B-Spline Based Adaptive Control of Shape Memory Alloy Actuated Robotic Systems

2002 ◽  
Author(s):  
Yavuz Eren ◽  
Constantinos Mavroidis ◽  
Jason Nikitczuk
Keyword(s):  
Adaptive Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Scale ◽  
Full Range ◽  
Spline Approximation ◽  
Variable Structure ◽  
Robotic Systems ◽  
Integral Control ◽  
B Spline

In this paper we present a novel controller for Shape Memory Alloy (SMA) actuated robotic systems. The new controller, called BAC (B-spline based Adaptive Control), is based on a hybrid combination of gain scheduling, B-spline approximation, variable structure control and integral control. The proposed controller shows excellent positioning accuracy and speed throughout the full range of motion of a SMA actuated robotic system in large-scale applications. To demonstrate the validity of BAC, a novel anthropomorphic SMA Actuated forearm/wrist mechanism is utilized in real-time PC based control experiments. BAC is experimentally compared to PID and integral variable structure controllers and it is shown that its performance is superior.

Design, Modeling and Control of a New Robotic Module Actuated by Shape Memory Alloy Springs

2009 ◽  
Author(s):  
Alireza Hadi ◽  
Mohammad Elahinia ◽  
Asadollah Ghazavi ◽  
Majid M. Moghadam
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Variable Structure ◽  
Robotic Systems ◽  
Modeling And Control ◽  
Modular Systems ◽  
Structure Control ◽  
Spring Type ◽  
Sma Spring ◽  
And Control

Modular robotic systems provide attractive benefits in the form of re-configurable robots that can change and adapt for special tasks. Self-reconfigurable is re-configurable robot with the ability to change their framework for different missions. One way to increase robots capabilities and to achieve self-configurable robots is to develop small, powerful and dexterous modules. In this paper, a new mechanism which uses Shape Memory Alloy (SMA) spring actuators is applied to develop a robotic module. Among the proposed modular systems until now, shape memory alloys especially the spring type are rarely used as actuators. The proposed mechanism is based on antagonistic application of SMA springs which provide faster actuation response. It is shown that the module mechanism is suitable for developing modular robotic systems, such as mobile robots, snake robots, and legged robots. The design of mechanical and electrical hardware of the module in addition to the sensing and actuating system is done talented in an optimum space. The same extendable modules communicate through a common bus in order to develop a distributed system. Consequently a proper module is presented to be applied in different robotic systems. Moreover, an effective non-linear control strategy which is variable structure control is applied for controlling the position of the module. Benefits and suitability of this controller for the module different configurations is verified using simulations and experiments.

scholarly journals Disturbance compensation-based output feedback adaptive control for shape memory alloy actuator system

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142199399
Author(s):  
Xiaoguang Li ◽  
Bi Zhang ◽  
Daohui Zhang ◽  
Xingang Zhao ◽  
Jianda Han
Keyword(s):  
Adaptive Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Method ◽  
Control Law ◽  
Reference Trajectory ◽  
Disturbance Compensation ◽  
Comparison Results ◽  
Control Scheme ◽  
Actuator System

Shape memory alloy (SMA) has been utilized as the material of smart actuators due to the miniaturization and lightweight. However, the nonlinearity and hysteresis of SMA material seriously affect the precise control. In this article, a novel disturbance compensation-based adaptive control scheme is developed to improve the control performance of SMA actuator system. Firstly, the nominal model is constructed based on the physical process. Next, an estimator is developed to online update not only the unmeasured system states but also the total disturbance. Then, the novel adaptive controller, which is composed of the nominal control law and the compensation control law, is designed. Finally, the proposed scheme is evaluated in the SMA experimental setup. The comparison results have demonstrated that the proposed control method can track reference trajectory accurately, reject load variations and stochastic disturbances timely, and exhibit satisfactory robust stability. The proposed control scheme is system independent and has some potential in other types of SMA-actuated systems.

scholarly journals Tunnel Deformation Inspection via Global Spatial Axis Extraction from 3D Raw Point Cloud

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6815
Author(s):  
Cheng Yi ◽  
Dening Lu ◽  
Qian Xie ◽  
Jinxuan Xu ◽  
Jun Wang
Keyword(s):  
Cross Sections ◽  
Point Cloud ◽  
Large Scale ◽  
Spline Approximation ◽  
Point Clouds ◽  
Driving Safety ◽  
Inspection Method ◽  
B Spline ◽  
3D Point Clouds ◽  
Spatial Axis

Global inspection of large-scale tunnels is a fundamental yet challenging task to ensure the structural stability of tunnels and driving safety. Advanced LiDAR scanners, which sample tunnels into 3D point clouds, are making their debut in the Tunnel Deformation Inspection (TDI). However, the acquired raw point clouds inevitably possess noticeable occlusions, missing areas, and noise/outliers. Considering the tunnel as a geometrical sweeping feature, we propose an effective tunnel deformation inspection algorithm by extracting the global spatial axis from the poor-quality raw point cloud. Essentially, we convert tunnel axis extraction into an iterative fitting optimization problem. Specifically, given the scanned raw point cloud of a tunnel, the initial design axis is sampled to generate a series of normal planes within the corresponding Frenet frame, followed by intersecting those planes with the tunnel point cloud to yield a sequence of cross sections. By fitting cross sections with circles, the fitted circle centers are approximated with a B-Spline curve, which is considered as an updated axis. The procedure of “circle fitting and B-SPline approximation” repeats iteratively until convergency, that is, the distance of each fitted circle center to the current axis is smaller than a given threshold. By this means, the spatial axis of the tunnel can be accurately obtained. Subsequently, according to the practical mechanism of tunnel deformation, we design a segmentation approach to partition cross sections into meaningful pieces, based on which various inspection parameters can be automatically computed regarding to tunnel deformation. A variety of practical experiments have demonstrated the feasibility and effectiveness of our inspection method.

scholarly journals Ni-Ti Shape Memory Alloy Coatings for Structural Applications: Optimization of HVOF Spraying Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Carmen De Crescenzo ◽  
Despina Karatza ◽  
Dino Musmarra ◽  
Simeone Chianese ◽  
Theocharis Baxevanis ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Large Scale ◽  
Thermal Spray Technology ◽  
Spray Parameters ◽  
Hvof Spraying ◽  
Structural Applications ◽  
External Stimuli ◽  
Steel Substrates ◽  
The Impact

This work aims at contributing to the development of a revolutionary technology based on shape memory alloy (SMA) coatings deposited on-site to large-scale metallic structural elements, which operate in extreme environmental conditions, such as steel bridges and buildings. The proposed technology will contribute to improve the integrity of metallic civil structures, to alter and control their mechanical properties by external stimuli, to contribute to the stiffness and rigidity of an elastic metallic structure, to safely withstand the expected loading conditions, and to provide corrosion protection. To prove the feasibility of the concept, investigations were carried out by depositing commercial NiTinol Ni50.8Ti (at.%) powder, onto stainless steel substrates by using high-velocity oxygen-fuel thermal spray technology. While the NiTinol has been known since decades, this intermetallic alloy, as well as no other alloy, was ever used as the SMA-coating material. Due to the influence of dynamics of spraying and the impact energy of the powder particles on the properties of thermally sprayed coatings, the effects of the main spray parameters, namely, spray distance, fuel-to-oxygen feed rate ratio, and coating thickness, on the quality and properties of the coating, in terms of hardness, adhesion, roughness, and microstructure, were investigated.

Nonlinear Control of a Shape Memory Alloy Actuated Manipulator

2002 ◽  
Vol 124 (4) ◽  
pp. 566-575 ◽  
Author(s):  
Mohammad H. Elahinia ◽  
Hashem Ashrafiuon
Keyword(s):  
Robust Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Algorithm ◽  
Weighted Average ◽  
Nonlinear Behavior ◽  
Variable Structure ◽  
Open Loop ◽  
Nonlinear Robust Control ◽  
Nonlinear Robust

This paper presents a nonlinear, robust control algorithm for accurate positioning of a single degree of freedom rotary manipulator actuated by Shape Memory Alloy (SMA). A model for an SMA actuated manipulator is presented. The model includes nonlinear dynamics of the manipulator, a constitutive model of Shape Memory Alloy, and electrical and heat transfer behavior of SMA wire. This model is used for open and closed loop motion simulations of the manipulator. Experiments are presented that show results similar to both closed and open loop simulation results. Due to modeling uncertainty and nonlinear behavior of the system, classic control methods such as Proportional-Integral-Derivative control are not able to present fast and accurate performance. Hence a nonlinear, robust control algorithm is presented based on Variable Structure Control. This algorithm is a control gain switching technique based on the weighted average of position and velocity feedbacks. This method has been designed through simulation and tested experimentally. Results show fast, accurate, and robust performance of the control system. Computer simulation and experimental results for different stabilization and tracking situations are also presented.

Model Reference Adaptive Control Based on KP Model for Magnetically Controlled Shape Memory Alloy Actuators

2017 ◽  
Vol 15 (1_suppl) ◽  
pp. 31-37 ◽  
Author(s):  
Miaolei Zhou ◽  
Yannan Zhang ◽  
Kun Ji ◽  
Dong Zhu
Keyword(s):  
Adaptive Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Method ◽  
Model Reference Adaptive Control ◽  
Positioning Accuracy ◽  
Model Reference ◽  
Hysteresis Nonlinearity ◽  
Adopted Model ◽  
Model Reference Adaptive

Introduction Magnetically controlled shape memory alloy (MSMA) actuators take advantages of their large deformation and high controllability. However, the intricate hysteresis nonlinearity often results in low positioning accuracy and slow actuator response. Methods In this paper, a modified Krasnosel'skii-Pokrovskii model was adopted to describe the complicated hysteresis phenomenon in the MSMA actuators. Adaptive recursive algorithm was employed to identify the density parameters of the adopted model. Subsequently, to further eliminate the hysteresis nonlinearity and improve the positioning accuracy, the model reference adaptive control method was proposed to optimize the model and inverse model compensation. Results The simulation experiments show that the model reference adaptive control adopted in the paper significantly improves the control precision of the actuators, with a maximum tracking error of 0.0072 mm. Conclusions The results prove that the model reference adaptive control method is efficient to eliminate hysteresis nonlinearity and achieves a higher positioning accuracy of the MSMA actuators.

Sign in / Sign up

Export Citation Format

Share Document