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.

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.

Tracking control of piezoelectric stack actuator using modified Prandtl–Ishlinskii model

2012 ◽  
Vol 24 (6) ◽  
pp. 753-760 ◽  
Author(s):  
Yuansheng Chen ◽  
Jinhao Qiu ◽  
Jose Palacios ◽  
Edward C Smith
Keyword(s):  
Tracking Control ◽  
Tracking Error ◽  
Hysteresis Model ◽  
Feedback Controllers ◽  
Modified Model ◽  
Creep Effect ◽  
Control Scheme ◽  
Feedforward Controller ◽  
Piezoelectric Stack Actuator ◽  
Symmetric Property

This article presents the development of Prandtl–Ishlinskii hysteresis model and tracking control of piezoelectric stack actuator with severe hysteresis. Classical Prandtl–Ishlinskii model is a linearly weighted superposition of many backlash operators with different threshold and weight values, which inherits the symmetric property of the backlash operator at about the center point of the loop formed by the operators. To describe the asymmetric hysteresis of piezoelectric stack actuators, two modified operators were developed, one for ascending branches and another for descending branches. Based on this modified model, a feedforward controller was designed to compensate the hysteresis. Since the modified model describes the inverse of hysteresis, the feedforward controller and the hysteresis of piezoelectric stack actuator canceled each other. To attenuate the creep effect and reduce tracking error, a feedback controller was proposed to work with the feedforward controller. Experimental results show that this control scheme that combines feedforward and feedback controllers greatly improves the tracking of the piezoelectric actuator and the error is less than 0.15 µm.

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.

Tracking Control of Piezoelectric Stack Actuator Using Modified Prandtl–Ishlinskii Model

2011 ◽  
Author(s):  
Yuansheng Chen ◽  
Jose Palacios ◽  
Edward C. Smith ◽  
Jinhao Qiu
Keyword(s):  
Tracking Control ◽  
Hysteresis Model ◽  
Tracking Accuracy ◽  
Feedback Controllers ◽  
Modified Model ◽  
Control Scheme ◽  
Different Types ◽  
Feedforward Controller ◽  
Hysteresis Control ◽  
Piezoelectric Stack Actuator

This paper presents the development of Prandtl–Ishlinskii hysteresis model and tracking control of piezoelectric stack actuator with severe hysteresis. Classic Prandtl–Ishlinskii model which is a linearly weighted superposition of many backlash operators with different threshold and weight values, inherits the symmetry property of the backlash operator at about the center point of the loop formed by the operator. To describe the asymmetric hysteresis of piezoelectric stack actuators, two sets of weighting parameters are proposed to modify the weight values of backlash operators in the ascending and descending branches. Hence, two weight values correspond to one operator. Each pair of the weight values slides smoothly from one to another when the output of their corresponding operator is at a desired threshold. A feedforward controller was designed based on the modified model, which can precisely describe the inverse of the hysteresis. Then the modified model and the hysteresis of the piezoelectric stack actuator cancelled each other. A feedback controller was design to compensate for actuator creep. Different types of signal are used to test the feedforward and feedback controllers. The results show that the proposed hysteresis control scheme which combines feedforward and feedback controllers greatly improves the tracking accuracy of the piezoelectric actuator and the error is less than 0.15 μm.

scholarly journals Fuzzy PID Feedback Control of Piezoelectric Actuator with Feedforward Compensation

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ziqiang Chi ◽  
Minping Jia ◽  
Qingsong Xu
Keyword(s):  
Feedback Control ◽  
Piezoelectric Actuator ◽  
Pid Control ◽  
Feedforward Control ◽  
Comparative Investigation ◽  
Preisach Model ◽  
Fuzzy Pid ◽  
Fuzzy Pid Control ◽  
Control Scheme ◽  
Feedforward Controller

Piezoelectric actuator is widely used in the field of micro/nanopositioning. However, piezoelectric hysteresis introduces nonlinearity to the system, which is the major obstacle to achieve a precise positioning. In this paper, the Preisach model is employed to describe the hysteresis characteristic of piezoelectric actuator and an inverse Preisach model is developed to construct a feedforward controller. Considering that the analytical expression of inverse Preisach model is difficult to derive and not suitable for practical application, a digital inverse model is established based on the input and output data of a piezoelectric actuator. Moreover, to mitigate the compensation error of the feedforward control, a feedback control scheme is implemented using different types of control algorithms in terms of PID control, fuzzy control, and fuzzy PID control. Extensive simulation studies are carried out using the three kinds of control systems. Comparative investigation reveals that the fuzzy PID control system with feedforward compensation is capable of providing quicker response and better control accuracy than the other two ones. It provides a promising way of precision control for piezoelectric actuator.

Fault-Tolerant Formation Tracking Control for Heterogeneous Multiagent Systems with Directed Topology

2021 ◽  
Vol 01 (01) ◽  
pp. 2150001
Author(s):  
Jianye Gong ◽  
Yajie Ma ◽  
Bin Jiang ◽  
Zehui Mao
Keyword(s):  
Tracking Control ◽  
Formation Control ◽  
Control Algorithm ◽  
Fault Tolerant ◽  
Control Technique ◽  
Fault Estimation ◽  
Consensus Control ◽  
Formation Tracking ◽  
Control Scheme ◽  
Aerial Vehicle

In this paper, the adaptive fault-tolerant formation tracking control problem for a set of heterogeneous unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) systems with actuator loss of effectiveness faults is investigated. The cooperative fault-tolerant formation control strategy for UAV and UGV collaborative systems is classified into the altitude consensus control scheme for follower UAVs and the position cooperative formation control scheme for all followers. The altitude consensus control algorithm is designed by utilizing backstepping control technique to drive all UAVs to a desired predefined height. Then, based on synchronization formation error information, the position cooperative formation control algorithm is proposed for all followers to reach the expected position and perform the desired formation configuration. The adaptive fault estimation term is adopted in the designed fault-tolerant formation control algorithm to compensate for the actuator loss of effectiveness fault. Finally, a simulation example is proposed to reveal the validity of the designed cooperative formation tracking control scheme.

scholarly journals Fault Location Measurement of Sensor Nodes based on Fuzzy Control Algorithm

2021 ◽  
Author(s):  
Nuo Yu
Keyword(s):  
Fuzzy Control ◽  
Measurement Method ◽  
Control Algorithm ◽  
Fault Location ◽  
Cluster Head ◽  
Sensor Nodes ◽  
Cluster Member ◽  
Cluster Heads ◽  
Fuzzy Control Algorithm ◽  
Location Measurement

Abstract Aiming at the problems of the traditional fault location measurement method for sensor nodes, such as more energy consumption and longer measurement time, a fault location measurement method for sensor nodes based on fuzzy control algorithm is designed and proposed. First of all, the fuzzy control algorithm is analyzed; then the clustering based on cluster head diagnosis is carried out for the network, that is, the nodes that meet the cluster head conditions and are set as normal cluster heads are selected as cluster heads. Finally, combined with the fuzzy control algorithm, the fault location of each cluster member node is measured directly by cluster head nodes. The simulation results show that the proposed method has good performance.

Robust Adaptive Tracking Control of Autonomous Underwater Vehicle-Manipulator Systems

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Mohan Santhakumar ◽  
Jinwhan Kim
Keyword(s):  
Adaptive Control ◽  
Control Algorithm ◽  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Dynamic Coupling ◽  
Unknown Parameters ◽  
Adaptive Tracking Control ◽  
Control Scheme ◽  
Robust Adaptive ◽  
Model Reference Adaptive

This paper proposes a new tracking controller for autonomous underwater vehicle-manipulator systems (UVMSs) using the concept of model reference adaptive control. It also addresses the detailed modeling and simulation of the dynamic coupling between an autonomous underwater vehicle and manipulator system based on Newton–Euler formulation scheme. The proposed adaptation control algorithm is used to estimate the unknown parameters online and compensate for the rest of the system dynamics. Specifically, the influence of the unknown manipulator mass on the control performance is indirectly captured by means of the adaptive control scheme. The effectiveness and robustness of the proposed control scheme are demonstrated using numerical simulations.

scholarly journals Region-of-interest-based rate control scheme for high-efficiency video coding

2014 ◽  
Vol 3 ◽  
Author(s):  
Marwa Meddeb ◽  
Marco Cagnazzo ◽  
Béatrice Pesquet-Popescu
Keyword(s):  
Video Coding ◽  
Rate Control ◽  
Control Algorithm ◽  
High Efficiency ◽  
Region Of Interest ◽  
Bit Allocation ◽  
Bit Rate ◽  
High Efficiency Video Coding ◽  
Control Scheme ◽  
Rate Control Algorithm

This paper presents a novel rate control scheme designed for the newest high efficiency video coding (HEVC) standard, and aimed at enhancing the quality of regions of interest (ROI) for a videoconferencing system. It is designed to consider the different regions at both frame level and coding tree unit (CTU) level. The proposed approach allocates a higher bit rate to the region of interest while keeping the global bit rate close to the assigned target value. The ROIs, typically faces in this application, are automatically detected and each CTU is classified in a region of interest map. This binary map is given as input to the rate control algorithm and the bit allocation is made accordingly. The algorithm is tested, first, using the initial version of the controller introduced in HEVC test model (HM.10), then, extended in HM.13. In this work, we first investigate the impact of differentiated bit allocation between the two regions using a fixed bit rate ratio in intra-coded frames (I-frames) and Bidirectionally predicted frames (B-frames). Then, unit quantization parameters (QPs) are computed independently for CTUs of different regions. The proposed approach has been compared to the reference controller implemented in HM and to a ROI-based rate control algorithm initially proposed for H.264 that we adopted to HEVC and implemented in HM.9. Experimental results show that our scheme has comparable performances with the ROI-based controller proposed for H.264. It achieves accurate target bit rates and provides an improvement in region of interest quality, both in objective metrics (up to 2 dB in PSNR) and based on subjective quality evaluation.

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