Position Servo Control Research Articles

Controllable Petri Net-Based Implementation Approach for Motor Control Systems

This paper presents a model-based implementation approach to realize a position servo control system for low-cost dc motors using a controllable Petri net (CrPN). The CrPN model inference engine is embedded inside the sensor node to form an autonomous agent, and the autonomous agent is further used to interpret and execute CrPN-based motor control models. The CrPN model can be evaluated to examine the properties of controllability and stability using reachability graphs before the model is deployed. The most important feature of the CrPN-based control approach is providing a feasible and low-cost solution without using any native code programming in microcontrollers. To evaluate the performance of our approach, proportional and proportional-integral position control schemes were both implemented using the CrPN approaches. The results from the Simulink simulations and the native code programming with C-language implementations were also provided for performance comparisons and validations.

Position Servo Control of the Transverse Flux Machine Based on an Armature Current RMS and Initial Phase Control Method

A control method for position servo control of Transverse flux machine (TFM) by controlling armature current Root-Mean-Square (RMS) and initial phase is proposed in this paper. Specifically, the voltage balance equation of TFM is provided, and the phasor diagrams are analyzed to achieve the expression of electromagnetic power of TFM. The expression indicates that the electromagnetic torque is determined by armature current RMS and the initial phase. A position servo control system of TFM is established based on the expression. The results of the position servo control curves show that the position servo control system of TFM is effective.

Development of FPGA based NURBS interpolator and motion controller with multiprocessor technique

The high-speed computational performance is gained at the cost of huge hardware resource, which restricts the application of high-accuracy algorithms because of the limited hardware cost in practical use. To solve the problem, a novel method for designing the field programmable gate array(FPGA)-based non-uniform rational B-spline(NURBS) interpolator and motion controller, which adopts the embedded multiprocessor technique, is proposed in this study. The hardware and software design for the multiprocessor, one of which is for NURBS interpolation and the other for position servo control, is presented. Performance analysis and experiments on an X-Y table are carried out, hardware cost as well as consuming time for interpolation and motion control is compared with the existing methods. The experimental and comparing results indicate that, compared with the existing methods, the proposed method can reduce the hardware cost by 97.5% using higher-accuracy interpolation algorithm within the period of 0.5 ms. A method which ensures the real-time performance and interpolation accuracy, and reduces the hardware cost significantly is proposed, and it’s practical in the use of industrial application.

A Simulation of an Electrical Servo Drive Based on Optimal Control

In paper, the problem of robustify LQR for a class of uncertain linear systems is considered. An optimal controller is designed for the nominal system and an integral sliding surface is constructed. The ideal sliding motion can minimize a given quadratic performance index, and the reaching phase, which is inherent in conventional sliding mode control, is completely eliminated. Then the sliding mode control law is synthesized to guarantee the reachability of the specified sliding surface. The system dynamics is global robust to uncertainties which satisfy matching conditions. A GROSMC is realized. To verify the effectiveness of the proposed scheme, a robust optimal sliding mode controller is developed for rotor position control of an electrical servo drive system.

Research on the Stability of the Position Servo Motor Control System Based on DSP

in this paper, a very low cost two-axis position servo system is developed. This system is controlled by DSP. We study the stability of the position servo control system. We use the PI control algorithm in our application. We achieved twice switching frequency by using PWM signals to share the switching dissipation ePWM module of the DSP. A numerical consideration is given. The simulation results demonstrate the stability of the proposed method.

BP-PID Control for Electro-hydraulic Proportional Position Servo System

The electro-hydraulic proportional position servo system is a kind of highly non-linear and time-varying system as well as parameter uncertainties. It is often difficult to achieve satisfactory control results with the traditional control methods. Considering that the adaptive neural network PID control method has the characteristics of online learning and adjustment PID control parameters adaptively, this paper puts forward to adopt BP-PID control method for the position servo control of electro-hydraulic proportional system. An online adaptive BP-PID controller is designed. The simulation model of the system is established based on Simulink platform. The step response and Sinusoidal tracking characteristics are researched for electro-hydraulic proportional position servo system by using traditional PID and BP-PID control algorithms through simulations and experiments. The results show that BP-PID has a strong ability of online learning and self-tuning PID parameters. Compared with the traditional PID control method, the BP-PID control has strong self-adaptability and robustness, and can significantly improve the step response speed and tracking control precision.

Research on the Positioning Servo Control Strategy for CNC System

In order to overcome thelimitation of the position servo control method of computerized numerical control(CNC) system, a control approach of generalized predictive control (GPC) ispresented in this paper. In the method, the GPC model calculates the optimalcontrol rate through the predictive model and rolling optimization as thecontroller of the position servo system. Compared with GPC and proportional-integral-derivative(PID) control, the simulative and experimental results show that the proposedcontrol approach has better the dynamic performance, steady-state performance,and robustness.

The Position Servo Control Strategy of High Dynamic Response Based on Electric Steering Gear

This paper studies the current loop, velocity loop and position loop controller of PMSM position servo system for Electric steering gear servo system. It makes research around the principle of PMSM vector control and three control loop control strategy. The control strategy bases on the principle of vector control of PMSM when id=0 and uses the classic PI control theory. A new method of decouple control for the current of direct axis and cross axis direct is presented. It will overcome the impact of EMF when the motor is working in high dynamic. The system uses the feed-forward control to compensate the position deviation of permanent magnet synchronous motor using in the steering gear. The paper also researches transfer function of feed-forward control of the location, and establishes the feed-forward controller model of the position loop. Simulation results demonstrate the effectiveness of our proposed scheme.

Servo Control of Thrust Position for 6DOF Magnetic Suspension Stage

A novel 6DOF magnetic suspension stage is studied in this paper, the magnetic suspension stage system includes a suspension system and a thrust servo system, and this paper only studies the thrust system. The thrust system is a nonlinear, multivariable, and strong coupling system. For achieving its precise servo control, we used the auto-disturbance rejection controller to observe the inner and outside disturbance, and to offset the system. The result of simulation and experiment shows that the control scheme applied in the thrust control system has better dynamic, static, and robust characteristics.

Adaptive Fuzzy Sliding Mode Control of Asymmetrical Hydraulic Cylinder Based on DSP

An adaptive fuzzy sliding mode control strategy is designed to solve the problem of nonlinear, disturbances and uncertain parameters in asymmetric hydraulic cylinder position servo control system. Variable parameters and external disturbances of the system are identified by adaptive function. Meanwhile fuzzy exponential velocity reaching law is introduced to reduce the chatting phenomenon. Simulation results show the system dynamic performance is improved, the chattering phenomenon which caused by traditional sliding mode variable structure is weakened and the proposed algorithm is feasible. The algorithm control experiment of asymmetric hydraulic cylinder was done on the DSP28335 hardware platform. The experiment proves the effectiveness of the algorithm and achieves a good control result.

Fuzzy logic‐based adaptive gravitational search algorithm for optimal tuning of fuzzy‐controlled servo systems

This study proposes an adaptive gravitational search algorithm (AGSA) which carries out adaptation of depreciation law of the gravitational constant and of a parameter in the weighted sum of all forces exerted from the other agents to the iteration index. The adaptation is ensured by a simple single input–two output (SITO) fuzzy block in the algorithm's structure. SITO fuzzy block operates in the iteration domain, the iteration index is the input variable and the gravitational constant and the parameter in the weighted sum of all forces are the output variables. AGSA's convergence is guaranteed by a theorem derived from Popov's hyperstability analysis results. AGSA is embedded in an original design and tuning method for Takagi-Sugeno proportional-integral fuzzy controllers (T-S PI-FCs) dedicated to servo systems modelled by second-order models with an integral component and variable parameters. AGSA solves a minimisation-type optimisation problem based on an objective function which depends on the sensitivity function with respect to process gain variations, therefore a reduced process gain sensitivity is offered. AGSA is validated by a case study that optimally tunes a T-S PI-FC for position control of a laboratory servo system.Representative experimental results are presented.

Driving properties of plane wire-driven robot

A three-DOF (degree of freedom) planar robot completely restrained and positioned parallel pulled by four wires was studied. The wire driving properties were analyzed through experiments. The restrained three-DOF planar platform was established based on slippery course and bearing, and dSPACE real-time control system was used to perform the platform’s motion control experiment on robot. Based on the kinematic equation and mechanical balance equation of moving platform, the stiffness of the robot system was analyzed and the calibration scheme of the system considering wire tension was put forward. Position servo control experiments were carried out, position servo tracking precision was analyzed, and real-time wire tension was detected. The results show that the moving error of the moving platform tracking is small (the maximum difference is about 3%), and the rotation error is large (the maximum difference is about 12%). The wire tension has wave properties (the wire tension fluctuation is about 10 N).

Cylinder Position Servo Control Based on Fuzzy PID

The arbitrary position control of cylinder has always been the hard challenge in pneumatic system. We try to develop a cylinder position servo control method by combining fuzzy PID with the theoretical model of the proportional valve-controlled cylinder system. The pressure differential equation of cylinder, pressure-flow equation of proportional valve, and moment equilibrium equation of cylinder are established. And the mathematical models of the cylinder driving system are linearized. Then fuzzy PID control algorithm is designed for the cylinder position control, including the detail analysis of fuzzy variables and domain, fuzzy logic rules, and defuzzification. The stability of the proposed fuzzy PID controller is theoretically proved according to the small gain theorem. Experiments for targets position of 250 mm, 300 mm, and 350 mm were done and the results showed that the absolute error of the position control is less than 0.25 mm. And comparative experiment between fuzzy PID and classical PID verified the advantage of the proposed algorithm.

Dynamic System of a Mechanical Press Driven by SRM for Flexible Process

The paper presents a mechanical press driven by Switched Reluctance Motor (SRM) and researches on its tracking performance and operating noise. A position servo control system is proposed with a hybrid closed-loop structure to achieve flexible process of servo press. Based on the working bench, experiments are made to measure the tracking performance and operating noise of the press. Experimental results indicate the press driven by SRM has better tracking performance and lower working noise.

Simulation and Analysis on Main Synchronized Hydraulic Cylinder of Huge Hydraulic Press

Nowadays, huge hydraulic press plays an important role in the heavy industry. The synchronized hydraulic cylinder is the key component, which will affect the performance of the press. Thus, a thorough investigation to the main cylinder is required. In this paper, a mathematical model was built for the position closed-loop control of active synchronous hydraulic cylinders, and transfer function of the corresponding single cylinder was deduced. Simulation and calibration of the working cylinder servo position control system was accomplished with MATLAB, so as to improve the response speed and stability of the single working cylinder system. The results showed that a single hydraulic piston cylinder had a better position control features, which offered a theory basis for the design of the main drivers of forging hydraulic machine synchronization system.

Pneumatic position servo control of magnetic resonance compatible needle insertion robot

This paper presents a control methodology that enables nonlinear model-base control of pulse width modulated (PWM) pneumatic position servo control system of a magnetic resonance (MR) compatible needle insertion robot used for MRI-guided prostate brachytherapy. Sliding mode control with a boundary layer is investigated based on the equivalent continuous-time dynamic model. Considering chattering in sliding mode control applications, especially in motion control of the robot, a fuzzy method is developed to tune the boundary layer of the sliding mode controller. Simulation and experimental results indicate that the controller is effective in both position control and trajectory tracking. With the boundary layer increasing, the steady state error of the response is becoming larger; however the maximum error is less than 0.2 mm. This steady state performance meets the accuracy requirement.

Inverse grey-box model-based control of a dielectric elastomer actuator

An accurate physical-based electromechanical model of a commercially available tubular dielectric elastomer (DE) actuator has been developed and validated. In this contribution, the use of the physical-based electromechanical model to formulate a model-based controller is examined. The choice of control scheme was dictated by the desire for transparency in both controller design and operation. The internal model control (IMC) approach was chosen. In this particular application, the inverse of the linearized form of the grey-box model is used to formulate the IMC controller. To ensure consistent control performance across the operating range of the DE actuator, a gain scheduling term, which linearizes the operating characteristics of the tubular dielectric elastomer actuator, is developed and implemented in series with the IMC controller. The IMC-based approach is investigated for servo control of the DE actuator position as well as its ability to provide vibration isolation of a payload subject to ground vibration.

Experimental Research on Trajectory Control of Walking Rehabilitation Training Robot

In order to improve the effect of smooth motion, the impedance control is introduced into the control system of walking rehabilitation training robot. An impedance control strategy for active rehabilitation training model is proposed and analyzed, and an adaptive control algorithm is proposed on that basis. The experimental tests of three control methods including PD position servo control, impedance control and adaption control are implemented on the robot prototype. The experimental results show that the robot can continuously adjust its gait trajectory according to the human-robot interaction force to meet the expected gait characteristics under the latter two control strategies. The feasibility and validity of the two control strategies is proved, which will be used in active rehabilitation training.

Research on the Servo Position Control System of the Carrying Manipulator Based on Pneumatic Drive

Ammunition fuse shell is carried rapidly by the carrying manipulator from heating furnace to molding machine, so manipulator need accurate repeated position. The servo position control system is established to meet manipulator multi-point and flexible location based on pneumatic driving system. Linear mathematical model of the servo position control system is built based proper assumption, and model was used to analyze control system theoretically. The carrying manipulator can satisfy demands including decided order and positions; the control character is good by debugging.

Research of the Electro-hydraulic Servo System Based on RBF Fuzzy Neural Network Controller

This article describes the composition and working principle of electro-hydraulic position servo control system, and establishes a systematic mathematical model. This article presents a controller which is based on Fuzzy neural networks for an electro-hydraulic speed governor. The design process of the RBF Fuzzy neural network control is introduced in detail. This controller which combines the advantages of the Fuzzy control and Neutral networks control can get the best PID parameters by self-adjustment on line. The simulation study proves that this control system has a better adaptability and can improve the control effect greatly.