Simulation Research On Position Control Of Loaders' Manipulator

With the rapid development of the technology of the Mechanics and Electronics, the applications of the automatization used in engineering machines are advancing. As the loader is one of the main types of the engineering machines, it is applied widely among the engineering operation. However, the work of shoveling material is manipulated by manipulator controlling the handle of the shaking arms or the bucket at present in domestic loader field. And during the process of the manual controlling, there is randomicity at the position of unloading and shoveling. At the mean while, due to the bucket can not flat automatically, the manipulator has to adjust the shoveling angle. Moreover, because of the objects of the work are complicated and changing from time to time, the loader has to vary its position too. So the efficiency of the shoveling is mostly determined by the experiences, skills and desires of the manipulators.In order to improve the work efficiency of the loader, and avoid the energy wasting resulting from the manipulators'limited skill level, the article do the researches that focoued on the shoveling auto-control of the manipulators on the loader. The detailed elaborations as following:1. On the basis of the structure character of the loader, the manipulator of the loader is composed of shaking arms, bucket and other parts as a 2-DOF robot arm. And according to the robot arm model, use the theory of D-H to gain the transformable matrix of bucket at first, then deduce the kinematic model of the loader's manipulator to calculate the angle position of the shaking arms and bucket. And get the relations between the end velocity of the bucket and turning angle velocity of the shaking arms, bucket at last. Furthermore, it adopts the Lagrange equation to set up the dynamic model.2. The three-dimensional model of the loader's manipulator is set up, with using the solidworks software. The steps as follows: firstly, build the three-dimensional modeling of the loader's parts, secondly, add restriction conditions to gain assembly figure of the manipulator, lastly, check the interference case of the loader's parts. When simulating under the environment of the Solidworks, the results of the angle and position of those points on the track of the bucket are calculated by software Visual C++. The program output the joint angle results every 0.1 seconds, and it will get 60 results in all. Finally, in order to verify the correctness of the kinematic model, using the"Animator"that included in the Solidworks software to realize the controlling of the track of the bucket.3. In this theme, digital electro-hydraulic proportional control technology is adopted, with using the high-speed switch valve controlled by PWM pulse signal. When changing the PWM pulse signal, the high-speed switch valve can realize the pressure control of the two controlling cavities of the plural channels valve, and then can realize the direction and velocity control of the radius oil tank and the circumrotate oil tank. The high-speed switch valve's dynamic character is analyzed in the theme, and the mathematical model of the plural channel valve-piston position controlling system is set up, based on the hydraulic-pressure system principle of the loader's manipulator. Then, the relationships between the cylinder displacement and the width of the PWM pulse singal are getted. In order to prepare for the system's simulation theory, it analyses the stabilization of the position controlling system.4. The plural channels valve-piston position controller of the manipulator is designed, with using the self-adaptation fuzzy PID method. In this self-adaptation fuzzy PID control system, the fuzzy controller's input languages variables are the absolute value of the cylinder displacement error |e| and error's change |ec|, and the output languages variables are parameters K p, K I, K D. Based on the experiences of the experiments, it selects the range of the input and the output variables, then can get the variables'membership functions. At the mean while, combining with the actual situation, the experts'experiences, it establishs the fuzzy control regulations fitted to the system. Lastly, under the Matlab/Simulink environment, with using the Fuzzy Logic Toolbox, the self-adaptation fuzzy PID control algorithm has been simulated and analyzed in the theme. And the results show that the self-adaptation fuzzy PID control algorithm has shorter adjusting time and lower overshoot than conventional PID control algorithm and it has simple structure. And the self-adaptation fuzzy PID control algorithm indeed improve the static and dynamitic characteristics of the system.The researches in this theme make a solid foundation for the loader's manipulator shoveling auto-control.