Model Of Arm Research Articles

Research on Trajectory Planning and Simulation of Six-Degree-of-Freedom Manipulator

To make the time of the mechanical arm in joint space movement as short as possible and improve work efficiency, it is momentous to plan the movement trajectory of the mechanical arm to content the necessary condition of a smooth movement curve of the mechanical arm. According to the working principle of the 6-DOF mechanical arm, the D-H modeling method is used to calculate the D-H arguments, and the six-degree-of-freedom mechanical arm D-H model is established using MATLAB’s Robotics toolbox, and the positive kinematics analysis is performed. According to the set up robot arm model, the trajectory designning of the mechanical arm to run by using the three-time polynomial interpolation technique and the five-time polynomial interpolation technique in the joint space comparison, and it is simulated in MATLAB. Simulation experiments show that the five-time polynomial interpolation technique makes the running curve of the mechanical arm smoother and more stable, and has more application value.

Star cluster formation and feedback in different environments of a Milky Way-like galaxy

ABSTRACT It remains unclear how galactic environment affects star formation and stellar cluster properties. This is difficult to address in Milky Way-mass galaxy simulations because of limited resolution and less accurate feedback compared to cloud-scale models. We carry out zoom-in simulations to re-simulate 100–$300 \,\rm {pc}$ regions of a Milky Way-like galaxy using smoothed particle hydrodynamics, including finer resolution ($0.4 \,\rm {M_{\odot }{}}$ per particle), cluster-sink particles, ray-traced photoionization from O stars, H2/CO chemistry, and interstellar medium heating/cooling. We select ∼$10^{6} \,\rm {M_{\odot }{}}$ cloud complexes from a galactic bar, inner spiral arm, outer arm, and inter-arm region (in order of galactocentric radius), retaining the original galactic potentials. The surface densities of star formation rate and neutral gas follow $\Sigma _\mathrm{SFR}\propto \Sigma _\mathrm{gas}^{1.3}$, with the bar lying higher up the relation than the other regions. However, the inter-arm region forms stars two to three times less efficiently than the arm models at the same Σgas. The bar produces the most massive cluster, the inner arm the second, and the inter-arm the third. Almost all clusters in the bar and inner arm are small (radii <5 pc), while 30–50 per cent of clusters in the outer arm and inter-arm have larger radii more like associations. Bar and inner arm clusters rotate at least twice as fast, on average, than clusters in the outer arm and inter-arm regions. The degree of spatial clustering also decreases from bar to inter-arm. Our results indicate that young massive clusters, potentially progenitors of globular clusters, may preferentially form near the bar/inner arm compared to outer arm/inter-arm regions.

Accessibility and Trajectory Planning of Cutter Changing Robot Arm for Large-Diameter Slurry Shield

Aiming at solving the problems of huge cost, long cycle and high risky during manual cutter changing process for shield machine, a cutter changing robot was designed to adapt to its narrow and complex space, the workspace and motion path of cutter changing robot arm were studied. Firstly, by analyzing the internal space and cutter layout characteristic, the configuration of the robot arm was proposed, and the dimension of each rod was designed using multi-objective optimization method. The kinematic model of the robot arm was established by using the D-H model method to analyze its reachable working space. While the inverse kinematic model of the robot arm was solved by the Newton-Raphson iterative method to complete the trajectory planning of the arm for all cutter locations, where the relationship between the target position and the joint variables was established. The motion stability of the robot was verified by virtual simulation and test. The results show that the working space of the designed robot arm meets the cutter changing requirements that all the cutter position can be reached. Moreover, the power output of the drive is smooth, which can transport the cutter weighing up to 250kg.

Compact Ultra-­Wideband Planar Inverted F Antenna on Laminated Paper­-Based Substrate with Reduced Specific Absorption Rate

This paper presents a laminated paper-based Planar Inverted F Antenna (PIFA) for wireless body area network (WBAN) applications. The major challenges like providing adequate thickness, uniformity of surface, and water wet ability associated with paper substrate have been transcended in this antenna design by laminating the substrate with a transparent sheet. The simulated and measured reflection coefficients of the fabricated antenna in free space and on human arm are remarkably good, validating the prototype’s utility. It can operate effectively in GSM, WMTS, GPS, DCS, ISM, WiMAX, HIPERLAN, WLAN, and UWB frequency bands with S11 less than -10 dB and the gain ranging from 0.94 to 9.53 dB (free space) and 1.03 to 6.07 dB (on-body). The electrical size of the proposed antenna is 0.16 λg x 0.12 λg at 0.7 GHz with a group delay below 2.3 ns over the desired frequency bands. The performance characteristics are also investigated on-body and it encompasses most of the desired frequency bands for the body area network. This paper also analyses the specific absorption rate (SAR) of the designed antenna by placing it on a tissue-layered human arm model, which is 0.64 Watt/kg, complying with the SAR safety guidelines.

Generalized Functional Observer for Descriptor Nonlinear Systems—A Takagi-Sugeno Approach

This paper concerns the design of a generalized functional observer for Takagi–Sugeno descriptor systems. Furthermore, a generalized structure is herein introduced for purposes of estimating linear functions of the states of descriptor nonlinear systems represented into a Takagi–Sugeno descriptor form. The originality of the functional generalized observer structure is that it provides additional degrees of freedom in the observer design, which allows for improvements in the estimation against parametric uncertainties. The effectiveness of the developed design is illustrated by a nonlinear model of a single link robotic arm with a flexible link. A comparison between the functional generalized observer and the functional proportional observer is given to demonstrate the observer performances.

Hydrodynamic Derivatives of a Ferry Ship Maneuvering in Deep and Shallow Water with Computational Fluid Dynamic Method

The mathematical model and hydrodynamic derivatives can be developed in the simulation program to investigate a ship’s maneuvering performance using numerical simulation. This research describes a study to investigate the hydrodynamic derivatives of maneuvering a ferry ship in shallow and deep water. Using virtual drift and rotating arm model simulated, the hydrodynamic derivatives for a ferry ship’s surging, swaying, and yawing motions were obtained through Computational Fluid Dynamics (CFD). The hydrodynamic derivatives of the ferry ship were analyzed from the model test data using the least-square method. This study investigated three conditions of the ferry ship with various water depth conditions. The simulation result indicated that the ferry ship’s water depth affected its maneuvering performance.

Dual arm coordination of redundant space manipulators mounted on a spacecraft

AbstractThe paper addresses a significant challenge in on-orbit robotics servicing and assembly, which is to overcome the saturation setback of force/torque on robot joint and spacecraft actuators during the post-capture stage while controlling a target spacecraft with uncontrolled large angular and linear momentums. The authors propose a novel solution based on two robust and efficient control algorithms: Optimal Control Allocation (OCA) and Non-linear Model Predictive Control (NMPC). Both algorithms aim to minimize joint torques, spacecraft actuator moments, contact forces, and moments of a compound redundant system that includes a common payload (target spacecraft) grasped by dual n-degree space robotics manipulators mounted on a chaser spacecraft. The OCA algorithm minimizes a quadratic cost function using only the current states and the system dynamics, but the NMPC also considers the future state estimates and the control inputs over a specified prediction horizon. It is computationally more involved but provides superior results in reducing joint torques. The literature to date in application of MPC to robotics mainly focuses on linear models but the dual arm coordination is highly non-linear and there is no MPC application on dual arm coordination. The proposed discretized technique offers exact realizations (of a non-linear model) with elegance and simplicity and yet considers the full non-linear model of the dual arm coordinating system. It is computationally very efficient. The computer simulation results show that the proposed algorithms work efficiently, and the minimum torques, contact forces, and moments are realized. The developed algorithm also is very efficient in tracking problems.

Analysis of the Antagonistic Arrangement of Pneumatic Muscles Inspired by a Biological Model of the Human Arm

Technical solutions based on biological models are the subject of research by a wide range of experts and mainly concern their mechanical use. When designing a suitable actuator, they use the physical methods of biological representatives, of which a large group consists of actuators generally referred to as artificial muscles, while another group uses compressed air as an energy carrier. In order to perform the measurements described in this article, a test mechanism based on the opposing arrangement of a pair of pneumatic muscles was constructed. Measurements on the test mechanism were made at set constant pressures in the range of 0.4 MPa to 0.6 MPa, while at each pressure, measurements were made for the counterload range from 0 N to 107.87 N. The measured values were recorded using a microcontroller and subsequently processed into graphic outputs. As part of the measurements, a comparative measurement of the same opposite arrangement of a pair of linear double-acting pneumatic actuators with a single-sided piston rod was also performed. The experiment and measurements were carried out in order to determine the suitability of using pneumatic artificial muscles in the selected arrangement for the implementation of a mechanism imitating the human arm. The target parameters of the experiment were the reaction speed of the course of force when filling the muscle under load and the reaction of the mechanism to a change in the set pressure in the pneumatic system. The summary of the comparison of the measured results is the content of the discussion in this article.

Modeling and Simulation for a Five DOF Robotic Arm Manipulator

Nowadays, service robots are used in a large number of applications in the service industry. With the booming service industry in third world countries, service robots are expected to be used in a wider range of applications, so it is of great importance to conduct research on service robots. This paper develops the model of a kinematic models for a 5 DOF robotic arm that used in service industry in SolidWorks. The robotic arm’s mathematical model is predicated on Denavit-Hartemberg (DH) method, which determine the robot joints angle vector. The procedure aims at describing the forward and inverse kinematic analysis, and finally determine the end effector’s position and orientation through the corresponding joints angle related to the coordinate system (CS), in order to control the robotic arm to reach the designated location in space. A simulation model of the robotic arm was built using the Matlab Robotics Toolbox to verify the correctness of forward and inverse kinematics, which also can simplify the calculation and analysis.

Stability Optimization Simulation of Industrial Robot in ROS Environment

This paper studies the end actuator motion state of an RRR industrial robot, and gives a bottom up decision-making scheme based on PID algorithm. Under the background of complex industrial control, any environmental factors will have a deep effect on the accuracy. The physical representation of the accuracy of the end effector is the electrical signal. Foscus on the signal difference from joint to joint, based on the ROS and gazebo, the simulation of the RRR mechanical arm model can theoretically and intuitively Reflect the differences. To minimize the error, proportional–integral–derivative controller will be sued in this model and then Adjust PID parameters of each controller. Assume that the external interference is a linear superposition of impulse signals. The impulse response which the model makes should return to normal as soon as possible. In this way, the purpose of anti-interference is achieved. At the same time, it focuses on solving the motion state of industrial manipulator. For general industrial robots, its actuator, a gripper, should have the function of reaching any position and taking any direction in a certain space area. In other words, if a reference frame o 'is fixed on the center of the hand claw, the robot can send o' to any direction at any position in the space area. The position and direction of the gripper are determined by the amount of motion from the base to the gripper pairs. In addition, with the rapid development of the Internet, image has become a common form of information. This paper will use image recognition technology to provide the required detection data and reference values for the PID controller. Thus, the workspace of the industrial robot can be reflected more completely.

Modeling and dynamic analysis of a robotic arm with pneumatic artificial muscle by transfer matrix method

Pneumatic artificial muscle (PAM) has attracted significant attention owing to its safe and compliant physical properties in industrial manipulators, along with advanced service technologies. Since PAM is prone to large deformation problems, actuation control, and dynamic identification is required to perceive considering precise and fast computation. This article presents a methodology for accurate dynamic modeling and analysis of a planar robotic arm in the presence of large deformations caused by the artificial muscle. This novel planar robotic arm with pneumatic actuation and spring loaded in an antagonistic form is designed and fabricated. This article deals with the displacement analysis of a new type of PAM-actuated mechanism for large deformation. The aim is to find an accurate mathematical model of this robotic arm with motion nonlinearity. Since vibration can be generated in the articulating operations according to the dynamic behavior of PAM, a transfer-matrix method is proposed to explore the effect of flexibility undergoing planar flexural deformation. An explanation of the procedure through presenting its general formulation is employed to experiment. The discrete method is analyzed beside the rich datasets generated for actuator identification in the preliminary experimental study. The transfer matrices are determined considering the flexibilities whereas results are verified using MSC.ADAMS©. Experimental validation and numerical modeling confirm that the presented modeling methods help to improve the performance of the pneumatic muscle drives in high-precision manipulators. This study leaves room for further development of this algorithmic framework with a more complicated mechanism with soft pneumatic network actuators for various designs.

Wearable Directional Button Antenna for On-Body Wireless Power Transfer

For the future application of wireless power transfer on the human body, a wearable directional button antenna, composed of 2×3 artificial magnetic conductor (AMC) cells, is proposed, where the kinetic energy antenna is put on the elbow, which then charges the receiving communication antenna on the upper arm. The radiator of the button antenna is a monopole antenna, which is top-loaded by two cylindrical substrates with different radii to achieve a low profile, and it is fed by the microstrip line made by textiles, including 100% cotton substrate and conductive textile. The AMC cells are put close to the feeding microstrip line in order to realize directional radiation to the other side. Meanwhile, a real human arm model of a Chinese women is built to accurately analyze the corresponding wave propagations. Consequently, two identical antenna prototypes are fabricated, and the corresponding measurements are implemented, where an on-arm approximate measurement method for the radiation pattern is proposed. The measurements agree well with the simulations. Additionally, the influence of the communication antenna on the kinetic energy antenna and the interactions between the antenna and the arm are analyzed. Finally, the transmission efficiency and the SAR values are investigated.

Statistical modeling of traffic noise at intersections in a mid-sized city, India

Abstract The modeling of traffic noise is more debated around intersections due to traffic flow and road geometry complexity. The available intersection-specific traffic noise models cannot be transferred to predict the traffic noise at intersections in the mid-sized Indian cities due to traffic heterogeneity, variety in driving conditions, and vehicle compositions. This article aims to develop an intersection-specific traffic noise model by collecting data at 19 intersections in Kanpur, India. The data include a wide range of traffic, road, and weather-related variables. Furthermore, significant input variables are determined and used in the statistical regression model to develop an intersection-specific traffic noise model for the mid-sized Indian cities. This study develops a separate entrance and exit arm model based on the corresponding influencing variables. The coefficient of determination (R 2) value is 0.74 and 0.69 for the developed model at the entrance and exit arms, respectively, whereas these models achieve R 2 values of 0.73 and 0.67 in the validation step. Also, the performance of developed models is evaluated on the standard and mean absolute errors as performance metrics. This study finds that traffic volume and receiver distance are relatively the most important variables in the entrance and exit arm noise models.

Parameter estimation of the shell transfer arm of a loading mechanism

The shell transfer arm is a key component of gun automatic loading mechanism, the coordination speed and positioning accuracy have an important impact on gun ammunition delivery effect. Establishing an accurate dynamic model is the foundation for better control and prediction, therefore, it is necessary to identify the dynamic parameters of the shell transfer arm. In this paper, the dynamic model is established based on the topology method. The parameter identification model of the shell transfer arm is constructed by applying the dynamic model and unscented Kalman filter theory. Dynamic parameters of the shell transfer arm such as the mass, inertia and centroid position are estimated under unscented Kalman filter scheme. By comparing the parameter estimation results with the nominal design values, the feasibility and effectiveness of applying the proposed method to identify the dynamic parameters of the shell transfer arm are verified.

Static Analysis of Manipulator Based on Solidworks and ANSYS Workbench

China has gradually achieved a far leading position in the field of industrial robots. The application of robots in various fields has also been widely promoted. Therefore, the safety and reliability of robot work need to be further improved. This paper is mainly for the safety and reliability of the robot arm in the work. Based on Solidworks and ANSYS, the workbench performs a static analysis of a robotic arm with six degrees of freedom. Firstly, the three-dimensional model of the robot arm is established by Solidworks. And then, it is introduced into the ANSYS workbench to simulate the actual force situation to analyze the force of the robot arm and obtain the change law of the stress on each component and the deformation of the key structure during operation. According to the analysis results of ANSYS workbench software, the design of each component of the robot arm has a certain degree of reliability, which can lay the foundation for subsequent research such as motion control.

Neuromechanics-Based Neural Feedback Controller for Planar Arm Reaching Movements.

Based on the principles of neuromechanics, human arm movements result from the dynamic interaction between the nervous, muscular, and skeletal systems. To develop an effective neural feedback controller for neuro-rehabilitation training, it is important to consider both the effects of muscles and skeletons. In this study, we designed a neuromechanics-based neural feedback controller for arm reaching movements. To achieve this, we first constructed a musculoskeletal arm model based on the actual biomechanical structure of the human arm. Subsequently, a hybrid neural feedback controller was developed that mimics the multifunctional areas of the human arm. The performance of this controller was then validated through numerical simulation experiments. The simulation results demonstrated a bell-shaped movement trajectory, consistent with the natural motion of human arm movements. Furthermore, the experiment testing the tracking ability of the controller revealed real-time errors within one millimeter, with the tensile force generated by the controller's muscles being stable and maintained at a low value, thereby avoiding the issue of muscle strain that can occur due to excessive excitation during the neurorehabilitation process.

A computational musculoskeletal arm model for assessing muscle dysfunction in chronic obstructive pulmonary disease.

Computational models have been used extensively to assess diseases and disabilities effects on musculoskeletal system dysfunction. In the current study, we developed a two degree-of-freedom subject-specific second-order task-specific arm model for characterizing upper-extremity function (UEF) to assess muscle dysfunction due to chronic obstructive pulmonary disease (COPD). Older adults (65years or older) with and without COPD and healthy young control participants (18 to 30years) were recruited. First, we evaluated the musculoskeletal arm model using electromyography (EMG) data. Second, we compared the computational musculoskeletal arm model parameters along with EMG-based time lag and kinematics parameters (such as elbow angular velocity) between participants. The developed model showed strong cross-correlation with EMG data for biceps (0.905, 0.915) and moderate cross-correlation for triceps (0.717, 0.672) within both fast and normal pace tasks among older adults with COPD. We also showed that parameters obtained from the musculoskeletal model were significantly different between COPD and healthy participants. On average, higher effect sizes were achieved for parameters obtained from the musculoskeletal model, especially for co-contraction measures (effect size = 1.650 ± 0.606, p < 0.001), which was the only parameter that showed significant differences between all pairwise comparisons across the three groups. These findings suggest that studying the muscle performance and co-contraction, may provide better information regarding neuromuscular deficiencies compared to kinematics data. The presented model has potential for assessing functional capacity and studying longitudinal outcomes in COPD.

Chinese Digital Arm (CDA): A High-Precision Digital Arm for Electrical Stimulation Simulation.

To effectively analyze the diffusion and accumulation of signals on the surface and inside the human body under electrical stimulation, we used the gray threshold of the Chinese Digital Human image dataset to segment an arm image and reconstruct the tissue to obtain its three-dimensional cloud point dataset. Finally, a semirefined digital arm entity model with the geometric characteristics of the actual human arm tissue was constructed using reverse engineering technology. Further input of the current signal stimulation under tDCS and tACS with additional analysis of the signal diffusion in the transient mode via model calculation revealed that DC electrical stimulation is likely to cause high-voltage burns. The effective depth achieved using the AC stimulation signal is considerable, and provides reference for the electrical stimulation selection. Simultaneously, in the digital arm model, the signal diffusion and tissue damage inside the arm can be analyzed by changing the field, which provides a theoretical basis for the experimental study of the human body.

An Intelligent Human-like Motion Planner for Anthropomorphic Arms Based on Diversified Arm Motion Models

In this paper, the human-like motion issue for anthropomorphic arms is further discussed. An Intelligent Human-like Motion Planner (IHMP) consisting of Movement Primitive (MP), Bayesian Network (BN) and Coupling Neural Network (CPNN) is proposed to help the robot generate human-like arm movements. Firstly, the arm motion model is decoupled in the aspects of arm structure and motion process, respectively. In the former aspect, the arm model is decoupled into different simple models through the Movement Primitive. A Hierarchical Planning Strategy (HPS) is proposed to decouple a complete motion process into different sub-processes. Based on diversified arm motion models, the Bayesian Network is used to help the robot choose the suitable motion model among these arm motion models. Then, according to the features of diversified arm motion models, the Coupling Neural Network is proposed to obtain the inverse kinematic (IK) solutions. This network can integrate different models into a single network and reflect the features of these models by changing the network structure. Being a major contribution to this paper, specific focus is on the improvement of human-like motion accuracy and independent consciousness of robots. Finally, the availability of the IHMP is verified by experiments on a humanoid robot Pepper.

Discrete Cosserat Static Model-Based Control of Soft Manipulator

In this letter, the continuous Cosserat static model is re-formulated by employing the piecewise linear strain (PLS) approach, which can obtain the analytic formula of the model to facilitate the controller design. The robust closed-loop control architecture based on the PLSCosserat static model for the soft arm around its workspace is then established. To validate the performance of the proposed model-based control scheme, the point-to-point and time-varying trajectory tracking experiments under external disturbances have been conducted on the soft manipulator actuated by cables.