Research Of Trajectory Control Of The Operative Side On Large-Sized Serial Boom System

With the rapid urbanization process and requirement for infrastruction of traffic engineering, the large-sized boom system has been more widely used, for example, the boom system of aerial platform vehicle used for work aloft and the boom system of truck mounted concrete pump used for transporting concrete. However, automation of the large-sized boom system is relatively low at present,which restricts the construction efficiency, even the integral level of construction. Therefore, it has theoretical and realistic significances to study on motion control of operative side of the large-sized boom system. The large-sized boom system always contains multiple redundant degrees of freedom, strong nonlinearity and flexible deformation. Moreover, the motion characteristics of highly real-time and randomicity are required for the large-sized boom system in practical application. Therefore, the factors mentioned abve may bring challenges to realize the trajectory control of the operative side on large-sized boom system.The boom system of concrete pump truck is taken as the research object in this work. And this paper carries out study in trajectory planning of redundant institution, joint motion control, experiment of trajectory control and vibration control respectively. The research contents in this work mainly include:(1) The D-H coordinate system of the boom system is eatablished, and forward kinematic is analyzed. For the redundant boom system, the trajectory planning method based on partitioning region is put forward. By dividing the work space into several regular subdomains and giving corresponding optimal rules to define the motion of the first three joints, the original redundant system becomes non-redundant system. With this method the inverser kinematics solution is realized timely, which solve the problem of real-time trajectory planning in practice. And the global optimal trajectories of the first three joints are also acquired by introducing partitioning region method, which is conducive to realize smooth motion of the boom system. By analyze the driving structure of each joint, the mapping relations between joint space and driving space are established.(2) For the joint motion, a combinational control strategy including flow feedforward control and Human Simulated Intelligent Control(HSIC) is put forward. By adopting indirect flow measuring method, the relative precise flow character is acquired in order to inprove the control precision of feedforward control, and by imitating the thinking mode and the control mode of person, the characteristic modal is summarized, and the control modes and inference rules are also designed. The proposed control strategy can effectively overcome the effects of nonlinearities and parametric uncertainties to realize stable and smooth joint motion. For the time-varying dead zone feature a bidirectional compensation strategy based on the depth is put forward. By formulating multiple stage compensation strategy for each direction, the problem of frequent alternating opertation caused by disturbances is solved. For the phenomenon of flow saturation appearing in trajectory motion, a control strategy of resistance to flow saturation is put forward, which is implemented by correcting the command velocity according to the real maximum flow rate, the desired trajectory of the tip can still be implemented in short supply of hydraulic oil efficiently.(3) In this work, the Lagrange method is applied to establish the strong nonlinearity flexible dynamics model of the boom system. Based on the established model, numerical analysis method is implemented to analyze the vibration response of the boom system with external periodical disturbances. Based on the analysis results, an active control strategy of Constant-Position Commandless Input Shaping Technique(CPCIST) is put forward to restrain the vibration of the boom system caused by external disturbance. By designing the control action including double impulses with reverse direction, vibration of the boom system can be obviously reduced. Furthermore, the boom system is avoided deviating from the original balance position in control process by applying the proposed method.(4) The hardware architecture and the remote control function of the control system are designed. The typical linear trajectory motion experiments are implemented on a real boom system. And the experimental results indicate that the solutions proposed in this work are feasible and effective, by which the smooth and accurate motion of the tip of the boom system can be realized. And these solutions proposed also lay the foundation for engineering application of the large-sized boom system motion control.