Applied Mechanics and Materials Vols. 130-134

Abstract: The non-fragile robust H_∞ control problem is investigated for the uncertain switched discrete time systems with multiple state and input time delays. As the system and controller parameters are polytopically uncertain, the delay-dependent sufficient conditions for the existence of the non-fragile robust H_∞ controller via state feedback are presented for the systems based on the multiple Lyapunov functions and state dependent switching rules. By using the cone complementarity linearization algorithm, the nonlinear matrix inequalities relevant to the controller design can be transformed into the nonlinear programming problems constrained by the linear matrices. The simulation results show the effectiveness of the controller design method.

Abstract: In the effort to make robot-assisted upper limb passive movement training effective for neurologic injuries suffered from stroke and spinal cord injury (SCI), a new fuzzy adaptive closed-loop supervisory control method for passive joint movement training is proposed. Firstly, high-level supervisory controller for the desired passive range of motion (PROM) is designed based on the impaired limb’s joint motion recovery, and then low-level closed-loop position tracking controller is presented to drive the robot stably and smoothly to stretch the impaired limb to move along the predefined trajectory. The suggested strategy was applied to the four degrees of freedom (DOF) Whole Arm Manipulator (WAM) rehabilitation robot to evaluate its performance. Experimental results carried out on the 4-DOF WAM rehabilitation robot show the effectiveness and potentialities of the fuzzy adaptive passive movement control in clinical application.

Abstract: A SLAMiDE（SLAM in Dynamic Environments) system is designed and realized in the paper, which supplies a holistic framework and a series of implementation methods for mobile robot SLAM in dynamic environments. A uniform target model is proposed in SLAMiDE system. The dynamic targets and static targets and the mobile robot pose are estimated simultaneously, by synthesized the research of the data association and dynamic targets detection and static SLAM based on local maps. Finally, the results of the experimental test prove that the SLAMiDE system can realize dynamic objects detection and mapping and location correctly.

Abstract: Because weight is unsymmetrical for the robot with hand-fused foot, a method is found to calculate the centroid coordinate from the perspective of Newtonian mechanics. Centroid coordinate of the robot is detected using ARM, pressure sensors, distance measuring sensors, and multiplexer. Software is designed for the centroid detection from 3 aspects as multiplexer chip selection, A/D conversion operations, and centroid calculation. Centroid projection detection has certain reference value for gait generation and path planning.

Abstract: To achieve the concise interpolation for spatial curves, the strategy of cross-octant interpolation was researched based on open-architecture CNC system. The sub-modules of the interpolation module for complete software type CNC system or NC embedded PC type system were designed. Take cylinder spiral-line and spatial line for instance, some studies that include principles and techniques of affine transformation, automatic cross-octant, and calling basic sub-modules of interpolation were carried out. The interpolation module for open-architecture CNC system can be divided into some sub-modules to develop. Thus, the balance between the openness and the real-time of the system are achieved. Some strategies and principles in this paper can be also applied to other spatial curves.

Abstract: Error sources which influence the end-executor’s accuracy are summarized. Based on an analysis of influence caused by the structural error and transmission error, we build a pose error model of industrial robots with screw theory. If regarding the inertia force of the robot system as the external force, the robot system will become a static system. The rigidity can be analyzed using the screw theory, then we establish the dynamic error modle which is caused by the inertia force and gravity. After the error parameters which influence the static error of Selective Compliance Assembly Robot Arm (SCARA) robot are expressed by two-dimensional discrete variable, error space of the end-executor’s track of robot are made. Position error which influenced by the error sources are analysed by comparision of difference. Total accuracy can be improved through controlling the error direction of the static error to counteract the dynamic error's influence. The error model provides an effective theoretical support for the design of industrial robots with different accuracy requirements.

Abstract: Aiming at the wild used tide gauge, a research project has been made. The purpose of the project is to build a standard test equipment which is used for calibration. The principle of the tide gauge is imitating water-level fluctuation of diurnal tides or semi-diurnal tides, based on controlling dynamic water flow which is 10 meters high and 8 tons heavy. This is a national standard test equipment which will be used by Tianjin National oceanic standard measuring center. In this paper, the digital PID control method is used for computerizing servo motor .First, the principle of servo motor control has been discussed, and then PID adjusting theory and method are also introduced. At the same time, software compiled is used to control servo motor. In the end, the corresponding results can be output on the hardware platform. The method above has been proven advisable.

Abstract: With application of the embedded microcontroller technology into the valve control, the valve control system of oil depot is designed on the basis of embedded microcontroller AnyCAN5000. The system constitutes of host computer and slave computer, giving designs of hardware and software systems, which is characterized by low cost and high reliability, and with application of the technology in practice the valve control system can bring good effect and meet needs of control.

Abstract: In this paper, an adaptive iterative learning control is presented for robot manipulators with unknown parameters, performing repetitive tasks. In order to overcome the initial resetting errors, an auxiliary tracking error function is introduced. The adaptive algorithm is derived along the iteration axis to search for suitable parameter values. The technical analysis shows convergence of the tracking errors. Finally, simulation results are provided to illustrate the effectiveness of the proposed controller.

Abstract: In view of the great fluctuation on objective functions which cause constraints dissatisfied, robust design is applied to the vehicle divided steering linkage optimization problem. A robust model is established by considering the kinematic pair clearance and structural error both in the objective functions and constrains. Optimum results show that,the design method can effectively guarantee the kinematics precision of steering mechanism and the transmission stability.