Folding cartons with fixtures: a motion planning approach

Packaging products such as telephones and two-way radios after assembly is a common manufacturing task. Carton folding is a packaging operation typically performed by human operators or with fixed automation. We present a flexible method to fold cardboard cartons using fixtures; a carton blank is folded by moving it through a fixture with a robot. This method uses interchangeable fixtures to enable rapid changeovers between product models. We outline an approach to design a fixture given a carton and a folding sequence. We present an implemented motion planning algorithm that generates all folding sequences for a carton by modeling it kinematically as a many degree-of-freedom robot manipulator with revolute joints and branching links. Folding fixtures constrain the carton motion to paths consisting of line segments in its configuration space. We characterize the set of valid paths for these carton robots and generate them using the motion planner. To illustrate the method, we selected a folding sequence for an example carton, designed a fixture, and demonstrated folding of the carton from blanks with an industrial robot.