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.

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.

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.

scholarly journals A dynamic parameter identification method of industrial robots considering joint elasticity

2019 ◽  
Vol 16 (1) ◽  
pp. 172988141882521 ◽  
Author(s):  
Hepeng Ni ◽  
Chengrui Zhang ◽  
Tianliang Hu ◽  
Teng Wang ◽  
Qizhi Chen ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Dynamic Model ◽  
Joint Stiffness ◽  
Dynamic Parameter ◽  
Industrial Robots ◽  
Identification Accuracy ◽  
Processing Algorithm ◽  
Identification Method ◽  
Joint Elasticity ◽  
Dynamic Parameter Identification

Considering the joint elasticity, a novel dynamic parameter identification method is proposed for general industrial robots only with motor encoders. Firstly, the unknown parameters of the elastic joint dynamic model are analyzed and divided into two types. The first type is the motion-independent parameter only including the joint stiffness, which can be identified by the static force/torque-deformation experiments without the dynamic model. The second type is the motion-dependent parameter composed of the rest of the parameters, which needs the dynamic excitation experiments. Therefore, these two types of parameters can be identified separately. Meanwhile, it is found that the rotor inertia parameters can be obtained from the manufacturer, which reduces the identification difficulty of other parameters. After obtaining the rotor inertia and joint stiffness, an approximate processing algorithm is proposed considering the motor friction to establish the linear identification model of other parameters. Hence, the least squares can be employed to identify the parameters, and the independence of the inertia and joint viscous friction parameters are not affected. Meanwhile, the exciting trajectories can be optimized throughout the robot workspace, which reduces the effect of measurement noise on identification accuracy. With the proposed separated identification strategy and approximate processing algorithm, the dynamic parameters can be obtained precisely without double encoders on each joint. Finally, a series of simulations are conducted to evaluate the good performance of the proposed method.

Dynamic Stiffness Identification of Bolted Joints

2011 ◽  
Vol 291-294 ◽  
pp. 1582-1588
Author(s):  
Tie Neng Guo ◽  
Bin Song ◽  
Dong Liang Guo ◽  
Zhong Qing Chen
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Stiffness ◽  
Dynamic Parameter ◽  
High Accuracy ◽  
Bolted Joints ◽  
Small Discrepancy ◽  
Identification Method ◽  
Stiffness Identification ◽  
Accuracy Result ◽  
The Relationship

The joint has a significant effect on the dynamic characteristic of the mechanism, and the identification of the stiffness of the joints has become a key problem. In this paper, a method is presented for identifying the dynamic characteristic of joints. An experiment is designed to test the dynamic parameter of the bolted joints specimen; the identification method, based on experiment, has a high accuracy result. By taking a specimen to experiment and identify the dynamic characteristic of joints, the relationship between the preload on the bolts and the joints stiffness is acquired. In order to validate the accuracy of the result, the FEM software is used to simulate. There are only a small discrepancy between the results of identification and simulation.

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