Study on a 4-DOF multi-dimensional vibration isolation platform based on 4-UPU parallel mechanism

2021 ◽  
Author(s):  
Ying Zhang ◽  
Xiaodong Guo ◽  
Shijia Yu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Kinematic Model ◽  
Experimental Studies ◽  
Optimization Method ◽  
Response Analysis ◽  
Vibration Model ◽  
Fixed Base ◽  
Physical Prototype

A novel 4-DOF (degrees of freedom) multi-dimensional vibration isolation platform (MDVIP) based on 4-UPU (U denotes universal joint, P denotes prismatic joint) parallel mechanism is put forward for vibration isolation of the sensitive devices. It consists of 4 limbs and each limb has two universal joints and a module of spring damper. The kinematic model and vibration model of the proposed MDVIP are established and analyzed. The main dimensions of the MDVIP and the parameters of the spring damper module are designed by optimization method to meet various design requirements and constraints. Both the virtual prototype and physical prototype of the MDVIP are built to testify the vibration isolation performance. The results of numerical calculation, simulation and experimental studies based on vibration response analysis show that the proposed MDVIP can isolate at least 78% vibration from the fixed base in three axial directions and 64% vibration in the direction around the Z-axis, and thus may attenuate the disturbances to the items on the moving platform to a large extent.

scholarly journals A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for Robotic Applications

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1468
Author(s):  
Luis Nagua ◽  
Carlos Relaño ◽  
Concepción A. Monje ◽  
Carlos Balaguer
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Humanoid Robots ◽  
Inverse Kinematic ◽  
Element Analysis ◽  
New Approach ◽  
Flexible Polymer ◽  
The Mathematical Model

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.

scholarly journals 3DOF Ultrasonic Motor with Two Piezoelectric Rings

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 834 ◽  
Author(s):  
Vytautas Jūrėnas ◽  
Gražvydas Kazokaitis ◽  
Dalius Mažeika
Keyword(s):  
Numerical Simulation ◽  
Magnetic Dipole ◽  
Attitude Control ◽  
Degrees Of Freedom ◽  
High Reliability ◽  
Experimental Studies ◽  
Main Idea ◽  
Ultrasonic Motor ◽  
Response Analysis ◽  
Magnetic Sphere

A novel design of a multiple degrees of freedom (multi-DOF) piezoelectric ultrasonic motor (USM) is presented in the paper. The main idea of the motor design is to combine the magnetic sphere type rotor and two oppositely placed ring-shaped piezoelectric actuators into one mechanism. Such a structure increases impact force and allows rotation of the sphere with higher torque. The main purpose of USM development was to design a motor for attitude control systems used in small satellites. A permanent magnetic sphere with a magnetic dipole is used for orientation and positioning when the sphere is rotated to the desired position and the magnetic field synchronizes with the Earth’s magnetic dipole. Also, the proposed motor can be installed and used for robotic systems, laser beam manipulation, etc. The system has a minimal number of components, small weight, and high reliability. Numerical simulation and experimental studies were used to verify the operating principles of the USM. Numerical simulation of a piezoelectric actuator was used to perform modal frequency and harmonic response analysis. Experimental studies were performed to measure both mechanical and electrical characteristics of the piezoelectric motor.

Jacobian approach to the kinestatic analysis of a full vehicle model with application to cornering motion analysis

2020 ◽  
Vol 234 (18) ◽  
pp. 3543-3559
Author(s):  
Guofeng Zhou ◽  
Junwoo Kim ◽  
Yong Je Choi
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Kinematic Chain ◽  
Contact Model ◽  
Vehicle Body ◽  
Spatial Parallel Mechanism ◽  
6 Degrees Of Freedom ◽  
Instantaneous Screw

The Jacobian approach to the kinestatic analysis of a planar suspension mechanism has been previously presented. In this paper, the theory is extended to three-dimensional kinestatic analysis by developing a full kinematic model and viewing it as a spatial parallel mechanism. The full kinematic model consists of two pairs of the front (double wishbone) and rear (multi-link) suspension mechanisms together with a newly developed ground-wheel contact model. The motion of each wheel of four suspension mechanisms is represented by the corresponding instantaneous screw at any instant. A vehicle is considered to be a 6-degrees-of-freedom spatial parallel mechanism whose vehicle body is supported by four serial kinematic chains. Each kinematic chain consists of a virtual instantaneous screw joint and a kinematic pair representing ground-wheel contact model. The kinestatic equation of the 6-degrees-of-freedom spatial parallel mechanism is derived in terms of the Jacobian. As an important application, a cornering motion of a vehicle is analysed under the assumption of steady-state cornering. A numerical example is presented to illustrate how to determine the optimal locations of strut springs for the least roll angle in cornering motion using the proposed method.

Redundant Parallel Mechanism for Haptic Applications

2010 ◽  
Vol 4 (4) ◽  
pp. 338-345 ◽  
Author(s):  
Jumpei Arata ◽  
◽  
Hideo Fujimoto
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Display Device ◽  
Parallel Mechanisms ◽  
Prototype Implementation ◽  
Haptic Devices ◽  
Multiple Degrees Of Freedom ◽  
High Rigidity ◽  
Wide Range ◽  
Fixed Base

With haptic devices becoming increasingly common in both industrial field and consumer use, parallel mechanisms have been widely introduced for their high rigidity, output, accuracy and high backdrivability due to their multi-legged structure and fixed base actuators. In general parallel mechanism, redundancy enlarges the working area and avoids singularity. The redundant parallel mechanism we present introduces these advantages into haptic applications. Introducing this mechanism into a multiple degrees-of-freedom (DOF) structure realizes a wide range of working areas in rotation. The redundant parallel mechanism implemented in translational force display device, and multi-DOF force display device demonstrate the advantages of the redundant parallel mechanism in haptic applications. Following an overview, we introduce the prototype implementation and evaluation of these devices and discuss the effectiveness of the redundant parallel mechanism in haptic applications.

scholarly journals Multi-DOF Ultrasonic Actuators for Laser Beam Positioning

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Ramutis Bansevicius ◽  
Dalius Mazeika ◽  
Vytautas Jurenas ◽  
Genadijus Kulvietis ◽  
Asta Drukteiniene
Keyword(s):  
Laser Beam ◽  
Piezoelectric Actuator ◽  
Degrees Of Freedom ◽  
Main Idea ◽  
Piezoelectric Transducers ◽  
Response Analysis ◽  
Numerical Verification ◽  
Physical Prototype ◽  
Harmonic Response Analysis ◽  
Output Characteristics

A novel design concept of multi-degree-of-freedom (multi-DOF) piezoelectric actuator is introduced in the paper. The main idea is to connect two identical piezoelectric transducers by hyperelastic material in order to increase the total number of degrees-of-freedom of the system. Such design principle also allows to separate vibrations of two piezoelectric transducers and to control them independently. The ring- and cylinder-type piezoelectric transducers were used to design two multi-DOF ultrasonic actuators for precise laser beam positioning. Reflecting mirror is mounted on the top of the actuator and is preloaded by magnetic force. Both disc- and cylinder-type actuators can realize up to six degrees-of-freedom, i.e., to rotate the mirror about three axes employing one transducer and to position mirror in the plane by using another transducer. Bidirectional rotation and translation motion of the mirror are obtained by switching excitation signals between different electrodes of the transducers. Both the numerical simulation and physical prototype were used to verify operating principle of the actuators. Numerical investigation of the piezoelectric actuator was performed to investigate modal-frequency and harmonic response analysis while experimental study was performed to measure electrical and mechanical output characteristics of the piezoelectric actuator. A mathematical model of contacting force control was proposed, and numerical verification was performed when the mirror need to be rotated according to the specific motion trajectory.

Workspace Generation for a 2 - DOF Parallel Mechanism Using Neural Networks

2012 ◽  
Vol 162 ◽  
pp. 121-130 ◽  
Author(s):  
Emilia Campean ◽  
Tiberiu Pavel Itul ◽  
Ionela Tanase ◽  
Adrian Pisla
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Two Degrees Of Freedom ◽  
Initial Testing ◽  
Network Application ◽  
Satellite Dish

The main purpose of the paper is to develop a neural network application destined to the workspace generation of a parallel mechanism, as an performant alternative to the workspace representation based on inverse kinematic model. The paper describes both algorithms. The initial testing was made for a parallel mechanism with two degrees of freedom that could be applied for the orientation of different systems like a TV satellite dish antennas, sun trackers, telescopes, cameras, radars etc.

Development of a novel 6-DOF hybrid serial-parallel mechanism for pose adjustment of large-volume components

2021 ◽  
pp. 095440622110263
Author(s):  
Shiwei Liu ◽  
Yu Sun ◽  
Gaoliang Peng ◽  
Yuan Xue ◽  
Anna Hnydiuk-Stefan ◽  
...  
Keyword(s):  
Large Volume ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Hybrid Mechanism ◽  
Spatial Parallel Mechanism ◽  
Hybrid Manipulator ◽  
Automated Docking ◽  
6 Degrees Of Freedom

In this paper, a novel 6-degrees-of-freedom (DOF) hybrid mechanism is proposed to realize position and posture adjusting for large-volume equipment. The designed hybrid manipulator is composed of the lower and upper modules, namely, a 3-DOF redundant spatial parallel mechanism (SPM) and a 3-DOF planar parallel mechanism (PPM), which has three rotational and three translational DOFs. According to the step-by-step pose adjusting strategy, the kinematics analyses of the lower and upper modules have been carried out systematically. For the whole hybrid mechanism, a complete kinematic model has been established; and visualized workspace of the kinematic model with regular shape and large volume demonstrates profound application prospects in engineering. In order to evaluate the performance of the proposed mechanism, experimental tests have been conducted in an automated docking system for pose adjustment of large and heavy components. The analysis results demonstrate the effectiveness and practicability of the new mechanism.

scholarly journals System integration and control design of a maglev platform for space vibration isolation

2019 ◽  
Vol 25 (11) ◽  
pp. 1720-1736 ◽  
Author(s):  
Zhaopei Gong ◽  
Liang Ding ◽  
Honghao Yue ◽  
Haibo Gao ◽  
Rongqiang Liu ◽  
...  
Keyword(s):  
System Integration ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Minimum Energy ◽  
Optimization Method ◽  
Dominant Factor ◽  
Loop Control ◽  
Scientific Experiments ◽  
Micro Vibration ◽  
Close Loop Control

Micro-vibration has been a dominant factor impairing the performance of scientific experiments which are expected to be deployed in a micro-gravity environment such as a space laboratory. The micro-vibration has serious impact on the scientific experiments requiring a quasi-static environment. Therefore, we proposed a maglev vibration isolation platform operating in six degrees of freedom (DOF) to fulfill the environmental requirements. In view of the noncontact and large stroke requirement for micro-vibration isolation, an optimization method was utilized to design the actuator. Mathematical models of the actuator's remarkable nonlinearity were established, so that its output can be compensated according to a floater's varying position and a system's performance may be satisfied. Furthermore, aiming to adapt to an energy-limited environment such as space laboratory, an optimum allocation scheme was put forward, considering that the actuator's nonlinearity, accuracy, and minimum energy-consumption can be obtained simultaneously. In view of operating in 6-DOF, methods for nonlinear compensation and system decoupling were discussed, and the necessary controller was also presented. Simulation and experiments validate the system's performance. With a movement range of 10 × 10 × 8 mm and rotations of 200 mrad, the decay ratio of −40 dB/Dec between 1 and 10 Hz was obtained under close-loop control.

Theoretical and Experimental Study on Active Stiffness Control of a Two-Degrees-of-Freedom Rope-Driven Parallel Mechanism

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Haiyu Gu ◽  
Cheng Wei ◽  
Zeming Zhang ◽  
Yang Zhao
Keyword(s):  
Parallel Mechanism ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Suppression ◽  
Control Law ◽  
Important Indicator ◽  
Control Scheme ◽  
Stiffness Model ◽  
Physical Prototype ◽  
Stiffness Control

Abstract Rope-driven mechanisms with the characteristics of high speed, low inertia, and high precision are widely utilized in numerous fields. Stiffness is an important indicator to illustrate the precision and compliance of the mechanism. However, realizing active stiffness control is difficult for the mechanisms due to the coupling of rope tension and controller stiffness. To solve the problem, a verification prototype, 2-DOF rope-driven parallel mechanism (RDPM), is designed and manufactured, and its mechanical model is established. And then the general stiffness model of the RDPM is derived. Meanwhile, the rope-hole friction is calculated based on the Stribeck model. An active stiffness control scheme considering the pose retention, vibration suppression, and friction compensation is proposed. According to the stiffness model and active stiffness control law, the linear motion stiffness of the RDPM is analyzed in detail. The conclusion shows the motion stiffness is linear with the controller stiffness and initial rope tension. Finally, the theoretical stiffness, simulation stiffness and experimental stiffness are calculated and compared by the co-simulation technique and physical prototype experiment. The error between experimental data and simulation data is within 10%, which verifies the stiffness model and active stiffness control scheme.

Inverse Kinematic Model of Humanoid Robot Hand

2014 ◽  
Vol 611 ◽  
pp. 75-82 ◽  
Author(s):  
Ivan Virgala ◽  
Alexander Gmiterko ◽  
Michal Kelemen ◽  
Ľubica Miková ◽  
Martin Varga
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Kinematic Model ◽  
Theoretical Aspect ◽  
Optimization Method ◽  
Inverse Kinematic ◽  
Human Hand ◽  
Robot Hand ◽  
Damped Least Squares

Our study deals with inverse kinematic model of humanoid robot hand. It is important for modeling to know biomechanics of biological human hand, what is discussed in the second section. Based on theoretical aspect of kinematic configuration of the hand, the hand consisting of 24 degrees of freedom is assumed. Subsequently, there are four numerical methods of inverse kinematics used, namely pseudoinverse method, Jacobian transpose method, damped least squares and optimization method. Each of them is simulated in software Matlab and the results are compared and discussed. In the conclusion the best method from the view of solution time and number of iteration cycles is evaluated.

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