Operation Of Robotic Manipulators Research Articles

Classification of Faults Operation of a Robotic Manipulator Using Symbolic Classifier

In autonomous manufacturing lines, it is very important to detect the faulty operation of robot manipulators to prevent potential damage. In this paper, the application of a genetic programming algorithm (symbolic classifier) with a random selection of hyperparameter values and trained using a 5-fold cross-validation process is proposed to determine expressions for fault detection during robotic manipulator operation, using a dataset that was made publicly available by the original researchers. The original dataset was reduced to a binary dataset (fault vs. normal operation); however, due to the class imbalance random oversampling, and SMOTE methods were applied. The quality of best symbolic expressions (SEs) was based on the highest mean values of accuracy (ACC¯), area under receiving operating characteristics curve (AUC¯), Precision¯, Recall¯, and F1−Score¯. The best results were obtained on the SMOTE dataset with ACC¯, AUC¯, Precision¯, Recall¯, and F1−Score¯ equal to 0.99, 0.99, 0.992, 0.9893, and 0.99, respectively. Finally, the best set of mathematical equations obtained using the GPSC algorithm was evaluated on the initial dataset where the mean values of ACC¯, AUC¯, Precision¯, Recall¯, and F1−Score¯ are equal to 0.9978, 0.998, 1.0, 0.997, and 0.998, respectively. The investigation showed that using the described procedure, symbolically expressed models of a high classification performance are obtained for the purpose of detecting faults in the operation of robotic manipulators.

An Active Fault-Tolerant Control Based on Synchronous Fast Terminal Sliding Mode for a Robot Manipulator

To maintain the safe operation and acceptable performance of robot manipulators when faults occur inside the system, fault-tolerant control must deal differently uncertainties and disturbances, especially with the occurrence of loss-effective faults. Therefore, in this paper, an active fault-tolerant control for robot manipulators based on the combination of a novel finite-time synchronous fast terminal sliding mode control and extended state observer is proposed. Due to the internal constraints of the synchronization technique, the position error at each actuator simultaneously approaches zero and tends to be equal. Therefore, the proposed controller can suppress the effects of faults and guarantee the acceptable performance of robot manipulators when faults occur. First, an extended state observer is designed to estimate the lumped uncertainties, disturbance and faults. Then, the information from the observer is used to combine with the main novel synchronous fast terminal sliding mode controller as a compensator. By combining the merits of the observer compensation, sliding mode and synchronization technique, the proposed fault-tolerant controller is able to deal with uncertainties and disturbances in normal operation mode and reduce the effects of faults in case faults occur, especially in the occurrence of loss-effective faults. Finally, the enhanced safety, reality and effectiveness of the proposed fault-tolerant control are evaluated through the control of a 3-DOF robot manipulator in both a simulated environment and experiment.

Dynamic Collision and Deadlock Avoidance for Multiple Robotic Manipulators

A flexible operation of multiple robotic manipulators operating in a dynamic environment requires online trajectory planning to ensure collision-free trajectories. In this work, we propose a real-time capable motion control algorithm, based on nonlinear model predictive control, which accounts for static and dynamic obstacles. The proposed algorithm is realized in a distributed scheme, where each robot optimizes its own trajectory with respect to the related objective and constraints. We propose a novel approach for collision avoidance between multiple robotic manipulators, where each robot accounts for the predicted movement of the neighboring robots. Additionally, we propose a method to reliably detect and resolve deadlocks occurring in a setup of multiple robotic manipulators. We validate our approach on pick and place scenarios involving multiple robotic manipulators operating in a common workspace in a realistic simulation environment set up in Gazebo. The robots are controlled using the Robot Operating System. Our approach scales up to 4 manipulators and computes a path for each robot in a simultaneous pick and place operation in 94% of all investigated cases without deadlock detection and 100 % of cases with the proposed deadlock resolution algorithm. In contrast, the investigated conventional path planners, such as PRM, PRM*, CHOMP and RRT-Connect, successfully plan a trajectory in at most 54% of all investigated cases for a simultaneous operation of 4 robotic manipulators hindering their application in setups of multiple manipulators.

Intelligent fuzzy logic-based sliding mode control methodologies for pick and drop operation of robotic manipulator

Intelligent fuzzy logic-based sliding mode control methodologies for pick and drop operation of robotic manipulator

Intelligent fuzzy logic-based sliding mode control methodologies for pick and drop operation of robotic manipulator

Intelligent fuzzy logic-based sliding mode control methodologies for pick and drop operation of robotic manipulator

Fuzzy Digital Filter Device Study for the Robot Manipulator

Рurpose of research. Situations that reduce the accuracy of links positioning often arise due to the drab of contacts during the operation of robot manipulator. One of this problem solutions is signal filtering. Modern digital filtering algorithms have a rather complex mathematical structure. Data processing in such filters takes long time. So the purpose of this work is to develop fast-acting fuzzy digital filter device capable to eliminate the problem of contact scrapping when positioning the links of robot manipulator.Methods. Generalized mathematical model was used in the development of digital filter device. This model is implemented by using fuzzy logic theory. Generalized mathematical model of the fuzzy digital filter includes a model determining a support of fuzzy output variable, a model for determining coefficients of fuzzy digital filter and a model for converting the output voltage into a rotation angle of robot manipulator servo drive. This mathematical model makes it possible to recalculate the voltage supplied to the input of fuzzy digital filter using two control coefficients thereby improving the positioning accuracy of robot manipulator links.Results. During experimental studies, comparative analysis of developed fast-acting device of fuzzy digital filter with Kalman filter was carried out. The RMSE standard error for two filters was calculated. The average RMSE value of the fuzzy digital filter was 0.0185 of Kallman's filter was 0.0193.Conclusion. Generalized mathematical model of fuzzy digital filter device consisting of three models is described. Device implementing determination of caliper of fuzzy output variable, experimental model of robot manipulator, experimental research and proposed mathematical model are presented.

Repetitive Motion Planning of Robotic Manipulators With Guaranteed Precision

Repetitive motion planning (RMP) plays a remarkable role in the operation of robotic manipulators. In this article, the RMP of robotic manipulators wherein the high precision of joint angle repeatability and end-effector motion is guaranteed is investigated. In particular, a novel pseudoinverse-based (P-based) RMP scheme is designed and proposed for robotic manipulators by applying a special difference rule to discretize the existing RMP scheme with P-based formulation. Such scheme is theoretically analyzed and proven to simultaneously guarantee joint angle repetitive precision and end-effector motion precision. Comparative simulation results of a five-link robotic manipulator and a universal robotic manipulator are provided to verify the effective performance of the proposed P-based RMP scheme. The physical realizability of the proposed scheme is further substantiated by implementing the scheme on a practical EPSON robotic manipulator.

Investigation on the Discretization of a Repetitive Path Planning Scheme for Redundant Robot Manipulators

Repetitive path planning (RPP) plays an important role in the operation of redundant robot manipulators. In this study, we investigate a new discrete-time RPP scheme depicted in the pseudoinverse-type formulation for redundant robot manipulators. Such a scheme is derived from the discretization of the previous continuous-time RPP scheme using a special numerical difference formula. Theoretical analysis shows that the proposed RPP scheme has the property of cube pattern in the end-effector planning accuracy. On the basis of a PUMA560 robot manipulator with different examples, comparative simulation results are presented to demonstrate the effectiveness and superiority of the proposed RPP scheme.

Operability Evaluation System and Comparison Experiment of Gesture Operation and Button Operation of Robot Manipulator

Robot manipulators are now widely used in manufacturing industries. When programmed to perform required movements via a process called teaching, they can accomplish a wide variety of complex tasks. In conventional teaching processes, a teaching pendant (TP), which is a tethered controller with which the operator inputs specific movement commands, is used. However, such devices normally have so many buttons that operators often experience difficulty in programming operations intuitively, so the teaching process consumes significant amounts of time and effort. To solve this problem, intuitive operation methods in which human body motions (such as hand gestures) are used as input to the robot have been studied. However, no quantitative comparisons between those new gesture-based and conventional teaching methods have yet been made. With that point in mind, the present paper proposes a virtual space-based evaluation system in which operators control the position and orientation of a six-degree-of-freedom virtual robot hand in order to evaluate and compare TP- and gesture-based operation methods. The experimental results show that when compared to TP-based methods, gesture-based operation methods achieved higher evaluations in terms of time and psychological aspects. In addition, four types of gesture-based operating methods were proposed in order to consider different ways in which position changes and orientation changes could be handled. The operability levels of the four gesture types were also compared quantitatively using the proposed evaluation system, and the obtained experimental results suggest that such differences can affect the cognitive burden imposed on the operator.

Active manipulator motion planning for planetary landform awareness

This paper presents an active motion planning approach for a robotic manipulator operating in planetary surface exploration missions. A monocular camera is employed to examine the visually salient regions in an image, from which landforms of potential interests are extracted, and two key metrics are established to evaluate the information richness of the landforms. A next-best view manipulator motion planning is proposed, in which motions of the manipulator are actively planned to reach a better viewpoint to view the target landform, the safety of such operation is guaranteed by real-time estimating the relative distance using ORriented Brief (ORB)–simultaneous localization and mapping. The proposed active motion planning method is validated by an experimental trial, results from which demonstrate that it is able to safely acquire a better viewing of a just-detected planetary landform with full autonomy.

Safety-oriented robot payload identification using collision-free path planning and decoupling motions

Abstract The paper presents a procedure for the identification of the inertial parameters of the payload mounted on the end-effector of a robotic manipulator operating in a collaborative setup. The procedure is therefore designed considering as a primary objective the safe execution of the payload estimation process, in terms of avoidance of physical objects and protected zones within the robot workspace, in which the presence of human operators is allowed and expected. The methods applied in the definition of the proposed operational sequence include a collision-free path planner and a joint trajectory generator that allows the safe execution of specific test motions. In particular, each one of such test motions decouples the effects of all but one inertial parameter of the payload, in order to improve the accuracy of identification. Experimental results on a redundant industrial manipulator demonstrate the feasibility of the proposed identification method.

Adaptive synchronised tracking control for multiple robotic manipulators with uncertain kinematics and dynamics

In this study, a new adaptive synchronised tracking control approach is developed for the operation of multiple robotic manipulators in the presence of uncertain kinematics and dynamics. In terms of the system synchronisation and adaptive control, the proposed approach can stabilise position tracking of each robotic manipulator while coordinating its motion with the other robotic manipulators. On the other hand, the developed approach can cope with kinematic and dynamic uncertainties. The corresponding stability analysis is presented to lay a foundation for theoretical understanding of the underlying issues as well as an assurance for safely operating real systems. Illustrative examples are bench tested to validate the effectiveness of the proposed approach. In addition, to face the challenging issues, this study provides an exemplary showcase with effectively to integrate several cross boundary theoretical results to formulate an interdisciplinary solution.

MULTISENSOR DATA FUSION BASED AUTONOMOUS MOBILE ROBOT WITH MANIPULATOR FOR TARGET DETECTION

This paper proposes a novel autonomous mobile robot in unknown environment navigating through obstacle s by computing the shortest path. Flood fill algorithm is used for pat h planning of the mobile robot. The concept of mini mum energy contour to perform the desired operation of robotic manipulator is ach ieved using Fuzzy algorithm. Object detection is do ne by utilizing a mobile robot with sensors and object recognition is achieved by image processing using Principal Component Analysis (PCA). This paper describes the implementation of multi sensor data f usion assisting a mobile robot to acquire a purposi ve behavior in the respective environment. This is achieved by directly integrati ng sensor information which helps the robot to succ essfully navigate and also enables fetch & retrieval operation of robotic mani pulator. In this approach, information is taken fro m distance sensors, position sensors and image sensor. This work also aims to pr ovide an optimal fusion of information from distrib uted multiple sensors using Kalman Filter.

Compatible MPID Optimal Controller for Flexible Operation of Two Link Manipulator

Robotic arms or manipulators are interrelated to electro mechanical modulations criteria’s. The controls of this type of manipulators are very authentic and difficult too. For flexible operation of robotic manipulators, controlling should be required for their tip vibrations and torque responses. In this article we initiate the proto type differences between responses of torques with PID Controller in open loop as well as in closed loop condition. For the closed loop, the physical phenomenon of PID Changes named as Modified PID Controller. The MPID Controller provides better performance rather than open loop PID at far end of two link Manipulator arm. The Electro mechanical modeling of the two link manipulator was done by using State Space technique named as an M-File. The entire graphical representations are providing by using MATLAB/Control tool box.

A Matlab-based framework for the remote control of a 6-DOF robotic arm for education and research in control theory

The paper provides an overview on the 6-DOF robot manipulator for control education and research at a robotic lab at TU-Dortmund. The Matlab-based framework for a safe and reliable remote operation of a standard industrial robotic manipulator enables students and researchers to conduct experiments in robotics and control in efficient and productive manner. In addition to an overview of the robot and the control framework the paper reports on the experiments of several student theses and project groups conducted in the past few years. The outlook sketches some challenges and perspectives for future utilization of the control framework in the context of students education and research.

Energy minimization of redundant manipulators using Generalized Pattern Search

Optimal motion planning is very important in the operation of robot manipulators. Its main target is the generation of a trajectory from start to goal that satisfies objectives, such as minimizing path traveling distance or time interval, lowest energy consumption or obstacle avoidance and satisfying the robot's kinematics and dynamics. Due to increasing demand on fuel consumption and the uprising political crisis, there is a need to optimize the energy consumption for stable and durable operation. In this paper, an optimal trajectory is designed for a three degree–of–freedom planar redundant manipulator under the criterion of minimum energy consumption. Each joint trajectory is assumed as a fourth order polynomial and the proposed algorithms are required to optimize the coefficients in such away the actuator torque will be minimized. Two optimization algorithms are presented here the Genetic Algorithm (GAs) and the Generalized Pattern Search (GPS). A simulation study to identify the optimal performance parameters is carried out using MATLAB. Comparison between the proposed two algorithms is carried out using the energy consumption per cycle, E, for validation.

1P2-S-054 大型ロボットアームのマニュアル操作における制振実験(宇宙ロボティクス3,生活を支援するロボメカ技術のメガインテグレーション)

1P2-S-054 大型ロボットアームのマニュアル操作における制振実験(宇宙ロボティクス3,生活を支援するロボメカ技術のメガインテグレーション)

Adaptive synchronization control of a robotic manipulator operating in an intelligent workcell

The formulation and implementation of a synchronization control scheme applicable to a robotic workcell is described. Such a workcell typically consists of a conveyor system that transports industrial workpieces, a binary camera to recognize the geometric and other characteristics of the workpiece, and a robotic manipulator that is suitably controlled to direct its end effector to achieve a synchronized rendezvous with the workpiece. Subsequent to a successful rendezvous, the robot may pick up the piece (in pick-an-place operations) or perform such other online operations as assembly, processing, or quality inspection. A methodology to ensure rapid rendezvous with accurate tracking is emphasized. Simulation and implementation results are compared and discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Numerical filtering for the operation of robotic manipulators through kinematically singular configurations

AbstractThe loss of independent degrees of freedom at singular configurations is an inherent characteristic of robotic manipulators. Due to the unavoidable singularity of mechanical wrists, singular configurations cannot be avoided by simply restricting the bounds of the workspace. Techniques for operating at singular configurations without inducing unacceptably high joint velocities or end effector tracking errors are presented. Extensions to the damped least‐squares formulation which incorporate estimates of the proximity to singularities and selective filtering of singular components are illustrated. The generality of the technique presented is illustrated in a computer simulation of a commercially available manipulator operating through singular configurations.