scholarly journals An Improved Redundant Robotic Arm Parameter Identification Method

2020 ◽  
Author(s):  
Shi-Ping Liu ◽  
Ziyan Ma ◽  
Jin-Liang Chen ◽  
Jun-Feng Cao ◽  
Yan Fu ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Linear Optimization ◽  
Viscous Friction ◽  
Friction Model ◽  
Robotic Arm ◽  
Identification Method ◽  
Observation Matrix ◽  
Optimization Function ◽  
Minimum Number ◽  
Actual Control

Abstract In order to establish the dynamic model of redundant robotic arm more accurately, this paper studies the identification method of the dynamic parameters of redundant robotic arm. A method of introducing the theory of spins based on the Newton-Euler dynamics equations, and using the Coulomb + viscous friction model to further derive the minimum parameter set through linearization is proposed. The method of offline identification of current measurement is used to realize the parameter identification of the robotic arm. The excitation trajectory is designed in the basic form of Fourier series. The non-linear optimization function is used to optimize the coefficient of the trajectory with the minimum number of conditions in the observation matrix as the goal Therefore, the available joint trajectories are obtained, and the obtained parameter set has high accuracy and can meet the needs of actual control. Finally, the method was experimentally tested by actual robot Walker, which verified the accuracy and effectiveness of the proposed method.

scholarly journals An improved parameter identification method of redundant manipulator

2021 ◽  
Vol 18 (2) ◽  
pp. 172988142110021
Author(s):  
Shi-Ping Liu ◽  
Zi-Yan Ma ◽  
Jin-Liang Chen ◽  
Jun-Feng Cao ◽  
Yan Fu ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Viscous Friction ◽  
Dynamic Parameter ◽  
High Accuracy ◽  
Friction Model ◽  
Service Robot ◽  
Redundant Manipulator ◽  
Spinor Theory ◽  
Identification Method ◽  
Optimization Function

To achieve more accurate simulation and control in the use of the manipulator, it is necessary to establish an accurate dynamic model of the redundant manipulator. The research of this article focuses on the dynamic parameter identification method of the redundant manipulator. In the study, the spinor theory is applied to the Newton–Euler dynamic equation, the Coulomb + viscous friction model is adopted, and the minimum parameter set is obtained by linearization derivation. The parameter identification of the manipulator is realized using the method of offline identification of the measured current, and the coefficient of the excitation trajectory is optimized using the nonlinear optimization function. Finally, the parameter set with high accuracy is obtained, and the motion trajectory of each joint can be obtained. The scheme has high accuracy and can meet the needs of practical application. To verify the accuracy and reliability of this method, we have carried out experiments on a service robot “Walker” and obtained the desired results.

A new identification method of the Stribeck friction model based on limit cycles

2014 ◽  
Vol 228 (15) ◽  
pp. 2678-2683 ◽  
Author(s):  
LL Liu ◽  
ZY Wu
Keyword(s):  
Parameter Identification ◽  
Limit Cycle ◽  
Limit Cycles ◽  
Friction Model ◽  
Limit Cycle Oscillation ◽  
Characteristic Parameters ◽  
Chain Code ◽  
Shape Characteristic ◽  
Identification Method ◽  
Model Based

This paper presents a new parameter identification method of the Stribeck friction model based on limit cycles. A single degree of freedom mass spring system driven by a belt is studied, and the Stribeck friction model is established between the mass and belt. Limit cycle oscillation will occur when the system is unstable. The limit cycle curve is described by some main shape characteristic parameters using the modified Freeman chain code method. Thus, the Stribeck friction parameters can be identified by using the ergodic search method to minimize the Euclidean distance of the theoretical and identified limit cycle shape characteristic parameters. The parameter identification method based on limit cycles is different from the traditional identification methods. It only needs the displacement and velocity responses of the system instead of the measurement of the friction force or motor voltage/current. All of these works can provide the reference for the research work of the friction parameter identification.

Modeling and Dynamic Parameter Identification of the SCHUNK Powerball Robotic Arm

2015 ◽  
Author(s):  
Amirhossein H. Memar ◽  
Ehsan T. Esfahani
Keyword(s):  
Parameter Identification ◽  
Viscous Friction ◽  
Dynamic Parameter ◽  
Human Robot Interaction ◽  
Least Square ◽  
Robotic Arm ◽  
Inverse Dynamic ◽  
Compact Design ◽  
Dynamic Parameter Identification ◽  
Linear Least Square

This paper presents the modeling and dynamic parameter identification of the 6-DoF SCHUNK Powerball LWA 4P robotic arm. Precise positioning, zero backlash and compact design of the joints which integrate two perpendicular axes, make this robot ideal for service robotics applications and human-robot interaction. Due to the significant effect of the lubricant temperature on the behavior of viscous friction in the harmonic drives, a systematic procedure is developed to overcome this problem. A series of experiments have been conducted to model the friction at each joint, then the procedure of identification has been applied based on an inverse dynamic model and linear least-square techniques. Finally, a verification trajectory is executed by the robot to validate the estimated parameters of the system.

A Continuous Velocity-Based Friction Model for Dynamics and Control With Physically Meaningful Parameters

2016 ◽  
Vol 11 (5) ◽  
Author(s):  
Peter Brown ◽  
John McPhee
Keyword(s):  
Optimal Control ◽  
Real Time ◽  
Viscous Friction ◽  
Friction Model ◽  
Time Dynamic ◽  
Proposed Model ◽  
Dynamics And Control ◽  
Minimum Number ◽  
Model Of Friction ◽  
Real Time Simulations

Friction is an important part of many dynamic systems, and, as a result, a good model of friction is necessary for simulating and controlling these systems. A new friction model, designed primarily for optimal control and real-time dynamic applications, is presented in this paper. This new model defines friction as a continuous function of velocity and captures the main velocity-dependent characteristics of friction: the Stribeck effect and viscous friction. Additional phenomena of friction such as microdisplacement and the time dependence of friction were not modeled due to the increased complexity of the model, leading to reduced performance of real-time simulations or optimizations. Unlike several current friction models, this model is C1 continuous and differentiable, which is desirable for optimal control applications, sensitivity analysis, and multibody dynamic analysis and simulation. To simplify parameter identification, the proposed model was designed to use a minimum number of parameters, all with physical meaning and readily visible on a force–velocity curve, rather than generic shape parameters. A simulation using the proposed model demonstrates that the model avoids any discontinuities in force at initial impact and the transition from slipping to sticking.

scholarly journals Parameter identification method of hydraulic automatic gauge control system based on chaotic wolf pack optimization algorithm

AIP Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 055302
Author(s):  
Yong Zhu ◽  
Guangpeng Li ◽  
Shengnan Tang ◽  
Wanlu Jiang ◽  
Zhijian Zheng
Keyword(s):  
Control System ◽  
Parameter Identification ◽  
Optimization Algorithm ◽  
Identification Method ◽  
Automatic Gauge Control

scholarly journals Study on Friction in Automotive Shock Absorbers Part 1: Friction Simulation Using a Dynamic Friction Model in the Contact Zone of an FEM Model

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 212-232
Author(s):  
Ludwig Herzog ◽  
Klaus Augsburg
Keyword(s):  
Ride Comfort ◽  
Viscous Friction ◽  
Simulation Method ◽  
Friction Model ◽  
Model Parameters ◽  
Dynamic Friction ◽  
Friction Modeling ◽  
Shock Absorbers ◽  
Operation Conditions ◽  
Wide Range

The important change in the transition from partial to high automation is that a vehicle can drive autonomously, without active human involvement. This fact increases the current requirements regarding ride comfort and dictates new challenges for automotive shock absorbers. There exist two common types of automotive shock absorber with two friction types: The intended viscous friction dissipates the chassis vibrations, while the unwanted solid body friction is generated by the rubbing of the damper’s seals and guides during actuation. The latter so-called static friction impairs ride comfort and demands appropriate friction modeling for the control of adaptive or active suspension systems. In this article, a simulation approach is introduced to model damper friction based on the most friction-relevant parameters. Since damper friction is highly dependent on geometry, which can vary widely, three-dimensional (3D) structural FEM is used to determine the deformations of the damper parts resulting from mounting and varying operation conditions. In the respective contact zones, a dynamic friction model is applied and parameterized based on the single friction point measurements. Subsequent to the parameterization of the overall friction model with geometry data, operation conditions, material properties and friction model parameters, single friction point simulations are performed, analyzed and validated against single friction point measurements. It is shown that this simulation method allows for friction prediction with high accuracy. Consequently, its application enables a wide range of parameters relevant to damper friction to be investigated with significantly increased development efficiency.

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