Research On Control System And Motion Planning Of Snake Robot Based On Orthogonal Joint

With the characteristics of high flexibility,small size and diverse forms of motion,the snake robot is attracting more and more attention from universities and research institutes.Its movements are diverse and can be used in narrow and complex environments to make it highly advantageous in the ground investigation,pipeline inspection,space assembly and other aspects.The snake robot in this paper is designed with the characteristics of small size and non-cable.The paper proposes a layered control model,completes the construction of the control system.The model of hierarchical control is proposed to complete the construction of the control system,and the motion control method of the snake robot suitable for orthogonal joints is proposed.The specific content is as follows.Firstly,according to the design indicators,the snake robot scheme design was completed,and a hierarchical control system was established to make the snake robot control system free from the constraints of cables,including the human-computer interaction layer,the head controller layer and the joint layer.The control command is sent to the head controller of snake robot wirelessly by the upper computer;the gait planning and the trajectory planning are performed in the head controller;and the motors are driven in the joint layer to move according to the desired command.The entire control process does not have an external cable for communication,thus achieving the goal of tetherless robot.Under the framework of the hierarchical control system,the development of software system of each layer is completed.Secondly,in order to make the robot have certain autonomy,the robot joints are equipped with a wealth of sensors,and the robot head is equipped with a camera,which can feedback the image information of the surrounding environment in real time.The inertial sensor system in the robot can effectively estimate the state of the robot itself.Based on the display complementary filtering algorithm and the extended Kalman filter algorithm,the quaternion model is used to estimate the pose of the snake robot,and the result of the three-dimensional motion capture system is used as a reference.Then,the kinematics model of the snake robot with orthogonal joints is established,and the top-level planning of the snake robot motion is carried out in the compute stick.The squat gait is designed by discretizing the serpenoid curve.By the method of designing the backbone curve and discretizing it,the planar tumbling gait and a spiral rolling gait are obtained and more new gaits can be designed as needed to meet the needs of different tasks.The trajectory planning is carried out in the joint layer and two kinds of joint controllers are established to complete the feedback control,so that the joint can be smoothly moved and has good accuracy and dynamic characteristics.Finally,a prototype of a snake robot is built,and the experiments of joint information fusion,joint performance test and snake robot motion are carried out.The information fusion algorithm,the reliability of control system communication,the driving ability of each joint,the gait planning and trajectory planning method are verified.