Trajectory Planning Of Aerial Platform Truck With Redundancy Based On Spatial Obstacle Avoidance

As a special equipment of rescuing and firefighting for high architecture, aerial work platform (AWP) truck of100-meter level is purchased and equipped with an increasing num-ber due to the growing recognition of the importance of people’s lives and property safety. Numerous key technologies have been raised during the self-development of large-scaled AWP for Chinese manufactures over these years. In response to the intelligentialized ten-dency for construction machinery, trajectory planning technology in case of obstacles for multi-joint boom with redundancy emerges. Rooting in the technical exploration of the R&D of the large-scaled AWP truck in corpora-tion with the domestic manufactures for DUT, this thesis presents a strategy for obsta-cle-avoidance trajectory planning based on geometrical graphics, robotic kinematics, heuristic path searching method, and variable cross-section beam model. Main finished work and re-searched contents are as follows:(1) First the boom system with multi-degree-of-freedom is modeled parametrically in ac-cordance with the real structure, then the D-H parameters and homogeneous transformation matrix are listed. For the simplification of spatial obstacle model, enveloping sphere, rectan-gle plane with boundaries, and the cylinder model are raised to describe the conflicting and non-conflicting principles between booms and obstacles. As a special case of spatial problems, planar collision-avoidance principle is analyzed using enveloping circle model and linear segment model.(2) The path is searched in the4-dimensional configuration space by compiling heuristic A*algorithm in Matlab program. Numerical simulation result of PTP planning shows the practicality and feasibility. The appraisal function of the path-searching for booms of AWP truck which comprises both prismatic and revolute joints is researched, and the optimal tra-jectory which contains fewest nodes and costs minimum time is acquired. With sequence of configurations in joint space gained, the minimum time intervals are determined based on real velocities of the driving cylinders, and cubic splines function interpolation is applied to plot kinematical curves of every joint. The result shows the feasibility of the algorithm which re-alizes the time optimal planning with obstacles avoided.(3) Depended on the idea of PTP planning, a method is designed in which the specific path is regarded as the edges of an obstacle, and selection rule for configurations of beginning and ending points is determined so as to guarantee that the tip of the boom moves along the expected path which realizes CP planning. For concave graph of the obstacle, a segmented method is applied the tracking effect of which is proved by the example.(4) The large deformation in long boom-extension working condition taken into consid-eration, mechanical model of combined boom with cross-section beam is studied, and the contrast is carried out of the results of planning for deformed boom model and rigid boom model.