Delta Parallel Manipulator Research Articles

Modeling, design and control of a 4-arm delta parallel manipulator employing type-1 and interval type-2 fuzzy logic-based techniques for precision applications

This paper presents the virtual design of a four-arm Delta parallel robot for potential applications in the food industry, specifically for the automated preparation of fast foods. Kinematic and dynamic models were developed based on the morphology of this type of robot. Cutting-edge and previously unexplored control strategies for these types of manipulators are then designed and implemented based on Fuzzy PD and Fuzzy PID configurations. Several performance indicators, such as the Integral Square Error (ISE), Integral Time Absolute Error (ITAE) and Integral Time Square Error (ITSE), were used to conduct a performance comparison of the control techniques, considering type-1 and interval type-2 fuzzy sets. In all the analyzed scenarios, the fuzzy controllers correspond to the Takagi–Sugeno–Kang model using linear functions of the inputs in the outputs. Among the main contributions of this work is the development of a detailed dynamic model of the robot in Simscape, incorporating realistic aspects that are often overlooked during analytical modeling. To ensure more accurate results, the rejection of external disturbances is thoroughly analyzed in simulations, considering elements such as time delays and control signal saturations. The results demonstrate the veracity of the proposed design for a four-arm Delta robot, both in models and in the Simscape/Simulink implementation. In the trajectory tracking task and external disturbance rejection, the superiority of the Fuzzy PID controller with interval type-2 fuzzy sets over fuzzy controllers with PD structure and over type-1 fuzzy sets is evidenced.

Forward Kinematics of Delta Manipulator by Novel Hybrid Neural Network

For the parallel configuration of the robot manipulator, the solution of Forward Kinematics (FK) is tough as compared to Inverse Kinematics (IK). This work presents a novel hybrid method of optimizing an Artificial Neural Network (ANN) specifically Multilayer Perceptron (MLP) with Genetic Algorithm (GA) and Step-wise Linear Regression (SWLR) to solve the complex FK of Delta Parallel Manipulator (DPM). The joint space angular positional data has been iterated using IK to generate point cloud of Cartesian space positional data. This data set is highly random and broad which leads to higher-order nonlinearity. Hence, normalization of the dataset has been done to avoid outliers from the dataset and to achieve better performance. The developed ANN based MLP gave a mean square error of 0.0000762 and an overall R2 value of 0.99918. Finally, the proposed network has been simulated to solve FK of the parallel manipulator and to check its efficacy. For given joint angles, the proposed network predicted positional values which are in good approximation with known trajectory solved by standard analytical method.

Computer vision-based high-quality tea automatic plucking robot using Delta parallel manipulator

Aiming to reduce the labour cost and improve the competitiveness of the tea production, this paper presents a complete solution, including the mechanical structure, the visual recognition system (VRS) and the motion control system of the high-quality tea automatic plucking robot. The design objectives involve high reliability and stability, ease of maintenance, cost-effectiveness, accurate recognition and localization of tea shoots, and high-efficient plucking manipulation. The VRS is established using the computer vision together with corresponding machine learning algorithms, where the Particle swarm optimization-Support vector machine algorithm and the deep convolutional neural YOLOv3 model are developed to recognize the tender tea shoots and localize the plucking point, according to the images captured by the global and local cameras, respectively. The Delta parallel manipulator equipped with a shear cutter is adopted to execute the trajectory tracking and tea plucking operations. The improved ant colony algorithm is utilized for path planning and trajectory smoothing of the manipulator. Simulation and laboratory platform experiment results verify the feasibility and effectiveness of the presented solution.

A new time-varying feedback RISE control for second-order nonlinear MIMO systems: theory and experiments

This study focuses on the development of a new class of the Robust Integral of the Sign of the Error (RISE) control law adequate for second-order nonlinear multi-input–multi-output systems. A revisit for the original RISE is done by altering some static feedback gains into time-varying nonlinear ones depending on the system states. The proposed controller takes advantage of both RISE control robustness towards uncertainties and the special behaviour of nonlinear feedback gains towards time-varied parameters. A Lyaponuv-based stability analysis to prove the semiglobal asymptotic tracking of the proposed new controller is included. In order to validate the relevance of the proposed controller, real-time experimental results are presented and discussed. Experiments have been conducted on a Delta parallel manipulator, in different operating conditions including payload and speed variations.

Virtual prototype and cosimulation applied to a 3 DOF Delta Parallel Manipulator for Kinematics & Kinetics Behavior Studies

This work presents the kinetics and kinematics analysis for delta-3 parallel manipulator. Kinematics and Kinetics validation was performed with a virtual prototype cosimulation using Solidworks and Labview and considering experimental data from physical prototype testing. In respect to the same testing path, comparisons of kinematics results from physical prototype against data of both virtual prototype and theoretical model, corroborate that positions of mobile platform have similar values in respect to the global coordinate system. On the other hand, actuator torques of theoretical model and virtual prototype reported conservative behaviors, whereas the torque of the physical prototype presents lower requirements under the same conditions. Work in unison of these computational tools allows a coherent study of mechanical systems and a direct comparison of the theoretical model, physical prototype and virtual prototype.

Evaluating concurrent design approaches for a Delta parallel manipulator

SUMMARYThis paper addresses the problem of optimal mechanisms design, for the geometric structure and control parameters of mechanisms with complex kinematics, which is one of the most intricate problems in contemporary robot modeling. The problem is stated by means of task requirements and performance constraints, which are specified in terms of the end-effector's position and orientation to accomplish the task. Usually, this problem does not fulfill the characteristics needed to use gradient-based optimization algorithms. In order to circumvent this issue, we introduce case studies of optimization models using evolutionary algorithms (EAs), which deal with the concurrent optimization of both: structure and control parameters. We define and review several optimization models based on the workspace, task and dexterity requirements, such that they guarantee an adequate performance under a set of operating and joint constraints, for a Delta parallel manipulator. Then, we apply several methodologies that can approximate optimal designs. Additionally, we compare the EAs with a quasi-Newton method (the BFGS), in order to show that the last kind of methods is not capable of solving the problem if the initial point is not very close to a local optimum. The results provide directions about the best state-of-the-art EA for addressing different design problems.

Accuracy Analysis of 3-RSS Delta Parallel Manipulator

Accuracy analysis of parallel manipulators is the first step in selecting an appropriate error model for further design. In this paper, the kinematic accuracy of a Delta parallel manipulator is evaluated by Jacobian and geometric error models. The Jacobian (or condition number) based error models have been widely used for analysis and optimal design of parallel manipulators. However, as it is highlighted in this study, these models are dependent on the choice of particular matrix norm and do not capture the directional nature of accuracy. The geometric error model, derived for the Delta parallel manipulator, computes the exact value of positioning errors in task space that arise due to errors in joint space. The proposed model is used to compute overall as well as individual positioning errors along each DOF. It is revealed that the kinematic accuracy exhibits a highly directional nature over the reachable workspace. Moreover, individual errors along each DOF should be analyzed for complete evaluation of the accuracy of the Delta parallel manipulator.

Delta Parallel Robot Based on Crank-Slider Mechanism

A three-degree-of-freedom Delta parallel manipulator driven by a crank-slider mechanism is proposed. In Cartesian space, a gate-shaped curve is taken as the path of the pick-and-place operation, combining with the inverse kinematics theory of the Delta robot, and a mathematical model of robot statia force transmission is established. The force and the output torque of the robot-driven joint are taken as the main performance indexes, and the value of the crank-slider mechanism applied to Delta robot is further measured. The simulation results show that the delta robot driven by the crank slider mechanism can reduce the force and output torque of the driving joint during the picking and discharging operation, and has good practical application value.

Force Transmission Performance Analysis of a Pure Translational Parallel Food Manipulators

The study discussed the force transmission performance of parallel food manipulator in order to design and confirm the power parameters of actuators. We take the Delta parallel food manipulator as example for analyzing force transmission of the food manipulator. In order to research on the load capability of parallel food manipulators, the concept of the force transmission capability is proposed. The force transmission capability of food manipulator can be used to confirm the power parameters of driving organs and describe the stability of force transmission in the work path or workspace of food manipulators. By analyzing force transmission capability of the Delta food manipulator, we obtain the relation of force transmission capability and condition number of the force Jacobian matrix and the distribution character of force transmission capability is analyzed primitively in whole workspace.

Control System Design of DELTA Parallel Manipulator Based on Real-time Ethernet

To overcome the shortages of current DELTA parallel manipulator controllers in openness and expansibility,a control system design is proposed using motion control platform EtherMAC(Ethernet for Manufacture Automation Control),which is based on real-time Ethernet.In this method,synchronous real-time control is realized under standard Ethernet without special network adapter and hard real-time operation system by communication bus using slave node synchronization and clock correction technology.Furthermore,with the modular-structured slave node FPGA IP core and component-based layered software architecture,DELTA manipulator can be developed quickly to adapt to different sorting and packaging situations.According to controller response time under prototype working condition,this method is proved to meet the requirements of synchronous real-time control.

Designing and optimization of parameters of delta‐4 parallel manipulator for a given workspace

AbstractIn the paper, the algorithm of designing some geometrical parameters of a Delta parallel manipulator has been described. The manipulator is to work in a specified workspace, which is given as a set of points. The first step of the algorithm seeks the possible solutions, and because there are an infinite number of them, the objective of the second step is to limit the number by an optimization. Owing to this, it is possible to find parameters of the manipulator, whose workspace contains the specified points. © 2003 Wiley Periodicals, Inc.