http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Efficient Control Framework for Robot Manipulators Performing Tasks Requiring Simultaneous Control of Tool Path and Orientation
In this dissertation, we develop a novel planning and pose control framework for articulated robots for motion along a spatial curve with constant speed. First, given a list of waypoints, we develop the spatial curve along passing through the waypoints by formulating a path-constrained and collision-free optimal trajectory planning algorithm in the presence of workspace obstacles. To generate finishing curves on a workpiece surface, we provide a novel solution to the problem of robot tool path generation to uniformly cover the surface area of a curved surface with varying curvatures by using a circular, flat finishing tool. A key aspect of motion on a surface or a spatial curve is to simultaneously control motion while controlling the end-effector orientation. To achieve this, we employ the concept of a rotation minimizing frame (RMF) associated with the geometric path. We develop the position control governing equations and present the control laws based on the time rate change of arc length of the path. From an analytical description of the relative orientation error dynamics, we derive a stabilizing orientation controller by utilizing the modified Rodrigues parameters to avoid the unwinding problem; since many robots are operated in the velocity control mode, i.e., the control command is joint velocity, we also provide similar control laws for such robots. We demonstrate the effectiveness of the proposed work via extensive simulation and real-time robotic experiments, which mimic common applications such as material handling and surface finishing. The electronic version of this dissertation is accessible from https://hdl.handle.net/1969.1/197354
Doctor of Philosophy Texas A&M University 2022 https://hdl.handle.net/1969.1/197354