Research On Multi-mode Locomotion Behavior Of Bionic Hexapod Robot In 3D Environment

Robots have played an important role in our society,and will replace humans in complex tasks such as exploring unknown environments,reconnaissance,and rescue.Traversing in complex environments is a huge challenge for robots.Researchers have developed a variety of bionic legged robots by analyzing the principles of animal motion.The bio-inspired legged robots adapt to the rugged natural environment by virtue of its excellent bionic motion characteristics,but they are still poorly adaptable to motion in complex 3D terrain.Therefore,combined with the studies of the multi-mode locomotion behavior of animals in complex 3D unstructured environments,it is of great significance to study the multi-mode locomotion of bionic hexapod robot in the complex 3D unstructured environments.RHex-style hexapod robot is the research object of this paper.The robot has simple structure but outstanding movement ability and rich movement gaits.However,the robot still has some shortcomings in climbing steps,and the research on narrow obstacle crossing is also lacking.Therefore,this paper studies the robot taversing the two challenging 3D obstacles.The main work is as follows:(1)RHex-style hexapod robots are designed,and combing the movement mode of cockroaches and the structural characteristics of the robot,two robot structures of the robot are optimized.Adding leg sprawl joints and head pitch-roll joints to the robot enhance the robot's ability to traverse narrow obstacles and climb steps.(2)In the aspect of step climbing,firstly,the previous climbing gait is analyzed,and its posture adjustment method is improved,so that robots with smaller body-to-leg ratio can climb higher obstacles.The robot with the improved climbing gait in the paper can climb a 190 mm step,2 times of its leg.Then,the claw-shape legs climbing gait is designed based on the claw shape of the legs when the insect is climbing and the characteristics of the robot legs,so that the robot can climb a 360 mm step,3.9 times of its leg length without changing the leg structure,And the lifting conditions of the gait are analyzed.Finally,the pitch joint is used to imitate the bending movement of the cockroach's neck when climbing,and the above climbing gaits are optimized,so that the climbing height of the C-leg climbing gait is increased by23.8%,the external climbing conditions of the claw-shape legs are reduced,and the climbing performance is improved.(3)In the aspect of narrow obstacles traversing,inspired by the the pitch-roll mode used by cockroaches when traversing obstacles,the traversing gaits of the two improved robots are designed.The robot with sprawl joints push the ground with its one side rear leg after pitching up,and folds the other side joint to make the robot roll passively under the gravity,so that the robot can traverse obstacles with spacing 90 mm about 54% of its body width.The robot with roll joint roll its body by twisting the head,then traverse the same 90 mm spacing obstacles.(4)Finally,the experimental environments are set up and the designed gaits are realized on the robots.In the built experimental environments,the improved climbing gait and clawshape legs climbing gait experiments are performed to test the actual performance of the gaits,and testing the impact of the bionic joint on the climbing performance.And obstacle traversing experiments are carried out on the robots with bionic joints to test the performance of the robot in traversing obstacles.