Innovative Design of Bionic Foot and Closed-Loop Feedback Control System for Quadruped Robot Adaptable to Sloped Muddy Terrains

Quadrupedal robotics has made great strides and has been widely used in navigation and rescue in recent years. Making quadrupedal robots to reduce slipping and sinking in muddy, slippery, and sloping terrains while walking stably and quickly is crucial for their utility and effectiveness in real-world exploration and rescue scenarios, such as mountainous areas or mud flats, but there is a great lack of research in this area. To solve this problem, this paper presents a novel innovative design of a quadrupedal robot foot and control system. First, the innovative design of the robot foot prototype was designed from a bionic perspective. Based on the research that frogs can move effectively on muddy surfaces, small protrusions imitating frog toe pads were added to the robot foot to enhance grip and resistance on slopes; a bionic hexagonal tread pattern was adopted to increase the contact area between the foot and the ground, and to achieve a high coefficient of friction and a high stability. Second, a foot-terrain interaction model was built to realistically restore the muddy environment with greater adhesion and easier sinking and sliding, in order to simulate the contact force on muddy terrain and the actual situation of partial plunging resulting from foot movement on muddy ground. Then, the robot controller and control strategy were constructed to adjust the posture to adapt to different slopes of muddy environments, and the robot gait and controller parameters were optimized using genetic algorithms for the complex characteristics of different muddy terrains in order to improve the speed and stability of the robot, so that the robot was able to walk stably and at high speeds in complex terrains with different slopes and degrees of mud. The results of simulation experiments show that the current commercially available quadruped robots are difficult to walk stably on muddy slopes. In contrast, our optimized frog-shaped bionic foot quadruped robot can walk stably and quickly on muddy slopes and can adapt to muddy terrain with different characteristics.