Controller Design on the Fingerspelling Robot Hand using Shape Memory Alloy

Author(s):  
Mina Terauchi ◽  
Kouta Zenba ◽  
Akira Shimada ◽  
Masanori Fujita
2020 ◽  
Vol 31 (13) ◽  
pp. 1543-1556
Author(s):  
Navid Moslemi ◽  
Soheil Gohari ◽  
Farzin Mozafari ◽  
Mohsen Gol Zardian ◽  
Colin Burvill ◽  
...  

The knee plays a significant role in locomotion and stability of the entire body through supporting the body weight and assisting the lower body kinematics during walking. However, the knee is at constant risk of becoming weakened due to disease, age, and accidents. One approach to treating weakened knee is wearing an assistive knee brace. To design a clinical knee brace, many factors such as weight and compliant mechanism should be considered. In this study, a novel smart assistive knee brace mechanism incorporated with wire actuators made of shape memory alloys is proposed to ameliorate the issues associated with weight and flexibility of existing brace designs. Unlike earlier studies, the proposed orthosis includes pressure sensor, shape memory actuator, and smart linkage. Furthermore, two distinct shape memory alloy actuator design concepts with improved stiffness are developed, and the best option is chosen systematically and prototyped. The novel mechanism proposed in this research overcomes the weight of the lower limb during swing phase using the combined shape memory alloy actuation and feed-forward controller design. As such, it can be used as a potential replacement to its conventional counterparts when the higher weight reduction as well as a flexible and controllable mechanism are simultaneously sought.


Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Manisekaran Varadharajan ◽  
Prakash Duraisamy ◽  
Anitha Karthikeyan

In this paper, the effect of quasi-periodic excitation on a three-leg supporter configured with shape memory alloy is investigated. We derived the equation of motion for the system using the supporter configuration and polynomial constitutive model of the shape memory alloys (SMAs) based on Falk model. Two sets of parameters and symmetric initial conditions are used to analyze the system. The system responded with a chaotic attractor and a strange nonchaotic attractor. Coexistence of these attractors is studied and discussed with corresponding phase portrait, bifurcation plot, and cross section of basin of attraction. We confirm the quasi-periodic excitation results with generation of strange nonchaotic attractors as discussed in the literature. The special properties like symmetricity and bistability are revealed and the parameter ranges of existence of such behaviors are discussed. The system is analyzed for different phases and the existence of bistability in martensite phase and transition phase is explained. While the system enters into austenite phase, the bistability behavior vanishes. The results provide insight knowledge into dynamical response of a quasi-periodically excited SMA leg support system and will be useful for design improvements and controller design.


Author(s):  
K Yang ◽  
C L Gu

This paper describes the development of an active robot hand, which allows smooth and lifelike motions for anthropomorphic grasping and fine manipulations. An active robot finger 10mm in outer diameter with a shape memory alloy (SMA) wire actuator embedded in the finger with a constant distance from the geometric centre of the finger was designed and fabricated. The practical specifications of the SMA wire and the flexible rod were determined on the basis of a series of formulae. The active finger consists of two bending parts, the SMA actuators and a connecting part. The mechanical properties of the bending part are investigated. The control system on the base of resistance feedback is also presented. Finally, a robot hand with three fingers was designed and the grasping experiment was carried out to demonstrate its performance.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Futoshi Kobayashi ◽  
George Ikai ◽  
Wataru Fukui ◽  
Fumio Kojima

A haptic feedback system is required to assist telerehabilitation with robot hand. The system should provide the reaction force measured in the robot hand to an operator. In this paper, we have developed a force feedback device that presents a reaction force to the distal segment of the operator's thumb, middle finger, and basipodite of the middle finger when the robot hand grasps an object. The device uses a shape memory alloy as an actuator, which affords a very compact, lightweight, and accurate device.


Robotica ◽  
1999 ◽  
Vol 17 (4) ◽  
pp. 373-382 ◽  
Author(s):  
Kuo-Yang Tu ◽  
Tsu-Tian Lee ◽  
Chi-Hsu Wang ◽  
Cu-An Chang

The Shape Memory Alloy (SMA) is a device which is lightweight and small in volume. The SMA can be used as the actuator of a micro-robot, but it is difficult to design a controller to handle the highly nonlinear properties of the SMA. In this paper, a Fuzzy Walking Pattern (FWP) is proposed to control a small biped robot, using an SMA as the actuator. In fact, the desired walking pattern of the small biped robot is used to construct the FWP. The proposed FWP can control the biped robot under the desired walking pattern, and handle the exceptional case when the biped robot is subject to disturbance. The proposed FWP not only solves the control problem of the SMA, but also provides a new method in controller design of the biped robot. In addition, a transputer network is designed to impelement the FWP. Experimental results demonstrate the functions of the FWP.


Robotica ◽  
2009 ◽  
Vol 27 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Vishalini Bundhoo ◽  
Edmund Haslam ◽  
Benjamin Birch ◽  
Edward J. Park

SUMMARYIn this paper, a new biomimetic tendon-driven actuation system for prosthetic and wearable robotic hand applications is presented. It is based on the combination of compliant tendon cables and one-way shape memory alloy (SMA) wires that form a set of agonist–antagonist artificial muscle pairs for the required flexion/extension or abduction/adduction of the finger joints. The performance of the proposed actuation system is demonstrated using a 4 degree-of-freedom (three active and one passive) artificial finger testbed, also developed based on a biomimetic design approach. A microcontroller-based pulse-width-modulated proportional-derivation (PWM-PD) feedback controller and a minimum jerk trajectory feedforward controller are implemented and tested in anad hocfashion to evaluate the performance of the finger system in emulating natural joint motions. Part II describes the dynamic modeling of the above nonlinear system, and the model-based controller design.


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