| Snake-like robot is a kind of redundant robot, which is based on the structure and motion characteristics of biological snake. A rope-driven snake-like robot is designed in this paper, which use the rope-driven to realize the motion of the continuous joint. So that it moves flexibly in small and unknown environment. Compared with the traditional robot, the robot has the characteristics of flexible movement and high control efficiency.First of all, the basic functional requirements and performance indexes are determined according to the characteristics of the rope-driven. The robot body is designed according to the described requirements. The design of the body mechanism includes snake arm design, driving device design and mobile platform design. The snake arm is connected in series by 5 joints and the joint is connected with the cross shaft universal joint, while the maximum deflection angle of adjacent joint is determined. Because the joint is driven by rope, a driving device is designed to arrange the driving element and the pulling device and it is installed at the end of the snake arm. The snake robot can move forward and backward through the design of the moving platform composed of walking screw slide. Combined with the movement of the mobile platform, the robot can complete the complex and varied movement.Then, the kinematics of the robot is analyzed according to the characteristics of the robot body mechanism and the rope driven mode. The D-H coordinate system is established for the snake arm, and the forward kinematics equation of the snake arm is listed, and the corresponding equation is solved. At the same time, the adjacent joint model is simplified and the changed length of each rope is calculated according to the deflection angle of the joint. It is converted to the corresponding motor pulse number to control the movement of the joint.Finally, a control system based on TwinCAT soft PLC as the main control unit is established. The system data communication is in the form of EtherCAT and CAN bus combinations. Snake robot online motion control program using PLC and C++ mixed programming. In this paper, the image acquisition module is designed to make the snake robot have the function of video monitoring and investigation. The mechanism parts of the snake robot are processed and the whole assembly is completed. The physical experiments are carried out to verify the overall performance of the body and the stability of the control system. |
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