Motion Control Study Of A Bionic Mobile Robot Inspired By Turtle Crawling And Goat Walking

In recent years,natural disasters such as flood and mudslide occurred frequently in our country,which caused great loss to people’s life and property safety.The post-disaster terrain is characterized by unstructured,deep and soft,etc.Conventional wheeled and tracked rescue equipment are prone to secondary trapping in such an environment,and artificial rescue is inefficient and easy to cause secondary accidents.In this context,it is becoming a growing trend that using more adaptable emergency rescue robots to replace artificial rescue and traditional rescue equipment.As the product of multidisciplinary integration,robot has been widely used in industry,military,medical and other fields.And quadruped robot has been widely used in search,rescue,logistics and other fields because of its small size,strong anti-interference and high walking stability.Inspired by turtles’ high stability and adaptability to soft ground and goats’ flexible and powerful terrain adaptability in nature,this thesis proposes a bionic quadruped robot for postdisaster rescue,and makes an in-depth study of the robot’s mechanical structure,moving gait,kinematics and dynamics.The main contents are as follows:(1)Analyze the body structure and movement mechanism of sea turtles and goats in nature,find out the biological advantages of high stability of sea turtles and strong terrain adaptability of goats,build bionic topological structure of quadruped robot combined with bionics,and build 3D robot modeling in SolidWorks with reference to biological size.The D-H method is used to analyze the motion of the robot legs,create the single-leg D-H coordinate system,and induce a formula of the forward kinematics equation and inverse kinematics equation of the leg and the coordinate of the foot.Moreover,the motion space of the robotic foot is obtained in MATLAB according to Monte Carlo method.(2)Referring to the crawling movements of turtle and goat and improving them,the crawling gait of turtle with alternating support and swing of body and limbs is planned for the robot in the soft terrain environment.Aiming at good ground,the goat gait with alternating support and swing of limbs in diagonal position is planned for the robot,and the foot motion path of compound cycloid is planned for the goat gait based on the zero impact principle.The virtual prototype model of the robot is established based on Adams,and the kinematic simulation of the two gaits is carried out to obtain the kinematic parameters of the two gaits,and to verify the rationality of the structure and the design of the gait.Finally,building the dynamic model of the robot leg and get the relationship between joint torque and motion through Lagrange method.(3)In order to improve the motion speed and stability of the robot,the size and gait parameters of the robot legs are optimized.The optimum length of each leg is determined by the principle that the moving space of the foot falls in the reasonable area to the maximum.The evaluation function of the robot’s motion performance is established with the indexes of motion speed,fuselage jitter difference,pitch Angle,roll Angle and side Angle.The aggregation cross test is designed to explore the influence of gait parameters on the motion performance and to obtain the optimal gait parameter value.Finally,the MATLAB and Adams co-simulation method is used to verify the motion performance of the robot after the optimization of leg length and gait parameters.(4)Establish the physical prototype of the robot to verify the two gaits and moving performance of the robot.The results show that the robot can move stably according to the planned gait under the walking gait of the turtle and the walking goat.And the robot has great moving ability and stability,which further verifies the correctness of the design.The research results can be used for reference to construct mobile rescue robots with high obstacle crossing,high stability and great terrain adaptability.