scholarly journals A Nonlinear Model and Parameter Identification Method for Rubber Isolators under Shock Excitation in Underwater Vehicles

2021 ◽  
Vol 9 (11) ◽  
pp. 1282
Author(s):  
Heye Xiao ◽  
Chizhen Xu ◽  
Ruobing Wang ◽  
Peixun Yu ◽  
Jie Zhou ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Nonlinear Model ◽  
Current Model ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Transient Responses ◽  
Isolation System ◽  
Shock Excitation ◽  
Identification Process ◽  
Identification Method

Rubber isolators are usually used to protect high-precision equipment of autonomous underwater vehicles (AUVs), avoiding damage from overlarge dynamic excitation. Considering the nonlinear properties of the rubber material, the nonlinear behavior of rubber isolators under shock exaltation is hard to be predict accurately without the available modal and accurate parameters. In view of this, the present study proposes a nonlinear model and parameter identification method of rubber isolators to present their transient responses under shock excitation. First, a nonlinear model of rubber isolators is introduced for simulating their amplitude and frequency-dependent deformation under shock excitation. A corresponding dynamic equation of the isolation system is proposed and analytically solved by the Newmark method and the Newton-arithmetic mean method. Secondly, a multilayer feed-forward neural network (MFFNN) is constructed with the current model to search the parameters, in which the differences between the estimated and tested responses are minimized. The sine-sweep and drop test are planned with MFFNN to build the parameter identification process of rubber isolators. Then, a T-shaped isolator composed of high-damping silicon rubber is selected as a sample, and its parameters were determined by the current identification process. The transient responses of the isolation system are reconstructed by the current mode with the identified parameter, which show good agreement with measured responses. The accuracy of the proposed model and parameter identification method is proved. Finally, the errors between the reconstructed responses and tested responses are analyzed, and the main mode of energy attenuation in the rubber isolator is discussed in order to provide an inside view of the current model.

Sensorless Parameter Identification Method for PMSM Based on Double Manifold Sliding Mode

2010 ◽  
Vol 171-172 ◽  
pp. 632-635
Author(s):  
Ze Cheng ◽  
Fa Bin Yan ◽  
Yan Li Liu ◽  
Ya Fei Ji
Keyword(s):  
Parameter Identification ◽  
Reference Model ◽  
Sliding Mode ◽  
Current Model ◽  
Dynamic Performance ◽  
Adaptive Model ◽  
Output Current ◽  
Identification Method ◽  
Real Model ◽  
The Stability

An adaptive model reference parameter identification method without sensors for PMSM is presented in this paper and this method is based on double manifold sliding mode. The real model of PMSM is selected as the reference model and the d/q frame observer which is constructed using current model of the motor is selected as the adjustable model. The manifold sliding mode surface is constructed using the output (current in d/q frame) errors of the two models. Proper parameters are selected to guarantee the stability of the observer. The adjustable model converges to the reference model and the running state of motor can be identified. Theoretical analysis and simulation results show that the proposed strategy has high static and dynamic performance，high tracking precision as well as stronger robustness.

Experimental Study of Dynamic Characteristics and Model Parameter Identification of Tensioner

2014 ◽  
Vol 988 ◽  
pp. 332-337
Author(s):  
Hong Yun Wang ◽  
Xiang Kun Zeng ◽  
Ji Yong Zhao
Keyword(s):  
Parameter Identification ◽  
Nonlinear Model ◽  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Identification Method ◽  
Serpentine Belt ◽  
Drive Systems ◽  
Set Up ◽  
Stiffness And Damping

Tensioners play a predominant role in the dynamic behavior of serpentine belt drive systems. The experimental set-up was carried out to study the dynamic characteristics of tensioner. Experimental results illustrate that tensioner shows hysteresis nonlinear dynamic characteristics, and dynamic stiffness and damping of slip motion of up stroke of tensioner are related to excitation frequency and amplitude. The first differential nonlinear model of tensioner was determined, and the parameter identification method of the model was introduced. The accurate of the nonlinear model and effectiveness of the parameter identification method was validated.

A Novel Parameter Identification Method for Tire Models

2016 ◽  
Author(s):  
Junzhao Jiang ◽  
Jianwei Lu ◽  
Jinhui Li ◽  
Lei Li
Keyword(s):  
Parameter Identification ◽  
Engineering Application ◽  
Lateral Force ◽  
Longitudinal Force ◽  
Modeling And Analysis ◽  
Identification Process ◽  
Identification Method ◽  
Identification Approach ◽  
Tire Modeling ◽  
Dynamics Models

A novel parameter identification method for dynamics models of pneumatic tire was presented. The parameter identification process and methodology relate to Nelder-Mead algorithm, genetic algorithm and random value method. Based on experimental data and tire modeling of PAC2002, the lateral force parameters, longitudinal force parameters and aligning moment parameters were identified by using the presented identification approach. It can be found that the novel parameter identification approach is more accurate and efficient, which can provide theoretic evidence for tire modeling and analysis. Moreover, a software system that integrates the parameter identification methodology was compiled and developed by using MATLAB and C++, which can provide a quick and efficient parameter identification process for engineering application in the future.

scholarly journals Design, simulation of AUV (VIAM-AUV1000) for research and rescue

2021 ◽  
Vol 3 (SI2) ◽  
pp. first
Author(s):  
HUY NGOC TRAN ◽  
Đức Tô Nguyễn ◽  
Thái Hoàng Huỳnh
Keyword(s):  
Nonlinear Model ◽  
Autonomous Underwater Vehicle ◽  
Sliding Mode ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Vehicle Model ◽  
Steering Angle ◽  
Ducted Propeller ◽  
Uncertainty Parameters ◽  
Compact Design

Autonomous Underwater Vehicles have gained popularity for the last decades, especially a lot of AUVs were considered as the most suitable tool for the purpose of reducing risks of people in dangerous marine operations. This paper presents the preliminary results of the research on hardware design, the controller of an autonomous underwater vehicle model for the task of survey, search and rescue ... With a compact design, AUV can operate in limited spaces. Through a unique ducted propeller and rudder located at the aft, the AUV can perform horizontal motion. It can also control pitch angle and depth motion by an inside mass shifter mechanism (MSM) which changes the vehicle center of gravity. In addition, The AUV is integrated with powerful eletronic system, highprecision sensors helping it carries on missions from simple to complex. The use of Sliding Mode Control (SMC) to independently design the heading and depth controllers for AUV demonstrates the steady stability of the controllers with the nonlinear model, uncertainty parameters and disturbances. Finally, the simulation results show that the SMC controllers can control the AUV nonlinear model to track the desired steering angle and depth with high accuracy and stability.

A method for autonomous collision-free navigation of a quadrotor UAV in unknown tunnel-like environments

Robotica ◽  
2021 ◽  
pp. 1-27
Author(s):  
Taha Elmokadem ◽  
Andrey V. Savkin
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Autonomous Underwater Vehicles ◽  
Three Dimensional ◽  
Underwater Vehicles ◽  
Practical Implementation ◽  
Challenging Problem ◽  
Quadrotor Uav ◽  
Navigation Algorithm ◽  
Aerial Vehicles ◽  
Quadrotor Uavs

Abstract Unmanned aerial vehicles (UAVs) have become essential tools for exploring, mapping and inspection of unknown three-dimensional (3D) tunnel-like environments which is a very challenging problem. A computationally light navigation algorithm is developed in this paper for quadrotor UAVs to autonomously guide the vehicle through such environments. It uses sensors observations to safely guide the UAV along the tunnel axis while avoiding collisions with its walls. The approach is evaluated using several computer simulations with realistic sensing models and practical implementation with a quadrotor UAV. The proposed method is also applicable to other UAV types and autonomous underwater vehicles.

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