Manual operation of intracardiac steerable catheter is inaccurate, requires dexterity for efficient manipulation of the catheter, and exposes the surgeons to intense radiation. This paper presents a robot-assisted catheter manipulation system with force feedback, monitor and a master-slave tele-operation system. We developed the mechanical system and applied it in the slave side to guarantee the manipulation safety in intravascular neurosurgery applications. The force information can be obtained from the load cell. When the catheter contacted to the vascular, the surgeon can feel the force feedback and avoids the damage. The experiments indicate that the proposed force feedback robotic catheter system can work well and facilitate the manipulation, avoid potential damages.
This paper deals with a control technique of eliminating the transient vibration generated in a dies-driving spindle of a form rolling machine. This technique is based on a model-based control with a rotational speed sensor. A rotational speed sensor is installed in a driven gear, namely a bull gear. A control model is composed of a reduced-order mechanical part expressed as a transfer function between the rotational speed of the dies and that of the bull gear. This control model estimates a dies speed after the rotational speed of the bull gear is acted on the transfer function. The difference between the estimated dies speed and the motor speed is calculated dynamically, and it is added to the velocity command to suppress the transient vibration generated at the dies. In this paper, the effectiveness of the model-based control in the existence of modeling error in the reduced-order model and the effectiveness of the model-based control integrated into the position control loop are verified by simulations. Simulations show satisfactory control results to reduce the transient vibration.
The capillary pumped loop (CPL) is a two-phase thermal control device, which has become more active and interesting in the domain of electronics cooling. A two-dimensional conjugate numerical model for the miniature flat plate capillary evaporator is presented to describe liquid and vapor flow, heat transfer and phase change in the porous wick structure, liquid flow and heat transfer in the compensation cavity and heat transfer in the vapor grooves and metallic wall. The entire evaporator is solved with SIMPLE algorithm as a conjugate problem. The shape and location of vapor-liquid interface inside the wick are calculated, and side wall effect heat transfer limit is introduced to estimate the heat transport capability of capillary evaporator. The influences of different wall materials on the performance of miniature flat plate evaporator are discussed in detail, and the results show that evaporator with combined wall is capable of dissipating high heat flux and stabilizes the electronics devices temperature at a moderate temperature level.
This paper presents a knowledge-based method for identifyi ng infeasible assembly operations in the context of assembly sequence planning. In addition the reas ons for the infeasibility are identified and these can guide product designers towards the necessary des ign changes to make a preferred assembly sequence feasible, or guarantee that an assembly sequence i ncludes a specific partial assembly state. This capability increases the usefulness of assembly seque nce planners as concurrent engineering tools by contributing to a closer integration between product des ign and assembly sequence planning. In the identification of infeasible assembly operations the concept of minimal infeasible sets of connections is introduced and two issues are addressed: the kno wledge-based generation of these minimal sets, and their suitability to form a basis for a concise expl anation of the causes of assembly operation infeasibility. Two simple examples illustrate practical a pplications of the method.
