Guang-Zhong Cao

On the Voltage Ripple Reduction Control of the Linear Switched Reluctance Generator for Wave Energy Utilization

This paper discusses about the voltage output ripple reduction and error minimization for the direct-drive, linear switched reluctance generator (LSRG)-based wave power generation system. First, the concept of the LSRG-based wave power generation system is studied. According to the characteristics of the LSRG, the suitable drive circuit dedicated to proper current excitation and generation is established. Second, the reasons that cause voltage output ripples are investigated. To reduce the remarkable ripples from phase current commutations, a current distribution function (CDF) is proposed based on the minimized copper loss principle. Third, the dual-loop control strategy with current and voltage as the inner and outer loop is constructed, implemented with the proposed CDF. Theoretical bases of the control strategy are derived. The simulation results prove that the proposed control algorithm is capable of voltage ripple suppression and error reduction within the range of ±0.5 V over the entire operation speed for wave energy extraction, validated by experimental verification.

Nonlinear Modeling of the Inverse Force Function for the Planar Switched Reluctance Motor Using Sparse Least Squares Support Vector Machines

In the advanced manufacturing industry, planar switched reluctance motors (PSRMs) have proved to be a promising candidate due to their advantages of high precision, low cost, low heat loss, and ease of manufacture. However, their inverse force function, which provides vital phase current command for precise motion, is highly nonlinear and hard to be accurately modeled. This paper proposes a novel inverse force function using sparse least squares support vector machines (LS-SVMs) to achieve nonlinear modeling for precise motion of a PSRM. The required training and testing sets of sparse LS-SVMs are first obtained from experimental measurement. A sparse LS-SVMs regression is further developed using training set to accurately model the inverse force function. Accordingly, the function is tested via the testing set to assess its feasibility. Finally, the proposed approach is applied to the PSRM system with dSPACE controller for trajectory tracking, and its effectiveness and superior performance are verified through experimental results.

Optimization Design of the Planar Switched Reluctance Motor on Electromagnetic Force Ripple Minimization

In planar switched reluctance motors (PSRMs), the electromagnetic force ripple minimization is important to reduce the noise and vibration for high-precision motions. In this paper, an improved PSRM by optimization design for minimization of the electromagnetic force ripple is proposed. The structure, principle, and mathematical model of the PSRM are clarified. Based on Ansoft Maxwell, optimization design of the PSRM is performed by improved structure with smaller pole pitch and incremental number of mover poles. Experiments of the improved PSRM are implemented based on dSPACE. The experimental results verify that the improved PSRM effectively reduces electromagnetic force ripple with planar trajectory tracking.

An adaptive control method for the linear switched reluctance motor based on DSP

The linear switched reluctance motor (LSRM) is a new kind of direct-drive actuator, however, it is very difficult to build an exact theoretic model for the LSRM. In this paper, an indirect self-tuner is proposed for position control of the LSRM by combining the recursive least squares (RLS) estimator with the minimum-degree pole placement method (MDPP) for controller design. Control system construction and operation based on one single Digital Signal Processor (DSP) are also established. Experimental results demonstrate the control scheme with on-line least-square parameter identification has a better performance than PID controller on modifying steady-error variances between each operation side in square-wave tracking. Experimental results prove that the control algorithm considering disturbances has smaller steady-state error compared with PID control algorithm.

Investigation of a rotary-linear switched reluctance motor

A novel direct-drive rotary-linear switched reluctance motor (RLSRM) is proposed. The motor has the advantages of robust mechanical structure, low manufacture cost and capability of operation under hostile environments. Simulation tools such as finite element analysis (FEA) are applied for the verification of motor performance and corresponding experiments are carried out to testify the simulation results. The authors expect that the innovative actuator design can be applied in industrial applications that require both rotary and linear motions.

High-Precision Dual-Loop Position Control of an Asymmetric Bilateral Linear Hybrid Switched Reluctance Motor

In this paper, to enhance the machine performance and realize a high-precision position control performance, a dual-loop position controller is employed for the asymmetric bilateral linear hybrid switched reluctance motor (ABLHSRM). Machine characteristics are investigated by finite-element method. The dual-loop controller is constructed by employing a tradition proportional-integral differential velocity controller as the inner loop and a fuzzy proportional differential (PD) controller for the outer loop. Experimental results demonstrate that both the position control performance and the velocity control performance under the dual-loop control algorithm are superior to the single-loop PD position control strategy. An absolute steady-state error of 4 μm can be achieved under the dual-loop control strategy. Performance comparison from the ABLHSRM and its asymmetric bilateral linear switched reluctance counterpart with the same dimensions are carried out. Position tracking results show that the rise time is improved for the proposed ABLHSRM under the proposed control scheme.

Optimization design of planar switched reluctance motors based on electromagnetic force characteristics

A new type of planar switched reluctance motor (PSRM) is proposed based on the switched reluctance principle. The configuration, principle, and mathematical model of the PSRM are clarified. According to the special structure form the complex magnetic circuit characteristic of the PSRM, 3D transient electromagnetic model of the PSRM is built based on ANSOFT Maxwell/3D. Based on the built model, the electromagnetic distributions and electromagnetic force characteristics of the PSRM are analyzed. In addition, the air gap and translator yoke of the PSRM are analyzed. Simulation results show that the length of the air gap and the thickness of the translator yoke are very important parameters for influencing the performance of the PSRM. The parameters of the optimal structure of the PSRM are revised via the simulation. A prototype of the PSRM is manufactured according to the optimization results, and experiments are performed. The design method is validated by the analysis of the experimental results. The theoretical foundation of the structure design and the development of the PSRM are provided. The PSRM is expected to be utilized in the application of high precision processing.

Vibration suppression of the flexible manipulator using optimal input shaper and linear quadratic regulator

This paper proposes a control strategy of a constrained planar flexible manipulator for vibration suppression using optimal input shaper (OIS) and linear quadratic regulator (LQR). An experimental setup of the flexible manipulator is presented, and the corresponding mathematical model is derived utilizing the assumed mode method and Lagrange dynamics equation. For the flexible manipulator, an OIS feedforward controller is applied to suppress its vibration and reduce time delay, and a LQR feedback controller is employed to control its angular position. Simulation and experiment are carried out, and the results related to the angular position tracking of the flexible manipulator are demonstrated. The effectiveness and superior performance of the proposed control strategy are verified.

Design and optimization for the linear switched reluctance generator

In this paper, a novel double-sided direct-drive linear generator based on switched reluctance principle is proposed. In order to acquire a higher power density, the optimization of structure parameters for the double-sided linear switched reluctance generator (DLSRG) is carried out. To observe the nonlinear phenomena in SR generator, two dimensional (2D) magnetic static field distributions is obtained. For imitation of real-time operation, transient magnetic field is analyzed by finite element method (FEM). Then through a series of simulation and analysis, a group of appropriate parameters for the DLSRG are obtained. It is expected that the novel direct-drive generator finds its applications in power conversion fields such as wave power utilization.

A path-planning algorithm of the automatic welding robot system for three-dimensional arc welding using image processing

This paper proposes a path-planning algorithm using image processing for three-dimensional (3-D) arc welding of the automatic welding robot system. First, the forward kinematics of the automatic welding robot system is analyzed. Then, the path-planning algorithm based on image processing is developed, and its script is described. Furthermore, the practical automatic welding robot system is presented, and the 3-D arc welding is carried out experimentally. The interaction interface of the image processing subsystem to display actually welding point and the desired welding point is used. Experimental results demonstrate that the tracking of 3-D welding seam can be successfully achieved, and the image of actually welding point tracks the desired welding point on the interaction interface. The welding trajectory can be automatic obtained based on the script algorithm using data generated by the image process subsystem. The proposed path-planning algorithm is verified.