Key Engineering Materials Vols. 419-420

Abstract: Harmonic drive has widespread applications for its compact size and high reduction ratios. It is often favored for electro-mechanical systems with space and weight limitation. In order to minimize the volume and improve its transmission capacity, more and more aborative design technologies are adopted. For structural analyses in assembly state and in transmission stage, Finite Element Analysis (FEA) can be widely applied to get proper parameters and performance. Flexspline usually endures large deformation under assembly force from wave generator. In transmission state, driving force leads to multiple tooth mesh contact between flexspline and circular spline teeth. In this paper, shell element is applied to build flexspline cone, and tapered beam element is used to model the teeth on the flexspline. Contact relation between flexspline and wave generator is simulated by contact element. Forced displacement of flexspline is imposed by contact analysis. Transmission forces are acted at the teeth tips on the flexspline in mesh state, whose values are determined according to experimental distribution. Simulations of assembly state and transmission state are computed in ANSYS. Deformation and stress distribution in assembly state are compared with that in transmission state. Some suggestions for long life and high performance design are present.

Abstract: In order to solve the confliction among the working space, precision and stiffness on the free-form surface, this paper puts forward a Multi-Agent alliance control model that is made up of the series robot Agent, the parallel moving platform Agent and the polishing tool system Agent and so on by organically introducing the MAS (Multi-Agent System) theory into the polishing. Through the introduction of virtual point-curve constraint, the dynamics of the constraint multi-body equation for the polishing system is established in order to accurately program the moving track of the robots. Meanwhile, the control parameters and the optimal path during the polishing can be optimized.

Abstract: A mobile robot prototype with independent propulsion and individual steering and a 5th steerable propulsive wheel has been developed. Different prototypes with diversified wheelbase, wheel stance, clearance, stability margin, altitude of center of gravity and 5th wheel posture can be achieved by reconfiguration. And a special prototype has been made to deal with the situation that the robot will go on traverse after it is flipped over.

Abstract: Based on the configurations of the track type travel mechanism, instead of wheels, the tracks were introduced into the rocker-type robot mobile system, and various configurations of the rocker-type track suspensions were obtained. Through analyzing characteristics of the suspensions, a rocker-type unsymmetrical W-shaped track mobile system was presented. The rear main tracks of the W-shaped tracks were longer than the front ones. The prototype’s obstacles-surmounting capabilities including ditch-crossing, step and stairs-climbing were analyzed. The prototype could climb up a 320mm-high step, climb down a 520mm-high step, cross a 490mm-wide ditch. The capabilities analysis and prototype test results indicated that the rocker-type unsymmetrical W-shaped track mobile platform had excellent passive adaptability to rugged unstructured terrain environments and strong obstacles-surmounting capabilities.

Abstract: Puncturing mud robot is a kind of trenchless device that can walk by itself in the earth. There are abroad appliance foreground and developing value as it can mainly pave PE pipe,PVC pipe,cable and optical fiber cable under the mud. Through researching on impacting construction of steerable air-powered impact mole in trenchless technology at home and abroad, the driving device of puncturing mud robot was designed. The device machinery character and work principle is recounted and device three-dimensional model was established and device virtual assembly was finished. The parameter equation of driving device was educed and effect from main parameter to output capability was analyzed. Based on analysis result, testing of impacting capability about driving device was put up and the academic result of the impacting capability was validated. The testing result indicates also that this driving device can meet puncturing power need. This paper can provides reference for collectivity design of puncturing mud robot.

Abstract: Underactuated flexible manipulator with redundant degrees of freedoms is investigated. Position control method of a single active joint driving the passive joint is given. According to the characteristics of nonholonomiclly redundant flexible manipulators, the optimal control strategy of multiple active joints driving the passive joints is proposed. As the elastic vibration of flexible links can not be eliminated only through position control, the vibration control schemes are presented again. The simulation results show that the elastic vibration is suppressed effectively. Therefore, for nonholonomically redundant flexible manipulator, both position control and vibration control are implemented successfully, which verifies the validity of the control schemes.

Abstract: The product surface coating is a very essential working procedure, especially the complicated surface coating thickness even directly influences outward appearance of the product. Therefore the high request to the surface coating craft is set. To adjust the spray gun's spraying angle and the flow of coating freely is needed. In order to meet complicated surface automatic spraying needs,the invention is based on the PLC complicated surface automatic spraying system, whether in the research and development of the mechanical device or in the design of control system, that the system of mechanical and electrical integration has satisfied request of the automation has been proven after the production examination.

Abstract: With regard to the high precise three-axis ship motion simulation turntable, the precision is influenced by strong dynamics coupling, such as the moment coupling when three frames rotating at the same time. Therefore, the coupling problem of three-axis ship motion simulation turntable was analyzed profoundly. Then, on the basis of the analysis, in order to restrain the disturbance of coupling torque, the method of dynamic robust compensation based on decoupling control was given. Finally, the compound control strategy including PID control, velocity feedback, position feedback ,input signal differential feedforward and dynamic robust compensation was employed, and a electromechanical Co-simulation of three-axis turntable based on ADAMS and MATLAB was completed. The results of the Co-simulation prove that the method given in this paper can restrain coupling disturbance and improve dynamic tracking performance of three-axis simulation turntable

Abstract: In this paper, multi-legged walking machine is simplified as one leg, which the whole machine is constructed by the modularization configuration of the legs in an axisymmetric way. Consequently, the control of one leg and its trajectory planning is the significant part for multi-legged walking machine. This paper, according to the structure of the walking machine's leg with 3-DOF open chains, calculates the terminal track of the leg using the principle of kinematics and presents a foot's controller based on dSPACE. In order to obtain the optimization of the foot's track, the three-cubic spline algorithm is considered. Depending on the model of the control system in Matlab, the paper provides a semi-physical simulation for a real leg using dSPACE. The feasibility of the planned track is demonstrated and the PID parameters have been adjusted.

Abstract: Resource-constrained multi-project scheduling problems (RCMPSP) consider precedence relationship among activities and the capacity constraints of multiple resources for multiple projects. RCMPSP are NP-hard due to these practical constraints indicating an exponential calculation time to reach optimal solution. In order to improve the speed and the performance of problem solving, heuristic approaches are widely applied to solve RCMPSP. This research proposes Hybrid Genetic Algorithm (HGA) and heuristic approach to solve RCMPSP with an objective to minimize the total tardiness. HGA is compared with three typical heuristics for RCMPSP: Maximum Total Work Content, Earliest Due Date, and Minimum Slack. Two typical RCMPSP from literature are used as a test bed for performance evaluation. The results demonstrate that HGA outperforms the three heuristic methods in term of the total tardiness.