Steerable miniature ambulatory robot based on piezoelectric actuation with a caltrop-like structure

Abstract

Conventional piezoelectric actuators or robots have advantages of miniature sizes, fast responses, good accelerations, and long stroke, but they are difficult to recover their movement after a sudden rollover or overturn. In order to achieve a consecutive motion in an abrupt environment, a steerable miniature ambulatory robot (SMAR) with a caltrop-like structure is proposed based on piezoelectric actuation. A kinematic model of the SMAR is developed to design the structure of the robot and to analyze the working principle. A preliminary prototype is fabricated to verify the working principle that it has a capacity of 2D motion, with the maximum speed of 320 mm s −1 and the minimum turning radius of 40 mm when the drive voltage is 200 V (peakpeak value). In addition, a control strategy designed in a LabVIEW system which can refine the eigenvalues from complex motion trajectories, is presented for robust steering to a target in a short time, especially after a sudden rollover. Therefore, this SMAR can realize arbitrary and fast movements in a 2D task space, which is also appropriate for a dynamic environment, such as in a moving or rolling channel, and it can also step down with a smooth movement due to its special caltrop-like structure.

Developments and Challenges of Miniature Piezoelectric Robots: A Review

“…[ 53 , 54 , 55 ] After decades of efforts, various MPRs with diverse mechanical structures, working principles and motion capabilities have been developed. Fortunately, MPRs have inherited the features of piezoelectric actuating elements and exhibit many unique advantages, including simple and compact structures, [ 56 , 57 , 58 ] fast speed, [ 59 , 60 , 61 ] high resolution, [ 62 , 63 , 64 ] agile movements [ 65 , 66 , 67 ] and so on. Many excellent reviews related topics of miniature robots and piezoelectric actuating elements have been separately addressed [ 68 , 69 , 70 , 71 , 72 ] ; however, the general summaries of various MPRs have been ignored.…”

Design, modeling and experiment of a miniature biped piezoelectric robot

“…For example, a patch-type piezoelectric robot was proposed by Liu et al [7], which could reach about 516 mm s −1 and have a load capacity of 200 g. Because the robot utilizes the ultrasonic resonant driving mode, its structure must have large stiffness and consume large power which brings difficulty to further miniaturize and realize untethered driving. Peng et al [29] proposed a millirobot with a caltrop-like patch-type structure which could move after turning over. Due to the high driving power and high driving frequency, it also cannot be driven untetheredly.…”