List of articles (by subject) robotics
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Open Access Article
1 - Dynamic Modelling and Control of a Dielectric Elastomer Actuator with Two Degrees of Freedom
Yaser Hesari Shahram Etemadi HaghighiDielectric elastomer actuators are capable of creating multi degrees of freedom in a single joint. In this paper, a double-cone dielectric elastomer actuator is assumed as a planar joint with two degrees of freedom. Because of theoretical complexities, mathematical form MoreDielectric elastomer actuators are capable of creating multi degrees of freedom in a single joint. In this paper, a double-cone dielectric elastomer actuator is assumed as a planar joint with two degrees of freedom. Because of theoretical complexities, mathematical formulation of dynamic equations is too complicated. To obtain the dynamic equations of motion, at first, experimental charts are used. At this stage forms of relations between displacements, voltages, forces and moments are proposed, and coefficients are optimized to keep the difference between experimental and estimated charts in minimum. Then dynamic equations of motion are derived based on Newton-Euler method, and state-space form of equations of the joint are obtained. As a second objective, joint stabilization around working point is considered. To stabilize the joint against external loads, or initial dislocations, a regulator controller is designed. The joint is over actuated. So using constraint equations, control rule is extracted and simulated. Simulations show successful performance around the working point. Manuscript profile -
Open Access Article
2 - Trajectory Tracking Control of a Novel Planner Continuum Robot
Seyed Shoja Amini ali keymasi khalajiResearchers have a special fondness for continuum robots (CRs) due to their various applications. CRs have been modeled in different ways. One of these methods is called lumped model. Although the lumped modeling of CRs needs multiple degrees of freedom, researchers hav MoreResearchers have a special fondness for continuum robots (CRs) due to their various applications. CRs have been modeled in different ways. One of these methods is called lumped model. Although the lumped modeling of CRs needs multiple degrees of freedom, researchers have considered only a few degrees of freedom. But considering such structures led to some issues in the accuracy of the controller. Therefore, in this paper, the dynamic modeling of a CR which is based on the lumped model is developed in a general form. Additionally, a control strategy based on sliding mode back-stepping control is proposed after introducing the first and second Lyapunov functions for stability proof. Moreover, a new function in the control law is used to avoid chattering phenomena. The proposed controller can reduce the settling time, which is one of the most important factors in controlling such robots. To demonstrate the efficiency of the proposed method, three different case studies are conducted for a planar 8-DOF continuum manipulator and the simulations are compared with the feedback linearization method (FL). The simulations show the effectiveness of the proposed method for controlling the continuum robot. Manuscript profile -
Open Access Article
3 - Optimal Design of a Novel Two-Branch Spray Painting Robot for Prescribed Process Space
Meisam Vahabi Majid AhiPainting of roadside blocks manually is costly and time-consuming and can cause road accidents for workers. This paper is devoted to the optimum design of a novel two-branch robot utilized as spray painting mechanism for side and top of the roadside blocks simultaneousl MorePainting of roadside blocks manually is costly and time-consuming and can cause road accidents for workers. This paper is devoted to the optimum design of a novel two-branch robot utilized as spray painting mechanism for side and top of the roadside blocks simultaneously. Considering painting process conditions and the block displacement pattern which can change both height and lateral location along the road, clear that the process could be carried out properly by means of two nozzles. Two planar process spaces are evolved in favour of two-dimensional paths where nozzles track during the process. A conceptual architecture is formed considering the same movements that nozzles are actuated to compensate the blocks’ horizontal displacements. One parallel and one serial manipulator of the robot structure a relation by common prismatic joint. Actuators are positioned close to the base of the truck so that dynamics of movable parts are to be improved logically. Due to the change in the height and lateral location of the blocks, position of joints be optimized in terms of stroke angle and process space could be best fitted into workspace, optimization problem is arisen and solved using Genetic algorithm (G.A.) which results in less angular stroke for lower nozzle and faster matching with block conditions. The optimized joint position and center of mass are far from the base, resulting in a large torque subjected to the base. To solve the problem, the joint position is shifted toward the base without a change in the optimum situation. Finally, results are studied and detailed further. Manuscript profile -
Open Access Article
4 - Direct Kinematics Solution of 3-RCC Parallel Robot using a Semi-Analytical Homotopy Method
Seyyed Mojtaba Varedi-Koulaei Masoumeh RahimiParallel 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 MoreParallel 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. Manuscript profile -
Open Access Article
5 - Design, Modeling and Adaptive Force Control of a New Mobile Manipulator with Backlash Disturbances
Hami Tourajizadeh Samira AfshariIn this paper a new model of the mobile robot is designed and modelled equipped by a manipulator which can perform an operational task. Also an adaptive force controller is designed and implemented on the robot to provide the capability of the operational task of the ro MoreIn this paper a new model of the mobile robot is designed and modelled equipped by a manipulator which can perform an operational task. Also an adaptive force controller is designed and implemented on the robot to provide the capability of the operational task of the robot. Kinematic and kinetic modelling of the robot is developed and a new force control method is proposed for controlling the manipulator of the mobile robot by which the external disturbances caused by its operational performance can be controlled. Therefore, in this paper, a new mobile robot is designed which is suitable for operational tasks like firing and its related modelling is presented. Afterwards, an adaptive force controller is designed and implemented in order to neutralize the destructive effect of the mentioned backlash disturbance. By conducting some analytic and comparative simulation scenarios, the correctness of modelling and efficiency of the designed force controller is verified and it is shown that the proposed closed loop mobile manipulator can successfully accomplish a firing operation in a large workspace of a mobile robot with good accuracy. Manuscript profile -
Open Access Article
6 - Comparative Study and Robustness Analysis of Quadrotor Control in Presence of Wind Disturbances
Reham MohammedControlling of the quadrotor has been noted for its trouble as the consequence of exceeds nonlinear system, strong coupled multivariable and external disturbances. Quadrotor position and attitude is controlled by several methodologies using feedback linearization, but w MoreControlling of the quadrotor has been noted for its trouble as the consequence of exceeds nonlinear system, strong coupled multivariable and external disturbances. Quadrotor position and attitude is controlled by several methodologies using feedback linearization, but when quadrotor works with unstructured inputs (e.g. wind disturbance), some limitations of this technique appear which influence flight work. Design control system with fast response, disturbance rejection, small error, and stability is the main objective of this work. So in this paper we can make use of new methods of control to design a controller of nonlinear robust with a reasonable performance to test the impact of wind disturbance in quadrotor control such as Fuzzy-PID controller and compared its results with the others four controllers which are PID tuned using GA, FOPID tuned using GA, ANN and ANFIS then discus which controller give the best results in the presence and absence of wind disturbance. The main objective of this paper is that performance of the designed control structure is computed by the fast response without overshoot and minim error of the position and attitude. Simulation results, shows that position and attitude control using FOPID has fast response and better steady state error and RMS error than Fuzzy-PID, ANFIS, ANN and PID tuned using GA without impact of wind disturbance but after impact of wind disturbance it was observed using Fuzzy-PID has fast response with minimum overshoot and better steady state error and RMS error than the other four controllers used in the paper and compared with most of literature reviews which didn't give the adequate results contrasted with the required position and attitude. The all controllers are tested by simulation under the same conditions using SIMULINK under MATLAB2015a. Manuscript profile -
Open Access Article
7 - Velocity Control of Nonlinear Unmanned Rotorcraft using Polytopic Modelling and State Feedback Control
Reza Tarighi Amir Hooshang Mazinan Mohammad Hosein KazemiPerformance and improvement of flight efficiency at various velocities for flight systems, in particular, rotorcrafts, with specific complexities in motion and its nonlinear equations are always of particular interest to researchers in the aerial and control domains. In MorePerformance and improvement of flight efficiency at various velocities for flight systems, in particular, rotorcrafts, with specific complexities in motion and its nonlinear equations are always of particular interest to researchers in the aerial and control domains. In this research, a new control algorithm is addressed based on the complete nonlinear Unmanned Rotorcraft (UR) model and its four main inputs. Exploiting state feedback and Polytopic Linear Parameter Varying (PLPV) modeling and using Linear Matrix Inequality (LMI), the velocity control problem is investigated. The trim points of the system are produced under different velocity control conditions. State feedback control gain matrix which plays a main role in producing the ultimate control signal, is computed by solving a set of LMIs under various conditions. Finally, instead of using a Nonlinear model, a Polytopic model is used for controller synthesis. With this goal, different scenarios for the proposed flight velocity control (in different dynamic ranges, minimum velocity to maximum velocity) are implemented. The simulation results demonstrate a very good performance of the proposed controller in the basis of PLPV modelling. It can be concluded that the proposed manner is useful to overcome the disruptions imposed on the flight system due to the changes in the equilibrium points and the uncertainties of the parameters and/or possible errors due to the unwanted possibilities in the system. Manuscript profile -
Open Access Article
8 - Analysis of the Dynamic Forces of 3D Printer with 4 Degrees of Freedom
sajjad pakzad ebrahim imaniThe use of parallel mechanisms in the structure of 3D printers are developing. Parallel mechanisms have excellent capabilities in terms of accuracy, stiffness and high load-bearing capacity. This article studies a 3D printer with four degrees of freedom that has three d MoreThe use of parallel mechanisms in the structure of 3D printers are developing. Parallel mechanisms have excellent capabilities in terms of accuracy, stiffness and high load-bearing capacity. This article studies a 3D printer with four degrees of freedom that has three degrees of linear freedom and one degree of rotational freedom. The advantages of this printer are greater than conventional Cartesian printers, including higher print speed and stiffness, and there are also higher degrees of freedom for manoeuvrability. In this paper, the Newton-Euler analytical method is used to analyse the inverse dynamics and identify the driving forces required by the 3D nozzle motion. By coding the inverse dynamic equations in the MATLAB software environment, the driving forces diagrams are extracted based on the printer's nozzle motion. To validate the inverse dynamics relationships, simulations with the Simmechanic model of MATLAB software have been performed. Through changing the speed of movement of the printer nozzle and also change of the velocity and acceleration of drives, the forces required for the drive also change. The effect of changes in print speed of a specific geometry on the driving forces is also studied. As well as, choosing the optimum print speed with regard to the motor driver power and the dynamics of the forces applied to the drivers and the less print time are the most important factors that are discussed in this article. Manuscript profile -
Open Access Article
9 - Design and Implementation of Embedded Direct Drive SCARA Robot Controller with Resolved Motion Rate Control Method
Shahram Dashti Mohsen Ashourian Farshid SoheiliMost of SCARA (Selective Compliance Articulated Robot Arm) direct drive robots today are equipped with a circular feedback system. The Resolved Motion Rate Control (RMRC) method increases the accuracy and compensates the lack of movement transmission system in accurate MoreMost of SCARA (Selective Compliance Articulated Robot Arm) direct drive robots today are equipped with a circular feedback system. The Resolved Motion Rate Control (RMRC) method increases the accuracy and compensates the lack of movement transmission system in accurate pick and place actions. In this study, a pick-and-place SCARA robot is developed by using a developed robot manipulator arm and controlling with its designed control systems. To make the end-effector of the SCARA robot arm following desired positions with specified joint velocities, the inverse kinematics technique, known as the RMRC generates motion trajectories automatically. In this research, the kinematics method has been applied with the Jacobian pseudo-inverse or Jacobian singularity-robust inverse to generate and record the pick-and-place motion of the SCARA robot. These records are then compared with the records after using RMRC methods. Several system features like the variation of samples during 50 seconds for the first and second robot joint, and mean deviation for the detailed analysis by the controller after using RMRC motion control algorithm demonstrates the preference of RMRC method in SCARA direct drive robots. Manuscript profile -
Open Access Article
10 - Reducing Image Size and Noise Removal in Fast Object Detection using Wavelet Transform Neural Network
mahmoud jeddi Ahmad Khoogar Ali Mehdipoor OmraniA robot detects its surroundings through camera information and its response requires a high-speed image process. Due to the increasing application of vision systems, various algorithms have been developed to increase speed of image processing. This paper proposes a dou MoreA robot detects its surroundings through camera information and its response requires a high-speed image process. Due to the increasing application of vision systems, various algorithms have been developed to increase speed of image processing. This paper proposes a double density Discrete Wavelet-based Neural Network to enhance feature extraction and classification of parts in each picture. The Discrete Wavelet-based Neural Network combines multi-scale analysis ability of the wavelet transform and the classification capability of the artificial neural network by setting the wavelet function as the transfer function of the neural network. The automatic assembly process needs to capture the image in an online process in order to recognize the parts in the image and identify the location and orientation of the parts. In this part, the two dimensional double density discrete wavelet transform have been applied to compress and remove noise from the captured Image. By applying a value for the threshold, the coefficients of the wavelet transform function are obtained using these coefficients and the characteristics of the wavelet coefficients are calculated. Subsequently, a multilayer perceptron is trained using these extracted features of the images. To find the best vector characteristics, various combinations of extracted properties have been investigated. This method has succeeded in object detection and results show that the Neural Networks and the training algorithm based on the wavelet transform function have exquisite accuracy in classification. Thus, the developed method is considered effective as compared to other state-of-the-art techniques. Manuscript profile -
Open Access Article
11 - Design, Modeling and Manufacturing a New Robotic Gripper with High Load Bearing Capability and Robust Control of its Mechanical Arm
vahid Boomeri Hami TourajizadehIn this paper, a new robotic gripper is proposed and modeled which is able to bear a high amount of load and it can be used as the claws of climbing robots. As the climbing robots are usually heavy and their configuration should be kept in height against the gravity, fi MoreIn this paper, a new robotic gripper is proposed and modeled which is able to bear a high amount of load and it can be used as the claws of climbing robots. As the climbing robots are usually heavy and their configuration should be kept in height against the gravity, firm grippers with no slippage possibility should be designed in order to guarantee the stability. The proposed new gripper is essentially required for the grip-based climbing robots which are heavy and are supposed to accomplish a specific operational task while they are grasping the pipe-shaped structures. The kinematic and quasi-static modeling of the proposed gripper is extracted and its related parameters are optimized to provide the maximum gripping force and the minimum slippage probability. Since these robust grippers are usually actuated by high torque motors, the reaction effect of the actuators force on the arm of the robot model is investigated here as a new study. Hence, the corresponding mechanical arm is also controlled, using a robust nonlinear controller to neutralize the destructive effect of extreme reaction forces or torques from the gripper motors to the robot arm during its mission. Thus, a robust controller is designed and implemented on the arm joint to cover the required positioning accuracy of the arm movement during the climbing motion. Afterward, the applicability of the proposed gripper and also the efficiency of the designed controller is verified by the aid of some analytic and comparative simulation scenarios performed in MATLAB-SIMULINK and MSC-ADAMS simulation. It is shown that the proposed gripper together with its related controlling algorithm for the arm can successfully provide a proper climbing mechanism for these kinds of robots which are supposed to climb through the structures and perform a special manipulating task. Manuscript profile -
Open Access Article
12 - A New Visual Servoing Method for Grasping and Assembling Objects using Stereo Image Based Feedback
mahmoud jeddi ahmad reza khoogarIn this paper, an eye-in-hand stereo image-based visual serving controller for industrial 6 degrees of freedom manipulator robots is presented. The visual control algorithms mostly use the relationship between camera speed and changes in image features, to determine the MoreIn this paper, an eye-in-hand stereo image-based visual serving controller for industrial 6 degrees of freedom manipulator robots is presented. The visual control algorithms mostly use the relationship between camera speed and changes in image features, to determine the end-effector movement path. One of the main problems of the classical IBVS method is the inability to estimate the distance of the object related to the camera, which requires peripheral equipment such as a laser rangefinder to estimate the depth. In this study, two cameras were mounted on the end-effector of a 6 DOF manipulator robot. The distance of the object to the camera is estimated by the equations associated with the epipolar plane, and the interaction matrix is updated at any time. For increasing response speed, the image interaction matrix was divided into two separate parts related to translational and rotational motion, and it was found that only the translational motion part is affected by distance. The control method separates the camera motion into three-stage based on pure rotation, pure translation, and hybrid motion, which has a better time response compared to the classical IBVS control methods. Additionally, a method for position prediction and trajectory estimation of the moving target in order to use in a real-time grasping task is proposed and developed using Recursive Least Square as the trajectory estimators in the image plane. The simulation results show that the proposed method increases the system response speed and improves the tracking performance. Manuscript profile