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The purpose of this paper is using a model-free reinforcement learning (RL) algorithm to optimize manipulability which can overcome difficulties of dilemmas of matrix inversion, complicated formula transformation and expensive calculation time.

Manipulability optimization is an effective way to solve the singularity problem arising in manipulator control. Some control schemes are proposed to optimize the manipulability during trajectory tracking, but they involve the dilemmas of matrix inversion, complicated formula transformation and expensive calculation time.

The redundant manipulator trained by RL can adjust its configuration in real-time to optimize the manipulability in an inverse-free manner while tracking the desired trajectory. Computer simulations and physics experiments demonstrate that compared with the existing methods, the average manipulability is increased by 58.9%, and the calculation time is reduced to 17.9%. Therefore, the proposed method effectively optimizes the manipulability, and the calculation time is significantly shortened.

To the best of the authors’ knowledge, this is the first method to optimize manipulability using RL during trajectory tracking. The authors compare their approach to existing singularity avoidance and manipulability maximization techniques, and prove that their method has better optimization effects and less computing time.

The aim of this paper is to describe how to make a co‐operative motion plan for a dual manipulator system to measure the radioactivity of wastes produced in decommissioning a nuclear power plant.

The system consists of two tasks: the main task generates the path of the measuring operation and the subtask maintains a good working position by co‐operative motion of the two manipulators.

A dual manipulator system requires an effective indicator of the current working position for the realisation of flexible co‐operative motion. Extended manipulability, which takes the motion limit of each joint angle into consideration, is shown to be an effective indicator.

Extended manipulability, which shows the motion possible from the current configuration, is offered as an improvement on conventional manipulability.

Proper platform pose is important for the mobile manipulator to accomplish dexterous manipulation tasks efficiently and safely, and the evaluation criterion to qualify manipulation performance is critical to support the pose decision process. This paper aims to present a comprehensive index to evaluate the manipulator’s operation performance from various aspects.

In this research, a criterion called hybrid manipulability (HM) is proposed to assess the performance of the manipulator’s operation, considering crucial factors such as joint limits, obstacle avoidance and stability. The determination of the optimal platform pose is achieved by selecting the pose that maximizes the HM within the feasible inverse reachability map associated with the target object.

A self-built mobile manipulator is adopted as the experimental platform, and the feasibility of the proposed method is experimentally verified in the context of object-grasping tasks both in simulation and practice.

The proposed HM extends upon the conventional notion of manipulability by incorporating additional factors, including the manipulator’s joint limits, the obstacle avoidance situation during the operation and the manipulation stability when grasping the target object. The manipulator can achieve enhanced stability during grasping when positioned in the pose determined by the HM.

This study aims to introduce a multi-configuration, three-finger dexterous hand with integrated high-dimensional sensors and provides an analysis of its design, modeling and kinematics.

A mechanical design scheme of the three-finger dexterous hand with a reconfigurable palm is proposed based on the existing research on dexterous hands. The reconfigurable palm design enables the dexterous hand to achieve four grasping modes to adapt to multiple grasping tasks. To further enhance perception, two six-axis force and torque sensors are integrated into each finger. The forward and inverse kinematics equations of the dexterous hand are derived using the D-H method for kinematics modeling, thus providing a theoretical model for index analysis. The performance is evaluated using three widely applied indicators: workspace, interactivity of fingers and manipulability.

The results of kinematics analysis show that the proposed hand has excellent dexterity. Additionally, three different experiments are conducted based on the proposed hand. The performance of the dexterous hand is also verified by fingertip force, motion accuracy test, grasping and in-hand manipulation experiments based on Feix taxonomy. The results show that the dexterous hand has good grasping ability, reproducing 82% of the natural movement of the human hand in daily grasping activities and achieving in-hand manipulations such as translation and rotation.

A novel three-finger dexterous hand with multi-configuration and integrated high-dimensional sensors is proposed. It performs better than the previously designed dexterous hand in actual experiments and kinematic performance analysis.

The purpose of this paper is to examine the effects of the use of the citation‐based journal impact factor for evaluative purposes upon the behaviour of authors and editors. It seeks to give a critical examination of a number of claims as regards the manipulability of this indicator on the basis of an empirical analysis of publication and referencing practices of authors and journal editors

The paper describes mechanisms that may affect the numerical values of journal impact factors. It also analyses general, “macro” patterns in large samples of journals in order to obtain indications of the extent to which such mechanisms are actually applied on a large scale. Finally it presents case studies of particular science journals in order to illustrate what their effects may be in individual cases.

The paper shows that the commonly used journal impact factor can to some extent be relatively easily manipulated. It discusses several types of strategic editorial behaviour, and presents cases in which journal impact factors were – intentionally or otherwise – affected by particular editorial strategies. These findings lead to the conclusion that one must be most careful in interpreting and using journal impact factors, and that authors, editors and policy makers must be aware of their potential manipulability. They also show that some mechanisms occur as of yet rather infrequently, while for others it is most difficult if not impossible to assess empirically how often they are actually applied. If their frequency of occurrence increases, one should come to the conclusion that the impact of impact factors is decreasing.

The paper systematically describes a number of claims about the manipulability of journal impact factors that are often based on “informal” or even anecdotal evidences and illustrates how these claims can be further examined in thorough empirical research of large data samples.

The aim of this paper is to develop a redundancy‐resolution (RR) algorithm to optimize the joint space trajectory of the six‐rotation‐axis industrial robot as performing arc‐welding tasks.

The rotation of the tool around its symmetry axis is clearly irrelevant to the view of the task to be accomplished besides some exceptional situations. When performed with a general 6‐degrees‐of‐freedom (DOF) manipulator, there exists one DOF of redundancy that remains. By taking advantage of the symmetry axis of the welding electrode, the authors decompose the required instantaneous twist of the electrode into two orthogonal components, one lying into the relevant task subspace and one into the redundant task subspace, respectively. Joint‐limits and singularity avoidance are considered as the optimization objectives.

The twist‐decomposition algorithm is able to optimize effectively the joint space trajectory. It has been tested and demonstrated in simulation.

A new RR algorithm is introduced for the six‐rotation‐axis industrial robot performing welding tasks. A new kinetostatic performance index is proposed on evaluating the kinematic quality of robotic postures. It can also be used in other applications like milling, deburing and many other tasks requiring less than 6‐DOF in tool frame.

Legged walking robots have numerous advantages over the wheel or tracked robots due to their strong operational ability and exposure to the complex environment. This paper aims to present details about the mechanical formation and a new conceptual elliptical trajectory generation discussed throughout the paper of the quadruped robot.

Initially, a realistic CAD model of the four-legged robot is developed in Solidwork-2019. The proposed model’s forward and inverse kinematics equations are deduced using Denavit–Hartenberg parameters. Based on geometry and kinematics, manipulability and obstacle avoidance are investigated. A method of galloping trajectory is proposed for aiming the increase of upright direction impulse, which is produced by ground reaction force at each step frequency. Furthermore, the locomotion equation of the ellipse trajectory is derived by setting transition angle polynomial of free-fall phase, stance phase and swing phase and the constraints.

Finally, a successive simulation on a 2D sagittal plane is performed to check and verify the usefulness of the proposed trajectory. Before the development of the full quadruped, a single prototype leg is generated for experimental verification of the dynamic simulations.

The proposed trajectory is novel in that it uses force tracking control, which is intended to improve the quadruped robot’s robustness and stability.

Admittance control is a typical complaint control methodology. Traditionally, admittance control systems are based on a dynamical relationship described by Voigt model. By contrast, after changing connection of spring and damper, Maxwell model produces different dynamics and has shown better impact absorption performance. This paper aims to design a novel compliant control method based on Maxwell model and implement it in a robot catching scenario.

To achieve this goal, this paper proposed a Maxwell model based admittance control scheme. Considering several motion stages involved in one catching attempt, the following approaches are adopted. First, Kalman filter is used to process the position data stream acquired from motion capture system and predict the subsequent object flying trajectory. Then, a linear segments with parabolic blends reaching motion is generated to achieve time-optimal movement under kinematic and joint inherent constraints. After robot reached the desired catching point, the proposed Maxwell model based admittance controller performs such as a cushion to moderate the impact between robot end-effector and flying object.

This paper has experimentally demonstrated the feasibility and effectiveness of the proposed method. Compared with typical Voigt model based compliant catching, less object bounding away from end-effector happens and the success rate of catching has been improved.

The authors proposed a novel Maxwell model based admittance control method and demonstrated its effectiveness in a robot catching scenario. The author’s approach may inspire other related researchers and has great potential of practical usage in a widespread of robot applications.

The purpose of this paper is to present a novel hybrid pre-tension mechanism for continuum manipulators to prevent wire slack and improve continuum robot payload capacity, as well as to present a new method to control continuum manipulators’ shape.

This research explains the hardware design of a hybrid pre-tension mechanism device and proposes a mathematic formulation wire-tension based on robot design. Also, the wire-tension control method and payload estimation model would be discussed.

Wire-tension is directly related to the continuum manipulators’ rigidity and accuracy. However, in the case of robot motion, wires lose their tension and such an issue leads to the inaccuracy and twist deformation. Therefore, the proposed design assists in preventing any wire slack and derailing the problem of the wires.

The novelty of this research is proposed pre-tension mechanism device design and control schematics. Proposed pre-tension mechanism designed to maintain up to eight wires simultaneously.

The usage of robot waiters in the hospitality industry is growing, thus increasing the number of human–robot interactions in frontline services. Focusing on robot waiters in restaurants, this study aims to propose the social cognition (SC)–psychological ownership (PO)–customer responses (CR) model, while examining the association between SC, PO, robot anthropomorphism and CR.

The hypotheses of this study are tested using a three-step mixed-method approach that includes partial least squares structural equation modeling (PLS-SEM), necessary condition analysis (NCA) and fuzzy-set qualitative comparative analysis (fsQCA).

PLS-SEM demonstrates the mediating role of psychological ownership on the relationship between SC, customer attitudes regarding being attended by a robot and revisiting intentions. Robot anthropomorphism enhances the relationship between SC and psychological ownership. NCA indicates that SC and psychological ownership are necessary conditions for the presence of favorable attitudes and revisiting intentions. FsQCA suggests that different configurations of the antecedent conditions lead to better attitudes and revisiting intentions.

Frontline hospitality robots need to be perceived as warm, competent, responsive and adaptable to customer requests to elicit positive responses. Managers should employ attractive robots displaying anthropomorphic features. Managers need to ensure that customers have some knowledge about robots before interacting with them. Managers should also consider customer heterogeneity and the context in which the robots will be deployed.

Based on the psychological ownership theory, this paper analyzes the relationship between SC, psychological ownership and CR. Anthropomorphism moderates the relationship between SC and psychological ownership.