DTSMA: Dominant Swarm with Adaptive T-distribution Mutation-based Slime Mould Algorithm

<abstract> <p>The slime mould algorithm (SMA) is a metaheuristic algorithm recently proposed, which is inspired by the oscillations of slime mould. Similar to other algorithms, SMA also has some disadvantages such as insufficient balance between exploration and exploitation, and easy to fall into local optimum. This paper, an improved SMA based on dominant swarm with adaptive t-distribution mutation (DTSMA) is proposed. In DTSMA, the dominant swarm is used improved the SMA's convergence speed, and the adaptive t-distribution mutation balances is used enhanced the exploration and exploitation ability. In addition, a new exploitation mechanism is hybridized to increase the diversity of populations. The performances of DTSMA are verified on CEC2019 functions and eight engineering design problems. The results show that for the CEC2019 functions, the DTSMA performances are best; for the engineering problems, DTSMA obtains better results than SMA and many algorithms in the literature when the constraints are satisfied. Furthermore, DTSMA is used to solve the inverse kinematics problem for a 7-DOF robot manipulator. The overall results show that DTSMA has a strong optimization ability. Therefore, the DTSMA is a promising metaheuristic optimization for global optimization problems.</p> </abstract>

Multi-Objective Swarm Intelligence Trajectory Generation for a 7 Degree of Freedom Robotic Manipulator

This work is aimed to demonstrate a multi-objective joint trajectory generation algorithm for a 7 degree of freedom (DoF) robotic manipulator using swarm intelligence (SI)—product of exponentials (PoE) combination. Given a priori knowledge of the end-effector Cartesian trajectory and obstacles in the workspace, the inverse kinematics problem is tackled by SI-PoE subject to multiple constraints. The algorithm is designed to satisfy finite jerk constraint on end-effector, avoid obstacles, and minimize control effort while tracking the Cartesian trajectory. The SI-PoE algorithm is compared with conventional inverse kinematics algorithms and standard particle swarm optimization (PSO). The joint trajectories produced by SI-PoE are experimentally tested on Sawyer 7 DoF robotic arm, and the resulting torque trajectories are compared.

Application of a computer vision system for recognizing tomato fruits and determining their position relative to the gripper device of the harvesting robot

The article presents a method for recognizing tomato fruits covered with foliage, de-termining their centers and boundaries using the OpenCV computer vision library and a hardware complex based on Raspberry Pi 4. The methods for solving the inverse kinematics problem for the five-link robotic manipulator designed by the authors, installed on a mobile plat-form, in order to create a robot for collecting fruits are considered. The simulation of the manipulator movement in the Scilab environment is performed.

Modeling the Delta Robot Movement along a Specified Trajectory in order to Determine the Force Factors Acting on its Drives and Hinges

Improving the productivity of machinery and auxiliary equipment has long been one of the main directions for the world industry development. Efforts to gain fractions of a percent of the indicator require both the improvement of existing mechanisms and the introduction of faster manipulators, such as a delta robot. One of the key design tasks for such mechanisms is determining the required drive characteristics. The article presents a solution of the inverse kinematics problem for a delta robot. An algorithm for planning the movement of the working body for performing a typical operation of object permutations is described. The issues of modeling the movement of a robot in the computer-aided design system Autodesk Inventor are considered. The dynamic characteristics of the manipulator have been obtained, on the basis of which it is possible to select drives, bearings and kinematic pairs.

Determination of the inverse kinematics branches of solution based on joint coordinates for UR-like serial robot architecture

This paper introduces a classification of the inverse kinematics solutions (or robot postures) of six-degree-of-freedom serial robots with a geometry based on or similar to Universal Robots' arms. The solution of the inverse kinematics problem is first presented briefly and the equations required to classify the robot postures(branches) based on the joint coordinates are then introduced.

Design and Analysis of Parallel Mechanism with Linear Drives Located on the Base at Specified Angles

The article considers a novel parallel mechanism with drives located on the base at different angles to its plane. This arrangement allows performing a relative movement between objects under water or in space (in aggressive environments). The new mechanism topology is compact for transportation and efficient for operation in aggressive environments. Structural synthesis has been performed; the number of degrees of freedom of the output link was calculated. A general approach to solving the inverse kinematics problem of positions is proposed and an example for a kinematic chain is shown. Denavit — Hartenberg matrices are used to solve the problem of positions. The position of the output link described by this matrix is used to represent the points of this link in the base coordinate system. The constraint equations are applied, which are the distances between the points of the base and the output link.

A Solution of the Inverse Kinematics Problem for a 7-Degrees-of-Freedom Serial Redundant Manipulator Using Gröbner Bases Theory

This article presents a solution of the inverse kinematics problem of 7-degrees-of-freedom serial redundant manipulators. A 7-degrees-of-freedom (7-DoF) redundant manipulator can avoid obstacles and thus improve operational performance. However, its inverse kinematics is difficult to solve since it has one more DoF than that necessary for reaching the whole workspace, which causes infinite solutions. In this article, Gröbner bases theory is proposed to solve the inverse kinematics. First, the Denavit–Hartenberg model for the manipulator is established. Second, different joint configurations are obtained using Gröbner bases theory. All solutions are confirmed with the aid of algebraic computing software, confirming that this method is accurate and easy to be implemented.