Applied Mechanics and Materials Vols. 713-715

Abstract: The standard ISO 10328 specifies the procedure for structural tests on lower limb prosthetic devices, as a method for quality control. Having the standard as reference, a machine is designed and implemented to follow the test routine, which if succeeded, shows the quality concept for the devices tested. Furthermore, it is shown the controller design process, which manage the application of a sinusoid force with specified amplitude, frequency and offset, in order to realize the dynamic test, by means of a double effect cylinder and proportional valves for pressure and flow.The dynamic model was calculated through a parametric identification technique in a pre-stabilized closed loop. Later, a hybrid control strategy was set using the differential flatness concept and a sliding modes controller, so that both identified model and real system could be properly controlled.

Abstract: The research project started with the need to found a viable solution to replace the upper extremities with artificial extremities, which have been affected by explosives such as land mines. For that purpose, it was essential the appliance of the design in the field of medicine for the construction of the anthropomorphic prosthesis. In order to do so, the concepts of biomechanics of the arm, including hand, as well as the types of handgrip was explored. According to the above, the concepts, moment, power, torque, four bar analysis were addressed, identifying the four bar mechanism and applying it on the design for the transmission of the movement in the phalanges..

Abstract: In the following article describing the mechanical design process of a balanced auto mobile platform, designed to assist large and heavy loads is made. This in turn allows deployment as a logistics assistant. Being a self-balanced design requires that your device carries a large mechanical component should therefore concentrate as much of the mass in the transverse axis of the engines. The procedure for a choice of engines according to the calculations already performed to further validate the design is done in SolidWorks. And the results obtained to date are described.

Abstract: The heat of the positioning platform is mainly caused by conduction of each functional unit, when it affected by the influence of internal and external heat source at work, the temperature of units would change, and the condition would make the platform component stiffness change, then lead to positioning platform dynamic characteristics change. In this paper, the finite method analysis platform dynamic connection stiffness with the regularity of temperature change, and by using the grey correlation method to optimize the platform stiffness influence of the four largest temperature sampling point, through the neural network modeling method to establish high precision positioning platform stiffness model, provide theory for the research on platform of dynamic characteristics of the model.

Abstract: Two kinds of dynamic load-carrying capacity (DLCC) evaluation methods for free-floating space manipulators (FFSM) in two typical on-orbit operating missions are proposed in this paper. DLCC evaluation is transformed into nonlinear programming problem (NPP) by introducing load-carrying coefficient to measure DLCC: in point-to-point task, penalty function method is adopted to approach the boundary of feasible region rapidly, then DLCC can be obtained through following iterations; in trajectory tracking task, NPP is solved by using multiple one-dimensional search, the dynamic load-carrying coefficient in discontinuous feasible region can be quickly solved through adjusting the searching boundary constantly. The effectiveness of the mentioned methods is verified by simulations.

Abstract: In this paper, a kind of multi-objective trajectory optimization method based on non-dominated sorting genetic algorithm II (NSGA-II) is proposed for free-floating space manipulator. The aim is to optimize the motion path of the space manipulator with joint angle constraints and joint velocity constraints. Firstly, the kinematics and dynamics model are built. Secondly, the 3-5-3 piecewise polynomial is selected as interpolation method for trajectory planning of joint space. Thirdly, three objective functions are established to simultaneously minimize execution time, energy consumption and jerk of the joints. At last, the objective functions are combined with the NSGA-II algorithm to get the Pareto optimal solution set. The effectiveness of the mentioned method is verified by simulations.

Abstract: This paper introduces a small negative pressure wall-climbing robot with the ARM system. It can complete the task on the surface of vertical, steep. First of all, describes the basic system structure of robot and mechanical configuration. Secondly, the mechanic analyses of robot dynamics modeling to explain the principle of its operation. Finally, an experiment tests the all common functions of the robot.

Abstract: Auxiliary hydraulic system being based on sensor detection is designed to control two execution parts synchronization precision work in main hydraulic lines. To design a servo drive control valve with three working positions, its each position have an oil inlet and two outlets. This valve can come true compensation flow for the single cylinder or all cylinders of the main lines at the same time. Have designed a device is used to control the auxiliary valve-control compensating device by the grating sensor comparison circuit.

Abstract: The direct torque control (DTC) system of the traditional asynchronous motor has many disadvantages, such as complex modeling and large amount of calculation, In order to improve the dynamic performance of the DTC system of the asynchronous motor, a direct torque control system is put forward. It uses space vector analysis method to calculate electromagnetic torque and stator flux linkage of asynchronous motor directly, follows the change of the stator flux linkage and torque, omits the complicated calculation, reduces the dependence on motor parameters. The simulation model of the DTC system of the asynchronous motor was established using SIMULINK software package. The feasibility of method is proved in theory, The results of simulation show that the modeling and simulation of the system has good static and dynamic performance, control precision of the system is higher, the stability is better.

Abstract: On the basis of a brief introduction of how the automatic gain control (AGC) of the digital reconnaissance receiver works,this article proposed a digital AGC design method based on the digital processor parts, which provide a guarantee for the digital reconnaissance receiver to work in the complex external electromagnetic signal environment. The engineering implementation of AGC is introduced with specific projects. Both simulation and engineering practice verify the feasibility of this program.