Locomotion control of a hydraulically actuated hexapod robot by robust adaptive fuzzy control and dead-zone compensation

Abstract

SUMMARYThis investigation presents locomotion control of a hydraulically actuated six-legged humanitarian demining robot by robust adaptive fuzzy control in conjunction with the dead zone compensation technique within independent joint control framework. For proper locomotion of the demining robot, accurate tracking of the desired joint trajectory is very important. However, high degree of nonlinearity, the uncertainties due to changing hydraulic properties, and delay due to the flow of oil and dead zone of the proportional electromagnetic control valve results into an inaccurate plant model for the hydraulically actuated robotic joints. Consequently, model-based classical control techniques result into a large tracking error. Therefore, adaptive fuzzy control technique, being a model independent control paradigm for complex and uncertain systems, is a good choice for such systems. In this work, a hydraulic dead zone compensated robust adaptive fuzzy control law has been proposed for locomotion control of hydraulically actuated hexapod demining robot. The experimental results exhibit a fairly accurate trajectory tracking of the leg joints and, consequently, very stable locomotion of the walking robot.

A smart hydraulic joint for future implementation in robotic structures

“…By solving Eq. (21) and using the superposition principle, the deflection of the beam can be computed as follows:…”

“…By taking inspiration from the hydraulic systems of spiders, 1 a flexible hydraulic joint suitable for being embedded on adaptive robotic structures has recently been proposed and investigated by the authors. [2][3][4][5]40 On the other hand, miniaturized hydraulic systems have been developed by several researchers for actuating anthropomorphic hand prostheses, [6][7][8][9][10][11] robotic catheters, [7][8][9][10][11][12][13][14][15][16][17] self-propelling endoscopes, 18,19 macro-scale hexapod robots, [20][21][22][23] surgical robotic systems, [24][25][26] and several other devices. Different kinds of micro-actuation systems have been investigated 27,28 and several micro-pump systems have been manufactured and their performances compared.…”

Towards dynamic alternating tripod trotting of a pony-sized hexapod robot for disaster rescuing based on multi-modal impedance control

“…Second, with more legs, hexapod robots can provide more load capacity. Over the past decade, the hexapod robots are extensively studied in several aspects, including robot design, [1][2][3][4] locomotion control, 5,6 and path planning. [7][8][9] However, most current hexapod robots still rely on traditional static gaits; thus, their speed is quite unsatisfactory for disaster rescuing.…”