scholarly journals Kinematic Performance Analysis of a Controllable Mechanism Welding Robot with Joint Clearance

2020 ◽  
Vol 327 ◽  
pp. 03006
Author(s):  
Junjie Gong ◽  
Wei Wei ◽  
Ganwei Cai ◽  
Yixin Liu ◽  
Sixu Peng
Keyword(s):  
Dynamic Performance ◽  
Great Influence ◽  
Parallel Robot ◽  
Rotational Inertia ◽  
Welding Robot ◽  
Residual Vibration ◽  
Position Errors ◽  
Tandem Welding ◽  
Vibration Time ◽  
End Members

Because the motor and reducer of the conventional tandem welding robot are installed at the revolute joint, the robot has large rotational inertia and long residual vibration time. However, due to the limitation of workspace and other reasons, the current parallel robot is not suitable for all series welding robots. Therefore, based on the concept of "multi-degree-of-freedom controllable mechanism", a new controllable mechanism welding robot is proposed in this paper. The driving motor and reducer, which have great influence on the main and branch chain of the welding robot, are installed on the frame. The advantage of this design is that the inertia of the robot mechanism is significantly reduced, and its dynamic performance is improved. The position errors of the end members of the welding robot moving along the circle, as well as the angle errors of each joints under the circle movements are analysed.

Optimal Design of a 4-DOF SCARA Type Parallel Robot Using Dynamic Performance Indices and Angular Constraints

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Songtao Liu ◽  
Tian Huang ◽  
Jiangping Mei ◽  
Xueman Zhao ◽  
Panfeng Wang ◽  
...  
Keyword(s):  
Optimal Design ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Singularity Analysis ◽  
Rigid Body Dynamics ◽  
Performance Indices ◽  
Global Dynamic ◽  
Transmission Angle ◽  
Body Dynamics ◽  
Rigid Design

This paper deals with the optimal design of a 4-DOF SCARA type (three translations and one rotation) parallel robot using dynamic performance indices and angular constraints within and amongst limbs. The architecture of the robot is briefly addressed with emphasis on the mechanical realization of the articulated traveling plate for achieving a lightweight yet rigid design. On the basis of the kinematic singularity analysis, two types of transmission angle constraints are considered to ensure the kinematic performance. A simplified model of rigid body dynamics is then formulated, with which two global dynamic performance indices are proposed for minimization by taking into account both inertial and centrifugal/Coriolis effects. In addition, the servomotor specifications are estimated using the Extended Adept Cycle. The proposed approach has successfully been employed to develop a prototype machine.

scholarly journals Parallel Robot Translational Performance Evaluation through Direction-Selective Index (DSI)

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
G. Boschetti ◽  
R. Rosa ◽  
A. Trevisani
Keyword(s):  
Performance Evaluation ◽  
Performance Index ◽  
General Framework ◽  
Dynamic Performance ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Performance Indexes ◽  
Definition Of ◽  
Performance Variations

Performance indexes usually provide global evaluations of robot performances mixing their translational and/or rotational capabilities. This paper proposes a definition of performance index, called direction-selective index (DSI), which has been specifically developed for parallel manipulators and can provide uncoupled evaluations of robot translational capabilities along relevant directions. The DSI formulation is first presented within a general framework, highlighting its relationship with traditional manipulability definitions, and then applied to a family of parallel manipulators (4-RUU) of industrial interest. The investigation is both numerical and experimental and allows highlighting the two chief advantages of the proposed DSIs over more conventional manipulability indexes: not only are DSIs more accurate in predicting the workspace regions where manipulators can best perform translational movements along specific directions, but also they allow foreseeing satisfactorily the dynamic performance variations within the workspace, though being purely kinematic indexes. The experiments have been carried out on an instrumented 4-RUU commercial robot.

scholarly journals Design of Augmented Nonlinear PD Controller of Delta/Par4-Like Robot

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Amjad J. Humaidi ◽  
Ahmed Ibraheem Abdulkareem
Keyword(s):  
Trajectory Tracking ◽  
Lyapunov Method ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Pd Controller ◽  
Comparison Study ◽  
Tracking Accuracy ◽  
Control Schemes ◽  
The Stability ◽  
Made In

This work presents the design of two control schemes for a Delta/Par4-like parallel robot: augmented PD (APD) controller and augmented nonlinear PD (ANPD) controller. The stability of parallel robot based on nonlinear PD controller has been analyzed and proved based on Lyapunov method. A comparison study between APD and ANPD controllers has been made in terms of performance and accuracy improvement of trajectory tracking. Also, another comparison study has been presented between augmented nonlinear PD (ANPD) controller and nonaugmented nonlinear PD (NANPD) controller in order to show the enhancement of introducing the augmented structure on dynamic performance and trajectory tracking accuracy. The effectiveness of augmented PD controllers (APD and ANPD) and nonaugmented nonlinear PD (NANPD) controller for the considered parallel robot are verified via simulation within the MATLAB environment.

scholarly journals Critical Parameters and Influence on Dynamic Behaviours of Nonlinear Electrostatic Force in a Micromechanical Vibrating Gyroscope

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Shuying Hao ◽  
Yulun Zhu ◽  
Yuhao Song ◽  
Qichang Zhang ◽  
Jingjing Feng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Bias Voltage ◽  
Electrostatic Force ◽  
Dynamic Performance ◽  
Great Influence ◽  
Critical Parameters ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Element Analysis ◽  
Dc Bias

The electrostatic force nonlinearity caused by fringe effects of the microscale comb will affect the dynamic performance of the micromechanical vibrating gyroscopes (MVGs). In order to reveal the influence mechanism, a class of four-degree-of-freedom (4-DOF) electrostatically driven MVG is considered. The influence of DC bias voltage and comb spacing on the nonlinearity of electrostatic force and the dynamic response of the MVG by using multiple time scales method and numerical simulation are discussed. The results indicate that the electrostatic force nonlinearity causes the system to show stiffness softening. The softening characteristics of the electrostatic force cause the offset of the resonance frequency and a decrease in sensitivity. Although the electrostatic nonlinearity has a great influence on the dynamic behaviour, its influence can be avoided by the reasonable design of the comb spacing and DC bias voltage. There exists a critical value for comb spacing and DC bias voltage. In this paper, determining the critical values is demonstrated by nonlinear dynamics analysis. The results can be supported by the finite element analysis and numerical simulation.

scholarly journals Workspace and Stiffness Analysis of 3D Printing Cable-Driven Parallel Robot with a Retractable Beam-Type End-Effector

Robotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 65
Author(s):  
Jinwoo Jung
Keyword(s):  
3D Printing ◽  
Natural Frequencies ◽  
Parallel Robot ◽  
Good Alternative ◽  
Construction Time ◽  
Single Plane ◽  
End Effector ◽  
Stiffness Analysis ◽  
Position Errors ◽  
Beam Type

3D printing is a widely used technology that has been recently applied in construction to reduce construction time significantly. A large 3D printer often uses a traditional Cartesian robot with inherent problems, such as position errors and printing nozzle vibrations, due to the long, heavy horizontal beam carrying it and a large amount of power required to actuate the heavy beam. A cable-driven parallel robot (CDPR) can be a good alternative system to reduce the vibrations and necessary power because the robot’s lightweight cables can manipulate the printing nozzle. However, a large 3D printing CDPR should be carefully designed to maximize the workspace and avoid cable interference. It also needs to be stiff enough to reject disturbances from the environment properly. A CDPR with a retractable beam-type end-effector with cables through the guide pulleys in a single plane is suggested for avoiding cable interference while maximizing the workspace. The effects of using the retractable end-effector on the workspace were analyzed relative to the cable connection points’ location changes. Static stiffness analysis was conducted to examine the natural frequencies, and the geometric parameters of the end-effector were adjusted to improve the lowest natural frequencies. Simulation results show that a retractable beam-type end-effector can effectively expand the wrench-feasible workspace.

Optimal Design of a River Boat Simulator

2012 ◽  
Author(s):  
Juan C. Blanco ◽  
Carlos F. Rodríguez
Keyword(s):  
Virtual Work ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Optimization Strategy ◽  
Dimensional Synthesis ◽  
Software Model ◽  
Optimization Methodology ◽  
Mechanical Devices ◽  
Multi Body ◽  
Optimal Configurations

Motion simulation platforms are mechanical devices designed to replicate the dynamics of a given vehicle. They are very attractive for training individuals such as drivers, pilots or passengers. This paper describes the dimensional synthesis of a river boat simulator that consists of a section of the boat (hull) mounted over a 3 DOF parallel robot with a passive weight compensator (3UPS + PU). Given that the dynamic performance of the robot depends strongly on its geometry, an optimization strategy was applied to find its optimal configuration. The optimization objective was to minimize the dynamic requirements of the driving actuators while accomplishing a typical simulation routine. We present the virtual work formulation of the simulator dynamics, which was previously verified with a multi-body software model. This formulation is used in an optimization methodology based on Genetic Algorithms. Different optimal configurations were found related to the set of constraints and sub-spaces of variables considered by the optimization formulation.

Simulation and Experimental Investigation of Stiffness of the High Acceleration Linear Feed Drives

2010 ◽  
Vol 97-101 ◽  
pp. 3113-3119
Author(s):  
Ping Ma ◽  
Cheng Xiang Liao ◽  
Zhen Hui Chen ◽  
Gong Zhen
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Great Influence ◽  
Linear Motor ◽  
Current Loop ◽  
Linear Induction Motor ◽  
Feed Drive ◽  
Feed Drives ◽  
High Acceleration ◽  
Motorized Spindles

In high speed machining, the feed drives with high velocity and high acceleration are necessary to make full use of the capacities of the high speed motorized spindles. The linear motor feed drive eliminates any mid- transmitting mechanism, which cause achieved the high acceleration. In this paper, the GD-Ⅲ linear induction motor feed drive is introduced, and its controller is modeled and its stiffness has been investigated with simulation program MATLAB & SIMULINK. The influence of the parameters of the controller on the dynamic performance has also been analyzed. The simulation shows that the positional loop proportional gain kv, velocity proportional gain kp, velocity loop integral time constant Tn and the current loop proportional gain kpi have great influence on the dynamics of the linear motor feed drive. In the end, the simulation is verified by the experimental results.

Kinematics and Stiffness Modeling of a 4-DOF Parallel Robot for Schönflies Motion Generation

2014 ◽  
Author(s):  
Shaoping Bai ◽  
Lasse Køgs Andersen ◽  
Carsten Rebbe Mølgaard
Keyword(s):  
Dynamic Performance ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Motion Generation ◽  
Stiffness Modeling ◽  
Pick And Place ◽  
Fea Simulation ◽  
Schönflies Motion ◽  
Pick And Place Operation ◽  
Good Agreement

This work deals with the design of parallel robots for the generation of pick-and-place operation, or Schönflies motion. The aim is to develop a robot with workspace optimized for fast pick-and-place operations, namely, a robot with a superellipsoidal reachable volume, which suits best for the pick-and-place operations on conveyers, where robots’ working areas are nearly rectangular. In this paper, the kinematics and stiffness modeling of the new robot are presented. A method of stiffness modeling by means of Castigliano’s Theorem is developed. Using the new method, the stiffness of the robot is analyzed. The results are compared with FEA simulation, which shows a good agreement between the results. The method is finally applied to the engineering design of the new robot for enhanced static and dynamic performance.

Design of Parallel Mechanisms for Flexible Manufacturing With Reconfigurable Dynamics

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Gianmarc Coppola ◽  
Dan Zhang ◽  
Kefu Liu ◽  
Zhen Gao
Keyword(s):  
Flexible Manufacturing ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Test Subject ◽  
Design Parameters ◽  
Parallel Mechanisms ◽  
Reconfigurable Mechanisms ◽  
Kinematic Properties ◽  
Full Simulation

Reconfigurable robotic systems can enhance productivity and save costs in the ever growing flexible manufacturing regime. In this work, the idea to synthesize robotic mechanisms with dynamic properties that are reconfigurable is studied, and a methodology to design reconfigurable mechanisms with this property is proposed, named reconfigurable dynamics (Re-Dyn). The resulting designs have not only the kinematic properties reconfigurable, such as link lengths, but also properties that directly affect the forces and accelerations, such as masses and inertias. A 2-degree of freedom (DOF) parallel robot is used as a test subject. It is analyzed and redesigned with Re-Dyn. This work also presents the robots forward dynamic model in detail, which includes the force balancing mediums. The connection method is directly utilized for this derivation, which is well suited for multibody dynamics and provides insight for design parameters (DPs). Dynamic performance indices are also briefly discussed as related to the Re-Dyn method. After redesigning the robot, a full simulation is conducted to compare performances related to a flexible manufacturing situation. This illustrates the advantages of the proposed method.

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