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In general, a multiple robotic manipulator system (MRMS) with uncertainties can be considered a composition system with a robotic manipulator subsystem (RMS) and a communication strength subsystem (CSS), and both subsystems are coupled to each other. In this paper, a new position tracking control scheme is proposed for the MRMS while considering the communication strength dynamics between robotic manipulators. The control scheme designed in this paper consists of two parts: the first part is to design the control protocol in the RMS, and the second part is to design the coupling relationship in the CSS. Through these two parts, we can achieve the position tracking of an MRMS. Firstly, the dynamical mathematical model of the RMS and CSS in the MRMS is constructed, and the corresponding assumptions are given. Then, the corresponding stability analysis is proposed, which provides the basis for a theoretical understanding of the underlying problem. Finally, an illustrative example is presented to verify the effectiveness of the proposed control scheme.

A non-linear optimal (H-infinity) control approach is proposed for the dynamic model of multi-degree-of-freedom (DOF) electro-hydraulic robotic manipulators. Control of electro-hydraulic manipulators is a non-trivial problem because of their non-linear and multi-variable dynamics. In this study, the considered robotic system consists of a multi-link robotic manipulator that receives actuation from rotary electro-hydraulic drives. The article's approach relies first on approximate linearisation of the state-space model of the electro-hydraulic manipulator, according to first-order Taylor series expansion and the computation of the related Jacobian matrices. For the approximately linearised model of the manipulator, a stabilising H-infinity feedback controller is designed. To compute the controller's gains, an algebraic Riccati equation is solved at each time-step of the control algorithm. The global stability properties of the control scheme are proven through Lyapunov analysis. The proposed control method retains the advantages of typical optimal control, i.e. fast and accurate tracking of the reference setpoints under moderate variations of the control inputs.

Introduction. Industrial robotic manipulators are becoming an integral part of modern enterprises due to their versatility and ability to perform complex operations with high precision and speed, including in extreme conditions. Effective implementation and operation of robotic manipulators requires an understanding of their design features, control methods, and manufacturing technologies. Main part. This review presents a classification of robotic manipulators based on their design features, number of degrees of freedom, and drive types. Their application areas and market trends are analyzed. This review points to the steady growth of the industrial robotic manipulator market, driven by the transformation of production processes in line with the concept of Industry 4.0. This article examines the structural components of robotic manipulators: the mechanical part, the drive, and the control system. It also presents an overview of modern materials used in the production of manipulators. A method for enhancing the performance properties of structural components through the use of materials with a nanocrystalline structure is proposed. Current development trends in industrial robotics are identified. It is noted that the integration of machine vision and artificial intelligence into manipulator control systems is becoming a key trend in robotics. Such solutions enable rapid response to changing operating conditions and the prevention of potential accidents. Conclusion. Industrial robotic manipulators continue to evolve, opening up new opportunities for automation and increased efficiency in production processes. Their further improvement requires an interdisciplinary approach combining engineering, software, and technological solutions. The results of this review can be used for selecting, designing, and implementing industrial robotic manipulators in enterprises, as well as for further scientific research in the field of robotics.

This paper describes a new robotic manipulator with three fingers based on an origami twisted tower design. The design specifications, kinematic description, and results from the stiffness and durability tests for the selected origami design are presented. The robotic arm is made of a 10-layer twisted tower, actuated by four cables with pulleys driven by servo motors. Each finger is made of a smaller 11-layer tower and uses a single cable directly attached to a servo motor. The current hardware setup supports vision-based autonomous control and internet-based remote control in real time. For preliminary evaluation of the robot's object manipulation capabilities, arbitrary objects with varying weights, sizes, and shapes (i.e., a shuttlecock, an egg shell, a paper cub, and a cubic block) were selected and the rate of successful grasping and lifting for each object was measured. In addition, an experiment comparing a rigid gripper and the new origami-based manipulator revealed that the origami structure in the fingers absorbs the excessive force applied to the object through force distribution and structural deformation, demonstrating its potential applications for effective manipulation of fragile objects.

In a future intelligent factory, a robotic manipulator must work efficiently and safely in a Human–Robot collaborative and dynamic unstructured environment. Autonomous path planning is the most important issue which must be resolved first in the process of improving robotic manipulator intelligence. Among the path-planning methods, the Rapidly Exploring Random Tree (RRT) algorithm based on random sampling has been widely applied in dynamic path planning for a high-dimensional robotic manipulator, especially in a complex environment because of its probability completeness, perfect expansion, and fast exploring speed over other planning methods. However, the existing RRT algorithm has a limitation in path planning for a robotic manipulator in a dynamic unstructured environment. Therefore, an autonomous obstacle avoidance dynamic path-planning method for a robotic manipulator based on an improved RRT algorithm, called Smoothly RRT (S-RRT), is proposed. This method that targets a directional node extends and can increase the sampling speed and efficiency of RRT dramatically. A path optimization strategy based on the maximum curvature constraint is presented to generate a smooth and curved continuous executable path for a robotic manipulator. Finally, the correctness, effectiveness, and practicability of the proposed method are demonstrated and validated via a MATLAB static simulation and a Robot Operating System (ROS) dynamic simulation environment as well as a real autonomous obstacle avoidance experiment in a dynamic unstructured environment for a robotic manipulator. The proposed method not only provides great practical engineering significance for a robotic manipulator’s obstacle avoidance in an intelligent factory, but also theoretical reference value for other type of robots’ path planning.

In this study, a quantum behaved particle swarm algorithm has used for inverse kinematic solution of a 7-degree-of-freedom serial manipulator and the results have been compared with other swarm techniques such as firefly algorithm (FA), particle swarm optimization (PSO) and artificial bee colony (ABC). Firstly, the DH parameters of the robot manipulator are created and transformation matrices are revealed. Afterward, the position equations are derived from these matrices. The position of the end effector of the robotic manipulator in the work space is estimated using Quantum PSO and other swarm algorithms. For this reason, a fitness function which name is Euclidian has been determined. This function calculates the difference between the actual position and the estimated position of the manipulator end effector. In this study, the algorithms have tested with two different scenarios. In the first scenario, values for a single position were obtained while values for a hundred different positions were obtained in the second scenario. In fact, the second scenario confirms the quality of the QPSO in the inverse kinematic solution by verifying the first scenario. According to the results obtained; Quantum behaved PSO has yielded results that are much more efficient than standard PSO, ABC and FA. The advantages of the improved algorithm are the short computation time, fewer iterations and the number of particles.

This paper develops a novel global nonsingular terminal sliding mode control (GNTSMC) strategy based on an adaptive super-twisting algorithm (STA) for tracking control of robotic manipulators with uncertain perturbations. A novel global nonsingular terminal sliding manifold is designed to steer the system trajectory to reach the switching surface at the beginning, thereby removing the reaching stage and achieving strong robustness throughout the entire response. Moreover, the proposed sliding manifold can ensure the finite time convergence of the trajectory error to the origin. Then, an adaptive STA, which does not require the boundary information of the perturbations, is devised not only to attenuate the chattering effect without degrading the tracking precision, but also to guarantee the finite time stability of the system. Finally, the superiority of the adopted GNTSMC is validated by comparative studies.

The main objective of a motion planning algorithm is to find a collision-free path in the workspace of a robotic manipulator in a point-to-point motion. Among the various motion planning methods available, sample-based motion planning algorithms are easy to use, quick and powerful in redundant robotic systems applications. In this study, different sampling-based motion planning algorithms are employed to select the most appropriate method for efficient collision-free motion planning. As a case study, finding a collision-free robotic displacement for welding a main pipe with other intersecting pipes and joints is considered. The robotic manipulator employed in this study has seven degrees of freedom, where six degrees are related to the manipulator joints and one degree is related to its base linear movement suspended from ceiling. Five criteria, time, path length, path time, path smoothness and process time are used to evaluate the efficiency of different sample-based motion planning algorithms. Finally, a smaller set of more efficient algorithms are introduced based on the defined efficiency evaluation criteria.

This paper is concerned with the problem of collision-free path planning for manipulators in multi-obstacle scenarios. Aiming at overcoming the deficiencies of existing algorithms in excessive time consumption and poor expansion quality, a path planning algorithm named Fast Bi-directional Rapidly-exploring Random Tree (FBi-RRT) with novel heuristic node expansion is proposed, which includes a selective-expansion strategy and a vertical-exploration strategy. The selective-expansion strategy is designed to guide the selection of the nearest-neighbor node to avoid the repeated expansion failure, thereby shortening the overall planning time. Also, the vertical-exploration strategy is developed to regulate the expansion direction of the collision nodes to escape from the obstacle space with less blindness, thus improving the expansion quality and further reducing time cost. Compared with previous planning algorithms, FBi-RRT can generate a feasible path for manipulators in a drastically shorter time. To validate the effectiveness of the proposed heuristic node expansion, FBi-RRT is conducted on a 6-DOF manipulator and tested in five scenarios. The experimental results demonstrate that FBi-RRT outperforms the existing methods in time consumption and expansion quality.

To achieve high-performance trajectory tracking for a manipulator, this study proposes a novel sliding mode control strategy incorporating a nonlinear disturbance observer. The observer is designed to estimate unknown models in real-time, enabling feedforward compensation for various uncertainties such as modeling errors, joint friction, and external torque disturbances. The control law is formulated by integrating the Backstepping method, Lyapunov theory, and global fast terminal sliding mode theory, ensuring global convergence to zero within finite time and enhancing system robustness. To address the inherent chattering issue in sliding mode control, a hybrid reaching law is developed by combining the exponential and power reaching laws. Additionally, the improved-fal (Imp-fal) function replaces the sign function in the switching control law, improving system response speed, preventing overshoot, and optimizing gain beyond the threshold value. Through simulation and comparative experiments conducted using MATLAB/Simulink, the controller model exhibited a 16.4% average reduction in the mean square value of tracking errors compared to existing control strategies, with improvements observed in various performance indicators. When applied to a self-developed three-degree-of-freedom manipulator experimental platform, the controller demonstrated a roughly 55% increase in tracking accuracy and a decrease in response time by approximately 45% compared to existing strategies. The experimental results validate the effectiveness, superiority, and practicality of the control strategy, providing a feasible solution for high-performance trajectory tracking in robotic arm systems.