A Review of Shape Memory Alloy Actuators in Robotics
Mohammad Mahdi Kheirikhah, Samaneh Rabiee, and Mohammad Ehsan Edalat Islamic Azad University, Qazvin Branch, Faculty of Industrial & Mechanical Engineering,
社区活动照片Nokhbegan Boulevard, Qazvin, Iran
kheirikhah@qiau.ac.ir, ,
m_ehsan_
Abstract. Shape Memory Alloys (SMAs) have been ud for a wide variety of
applications in various fields such as robotics. If the materials subjected to an
appropriate thermomechanical process, they have ability to return to their initial
shape. Often, they are ud as actuators in robotic applications. The purpo of
this paper is to prent a brief review of literatures which using SMA in differ-
ent robots' structure. First an introduction about shape memory effect of the
materials will prent. Then an asssment of done rearches in application of
the materials in robots' structure will accomplish and is devoted to the follow-
成都海拔高度ing area of robotics: Crawler, jumper, flower, fish, walker, medical and Bio-
mimetic robotic hand.
Keywords: Shape Memory Alloys, robotic, review, actuator.
怎么安装软件1 Introduction
SMA constitute a group of metallic materials with the ability to recover a previously defined length or shape when stand under a thermodynamics process.
Although a relatively wide variety of alloys prent the shape memory effect (SME), but only tho that can recover from a large amount of strain or generate an expressive restitution force are of commercial interest [1]. The typical attribute of the materials is that their parameters can’t be deter
mined by simple interpolation of properties of alloys included in the compound. Superplasticity, superelasticty, acid resistance and SME make the compounds technically important [2].
It has been found that many materials exhibit the shape memory effect (SME), nickel-titanium alloy known as NiTiNOL. This SMA is believed to be one of the most important candidates for smart materials [3]. SMA bad on Ni-Ti are the alloys most frequently ud in commercial applications becau they combine good mechanical properties with shape memory effect[1].
In 1938, Greninger and Mooradian first obrved the SME for copper-zinc alloys (Cu-Zn) and copper-tin alloys (Cu-Sn). Yet nearly 30 years elapd until Buehler and his colleagues applied in 1965 for the first patent for a NiTiNOL, from the Naval Ord-nance Laboratory. Near the end of the 1960s, Raychem developed the first industrial SMA applications in aeronautics with the Cryofit connector for F-14 airplane hydraulic circuits. Meanwhile at the University of Iowa, Andrean’s interest in dental alloys led
A Review of Shape Memory Alloy Actuators in Robotics 207
to the implantation of the first superelastic dental braces made from Ni-Ti in 1975. Buehler suggested using SMA in dentistry for different implants that could retain the shape memory [4].
The transition from one form of crystalline structure to another creates the mecha-nism by which the shape change occurs in SMAs. This change involves transition from a monoclinic crystal form (martensite) to an ordered cubic crystal form (austen-ite)[5]. The austenite pha is stable at high temperature, and the martensite is stable phas, martensite and austenite, is accompanied by variations in its resistivity [6].
structural pha transformation, allows their u as actuator in many applications such as: aerospace, instrumentation, robotics, biomaterials (medical prosthes or Micro-systems) and the other application [7].
SMAs are usually available in the form of a wire, pipes, springs or ribbons. So, it the field of classical drives, such as the electric or hydraulic motors. Thus the drives bad on metals with the shape memory effect are the subject of rearch in many institutions, which are interested in the rearch of robotics. In this paper, there are prented an asssment of application of SMA actuators in robotics' different branches such as crawler robots, jumper robots flower robots, fish robots, walker robots, medical robots and Bio-mimetic robotic hand.
2 Crawler Robot
Liu and Liao [8] prented the development and testing of a snake robot that us SMAs as actuators in 2004. An eight-gment robot was designed to move similar to the rectilinear motion of a natural snake. A pair of SMA wires had been implemented into each gment. One of the SMA wires in each gment was heated at a time, and it acted like a muscle to change the shape of the gment. A prototype robot was built, and it could move well with the desired locomotion. As shown in Fig. 1, when the lower wire is activated, the distance between its two ends is extended to 4 cm, and the distance between its two ends of the upper wire is shorten to 2 cm.
In the same year, Lee et al [9] introduced a novel bio-mimetic micro robot with simple mechanism using SMA to generate earthworm-like locomotion. A two-way linear actuator using SMA spring and silicone bellows had been applied to the micro
Fig. 1. Segments with activated SMA wires [8]
208 M.M. Kheirikhah, S. Rabiee, and M.E. Edalat
robot. Fig. 2 shows the locomotive principle of the propod micro robot. The front needles clamp a contact surface and the rear body slides forward when SMA spring is contracted by heating. After the contraction of the SMA spring, the deformation energy of the silicone bellows makes the SMA spring elongate when it cools. At that time, the rear needles clamp the contact surface and the front body slides forward. Finally, the bellows’ spring force is equal to that of SMA spring as initial equilibrium state.
Fig. 2. Principle of locomotion [9]
The undulatory locomotion of living earthworms had been investigated deeply from the biological point of view by Menciassi et al [10] in 2004, but attempts of replication of earthworm models in real size were limited. Their robot had some mod-ules that each module was actuated by one or more SMA springs. Preliminary tests demonstrated that the earthworm prototypes can move with a speed of 0.22 mm/s, thus approximating the behavior of biological earthworms.
real ones. Prototypes with or without micro-legs (which affect the locomotion per-formance) had been developed.
Along them, in 2004 Qin et al [12] that prented the design of a SMA driving mi-cro-wheeled-robot, which had a 45mm×15mm×30mm size. Their paper shows the controlled by Yao et al [13] in the same year. In this robot the SMA spring was heated by pul current by PIC controller (a kind of single-chip) and was cooled by air.
Pipe inspection is a very important issue in construction. The inspection of low di-ameter canalizatio
ns is a pending issue nowadays, however it would help to repair and maintain a large amount of installations. Conventional in-pipe moving mechanisms for pipe inspection, driven by electromagnetic motors, have large volume and mass. The SMA actuator can be an alternative for a small-sized in-pipe moving mechanism due to this robot had three degrees of freedom (DOF) with 3 SMA wires.
In year 2005, using twelve novel SMA linear actuators, which could stretch and shrink along its axis and could bear some radial force and bend, a miniature worming
certain span.
A Review of Shape Memory Alloy Actuators in Robotics 209
Menciassi et al [16] expanded the development of gmented artificial crawlers with passive hook-shaped frictional microstructures in 2006. There were described the mechanical model, the design and the fabrication of a SMA-actuated gmented mi-crorobot, who locomotion had been inspired by the peristaltic motion of Annelids, and in particular of earthworms (Lumbricus Terrestris).
Caterpillars are some of the most successful scansorial and burrowing animals and yet they lack a hard skeleton. Their hydrostatic body and prolegs provide astonishing fault-tolerant maneuverability and powerful, stable, passive attachment. Trimmer et al [17] in 2006 described some of the biomechanics of caterpillar locomotion and grip-
cone rubber. It moved by SMA springs as actuators, bonded directly to the inside of the body wall. Also a kind of gripper was designed for this robot that provided its vertical movements by 3 SMA springs.
In the next year, 2007, also an investigation on the structure of caterpillar's body was prented by Kate et al [18] where in each gments of this robot there were ud 2 SMA wires as an actuator too.
Spring type SMA actuators are lected to fabricate an inchworm-like moving mechanism that consists of clamping and moving modules (Fig.3). For lection of proper operating type (a bias type or a differential type) for clamping module and moving module, displacements and dynamic characteristics of each operating type traction force of 0.4N were obtained from the driving experime
nt in a pipe with the diameter of 39mm.
Fig. 3. Structure of in-pipe moving mechanism [19]
3 Jumper Robots
Locomotion over rough terrain has been achieved mainly by rigid body systems including crawlers and leg mechanisms. Sugiyama and Hirai [20] prented an alter-native method of moving over rough terrain, one that was employed deformation in 2004.大学生运动会
210 M.M. Kheirikhah, S. Rabiee, and M.E. Edalat
The circular soft robot consisted of a circular elastic shell with a t of soft actua-tors inside. The robot has eight SMA actuators which deforms the robot body.Fig. 4 shows a quence of snapshots of the prototype jumping. The prototype can jump a distance of 80mm, which is twice its diameter.
Fig. 4. Circular soft robot jumping [20]
In 2005, the principle of crawling and jumping as performed through deformation of a robot body was described by Sugiyama et al[21]. Then, in a physical simulation, they investigated the feasibility of the approach. Next, authors showed experimentally that prototypes of a circular robot and a spherical robot could crawl and jump.
纨绔的意思
In the same year, Shiotsu et al [22] created two prototypes of a spherical soft robot to asss experimentally the feasibility of a deformable robot crawling and jumping. Prototype A was for crawling and consisted of 18 SMA coils and shells made of spring steel. The core inside the spherical body included circuits to drive SMA coils, a microprocessor, and a rial communication circuit. Prototype B was for both crawl-ing and jumping. This prototype consisted of 22 SMA coils – 18 for crawling and jumping and 4 for jumping. Circuits to drive SMA coils and a microcomputer were outside of the prototype.
4 Flower Robots
As a smart home rvice robot, the flower robot has various intelligent functions, such as moving mechanism, nsing ability, and home appliance functions. Especially, the moving function is very important function among the various function. The moving function of flower robot has consisted of the blooming of flower, the swaying of the tor for stem structure, authors adopted coil type SMA and then propod silicone stem structure with 3 coil type SMA. They designed and fabricated the stem structure with 8mm of diameter and 50mm of length.
After a year, in 2008, Huang et al [24], focud on the movement of the flower ro-
A Review of Shape Memory Alloy Actuators in Robotics 211
Fig. 5. The movement of stem and flower petal [24]
silicone rod, a spring and a wire with one side of SMA were connected to drive the petal of the flower robot. In the design of leafage, a SMA wire was bonded to one surface of the leafage. The fashion of motion in leafage was same with the stem struc-ture. Fig.5 shows the movement of stem and flower petal.
开心色色网
5 Fish Robots
利客隆超市笔记本屏幕亮度Fishes are regarded as highly maneuverable and effortless swimmers due to their natural fishes. In some of them, SMA is ud as an actuator.
was able to furnish a thrust for swimming of a robotic fish. The caudal peduncle ac-tuator was bad on concepts of ferromagnetic shape memory alloy (FSMA) compos-
ite and hybrid mechanism that could provide a fast respon and a strong thrust. The caudal peduncle actuator was inspired by Scomber Scombrus. The morphology of an average size Scomber Scombrus was investigated, and a 1:1 scale caudal peduncle actuator prototype was modeled and fabricated. The tail was a composite consisted of
superelastic NiTi SMA framework and two polymer impermeable membranes, which
ure joints, electrical wiring and attachment pads for SMA actuators were all embed-ded in a single layer of copper laminated polymer film. Finally this package was sandwiched between two layers of glass fiber. Instead of using individual actuators to rotate each joint, each actuator rotated all the joints to a certain mode shape and undu-latory motion was created by a timed quence of the mode shapes.
by Wang et al [27]. Fish swims by their undulating body and/or fins.To simplify en-
