PID and Fuzzy Logic Control of Ball and Beam System Using Particle Swarm Optimization

In this research, we carried out the modeling of the ball and beam system (BBS) within the MATLAB/Simulink framework by applying both proportional-integral-derivative (PID) and fuzzy logic control strategies to govern the dynamics of this constructed model. The underlying non-linear dynamic equations adjusting the behavior of the BBS system are based on Newton’s second law of motion. The physical installation of the BBS, designed for potential real-time application, comprises a lengthy beam subject to movement through the action of a DC servomotor, with a ball traversing the beam in a reciprocating manner. A distance sensor is strategically placed in front of the beam to determine the exact position of the ball. In this system, an electrical control signal applied to the DC servomotor causes the beam to pivot about its horizontal axis, thereby enabling the ball to move freely along the beam's length. To avoid the risk of losing the ball equilibrium on the beam and to achieve precise system control, a mathematical model was devised and implemented within the MATLAB/Simulink environment. The use of the particle swarm optimization (PSO) algorithm was aimed at tackling the task of refining and optimizing the PID controller specifically designed for the linearized ball and beam control system. The presented system is controlled using both PID and fuzzy logic, and the use of the PSO algorithm enhances the system’s responsiveness efficiency.

Motion Stability Analysis of Non-sinusoidal Oscillation of Mold Driven by Servomotor

The investments of the electro-hydraulic servo system of the mold non-sinusoidal oscillator are great, the modification ratio of the mechanical type is unable to be adjusted online, and some continuous casters suffer from server resonance during the casting. A mold non-sinusoidal oscillation mechanism driven by servomotor is proposed and the prototype is produced in the lab, the investment is low and the modification ratio is can be adjusted online, and the stability problem is studied. At first the dynamics model of the servomotor non-sinusoidal oscillation is established, and the kinematics differential function is deduced. Furthermore, based on the harmonic balance method, the eigenvalues of the system are solved; the criterion of the stability of the system is put forward. In addition, the eigenvalues and harmonic with different oscillating parameters are analyzed. Analytical results show that the real parts of the eigenvalues are positive, the system will be unstable, and the resonance will occur when the positive real parts of the eigenvalues are extremum. A foundation is established for solving the running smooth problem and next application of this mechanism.

Inverse dynamics and servomotor parameter estimation of a 2-DOF spherical parallel mechanism

A novel reconfigurable 5-DOF hybrid manipulator―TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limb- stroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper, on the basis of inverse dynamic formula- tion of the 2-DOF spherical parallel mechanism, an approach is proposed for esti- mating the servomotor parameters including moment of inertia, rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.

Energy-saving and accurate motion control of a hydraulic actuator with uncertain negative loads

Pump controlled hydraulic actuators are wildly used in the aerospace industry owing to the advantages of energy-saving and integrated configurations.Negative loads may occur to actuators due to external force loads or the inertial force when the actuator decelerates significantly.Uncertain negative load working conditions may cause cavitation,actuator vibration,and even instability to the motion control if the actuator is without sufficient meter-out damping.Various types of hydraulic configuration schemes have been proposed to deal with negative loads of hydraulic actuators.However,few of them can simultaneously achieve energy saving and high control accuracy.This study proposes an energy-saving and accurate motion tracking strategy for a hydraulic actuator with uncertain negative loads.The actuator’s motion is driven by a servomotor pump,which gives full play to the advantage of energy-saving.The meter-out pressure is controlled by proportional valves to provide the optimized meter-out damping.The nonlinear adaptive robust control law is designed,which guarantees the control stability and achieve high tracking accuracy.An integrated direct/indirect adaptation law obtains satisfactory parameter estimations and model compensation for asymptotic motion tracking.Comparative experiments under different working conditions were performed to validate the advantages of the proposed control strategy.

大庆油田甲醇分公司汽轮机组伺服机构改造分析

大庆油田化工有限公司ENK25／28／37．5汽轮机组调速系统在运行期间存在配置复杂、部件多、漏油点多等，给机组带来了较大的安全隐患。本次调速系统技术改造主要针对以上几个问题，采用了德国VOITH公司生产的伺服马达——Semmotor控制调速系统，并开创了国产化机组Servomotor控制调速系统的先河。