scholarly journals The Study of Dynamic Modeling and Multivariable Feedback Control for Flexible Manipulators with Friction Effect and Terminal Load

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1522
Author(s):  
Fuli Zhang ◽  
Zhaohui Yuan
Keyword(s):  
Dynamic Model ◽  
Vibration Suppression ◽  
Control Method ◽  
Coupling Effect ◽  
Flexible Manipulator ◽  
Flexible Beam ◽  
Robot Dynamics ◽  
Joint Friction ◽  
Balance Principle ◽  
Multivariable Feedback

The flexible manipulato is widely used in the aerospace industry and various other special fields. Control accuracy is affected by the flexibility, joint friction, and terminal load. Therefore, this paper establishes a robot dynamics model under the coupling effect of flexibility, friction, and terminal load, and analyzes and studies its control. First of all, taking the structure of the central rigid body, the flexible beam, and load as the research object, the dynamic model of a flexible manipulator with terminal load is established by using the hypothesis mode and the Lagrange method. Based on the balance principle of the force and moment, the friction under the influence of flexibility and load is recalculated, and the dynamic model of the manipulator is further improved. Secondly, the coupled dynamic system is decomposed and the controller is designed by the multivariable feedback controller. Finally, using MATLAB as the simulation platform, the feasibility of dynamic simulation is verified through simulation comparison. The results show that the vibration amplitude can be reduced with the increase of friction coefficient. As the load increases, the vibration can increase further. The trajectory tracking and vibration suppression of the manipulator are effective under the control method of multi-feedback moment calculation. The research is of great significance to the control of flexible robots under the influence of multiple factors.

Dynamic Coupling and Control of Flexible Space Robots

2020 ◽  
Vol 20 (09) ◽  
pp. 2050103
Author(s):  
Yanfeng Du ◽  
Cong Wang
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Coupling Effect ◽  
Space Robot ◽  
Flexible Manipulator ◽  
Flexible Manipulators ◽  
Dynamic Coupling ◽  
Input Shaper ◽  
Flexible Panels ◽  
And Control

The dynamic modeling and coupling effect of a space robot are complex when the flexible manipulator and solar panels are considered. This paper investigates the dynamic coupling effect and control of a flexible space robot with flexible manipulators and flexible panels. The equations of motion are derived for the robot model both of the rigid-flexible type and flexible-flexible type. The flexible space robot dynamic model is verified by comparison with the results generated by the ADAMS software, for which good agreement has been obtained. The dynamic coupling matrix of the flexible space robot is derived based on the dynamic model. The effects of the central rigid body mass and the joints angle on the dynamic coupling are analyzed. A control method is proposed to manipulate the flexible space robot based on the system dynamic model. The multiple-impulse robust (MIR) input shaper is used to suppress the vibration of flexible structures in the proposed controller. Appropriate design parameter and frequency scaling factor are selected for the MIR input shaper to suppress the flexible vibration. The flexible space robot control is conducted to illustrate the effect of the proposed controller. It is shown that the proposed control method can realize the desired joints manipulation, while suppressing the vibration of the flexible manipulators and flexible panels.

On the Properties of a Dynamic Model of Flexible Robot Manipulators

1998 ◽  
Vol 120 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Marco A. Arteaga
Keyword(s):  
Dynamic Model ◽  
Structural Properties ◽  
Robot Manipulators ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Control Design ◽  
Flexible Manipulator ◽  
Robot Dynamics ◽  
Flexible Link ◽  
Flexible Robot

Control design of flexible robot manipulators can take advantage of the structural properties of the model used to describe the robot dynamics. Many of these properties are physical characteristics of mechanical systems whereas others arise from the method employed to model the flexible manipulator. In this paper, the modeling of flexible-link robot manipulators on the basis of the Lagrange’s equations of motion combined with the assumed modes method is briefly discussed. Several notable properties of the dynamic model are presented and their impact on control design is underlined.

scholarly journals Vibration Response and Power Flow Characteristics of a Flexible Manipulator with a Moving Base

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yufei Liu ◽  
Wei Li ◽  
Xuefeng Yang ◽  
Mengbao Fan ◽  
Yuqiao Wang ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Power Flow ◽  
Flow Characteristics ◽  
Flexible Manipulator ◽  
Rigid Base ◽  
Flexible Beam ◽  
Noticeable Effect ◽  
Moving Base ◽  
Vibration Responses ◽  
Motion Characteristics

Flexible manipulator generally can be modeled as a coupling system with a flexible beam and a rigid moving base. This paper investigates the vibration responses and power flow of a flexible manipulator with a moving base (FMMB). Considering the motion characteristics of the rigid base, the moving base is modeled to have a motion with disturbances, and the dynamic model of the FMMB is established. With the dynamic model, vibration responses of the FMMB for the rigid base having disturbance velocities and accelerations are specifically presented. Subsequently, to investigate the effect of the disturbances on the vibration energy distributions of the FMMB, power flow of the FMMB is exhibited. To verify the dynamic model, an ADAMS physical model of the FMMB is constructed. It reveals that the motion characteristics of the rigid base have a noticeable effect on the vibration responses and power flow of the FMMB and should be considered. The results are significant and contribute to the vibration control of flexible manipulators.

Vibration control of coupled Duffing oscillators in flexible single-link manipulators

2020 ◽  
pp. 107754632095259
Author(s):  
Jie Huang ◽  
Jinchen Ji
Keyword(s):  
High Speed ◽  
Vibration Suppression ◽  
Control Method ◽  
Negative Impact ◽  
Nonlinear Modeling ◽  
Flexible Manipulator ◽  
Flexible Link ◽  
Structural Nonlinearity ◽  
Single Link ◽  
Coupled Duffing Oscillators

Motion-induced oscillations of the flexible single link and its payload at the tip have negative impact on the anticipated performance of the flexible manipulators and thus should be suppressed to achieve tip positioning accuracy and high-speed operation. Because of the structural flexibility, the dynamics of the flexible manipulator can be described by coupled Duffing oscillators when considering the inherent structural nonlinearity of the flexible link into the dynamic modeling. However, little research has been focused on addressing the dynamic coupling issue in the nonlinear modeling of flexible-link manipulators using coupled Duffing oscillators. This article presents coupled Duffing oscillators for the nonlinear modeling of flexible single-link manipulators and then proposes a control method for suppressing the nonlinear vibrations of the coupled Duffing oscillators. Simulated and experimental results obtained from a flexible single-link manipulator test bench are in good agreement with the proposed nonlinear modeling and also demonstrate the effectiveness of the proposed control techniques for vibration suppression of the flexible manipulator.

SSPS Dynamic Modeling and the Flexible Vibration Suppression

2015 ◽  
Vol 799-800 ◽  
pp. 724-727
Author(s):  
Ran Wang ◽  
Hao Tian ◽  
Hong Liu Wang ◽  
Yang Zhao ◽  
Chen Yang ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Vibration Suppression ◽  
Control Method ◽  
Flexible Structures ◽  
Order Reduction ◽  
Equivalent Strain ◽  
Solar Array ◽  
Beam Model ◽  
Dynamics Modeling ◽  
Assumed Mode Method

Space solar power satellite (SSPS) as a very large flexible spacecraft structure with complex configuration, large size and number of units bring the difficulties to dynamics modeling and analysis. Considering SSPS structure characteristics, equivalent strain and kinetic energy theory is adopted to establish the equivalent beam model of SSPS truss structure. The assumed mode method is adopted to describe the flexible body. The modal truncation method implements the dynamics system order reduction. Mixed coordinates method is adopted to establish the rigid-flexible coupled dynamic model. The established dynamic model can reflect dynamic characteristics of SSPS, achieve control requirements for SSPS and decrease the workload of simulation calculation. The independent modal space control (IMSC) method is proposed to active control research view of the large displacement, nonlinearity, low and dense mode frequency, light damping of flexible structures. Simulation results on flexible solar array show the effectiveness of the control method.

scholarly journals Modelling and Composite Control of Single Flexible Manipulators with Piezoelectric Actuators

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
En Lu ◽  
Wei Li ◽  
Xuefeng Yang ◽  
Mengbao Fan ◽  
Yufei Liu
Keyword(s):  
Vibration Suppression ◽  
Control Method ◽  
Sliding Mode ◽  
Piezoelectric Actuators ◽  
Flexible Manipulator ◽  
Optimal Placement ◽  
Flexible Manipulators ◽  
Linear Quadratic ◽  
Fast Subsystem ◽  
Slow Subsystem

The piezoelectric actuators are used to investigate the active vibration control of flexible manipulators in this paper. Based on the assumed mode method, piezoelectric coupling model, and Hamilton’s principle, the dynamic equation of the single flexible manipulator (SFM) with surface bonded actuators is established. Then, a singular perturbation model consisted of a slow subsystem and a fast subsystem is formulated and used for designing the composite controller. The slow subsystem controller is designed by fuzzy sliding mode control method, and the linear quadratic regulator (LQR) optimal control method is used to design fast subsystem controller. Furthermore, the changing trends of natural frequencies along with the changes in the position of piezoelectric actuators are obtained through the ANSYS Workbench software, by which the optimal placement of actuators is determined. Finally, numerical simulations and experiments are presented. The results demonstrate that the method of optimal placement is feasible based on the maximal natural frequency, and the composite controller presented in this paper can not only realize the trajectory tracking of the SFM and has a good result on the vibration suppression.

A Constrained Lagrange Formulation of Multilink Planar Flexible Manipulator

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
M. Vakil ◽  
R. Fotouhi ◽  
P. N. Nikiforuk ◽  
H. Salmasi
Keyword(s):  
Closed Form ◽  
Dynamic Model ◽  
Vibration Suppression ◽  
Equations Of Motion ◽  
Flexible Manipulator ◽  
Dynamic Equations ◽  
Flexible Link ◽  
Element Analysis ◽  
Constraint Matrix ◽  
Generalized Coordinates

In this article, the closed-form dynamic equations of planar flexible link manipulators (FLMs), with revolute joints and constant cross sections, are derived combining Lagrange’s equations and the assumed mode shape method. To overcome the lengthy and complicated derivative calculation of the Lagrangian function of a FLM, these computations are done only once for a single flexible link manipulator with a moving base (SFLMB). Employing the Lagrange multipliers and the dynamic equations of the SFLMB, the equations of motion of the FLM are derived in terms of the dependent generalized coordinates. To obtain the closed-form dynamic equations of the FLM in terms of the independent generalized coordinates, the natural orthogonal complement of the Jacobian constraint matrix, which is associated with the velocity constraints in the linear homogeneous form, is used. To verify the proposed closed-form dynamic model, the simulation results obtained from the model were compared with the results of the full nonlinear finite element analysis. These comparisons showed sound agreement. One of the main advantages of this approach is that the derived dynamic model can be used for the model based end-effector control and the vibration suppression of planar FLMs.

Vibration suppression of a rotating cantilever beam under magnetic excitations by applying the magnetostrictive material

2018 ◽  
Vol 30 (4) ◽  
pp. 576-592 ◽  
Author(s):  
Xueping Xu ◽  
Qinkai Han ◽  
Fulei Chu ◽  
Robert G Parker
Keyword(s):  
Dynamic Model ◽  
Cantilever Beam ◽  
Vibration Suppression ◽  
Control Method ◽  
Dynamic Equations ◽  
Width Ratio ◽  
Energy Potential ◽  
Bending Vibration ◽  
Magnetic Excitations ◽  
Feedback Control Method

The dynamic model and vibration suppression of a rotating cantilever beam under magnetic excitations are investigated in this article. The nonlinear constitutive relation of magnetostrictive materials is presented. The layout of the control system is demonstrated and explained. The kinetic energy, potential energy of the system, and work done by the electromagnetic force are obtained. The dynamic equations of the system are obtained and discretized by the Hamilton principle and Galerkin approach, respectively. Based on the negative feedback control method, the control scheme is implemented by the magnetostrictive layer. The dynamic model and control method are validated by the references. Various parameter values of the magnetic excitations and rotating beam systems are investigated to reveal their effects on the control behaviors of the bending vibration. Results illustrate that the magnetic excitations bring negative stiffness in the system and increase the responses of beam greatly. The magnetostrictive suppression is effective and can be regarded as the damping effect in the dynamic equations. Increasing the control gain, bias magnetic field and width ratio of the magnetostrictive layer to the controlled layer are beneficial to the vibration control. However, enlarging the angular velocity and pre-stress is harmful to the vibration suppression.

scholarly journals Optimal Trajectory Planning of the Variable-Stiffness Flexible Manipulator Based on CADE Algorithm for Vibration Reduction Control

2021 ◽  
Vol 9 ◽  
Author(s):  
Qiang Cheng ◽  
Wenxiang Xu ◽  
Zhifeng Liu ◽  
Xiaolong Hao ◽  
Yi Wang
Keyword(s):  
Trajectory Planning ◽  
Optimal Trajectory ◽  
Vibration Suppression ◽  
Control Method ◽  
Minimum Energy ◽  
Variable Stiffness ◽  
Robotic Manipulators ◽  
Flexible Manipulator ◽  
Vibration Displacement ◽  
Optimal Trajectory Planning

Robotic manipulators are widely used for precise operation in the medical field. Vibration suppression control of robotic manipulators has become a key issue affecting work stability and safety. In this paper an optimal trajectory planning control method to suppress the vibration of a variable-stiffness flexible manipulator considering the rigid-flexible coupling is proposed. Through analyzing the elastic deformation of the variable-stiffness flexible manipulator, a distributed dynamic physical model of the flexible manipulator is constructed based on the Hamilton theory. Based on the mathematical model of the system, the design of the vibration damping controller of the flexible manipulator is proposed, and the control system with nonlinear input is considered for numerical analysis. According to the boundary conditions, the vibration suppression effect of the conventional and the variable-stiffness flexible manipulator is compared. The motion trajectory of the variable-stiffness flexible manipulator and compare the vibration response from different trajectories. Then, with minimum vibration displacement, minimum energy consumption and minimum trajectory tracking deviation as performance goals, the trajectory planning of the variable-stiffness flexible manipulator movement is carried out based on the cloud adaptive differential evolution (CADE) optimization algorithm. The validity of the proposed trajectory planning method is verified by numerical simulation.

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