Comprehensive stiffness regulation on multi-section snake robot with considering the parasite motion and friction effects

Abstract

Snake robots have been widely used in challenging environments, such as confined spaces. However, most existing snake robots with large length/diameter ratios have low stiffness, and this limits their accuracy and utility. To remedy this, a novel ‘macro-micro’ structure aided by a new comprehensive stiffness regulation strategy is proposed in this paper. This improves the positional accuracy when operating in deep and confined spaces. Subsequently, a comprehensive strategy for regulating the stiffness of the system is then developed, along with a kinetostatic model for error prediction. The internal friction, variation of cable stiffness as a function of tension, and their effects on the structural stiffness of the snake arm under different configurations have been incorporated into the model to increase the modelling accuracy. Finally, the proposed models were validated experimentally on a physical prototype and control system (error: 4.3% and 2.5% for straight and curved configurations, respectively). The improvement in stiffness due to the adjustment of the tension in the driving cables (i.e. average 183.4%) of the snake arm is shown.

Porcospino Flex: A Bio-Inspired Single-Track Robot with a 3D-Printed, Flexible, Compliant Vertebral Column

“…There are various locomotion principles for ground mobile robots, including wheeled [3,4], legged [5,6], tracked [7,8], and hybrid designs [9][10][11][12]. Moreover, other bio-inspired locomotion principles are proposed in the scientific literature [13][14][15]. Each design choice involves a trade-off between various factors, including their maximum speed, obstacle crossing ability, step/stair climbing ability, slope climbing ability, walking capability on soft terrain, walking capability on uneven terrain, energy efficiency, mechanical complexity, control complexity, and technology readiness [2].…”