scholarly journals An Improved Dynamic Friction Model Using a Data-Based Approach

2017 ◽  
Author(s):  
Nathan A. Weir ◽  
Andrew G. Alleyne
Keyword(s):  
Control Systems ◽  
Friction Model ◽  
Model Parameters ◽  
Model Accuracy ◽  
Precision Motion Control ◽  
Frequency Domains ◽  
Slope Function ◽  
The Time Domain ◽  
Precision Motion ◽  
Fitting Model

A significant challenge associated with the development of precision motion control systems is the identification and modeling of friction. In particular, dynamic (presliding) friction is often difficult to accurately model in both the time domain and frequency domain simultaneously. We present a data-based modification to an existing friction model, known as the Dahl Dynamic Hysteresis Model (DHM), which incorporates an empirical friction slope function to provide a more accurate representation of arbitrarily shaped hysteresis curves. This data-based approach avoids the added complexity of identifying or fitting model parameters, and can be implemented with a simple look up table. Simulation results are validated with measured friction data collected from an experimental testbed. We show that the data-based approach significantly improves the friction model accuracy in both the time and frequency domains.

A linear differential formulation of friction forces for adaptive estimator algorithms

Robotica ◽  
2001 ◽  
Vol 19 (4) ◽  
pp. 407-421 ◽  
Author(s):  
C. J. Tsaprounis ◽  
N. A. Aspragathos
Keyword(s):  
Differential Equation ◽  
Friction Coefficient ◽  
Control Systems ◽  
Friction Model ◽  
Model Parameters ◽  
Coefficient Function ◽  
Stick Slip ◽  
Friction Forces ◽  
Differential Formulation ◽  
Linear Differential

In this paper a new approach for the formulation of the friction forces velocity function is introduced. The scope of this formulation is to facilitate the implementation of control laws for systems where friction forces appear. The friction model includes the exponential decay part, the Coulomb and viscous friction. The introduced formulation is based on the observation that the friction coefficient function of velocity can be presented as the solution of a linear differential equation. Due to this linearity, the parameters of the derived differential equation can be estimated easily by an adaptive system. The estimation of these parameters is equivalent to the estimation of the friction coefficient in the full range of operational velocities. This knowledge gives to the designed control systems the potential to avoid successfully the stick-slip phenomenon.A control law for one D.O.F. system, where friction appears, is designed in order to prove the applicability of the proposed formulation of the friction model in control systems. A MRAC adaptive algorithm estimates the differential friction model parameters, using the measured friction force, while a sliding controller adjusts the motion of the mechanical system. The proposed friction model can be used in any control system where friction forces have to be compensated. The linear form of the model is suitable for common adaptive estimators. Therefore, the proposed structure is suitable for robotic applications, such as assembly, deburring, etc.

Design of Numeric Control Interpolation Compensation Algorithm Based on DSP

2012 ◽  
Vol 433-440 ◽  
pp. 5686-5691
Author(s):  
Xin Na Wang ◽  
Xi Yan Bi ◽  
Ping Chuan Zhang
Keyword(s):  
Control Systems ◽  
Real Time ◽  
High Speed ◽  
Logic Circuits ◽  
Pulse Number ◽  
Precision Motion Control ◽  
Digital Control Systems ◽  
Acceleration And Deceleration ◽  
Precision Motion ◽  
Circular Interpolation

Using the TMS320C31 floating-point family DSP devices from the U.S. TI Company to have built the slave system for numeric control lathes. It makes full use of the advantages of TMS320C31 DSP, such as high-speed, high precision motion control in real time, to implement the linear and circular interpolation algorithms, sports section of acceleration and deceleration control content. Experiments show that: not only ensured the precision of digital control systems, and improved the interpolation of real time; solved the uniform allocation while any given pulse number in interpolation cycle; overcame the poor flexibility of original digital logic circuits of interpolation. Multi-axis control can be achieved to improve overall system performance. It’s with high practical value.

Controller Design for Flexible Systems With Friction: Pulse Amplitude Control

2004 ◽  
Vol 127 (3) ◽  
pp. 336-344 ◽  
Author(s):  
Jae-Jun Kim ◽  
Tarunraj Singh
Keyword(s):  
Control Systems ◽  
Pulse Width ◽  
Controller Design ◽  
Reference Value ◽  
Pulse Amplitude ◽  
Residual Vibration ◽  
Stick Slip ◽  
Amplitude Control ◽  
Precision Motion Control ◽  
Precision Motion

Accounting for friction is important when designing controllers for precision motion control systems. However, the presence of the friction and the flexibility in the system yields undesirable behaviors such as residual vibration and stick-slip oscillation near the reference value. In the proposed development, a pulse amplitude modulated controller with user-specified pulse width, is used to initiate the motion so as to permit the system to coast to the desired final position after the final pulse, with zero residual vibrations. The proposed technique is illustrated on the floating oscillator benchmark problem, where friction acts on the first mass. Numerical simulation illustrates the effectiveness of the proposed technique.

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