Development Of A Bionic Kangaroo Robot System And Its Motion Analysis During Take-Off

With widespread use of robots in human life, robots need to face a more complex environment. Especially in the activities of archaeological exploration, interstellar exploration, military reconnaissance, anti-terrorism, etc. the requirements in both bionic characteristics and obstacle abilities become more demanding.In this paper, a kangaroo robot system is designed, and the movement of the robot during take-off is analyzed. The specific contents of this paper are as follows:1) Design of mechanical system of kangaroo robotOn the basis of analyzing the mechanism and architecture of kangaroo, the robot system is designed. Firstly, in the comparative analysis of several ways of bounce programs, the robot adopts the mode of multi linkage spring mechanism driven by electric motor; then, the kangaroo robot's mechanical structure is divided into the bouncing mechanism, the transmission mechanism and the balance mechanism, and has carried on the detailed design of each mechanism. While the bouncing mechanism is two legs, each of them composed of two parallel quadrilateral mechanism with an arc-shaped foot, which not only reduces the number of active joints but also provide the conditions for adjusting the take-off angle. The design of transmission mechanism adopts a five reduction gear group with an independent clutch release mechanism, which can achieve a reduction ratio of 1:168.75 and the controllability of the point on releasing energy; the balance mechanism is realized by the rotation of the tail.2) Design of electronic control system of kangaroo robotBy analyzing the laws of robot's motion and its function requirements, the control flow of robot's motion is obtained,according to the motion control flow, the design requirements of the robot control system are given, the electronic control system is designed according to the design requirements,The electric control system comprises a main control subsystem, a sensing subsystem, an operation subsystem, a power subsystem and an associated computer monitoring system. The system can realize not only the acquisition and processing of the attitude, the joint angles, the height of the jump of the robot, but also the control the driving system, and the communication with the associated computer monitoring system.3) Motion analysis of the robot during take-offAccording to the mechanical structures and motion characteristics of kangaroo robot, the analysis model of the robot on take-off phase is established, and through the calculation of the mathematical models and the virtual simulation technology, the simulation analyses of the robot during take-off are carried out, which verifies the rationality of the mechanical design. First of all, the kinematics and dynamics models of the robot during take-off are established based on the mechanical structures, and the change laws of the displacement and velocity during take-off are obtained by the kinematic modeling, also the energy conversion efficiency and the jumping heights and distances in different take-off angles are carried out, in addition, through the dynamic analysis, the support force from the ground to robot is obtained. Through the simulation it can be obtained that the displacement and velocity in the vertical direction are larger than in the horizontal direction, and the robot has a greater energy conversion efficiency during take-off, which is in accordance with the movement of kangaroos, meanwhile the supporting force form ground to robot is a nonlinear changed force, it increased first and then decreased, this characteristic can effectively avoid the premature jumping, so that the mechanism has good bionic jumping characteristics and higher energy conversion efficiency. Then, the simulation experiments based on virtual prototype are carried out, as the leg is the main moving part of the robot during take-off, so in Solidworks, the model of the robot is simplified, the leg part is retained, and the leg model is introduced into the ADAMS. By analyzing the results, we can see that the trend of the robot's motion during take-off is consistent with kangaroos' movement, which proves the rationality of the mechanism design.