Realization of High-Fidelity Controlled-Phase Gates in Extensible Superconducting Qubits Design with a Tunable Coupler

High-fidelity two-qubit gates are essential for the realization of large-scale quantum computation and simulation. Tunable coupler design is used to reduce the problem of parasitic coupling and frequency crowding in many-qubit systems and thus thought to be advantageous. Here we design an extensible 5-qubit system in which center transmon qubit can couple to every four near-neighboring qubits via a capacitive tunable coupler and experimentally demonstrate high-fidelity controlled-phase (CZ) gate by manipulating central qubit and one near-neighboring qubit. Speckle purity benchmarking and cross entropy benchmarking are used to assess the purity fidelity and the fidelity of the CZ gate. The average purity fidelity of the CZ gate is 99.69±0.04% and the average fidelity of the CZ gate is 99.65±0.04%, which means that the control error is about 0.04%. Our work is helpful for resolving many challenges in implementation of large-scale quantum systems.

Mapping Relation between Contour Error Components of Crankshaft Pin Journal and Axis Position Control Error of Oscillating Grinding Machine

Automatic crankshaft production lines require high reliability and accuracy stability for the oscillating grinding machine. Crankshaft contour error represent the most intuitive data in production field selective inspection. If the mapping relation between the contour error components of the crankshaft pin journal and the axis position control error of the oscillating grinding machine can be found, it would be great significance for the reliability maintenance of the oscillating grinding machine. Firstly, a contour error decomposition method based on ensemble empirical mode decomposition (EEMD) is proposed. Secondly, according to the contour generating principle of the pin journal by oscillating grinding, a calculation method to obtain the effect of the axis position control error of the oscillating grinder on the contour error of the pin journal is proposed. Finally, through the grinding experiments, the error data are acquired and measured to calculate and decompose the contour error by using the proposed methods for obtaining the mapping relation between the crankshaft pin journal contour error and the axis position control error. The conclusions show that the proposed calculation and decomposition methods can obtain the mapping relation between the contour error components of the crankshaft pin journal and the axis position control error of the oscillating grinding machine, which can be used to predict the key functional component performance of the machine tool from the oscillating grinding workpiece contour error.

Design Control and Performance of a Cable-driving Module with External Encoder and Force Sensor for Cable-Driven Parallel Robots

Cable-driven parallel robots (CDPRs) have the characteristic of easy deployment, which endows CDPRs with flexible workspace, freely configurable degrees of freedom (DOF), and various configurations, greatly expanding their range of applications. Modular design provides excellent convenience and feasibility for deployment, which is a crucial issue of CDPR design. A highly integrated cable-driving module is designed in this paper, which includes the winding bobbin, servo motor, force sensor, external encoder, electromagnetic brake, as well as other devices. Experiments show that the maximum cable length control error is less than 0.16%, and the maximum cable tension control error is less than 8% in the back-and-forward rotation test. Furthermore, using the proposed module, a CDPR with eight cables and 6 DOFs is constructed rapidly, whose dimension is 850×850×650 mm3. Results show that the robot's trajectory errors are all less than 4.5 mm, and the Root-Mean-Square-Error (RMSE) is 2.1 mm. Besides, the compliance control experiments show that the robot's tracking error in impedance control mode is less than 2 mm, and the RMSE is 0.95 mm. Moreover, the dragging force in teaching mode is less than 2.5 N, which demonstrates good follow-up performance. The proposed compact cable-driving module with high precision could be helpful for the design and rapid deployment of modular CDPRs.

Optimization of the Yaw Control Error of Wind Turbine

Yaw system is an important part of wind turbine control system, yaw error is an important performance index of wind turbine, which has great influence on power generation. The wind utilization and the output of the power generation have been determined by the yaw error. In order to make the wind turbine better aligned toward the wind direction, reduce the yaw error, and increase the power generated by the unit, the angle errors of yaw control of wind turbine have been analyzed, in this paper, and the method of wind test, the strategy of yaw control have been studied respectively. Based on the results of the study, the method of wind test, the restart control strategy of yaw system and the performance of control strategy of yaw system have been optimized in this paper. In this way, the three important links are optimized, it will effectively reduce the yaw error as well as significantly improve the wind turbine generating electricity.

THE INFLUENCE OF THE METHOD OF ADAPTIVE SELF-DIAGNOSIS ON THE PROCESS OF PREVENTING THE CONSEQUENCES OF MODULE FAILURES ENTERPRISE INFORMATION SYSTEM

The study continues the properties of functional stability. Functional stability means the property of an information system to maintain its functioning, possibly with a decrease in quality, for a specified time under the influence of external and internal destabilizing factors. External and internal destabilizing factors are failures, failures of system modules, mechanical damage, thermal effects, errors of service personnel. The main stages of ensuring functional stability are the detection of the module that failed in the control, diagnosing the module that failed and the restoration of the information system of the enterprise. The peculiarity of enterprise information systems is that they must function autonomously. With their help, the systems can increase the productivity of all production centers while reducing the number of people employed in production and significantly reducing the share of manual labor. The paper investigates how, based on the functional dependence of failure probability on a certain probability value at different values, the probability of control error of the second kind can determine the recommended interval of the result, which will provide, given the intensity of readiness control allowable failure probability. It is illustrated how at a given intensity of the result it is possible to determine such an intensity of readiness control at which the probability of skipping will not exceed the maximum allowable value. It is shown that we can talk about the weak dependence of the probability of skipping on the control error of the second kind, which means that the achievement of a given control reliability is based on the intensity of readiness control and less depends on the reliability of individual basic checks. For the case when in the intervals between the issuance of the result the system checks the readiness of the modules is randomly described the method of calculating the probability of skipping.

Design and Experiment of a Compact Cable-Driving Module for Reconfigurable Cable-Driven Parallel Robots

Cable-driven parallel robots (CDPRs) have the characteristics of reconfigurability, which endows CDPRs with flexible workspace, freely configurable degrees of freedom and various configurations, greatly expanding their range of applications. Modular design provides great convenience and feasibility for the realization of reconfiguration, which is a key issue of reconfiguration research. However, most existing CDPRs have problems of low modularity and low system integration, which brings inconvenience to the realization of reconfiguration. In this paper, a highly integrated and high precision cable-driving module is designed, which can accurately control the length and tension of the cable. In addition, experimental verification is performed. The single-module experiment shows that the module has good ability for cable length and cable tension control. The cable length control error is less than 0.2mm, and the cable tension control error is less than 0.8N. Furthermore, based on the proposed module, a CDPR with 8 cables and 6 degrees of freedom is constructed rapidly. The open-loop tracking error of the robot is measured by laser tracker. Results show that the tracking error is less than 4.5mm and the Root-Mean-Square-Error (RMSE) is 2.1mm. Besides, the compliance control experiment of the robot shows that the tracking error in impedance control mode is less than 2mm, and the RMSE is 0.95mm, and the drag force in teaching mode is less than 2.5N, which demonstrates good follow-up performance. The proposed compact cable-driving module with high precision could be useful for the design and rapid construction of reconfigurable CDPRs.