State machine based nonlinear hysteresis model

Mechatronics ◽  
2015 ◽  
Vol 31 ◽  
pp. 215-221
Author(s):  
Andreas Meister ◽  
Steffen Buechner ◽  
Arvid Amthor
Keyword(s):  
State Machine ◽  
Hysteresis Model ◽  
Nonlinear Hysteresis

A Force Control Joint for Robot–Environment Contact Application

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
Qilong Wang ◽  
Wei Wang ◽  
Xilun Ding ◽  
Chao Yun
Keyword(s):  
Force Control ◽  
Model Simulation ◽  
Industrial Robot ◽  
Artificial Muscle ◽  
Hysteresis Model ◽  
Link Length ◽  
Nonlinear Hysteresis ◽  
The Difference ◽  
Parallel Configuration ◽  
Improved Accuracy

Accurate and robust force control is still a great challenge for robot–environment contact applications, such as in situ repair, polishing, and assembly. To tackle this problem, this paper proposes a force control joint with a parallel configuration, including two identical four-bar linkages driven by linear springs to push up the output end of the joint, and a parallel-connected pneumatic artificial muscle (PAM) to pull down its output end. In the new design, the link length of the linkages will be optimized to make the difference between the profile of the linkage and that of PAM constant within the limits of the joint given the force–displacement profile of PAM at a certain level of its input pressure. Furthermore, PAM's nonlinear hysteresis effect, which is believed to limit the accuracy of the joint's force control, will be represented by a new dynamics model that is to be developed from the classical Bouc–Wen (BW) hysteresis model. Simulation tests are then conducted to reveal that the adoption of the PAM hysteresis model yields improved accuracy of force control, and a series of curve trajectory tracking experiments are performed on a six-joint universal industrial robot to verify that the parallel force control joint is capable to enhance force control accuracy for robot contact applications.

Hysteretic Behaviors of Yield Stress in Smart ER/MR Materials: Experimental Results

2006 ◽  
Vol 326-328 ◽  
pp. 1459-1462
Author(s):  
Young Min Han ◽  
Quoc Hung Nguyen ◽  
Seung Bok Choi ◽  
Kyung Su Kim
Keyword(s):  
Yield Stress ◽  
Smart Materials ◽  
Hysteretic Behavior ◽  
Preisach Model ◽  
Hysteresis Model ◽  
First Order ◽  
Input Field ◽  
Nonlinear Hysteresis ◽  
Field Dependent ◽  
Discrete Manner

This paper experimentally investigates the hysteretic behaviors of yield stress in electrorheological (ER) and magnetorheological (MR) materials which are known as smart materials. As a first step, the PMA-based ER material is prepared by dispersing the chemically synthesized polymethylaniline (PMA) particles into non-conducting oil. For the MR material, commercially available one (Lord MRF-132LD) is chosen for the test. Using the rheometer, the torque resulting from the shear stress of the ER/MR materials is measured, and then the yield stress is calculated from the measured torque. In order to describe the hysteretic behavior of the fielddependent yield stress, a nonlinear hysteresis model of the ER/MR materials is formulated between input (field) and output (yield stress). Subsequently, the Preisach model is identified using experimental first order descending (FOD) curves of yield stress in discrete manner. The effectiveness of the identified hysteresis model is verified in time domain by comparing the predicted field-dependent yield stress with the measured one.

The Hysteresis Model of Terfenol-D with Magneto-Stress Coupling

2011 ◽  
Vol 121-126 ◽  
pp. 4820-4825
Author(s):  
Ai Hua Meng ◽  
Han Lin He ◽  
Min Kong ◽  
Ming Fan Li
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Constitutive Relation ◽  
Hysteresis Model ◽  
Hysteresis Behavior ◽  
Nonlinear Hysteresis ◽  
Nonlinear Constitutive Relation

The output of Terfenol-D is nonlinear and hysteretic under the effect of magnetic field and prestress. The nonlinear constitutive relation between magnetostriction and magnetization with magneto-stress coupling was built in consideration of the magnetostriction saturation and the prestress correlation. Then, the hysteresis behavior of Terfenol-D was modeled based on the Jiles-Atherton model. The error of magnetostriction between simulations and experimental data is less than 6%. This result indicates that the model can adequately predict the nonlinear hysteresis and magneto-stress coupling character of Terfenol-D.

PREISACH MODEL OF ER FLUIDS CONSIDERING TEMPERATURE VARIATIONS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1325-1331 ◽  
Author(s):  
Y. M. HAN ◽  
S. B. CHOI ◽  
H. J. CHOI
Keyword(s):  
Tracking Error ◽  
Preisach Model ◽  
Hysteresis Model ◽  
Temperature Variations ◽  
New Approach ◽  
Model Inversion ◽  
Nonlinear Hysteresis ◽  
Discrete Manner ◽  
Er Fluids ◽  
Er Fluid

This paper presents a new approach for hysteresis modeling of an electro-rheological (ER) fluid. The Preisach model is adopted to describe change of an ER fluid hysteresis with temperature, and its applicability is experimentally proved by examining two significant properties under two dominant temperature conditions. As a first step, the polymethylaniline (PMA)-based ER fluid is made by dispersing the chemically synthesized PMA particles into non-conducting oil. Then, using the Couette type electroviscometer, multiple first order descending (FOD) curves are constructed to consider temperature variations in the model. Subsequently, a nonlinear hysteresis model of the ER fluid is formulated between input (electric field) and output (yield stress). A compensation strategy is also formulated in a discrete manner through the Preisach model inversion to attain desired shear stress of the ER fluid. In order to demonstrate the effectiveness of the identified hysteresis model and the tracking performance of the control strategy, the field-dependent hysteresis loop and tracking error responses are experimentally evaluated in time domain and compared with responses obtained from Bingham model.

scholarly journals A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7638
Author(s):  
Trung Thien Hoang ◽  
Luke Sy ◽  
Mattia Bussu ◽  
Mai Thanh Thai ◽  
Harrison Low ◽  
...  
Keyword(s):  
Liquid Metal ◽  
New Technologies ◽  
Model Parameters ◽  
Rubber Tube ◽  
Hysteresis Model ◽  
New Class ◽  
Nonlinear Hysteresis ◽  
Piezoresistive Sensor ◽  
Elastic Rubber ◽  
Soft Actuators

Soft actuators (SAs) have been used in many compliant robotic structure and wearable devices, due to their safe interaction with the wearers. Despite advances, the capability of current SAs is limited by scalability, high hysteresis, and slow responses. In this paper, a new class of soft, scalable, and high-aspect ratio fiber-reinforced hydraulic SAs is introduced. The new SA uses a simple fabrication process of insertion where a hollow elastic rubber tube is directly inserted into a constrained hollow coil, eliminating the need for the manual wrapping of an inextensible fiber around a long elastic structure. To provide high adaptation to the user skin for wearable applications, the new SAs are integrated into flexible fabrics to form a wearable fabric sleeve. To monitor the SA elongation, a soft liquid metal-based fabric piezoresistive sensor is also developed. To capture the nonlinear hysteresis of the SA, a novel asymmetric hysteresis model which only requires five model parameters in its structure is developed and experimentally validated. The new SAs-driven wearable robotic sleeve is scalable, highly flexible, and lightweight. It can also produce a large amount of force of around 23 N per muscle at around 30% elongation, to provide useful assistance to the human upper limbs. Experimental results show that the soft fabric sleeve can augment a user’s performance when working against a load, evidenced by a significant reduction on the muscular effort, as monitored by electromyogram (EMG) signals. The performance of the developed SAs, soft fabric sleeve, soft liquid metal fabric sensor, and nonlinear hysteresis model reveal that they can effectively modulate the level of assistance for the wearer. The new technologies obtained from this work can be potentially implemented in emerging assistive applications, such as rehabilitation, defense, and industry.

Control Algorithm for Nanoscale Positioning of a 6DOF Stewart Platform

2007 ◽  
Author(s):  
Yung Ting ◽  
Ho-Chin Jar ◽  
Chun-Chung Li
Keyword(s):  
Measurement Method ◽  
Control Algorithm ◽  
Cost Effective ◽  
Stewart Platform ◽  
Preisach Model ◽  
Hysteresis Model ◽  
Nonlinear Hysteresis ◽  
Control Scheme ◽  
Feedforward Controller ◽  
Minimum Points

A 6DOF Stewart platform driven by piezoelectric actuators was designed for applications in need of nanoscale positioning. By using flexural joints and an error compensation model based on a minimum-points-3-axes measurement method, the manufacturing and assembly errors can be offset. The design of a feedforward controller that is able to reduce the nonlinear hysteresis effect of the piezoelectric actuator is the focus of this article. A dynamic Preisach model is developed to improve the accuracy of hysteresis model, whose inverse model is used as the feedforward controller. Such a control scheme is cost-effective without employing expensive sensors for feedback control. Experimental data shows that the platform can achieve the objective of nanoscale positioning.

scholarly journals Model and Experimental Study on Optical Fiber CT Based on Terfenol-D

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2255 ◽  
Author(s):  
Wang Li ◽  
Xia Kewen ◽  
Weng Ling
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Fiber Bragg Grating ◽  
Current Transformer ◽  
Bias Current ◽  
Bragg Grating ◽  
Hysteresis Model ◽  
Strain Sensing ◽  
Prestressing Force ◽  
Nonlinear Hysteresis

A nonlinear hysteresis model of magneto-mechanical-thermo coupling for Terfenol-D materials is presented according to Wiss ferromagnetic theory, thermodynamics relations and Jiles–Atherton model. Numerical calculation and experimental results show that the mode well reflects the magnetostrictive characteristics of Terfenol-D rod under the coupling of stress, temperature and magnetic field. A fiber Bragg grating current transformer based on Terfenol-D material is designed according to the strain sensing mechanism of fiber Bragg grating and the demodulation principle of unbalanced M–Z interferometer. The theoretical analysis and research on the working characteristics of the fiber current transformer under the influence of different prestressing force and bias current are carried out. The results are important for the design and application of the current transformer with the Terfenol-D material.

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