دانلود رایگان ترجمه مقاله حرکت هزارپا مانند یک میکرو ربات قطعه ای (نشریه اسپرینگر 2011)

حرکت هزارپا مانند یک میکرو ربات قطعه ای

Myriapod-like ambulation of a segmented microrobot

Abstract

Segmented myriapod-like bodies may offer performance benefits over more common fixed body morphologies for ambulation. Here, the design of a segmented ambulatory microrobot with a flexible backbone is presented. A dynamic model describing the motion of the microrobot is used to determine body parameters. A three-segment microrobot was fabricated using the Smart Composite Microstructures process and piezoelectric bimorph actuators, and forward locomotion on a flat surface was demonstrated. The footprint of the 750 mg microrobot is 3.5 by 3.5 cm, and it has potential advantages over rigid body hexapedal microrobots in climbing, versatility, and stability.

1 Introduction

Advances in microfabrication techniques and an improved understanding of the locomotory mechanisms of insects have enabled recent success in the development of ambulatory microrobots. Examples of successful combinations of biological inspiration and layered composite manufacturing are RoACH, a 2.4 g autonomous hexapod robot capable of speeds up to one body length per second (Hoover et al. 2008), DASH, an autonomous robot modeled after a cockroach robust enough to withstand falls at 10 m/s and larger at about 10 cm in length (Birkmeyer et al. 2009), and HAMR, a microrobot that has demonstrated forward locomotion and weighs only 90 mg (Baisch and Wood 2009). Each of these robots was created using the Smart Composite Microstructures (SCM) method of fabrication (Wood et al. 2008). Additionally, they were all modeled after cockroaches, utilize the alternating tripod gait seen in insects, and have a central body that houses electronics and actuators and use six comparably massless legs.

An alternative to fixed bodies and hexapod morphologies is to use a segmented body with flexibility in the backbone that allows relative motion between segments, similar to myriapods. A study of myriapods indicates that segmented, many-legged robots may have advantages over more traditional morphologies, including:

1- Speed: While cockroaches and other rigid-body hexapods can achieve maximum speeds of 40–50 body lengths/ second (Full and Tu 1991), the fastest recorded speed of centipedes is slightly less at around 10 body lengths/second (Manton and Harding 1952); however, centipedes are still agile creatures, able to catch live prey, including cockroaches and other similarly sized or even larger insects and mammals. In addition to utilizing body undulations to amplify step size, the flexibility inherent in the bodies of centipedes allows them to morph to surfaces, easily turn, and transition between horizontal and vertical surfaces. This has the potential to make centipede microrobots faster than similarly sized rigid body hexapod robots on rough terrain and when changing direction.

2- Stability: The large number of legs characteristic to centipedes, up to 191 in some species of myriapods (Edgecombe and Giribet 2006), allows for a variety of gaits and added stability. In many cases, centipedes form a tripod by grouping legs together into clumps (Anderson et al. 1995). With many legs distributed along the length of the body, the center of mass is likely to remain within the triangle of support, allowing for static stability.

3- Robustness: Studies involving the removal of different numbers of legs from centipedes were performed with insignificant changes in locomotory capabilities, including gait, speed, and stability, suggesting a multi-segment robot could be robust to failures (Manton and Harding 1952).

4- Climbing and agility: The number of attachment points increases linearly with the number of segments of the centipede or robot, and the flexibility in the body allows centipedes to curl around ledges and move from horizontal to vertical surfaces without drastic gait changes.

5- Versatility and adaptability: The modular design of a segmented centipede robot would enable adding and removing segments to better perform different tasks.