Key Technology Research Of Hopping Robot Based On Hydraulic Driving

Hopping robots have stonger adaptability of terrain compared with wheel, crawler and other mobile robots. Existing hydraulic-driven robots mostly adopt linear hydraulic cylinder as the main drive device which has some weakness in bionic, structure and weight. This paper treats a hopping robot as the main to explore the mechanism of the robot’s jumping. A swinging hydraulic cylinder is treated as the joint dvive device of the hopping robot. And this paper alse does some research on related key technology.Firstly, this paper draws out the physical model of the hopping robot. The simulation of dynamic model based on Lagrange equation and SimMechanics respectively verifies the correctness of the two models. Based on simulation results, the mechanism of robot’s jumping is analyzed from force-speed and energy conversion. The factors affecting the robots jumping height are also analyzed by the simulation. With the dynamic model, the suboptimal trajectories of jumping highest and jumping most effective are obtained by means of varing point spline interpolation.Secondly, according to the requirements of hopping robot’s diving device and structure, this paper does some research on the structure design, size optimatation and production testing of a single leaf swinging hydraulic cylinder. And a protype of hopping robot is developed with the swinging hydraulic sylinder.Thirdly, this paper designs the hopping robot’s hydraulic control circuit with the form of hydraulic drive and makes the transfer function model of the valve-controlled electo-hydrauluc servo system. With the Simulink model, response characteristics of system and the effect of nonlinear factors (delay, saturation, dead zone and nonlinear friction) to system are analyzed. And it compares and analyzes the control effect to electo-hydrauluc servo system of PID controller, Fuzzy controller, Fuzzy-PID hybrid controller.Then, the hopping robot’s drive control system is designed. And the hardware and software of the drive control system are designed and tested which make the robot system have the abilities of driving, sensing, controlling and data collecting.Finally, the experiment study of rotationg hydraulic cylinder and hopping robot is done with the experiment platform. Experiments of hydraulic cylinder demonstrate the effectiveness of sealing improvement and also demonstrate the closed-loop stability and fast-responsibility of the valve-controlled electo-hydrauluc servo system. And the response performance of hydraulic cylinder is related to system pressure, the load and PID. parameters. The hydraulic cylinder has good tracking capasibility without load, and the system bandwidth is about 0-28rad/s. Hopping robot experiments demonstrate the stability of system. And the greater of system pressure, the faster of response, the lager of overshoot and adjusting time and the more of oscillation. The phenomena of "like-crawing" in slow trajectory tracking and longer responding time compared with robot takeoff stretch time in fast trajectory tracking are analyzed. The experiment of robot jumping off the groud verifies the robot’s jumping ability. And factors affecting the height of robot jumping are the system pressure, the mass ratio of hip, takeoff angle and stretching angle. Comparing between theoretical and experimental, the correctness of hopping robot model is proved. And the robot can jump vertically up to 3.5cm under experimental condition.