scholarly journals Decomposed dynamic control for a flexible robotic arm in consideration of nonlinearity and the effect of gravity

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769410 ◽  
Author(s):  
Haibin Yin ◽  
Yongguang Li ◽  
Junfeng Li
Keyword(s):  
Dynamic Model ◽  
Experimental Verification ◽  
Disturbance Rejection ◽  
Sliding Mode ◽  
Dynamic Control ◽  
Robotic Arm ◽  
Strong Nonlinearity ◽  
Nonlinear Dynamic Model ◽  
Residual Vibration ◽  
Theoretical Derivation

This article presents a nonlinear dynamic model of a flexible robotic arm considering nonlinearity from elastic deformation and the effect of gravity. The dynamic model can be decomposed into separate flexible and rigid subsystems. A decomposed dynamic control, including flexible and rigid dynamic controls, is proposed for the controller of the flexible robotic arm. Optimization is used in this flexible dynamic control to obtain the desired trajectory and can deal offline with strong nonlinearity, but it is excessively dependent on the accuracy of the model, so it is not robust enough and has poor disturbance-rejection capabilities. The rigid dynamic control, by contrast, is expected to be sufficiently robust to compensate for uncertain factors. Therefore, a hybrid sliding mode control is proposed to track the desired trajectory and further suppress residual vibration. Additionally, the actual flexible modes are estimated to accurately calculate the component of the proposed controller. This study addresses the theoretical derivation and experimental verification of the proposed controller.

Nonlinear dynamic modeling and adaptive sliding control of the milling head for efficient and powerful machining

2016 ◽  
Vol 232 (3) ◽  
pp. 381-393 ◽  
Author(s):  
Pengbing Zhao ◽  
Jin Huang ◽  
Yaoyao Shi
Keyword(s):  
Sliding Mode Control ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Sliding Mode ◽  
Numerical Control ◽  
Adaptive Sliding Mode Control ◽  
Nonlinear Dynamic Model ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
Control Precision

Milling head is an essential assembly in the five-axis computer numerical control machine tools, positioning precision of which directly affects the machining accuracy and surface quality of the processed parts. Considering the influence of nonlinear friction in the transmission mechanism and the uncertain cutting force disturbance on the control precision of the milling head, the static and dynamic performances of the milling head are analyzed; relationships among the drive torque, load torque, motion direction and system parameters are discussed; and, finally, nonlinear dynamic model of the milling head is established. A novel adaptive sliding mode control scheme based on the variable switching gain and the adjustable boundary thickness is proposed for this nonlinear dynamic model; the stability of the closed-loop system is guaranteed by the Lyapunov theory. Experimental results show that the proposed adaptive sliding mode control can reduce the chattering in the traditional sliding mode control and can achieve high control precision without knowing the boundaries of uncertainties in advance.

A new robust combined control system for improving manoeuvrability, lateral stability and rollover prevention of a vehicle

2019 ◽  
Vol 234 (1) ◽  
pp. 198-213 ◽  
Author(s):  
Mohammad Amin Saeedi
Keyword(s):  
Control System ◽  
Dynamic Model ◽  
Control Method ◽  
Sliding Mode ◽  
Lateral Stability ◽  
Steering Control ◽  
Nonlinear Dynamic Model ◽  
Active Steering ◽  
Combined Control ◽  
Active Steering Control

This paper presents a new effective method in order to achieve an appropriate performance for a four-wheeled vehicle during different conditions. The main goal of the study is focused on the handling improvement and lateral stability increment of the vehicle using a robust combined control system. First, in order to increase the vehicle's manoeuvrability, an active steering control system is proposed based on the sliding mode control method and using the simplified dynamic model. The tracking of the desired values of the yaw rate and lateral velocity of the vehicle is the main purpose for using the controller. Also, in order for verifying the performance of the sliding mode controller, the linearization feedback control method is used to design the active steering control system. Moreover, to improve the directional stability of the vehicle, a new active roll control system is proposed. In this control system, the roll angle is considered as the state variable as well as the active anti-roll-bar is utilized as an actuator to generate the roll moment. Then, a 14-degrees-of-freedom nonlinear dynamic model of the vehicle validated using CarSim software is utilized. Afterward, the performance of the designed combined control system is investigated at various velocities. The simulation results confirm that the combined control system has an important effect on vehicle's manoeuvrability improvement and its lateral stability increment, especially during severe transient manoeuvre.

Analysis of Tourism Ecology Capacity Based on the Nonlinear Dynamic Model

2009 ◽  
Vol 11 (2) ◽  
pp. 163-168
Author(s):  
Long LV ◽  
Zhenfang HUANG ◽  
Jiang WU
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Model

scholarly journals Development, Modeling and Control of a Dual Tilt-Wing UAV in Vertical Flight

Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 71
Author(s):  
Luz M. Sanchez-Rivera ◽  
Rogelio Lozano ◽  
Alfredo Arias-Montano
Keyword(s):  
Dynamic Model ◽  
Attitude Control ◽  
Test Bench ◽  
Aerodynamic Coefficients ◽  
Nonlinear Dynamic Model ◽  
Modeling And Control ◽  
Drag And Lift ◽  
And Control ◽  
Dynamics Method ◽  
Indoor And Outdoor

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.

Integral barrier Lyapunov functions-based integrated guidance and control design for strap-down missile with field-of-view constraint

2021 ◽  
pp. 014233122098132
Author(s):  
Bin Zhao ◽  
Zhenxin Feng ◽  
Jianguo Guo
Keyword(s):  
Sliding Mode ◽  
State Equation ◽  
Field Of View ◽  
Feedback Form ◽  
Theoretical Derivation ◽  
Guidance And Control ◽  
Integrated Guidance And Control ◽  
Twisting Algorithm ◽  
And Control ◽  
Special Time

The problem of the integrated guidance and control (IGC) design for strap-down missile with the field-of-view (FOV) constraint is solved by using the integral barrier Lyapunov function (iBLF) and the sliding mode control theory. Firstly, the nonlinear and uncertainty state equation with non-strict feedback form for IGC design is derived by using the strap-down decoupling strategy. Secondly, a novel adaptive finite time disturbance observer is proposed to estimate the uncertainties based on an improved adaptive gain super twisting algorithm. Thirdly, the special time-varying sliding variable is designed and the iBLF is employed to handle the problem of FOV constraint. Theoretical derivation and simulation show that the IGC system is globally uniformly ultimately bounded and the FOV angle constraint is also guaranteed not only during the reaching phase but also during the sliding mode phase.

Geometry optimization of a planar double wishbone suspension based on whole-range nonlinear dynamic model

2021 ◽  
pp. 095440702110262
Author(s):  
Zhihua Niu ◽  
Sun Jin ◽  
Rongrong Wang ◽  
Yansong Zhang
Keyword(s):  
Dynamic Model ◽  
Geometry Optimization ◽  
Analytical Models ◽  
Small Displacement ◽  
Nonlinear Dynamic Model ◽  
Computational Accuracy ◽  
Suspension Systems ◽  
Geometry Design ◽  
Dynamic Performances ◽  
Suspension Geometry

Dynamic analysis is an essential task in the geometry design of suspension systems. Whereas the dynamic simulation based on numerical software like Adams is quite slowly and the existing analytical models of the nonlinear suspension geometry are mostly based on small displacement hypothesis, this paper aims to propose a whole-range dynamic model with high computational efficiency for planar double wishbone suspensions and further achieve the fast optimal design of suspension geometry. Selection of the new generalized coordinate and explicit solutions of the basic four-bar mechanism dramatically reduce the complexity of suspension geometry representation and provide analytical solutions for all of the time varying dimensions. By this means, the running speed and computational accuracy of the new model are guaranteed simultaneously. Furthermore, an original Matlab/Simulink implementation is given to maintain the geometric nonlinearity in the solving process of dynamic differential equations. After verifying its accuracy with an ADAMS prototype, the presented whole-range model is used in the vast-parameter optimization of suspension geometry. Since both kinematic and dynamic performances are evaluated in the objective function, the optimization is qualified to give a comprehensive suggestion to the design of suspension geometry.

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