigated by Newton-Euler iterative method. All calculations were carried out in MATLAB software and were verified by ADAMS software. By writing the equilibrium equations, the angle of torso at each time was achieved. In the next step, because of uncertainties in manufacturing and some parameters like mass, length, etc. adaptive computed torque control was used on each leg to achieve the maximum torque that each joint needs for stable walking.

This paper formulates a method that provides an index for evaluating the coupling effects between the degree-of-freedom motions of six-degrees-of-freedom PARALLEL manipulators. The aim is to provide guidance for the initial design of mechanisms in which the decoupling of the displacement with respect to degrees of freedom motion is required. It is based on singular-value decomposition to the properties of the joint space inverse mass matrix. The method uses a transformation matrix, the product of transposed Jacobian matrix and an orthogonal unitary matrix. Each element of the matrix quantifies the degree of coupling effects between degree-of-freedom motions with respect to the physical task space frame. A mathematical description of the method is presented, with the analysis supported by results from simulations and experiments. The results of the simulations show good agreement with the experimental results, indicating the good potential of the proposed method to provide guidance to mechanism designers in assessing the magnitude of the coupling effects at the initial design stage.

The process of empowering muscles in order to make them to a normal and common value is an expensive and prolonged work. There are some commercial exercise machines used for this purpose called rehabilitation systems. However, these machines have limited use because of some reasons. In this paper, an algorithm and an improved rule are presented for designing a rehabilitation intelligent system of lower limbs by a 6-DOF Stewart PARALLEL ROBOT. Impedance control and adaptive control are used to control of ROBOT. Estimation and optimization of control parameters will be done by NN and GA, respectively. Thereafter, the results of simulations are presented by defining a physiotherapy standard mode on desired trajectory. MATLAB Simulink is used for simulations. It shows that proposed algorithm in comparation with other similar methods is a low-cost method and needs to less energy and force with high accuracy.

This paper presents the closed-form calibration procedure of a 5-DOF Mitsubishi ROBOT. In this method only the joint angle information is required. But due to the limitation of the ROBOT degrees of freedom it is not possible to attach the end-effector of the ROBOT directly to the ground; however, we can use a bar with two ball end joints for this purpose. By doing this, the ROBOT can move freely in space. The most limiting factor of the closed-loop calibration of ROBOT is that we cannot measure the non-moving joints, and we have to use other joint to estimate the motion of these joints. A novel approach to estimate the non-moving degrees of freedom are presented in the paper that can be extended to other ROBOTs. Experimental results validate the proposed method and the deviation of the joint parameters compared with the nominal values of the ROBOT parameters delivered in the catalogue is very limited and are in an acceptable ranges.