Deformable linear objects (DLOs) have a wide variety of applications in a range of fields. Their key characteristic is that they extend much further in one of their dimensions than in the other two. Accurate motion planning is particularly important in the case of DLOs used in robotics applications. In this paper, a new strategy for planning the motions of DLOs under multiple constraints is proposed. The DLO was modeled as Cosserat elastic rods so that the deformation is simulated accurately and efficiently. The control of the motion of the DLO was enhanced by supplementing one gripper installed at each end with additional supports. This allows DLOs to undergo complex deformations, and thus avoid collisions during motion. The appropriate number of supports and their positions were determined, and then a rapidly exploring random tree algorithm was used to search for the best path to guide the DLO toward its target destination. The motion of the simulated DLO is described as it is controlled using two grippers and specific numbers of supports. To prove that the proposed DLO motion planning strategy can successfully guide relatively long DLOs through complex environments without colliding with obstacles, a case study of the strategy was conducted when guiding a DLO through a puzzle.

Enhancing graphical objects whose behaviors are governed by the laws of physics is an important requirement in modeling virtual physical environments. In such environments, the user can interact with graphical objects and is able to either feel the simulated reaction forces through a physical computer interface such as a force feedback mouse or through such interactions, objects behave in a natural way. One of the key requirements for such interaction is determination of the type of contact between the user controlled object and the objects representing the environment. This paper presents an approach for reconstructing the contact configuration between two objects. This is accomplished through usage of the time history of the motion of the approaching objects for inverse trajectory mapping of polygonal representation. In the case of deformable objects and through usage of mass-spring-damper system this paper also presents a special global filter that can map the local deformation of an object to the adjacent vertices of polygonal mesh. In addition to offering a fast computational framework, the proposed method also offers more realistic representation of the deformation. The results of this paper are shown through detailed examples and comparison analysis using different computational platforms.

A new approach to the control of indirect simultaneous positioning of deformable objects is presented. Many manufacturing processes that deal with deformable objects such as clothes and rubber sheets involve a positioning of multiple points on a deformable object. The multiple points should be guided simultaneously to the desired locations. Moreover, these positioned points cannot be manipulated directly. This operation is referred to as indirect simultaneous positioning. In this article, we will propose a new control law for indirect simultaneous positioning of a deformable object based on its uncertain model and will show the robustness of the proposed control law. First, a simplified physical model of a deformable object is developed for its positioning operation. Second, indirect simultaneous positioning of an extensible object is formulated. Based on a linearized model of an extensible object, we will propose a novel control law for indirect simultaneous positioning. Next, we will prove the robustness of the proposed control law theoretically. Finally, experimental results will show the robustness of our proposed control law against the discrepancy between a real fabric and its uncertain model.