Study On Trajectory Control Of A Five Degrees Of Freedom Train Of Coal Sampling Machine

So far, the majority of coal enterprises have two ways to sample the coal in the train mechanically, when the train is stationary, the sampling head inserted into the compartment. This approach has the advantage that can achieve full cross-section sample, but the drawback is that each section of the train to be sampled must be stationary, which lead the significant sampling efficiency decreased undoubtedly. In order to improve the sampling efficiency there is an another way, when the train is traveling, the sampling head extending into the compartment(double dynamic sampling).This sampling method reduces the time of trains pause, sampling efficiency has been significantly improved. However, due to the technical limitations, the sampling head in this method can only be inserted into the surface of the coal samples, can not achieve full section sampling, so it is difficult to ensure the representative of the collected samples. Therefore, in order to realize full section sampling effectively under the condition of train of coal sampling machine and train are at double acting, it is necessary to make further researching on the movement and control system of sampling machine.In this topic, it makes the five degrees of freedom train of coal sampling machine as the object to research. It is composed of a plurality of cylinder, a rotary motor and a mechanical arm which are connected, and driven by the hydraulic system, electromechanical integration device can complete the specified trajectory. In order to solve the problem of how to control the motion trajectory of sampling machine, the main contributions are as follows:First of all, according to the structural characteristics and movement of the five degrees of freedom train of coal sampling machine, making kinematics model for sampling machine with the D-H method, determining the key parameters. Doing the kinematic analysis to sampling machine and determine the geometric relationship between the joint variables and determine the corresponding hydraulic cylinder.Secondly, determine the hydraulic of sampling machine work scope, providing a reference basis for the formulation of the trajectory. Using optimization function in Matlab, taking the minimizing of the sum of motion acceleration’s absolute value maximum of the forearm cylinder、the sampling head swing cylinder of hydraulic and Martha turning as the manipulators objective function; And taking the arm angle of sampling machine as design variables, making trajectory planning optimization of nonlinear problem with constants, the manipulator moved according to the predetermine trajectory scheme smooth and steady, the optimal drive curves was obtained.Finally, according to the sampling machine motion control system, study on the problem of communication between the MATLAB and the C240 motion controller. Base on the methods of multi axis synchronous control, put forward a virtual axis synchronous control method, and do experimental verification and synchronization control of sampling machine by using Siemens SIMOTION C240 motion controller. Then, according to the sampling head trajectory uncertainty, put forward the method of variable motion control based on MATLAB.