A Novel Voice-Coil Actuated Mini Crawler for In-Pipe Application Employing Active Force Control With Iterative Learning Algorithm

Abstract

This study proposes the design and development of an in-pipe mini crawler (or robot) capable of performing its various tasks with the ability to reject undesired disturbances resulting from friction and viscosity, as it was modeled, simulated, and experimented using an iterative learning algorithm (ILA)-based active force control (AFC) strategy. The crawler motion was executed based on a rapid and successive pushpull action plus friction that causes the crawler to move in an earthworm-like manner using a linear voicecoil actuator (VCA). A novel self-adjusted mechanism was designed to ensure that the crawler remained concentric in the pipe as it slides along the inner surface of the pipe. A novel control strategy was also proposed consisting of the AFC-based controller cascaded with a proportional-integral-derivative (PID) controller to control the crawler movement and expel off the applied perturbations. An intelligent PD-type ILA was employed to automatically tune the AFC while online. For the validation part, a prototype was designed, developed, and later experimented with using the proposed technique for a given set of conditions. The system integration employed a hardware-in-the-loop (HIL) test configuration utilizing LabVIEW. Experimental results are in good agreement with the simulation counterpart, thereby indicating the practicality and feasibility of the control system in performing accurate and robust trajectory tracking. This shall serve as a good basis for designing more challenging tasks related to miniature crawling mechanism inpipe applications.

Dynamic and steady-state performance analysis of a linear solenoid parallel elastic actuator (LSPEA) with nonlinear stiffness

“…Linear EMAs (LEMAs) can generate thrust directly on the end effector, which has better dynamic performance and higher reliability. According to different moving parts, EMAs can be divided into moving magnet actuators (MMAs) [9,10], voice coil actuators (VCAs) [11] and electromagnets [12].…”

Design of a novel inchworm in-pipe robot based on cam-linkage mechanism

“…The in-pipe robot system, according to existing moving modes and contact forms with pipe wall, can be classified into several classical forms, including pig type, [4][5][6] wheel type, [7][8][9][10] wall-press type, [11][12][13] walking type, 14,15 screw type, [16][17][18][19][20][21] inchworm type, [22][23][24][25] and swimming type. 26,27 The wall-press robots, suitable for walking in circular pipes, have three sets of wheels or legs circularly located 120°apart from each other.…”