Showing papers on "Proportional control published in 2013"

Lyapunov Function-Based Current Controller to Control Active and Reactive Power Flow From a Renewable Energy Source to a Generalized Three-Phase Microgrid System

Abstract: In this paper, a novel current control technique, implemented in the a-b-c frame, for a three-phase inverter is proposed to control the active and reactive power flow from the renewable energy source to a three-phase generalized microgrid system. The proposed control system not only controls the grid power flow but also reduces the grid current total harmonic distortion in the presence of typical nonlinear loads. The control system shapes the grid current taking into account the grid voltage unbalance, harmonics as well as unbalance in line side inductors. The stability of the control system is ensured by the direct method of Lyapunov. A SRC is also proposed to improve the performance of the current controller by estimating the periodic disturbances of the system. The proposed control system (implemented digitally) provides superior performance over the conventional multiple proportional-integral and proportional-resonant control methods due to the absence of the PARK's transformation blocks as well as phase lock loop requirement in the control structure. A new inverter modeling technique is also presented to take care of unbalances both in grid voltages and line side inductors. Experimental results are provided to show the efficacy of the proposed control system.

Training Strategies for Mitigating the Effect of Proportional Control on Classification in Pattern Recognition Based Myoelectric Control.

Abstract: The performance of pattern recognition based myoelectric control has seen significant interest in the research community for many years. Due to a recent surge in the development of dexterous prosthetic devices, determining the clinical viability of multifunction myoelectric control has become paramount. Several factors contribute to differences between offline classification accuracy and clinical usability, but the overriding theme is that the variability of the elicited patterns increases greatly during functional use. Proportional control has been shown to greatly improve the usability of conventional myoelectric control systems. Typically, a measure of the amplitude of the electromyogram (a rectified and smoothed version) is used to dictate the velocity of control of a device. The discriminatory power of myoelectric pattern classifiers, however, is also largely based on amplitude features of the electromyogram. This work presents an introductory look at the effect of contraction strength and proportional control on pattern recognition based control. These effects are investigated using typical pattern recognition data collection methods as well as a real-time position tracking test. Training with dynamically force varying contractions and appropriate gain selection is shown to significantly improve (p<0.001) the classifier’s performance and tolerance to proportional control.

Model-based rational feedback controller design for closed-loop deep brain stimulation of Parkinson's disease

Abstract: Objective. To explore the use of classical feedback control methods to achieve an improved deep brain stimulation (DBS) algorithm for application to Parkinson's disease (PD). Approach. A computational model of PD dynamics was employed to develop model-based rational feedback controller design. The restoration of thalamocortical relay capabilities to patients suffering from PD is formulated as a feedback control problem with the DBS waveform serving as the control input. Two high-level control strategies are tested: one that is driven by an online estimate of thalamic reliability, and another that acts to eliminate substantial decreases in the inhibition from the globus pallidus interna (GPi) to the thalamus. Control laws inspired by traditional proportional-integral-derivative (PID) methodology are prescribed for each strategy and simulated on this computational model of the basal ganglia network. Main Results. For control based upon thalamic reliability, a strategy of frequency proportional control with proportional bias delivered the optimal control achieved for a given energy expenditure. In comparison, control based upon synaptic inhibitory output from the GPi performed very well in comparison with those of reliability-based control, with considerable further reduction in energy expenditure relative to that of open-loop DBS. The best controller performance was amplitude proportional with derivative control and integral bias, which is full PID control. We demonstrated how optimizing the three components of PID control is feasible in this setting, although the complexity of these optimization functions argues for adaptive methods in implementation. Significance. Our findings point to the potential value of model-based rational design of feedback controllers for Parkinson's disease.

Tuning of Proportional Retarded Controllers: Theory and Experiments

Abstract: This brief provides simple tuning rules for the proportional retarded (PR) control of second order systems requiring strong closed-loop damping. A frequency domain analysis allows determining the σ-stabilizability regions of the controller. The analysis provides explicit formulae for tuning the three parameters of the PR controller, namely, the proportional gain, the retarded gain, and the delay. The performance of the PR closed-loop control is experimentally compared with that of a proportional derivative (PD) controller. The experiments show that the PR controller outperforms the PD controller fed using velocity estimates obtained from a high-pass filter in terms of noise amplification, control effort, and position error, and has a similar performance compared with a PD controller supplied with velocity estimates produced by an observer. Numerical implementation of the PR controller is computationally less demanding than the corresponding implementation of PD algorithms using velocity estimation based on filters or observers, since it does not need solving ordinary differential equations and only requires performing two products and a few memory registers for implementing the time delay.

Continuous-time Proportional-Integral Distributed Optimization for Networked Systems

Abstract: In this paper we explore the relationship between dual decomposition and the consensus-based method for distributed optimization. The relationship is developed by examining the similarities between the two approaches and their relationship to gradient-based constrained optimization. By formulating each algorithm in continuous-time, it is seen that both approaches use a gradient method for optimization with one using a proportional control term and the other using an integral control term to drive the system to the constraint set. Therefore, a significant contribution of this paper is to combine these methods to develop a continuous-time proportional-integral distributed optimization method. Furthermore, we establish convergence using Lyapunov stability techniques and utilizing properties from the network structure of the multi-agent system.

Experimental studies on active vibration control of a smart composite beam using a PID controller

Abstract: This paper presents experimental verification of the active vibration control of a smart cantilever composite beam using a PID controller. In order to prevent negative occurrences in the derivative and integral terms in a PID controller, first-order low-pass filters are implemented in the derivative action and in the feedback of the integral action. The proposed application setup consists of a composite cantilever beam with a fiber-reinforced piezoelectric actuator and strain gage sensors. The beam is modeled using a finite element method based on third-order shear deformation theory. The experiment considers vibration control under periodic excitation and an initial static deflection. A control algorithm was implemented on a PIC32MX440F256H microcontroller. Experimental results corresponding to the proposed PID controller are compared with corresponding results using proportional (P) control, proportional‐integral (PI) control and proportional‐derivative (PD) control. Experimental results indicate that the proposed PID controller provides 8.93% more damping compared to a PD controller, 14.41% more damping compared to a PI controller and 19.04% more damping compared to a P controller in the case of vibration under periodic excitation. In the case of free vibration control, the proposed PID controller shows better performance (settling time 1.2 s) compared to the PD controller (settling time 1.5 s) and PI controller (settling time 2.5 s). (Some figures may appear in colour only in the online journal)

Shunt reactive VAR compensator for grid-connected induction generator in wind energy conversion systems

Abstract: This work presents the control design for compensating reactive power requirement of induction generator (IG) in wind generation systems using STATic COMpensator (STATCOM). A mathematical model of IG is developed in synchronously rotating d–q–0 axis. The STATCOM is realised using voltage source inverter for which the switching function model is derived and employed here. Instantaneous p–q theory and symmetrical components theory are considered for reference current generation. The current control uses an optimal proportional controller designed using linear quadratic regulator (LQR) approach. Comparative analysis is also made between hysteresis current control and LQR. Simulation and experimental results indicate that the suggested control techniques make the supply power factor close to unity.

Fractional order adaptive controller for stabilised systems via high-gain feedback

Abstract: Controllers based on fractional order calculus are gaining more and more interests from the control community This type of controllers may involve fractional integration, fractional differentiation and/or fractional systems in their structure or implementation They have been introduced in the control applications in a continuous effort to enhance the system control quality performances and robustness In this study, a new scheme of fractional order adaptive controller via high-gain output feedback for a class of linear, time-invariant, minimum phase and single input-single output systems of relative degree one is proposed The basic idea of the new design is a further modification in the adaptive proportional control law by the introduction of a fractional integration besides of the regular one of the squared output of the system in the adaptation gain of the control strategy An analytical stability proof of the feedback control system is presented The control quality enhancement of the proposed control scheme compared with the classical one has been presented through the simulation results of an illustrative example

Inversion based direct position control and trajectory following for micro aerial vehicles

Abstract: In this work, we present a powerful, albeit simple position control approach for Micro Aerial Vehicles (MAVs) targeting specifically multicopter systems. Exploiting the differential flatness of four of the six outputs of multicopters, namely position and yaw, we show that the remaining outputs of pitch and roll need not be controlled states, but rather just need to be known. Instead of the common approach of having multiple cascaded control loops (position - velocity - acceleration/attitude - angular rates), the proposed method employs an outer control loop based on dynamic inversion, which directly commands angular rates and thrust. The inner control loop then reduces to a simple proportional controller on the angular rates. As a result, not only does this combination allow for higher bandwidth compared to common control approaches, but also eliminates many mathematical operations (only one trigonometric function is called), speeding up the necessary processing especially on embedded systems. This approach assumes a reliable state estimation framework, which we are able to provide with through previous work. As a result, with this work, we provide the missing elements necessary for a complete approach on autonomous navigation of MAVs.

Equivalent Switch Circuit Model and Proportional Resonant Control for Triple Line-Voltage Cascaded Voltage-Source Converter

Abstract: This paper studies the modeling and control for a triple line-voltage cascaded voltage-source converter. The unbalanced current of each cascaded unit results in complicated control algorithm and structure due to its structural characteristic, and there exists a double-frequency fluctuation for each dc-capacitor voltage. To solve the aforementioned problems, an equivalent switch circuit model for the converter is established in this paper based on the external circuit characteristic, and a simple proportional resonant control strategy for the model is also proposed. The technique realizes the power factor regulation and the balanced stable transmission of the converter power in a two-phase stationary frame. And by adding an ac-side voltage compensation control for each converter, the double-frequency fluctuation of each dc-link voltage is effectively restrained. Besides, the strategy adopts a carrier phase-shifting space vector pulsewidth modulation suitable for the structural characteristics, which effectively simplifies the modulation algorithm. The proposed strategy has such advantages as less hardware and computation, simpler control structure, better dynamic and static performance, and better robustness. The experimental results have verified the feasibility and availability of the proposed model and its control method.

The Development of a High-Speed Segment Erecting System for Shield Tunneling Machine

Abstract: The present study is focused on developing an effective high-speed segment erecting system, which is specific for modern shield tunneling machine. The big steady-state error and large impact force caused by high motion speed and large inertia load are main restrictions for the conventional segment erector to realize high-speed segment erecting. To overcome the bottleneck, a new hydraulic system that is based on electrohydraulic proportional control technology is designed, the actuator speed of which is adjustable and controllable. The kinematic and dynamic models are established to determine the displacement of each actuator and calculate joint force, respectively. A combined motion law is then selected to reduce joint force during acceleration and deceleration stages. Furthermore, a superior control strategy that is able to precisely and smoothly control the segment erector at high speed is chosen by comparing the experimental performances of four different control strategies. Experiments are carried out on a segment erector test rig. The experimental results show exceptional performances of the speed and position compound control system in terms of accuracy and impact force. The maximum rotation speed of the new system can be increased to more than three times of that of the present erecting system. In addition, high steady-state accuracy can be achieved with the new system while its impact force is just about one-third of the position control system.

Force controlled contour following on unknown objects with an industrial robot

Abstract: This paper deals with controller features which improve force controlled contour following. This kind of robot force control may by used in surface finishing tasks like polishing, deburring or grinding. The already introduced proportional controller with positive position feedback brought very good results in force control of a position controlled robot in both impact and contact phase. If the characteristics of the environment which should be finished with the robot tool are not constant, unfavorable contact forces may occur which can damage the tool or the workpiece. For the purpose of adapting the current inclination angle between robot end-effector and environment we investigate the insertion of an additional integrator into the force controller. Thereby, it will be possible to reduce static control errors. However, more attention should be paid during its parameterization with respect to the stability boundary of the closed loop control. Another novel feature in this paper is the variation of the end-effector velocity as a function of the force control error. With this idea force peaks can be decreased or the loss of contact between robot end-effector and environment can be avoided, e.g. when the inclination angle of the environment changes. All algorithms proposed in this paper are successfully verified by practical experiments.

Three effective vectors-based current control scheme for four-switch three-phase trapezoidal brushless DC motor

Abstract: This study presents a novel three effective vectors (TEV) current control scheme for four-switch three-phase inverter in cost-effective brushless DC motor drive with improved performance. This scheme overcomes the possible distortion of three-phase currents caused by phase C back-EMF, and quasi-square current waveforms are attained by inserting two adjusting vectors in each control period based on the conventional switching modulation scheme. The duty cycles of the two adjusting vectors are further calculated using a simple P controller. Integral variable structure control principle with advantages of high bandwidth and strong robustness against external disturbance is used to control the tracing of reference current by actual currents. The stability of the proposed TEV current control scheme is demonstrated by selecting a candidate Lyapunov function, based on which the range of duty cycles of adjusting vectors are also determined. Experimental results verify that the proposed scheme is simple and can provide small current ripple, with good performance in speed.

Adaptive speed tracking control for autonomous land vehicles in all-terrain navigation: An experimental study

Abstract: This paper develops a nonparametric controller with an internal model control (IMC) structure for the longitudinal speed tracking control of autonomous land vehicles by designing a proportional and internal model control (IMC) cascade (P-IMC) controller. An IMC architecture is employed in the inner control loop by establishing a nonparametric longitudinal dynamical model, whereas a P controller is designed for the outer control loop. An approach for estimating the terrain effects and compensating for the model errors is also introduced. The differences from other nonparametric controllers are discussed, and the stability of the P-IMC controller is analyzed and validated experimentally. The P-IMC controller is compared with the SpAM+PI to illustrate its advantages. The experimental results of autonomous all-terrain driving show the effectiveness of the P-IMC controller. © 2013 Wiley Periodicals, Inc.

Closed-Form Critical Conditions of Subharmonic Oscillations for Buck Converters

Abstract: Based on a general critical condition of subharmonic oscillation in terms of the loop gain, many closed-form critical conditions for various control schemes in terms of converter parameters are derived. Some previously known critical conditions become special cases in the generalized framework. Given an arbitrary control scheme, a systematic procedure is proposed to derive the critical condition for that control scheme. Different control schemes share similar forms of critical conditions. For example, both V2 control and proportional voltage mode control have the same form of critical condition. A peculiar phenomenon in average current mode control where subharmonic oscillation occurs in a window value of pole can be explained by the derived critical condition. A ripple amplitude index to predict subharmonic oscillation proposed in the past research has limited application and is shown invalid for a converter with a large pole comparable to the switching frequency.

Clamping Force Control for an Electric Parking Brake System: Switched System Approach

Abstract: This paper addresses the modeling, controller design, and stability analysis of an electric parking brake system in which a screw-nut self-locking mechanism is used. The system is modeled as a state-dependent switched system according to the operating mode. A nonlinear proportional (P) clamping force controller using the measured force is proposed to enhance the performance specifications. We show the uniform stability of the state-dependent switched system with the nonlinear P controller using a common Lyapunov theorem and LaSalle's invariance principle. We derive the conditions to assure stable self-locking operation of the system. We also show the existence of the largest invariant set depending on the target braking force. This analysis offers a guideline as to how a nonlinear controller can be designed in view of the self-locking stability and control performance. Through simulation and experimental results, we confirm that the solution is locally uniformly ultimately bounded. Through the experimental results, we show that the nonlinear P controller outperforms a simple on/off controller in terms of the average and deviation of the braking force error. Furthermore, it is experimentally verified that the system is also able to function as a pseudo-antilock braking system.

Flight and wind tunnel tests of closed-loop active flow control

Abstract: Closed-loop active flow control is applied in wind-tunnel tests to an industry-relevant civil aircraft half-model designed by Airbus and in full-scale free-flight experiments with a Stemme S10 glider. The focus of this contribution is on closed-loop control. Moreover, it is shown that our approach can be used for very different setups. For this, the modeling of the dynamic responses of the two systems and the synthesis of robust controllers are compared. For the highly three-dimensional wind-tunnel model, differential pressures are used as surrogate control variables as a correlation with the lift can be described by a lookup table. Two control inputs, pulsed blowing, and two output variables are exploited. In the glider study, with a profile that experiences a mostly two-dimensional flow, an approximate pressure gradient is used instead as a single output to avoid the necessity of such a lookup table. Active flow control is done again, exploiting pulsed blowing. For the controller synthesis, both in the ...

Particle Swarm Optimization and Gradient Descent Methods for Optimization of PI Controller for AGC of Multi-area Thermal-Wind-Hydro Power Plants

Abstract: The automatic generation control (AGC) of three unequal interconnected Thermal, Wind and Hydro power plant has been designed with PI controller. Further computational intelligent technique Particle Swarm Optimization and conventional Gradient Descent technique have been used to improve the performance of Automatic Generation Control (AGC) system. The reheat turbine for thermal area and appropriate generation rate constraint (GRC) have been considered for thermal area. Particle swarm optimization (PSO) technique and Gradient Descent methods are used to simultaneously optimize the proportional gain (Kp), integral gains (Ki), speed regulation parameter (Ri) and frequency bias (Bi) parameter of different areas. Most of the literature for AGC used classical approach based on integral squared error (ISE) technique etc. for optimal selection of controller parameters. This is a trial and error method; extremely time consuming when several parameters have to be optimized simultaneously. The computational intelligence based technique like PSO is more efficient and fast technique for optimization of different gains in load frequency control. Further the performance of PSO is better than GD method for optimization of various parameters and the controller gives the improved dynamic performance for three area network with Thermal -- Wind-Hydro power plants. MATLAB/SIMULINK is used as a simulation tool.

Current-mode IPT system efficiency optimizing control circuit and method

Abstract: The invention discloses a voltage-mode IPT system efficiency optimizing control circuit and method. A primary-side control circuit comprises a primary-side voltage adjustment circuit, a high-frequency inverter circuit, a primary-side compensation circuit, a primary-side coil, a primary-side current detection module, a primary side and secondary side current ratio controller and a primary-side coil constant-current control module. A secondary-side control circuit comprises a secondary-side coil, a secondary-side compensation circuit, a rectification and filter circuit, a secondary-side voltage adjustment circuit, a secondary-side current detection module and a secondary-side constant-voltage control module. The voltage-mode IPT system efficiency optimizing control circuit has the advantages that the relationship between the primary side and secondary side current ratio and system transmission efficiency is fully utilized, and the primary side and secondary side current ratio control idea is adopted for achieving the optimization of system efficiency; the voltage-mode IPT system efficiency optimizing control circuit is simple in structure and convenient to use; on the premise that secondary-side output voltage is stable, the voltage-mode IPT system efficiency optimizing control circuit ensures that the system achieves maximum-efficiency output within a wide load range through primary side and secondary side current and voltage detection and the adoption of a multi-path proportional controller,.

Closed-loop control of single phase selective harmonic elimination PWM inverter using proportional-resonant controller

Abstract: This paper deals with the application of the selective harmonic elimination technique of a closed-loop control scheme of single-phase PWM inverter employing proportional resonant controller. Selective harmonics elimination (SHE) technique is used to eliminate low order harmonics with relatively low inverter switching frequency. The major challenge which faces this technique is solving large numbers of nonlinear transcendental equations at each modulation index to generate the power inverter switching patterns. Proportional resonant controller is employed to reduce both magnitude and phase errors of the load voltage. Simulation of the proposed system is reported. The simulation results show that this system is capable of producing load voltage with low total harmonic distortion (THD).

Algorithm for three-dimensional control of needle steering via duty-cycled rotation

Abstract: Proportional control of curvature of a flexible bevel-tipped needle can be accomplished by rotating the needle shaft with a duty cycle Using this technique, an algorithm for image-guided path-following control in two dimensions, based on an autonomous vehicle controller, has been previously demonstrated This paper describes a computationally simple algorithm that extends the path-following control to three dimensions Results from simulation are presented

Study on Improved Fuzzy Immune PID Controller for Maglev Transportation System with Track Irregularity

Abstract: Track irregularity is one of the most important aspects of the suspension control performance impact in maglev transportation system (MTS). Due to the track irregularity phenomenon of suspension system, the Fuzzy PID(F-PID) control is unable to accurately track irregularity of track changes. Based on the qualitative analysis to MTS, through modifying conventional F-PID controller, the article establishes Fuzzy Immune PID(FI-PID) Controller based on the biological immune system theory. The control strategy designed nonlinear P controller, using the immune algorithm of on-line adjustment of P and the fuzzy control approximating the nonlinear function of the immune P control parameters and the fuzzy control designed the ID controller for adjusting the parameters of I and D for enhancing the robust performance of the suspension system and adapting to the change of track irregularity. Simulation results show that the FI-PID control is confirmed more effectively to realize tracking compared with F-PID, faster response speed, more simple structure, easier operation for the track interference and load disturbance of the suspension system. This provides a very good way to solve the interference problem of orbit of the maglev transportation system.

Energy efficiency of a hydrostatic drive with proportional control compared with volumetric control

Abstract: There are uninvestigated areas connected with behaviour of elements in hydraulic systems with different structures. Unawareness of proportions of the energy, volumetric, pressure and mechanical losses in elements is often the case. Problems connected with energy efficiency are essential for improvement of functionality and quality of hydrostatic drive systems, characterised by unquestioned advantages but also by relatively low efficiency in comparison with other types of drive. Energy efficiency of hydrostatic transmissions, particularly those with throttling control of the motor speed, and also efficiency of the hydraulic servo-mechanism systems may be in fact higher than the values most often quoted in publications on the subject. Possibility of calculating the real value of the hydraulic system overall efficiency as a function of many parameters influencing it, becomes a tool of complete evaluation of the designed system quality. The paper compares efficiencies of systems with cylinder proportional control and efficiency of the system volumetric control by a variable capacity pump. Presented are also two schematic diagrams of the investigated hydrostatic systems, their principle of operation and problems of studying losses in elements and energy efficiency of systems consisting of a feed assembly, control set and cylinder.

MEMS-based state feedback control of multi-body hydraulic manipulator

Abstract: This paper presents closed-loop state feedback motion control of a heavy-duty hydraulic manipulator using solely micro-electro-mechanical systems (MEMS) rate gyroscopes and linear accelerometers for joint angular position, velocity and acceleration feedback. For benchmarking, incremental encoders with 2 million counts per revolution are also used to supply the joint motion state feedback. The two motion state estimation methods are compared using Cartesian path trajectory closed-loop control experiments with both position feedback-based proportional control and motion state-based feedback control. The experiments show that the proposed MEMS-based state feedback control yields comparable tracking results compared with the high accuracy encoder. Furthermore, the MEMS-based angular acceleration estimation in particular is free from typical differentiation induced noise amplification and post-filtering phase-lag.

A Proportional Resonator-based control scheme to suppress AC components in circulating current of Modulator Multilevel Converter

Abstract: The Modular Multilevel Converter (MMC) is an emerging topology in the line of multilevel converters for high and medium voltage applications. This paper proposes the control technique to tackle the pressing issue of ac component in circulating current. By an additional minor loop having Proportional Resonator controller for suppresing ac components in circulating current to zero. With PR control it is also now possible to introduce the output current control. This paper also presents application of antiwind up control with PR to avoid problems like windup or rollover arise in working under saturation or sustained error input. This control can be applied to single phase also as opposed to methods discussed previously. Simulation results are been provided for 3 phase grid connected system, using circulating current control and tracking of output current to be given as feedback signal.

Proportional control hydraulic valve structure

Abstract: The invention provides an engine proportional control hydraulic valve structure applicable to the field of automobile engines A spring (1) and a spool (4) are sequentially arranged in a valve body (3) of a hydraulic valve, a plurality of oil holes (12) are formed on the valve body (3), a coil assembly (10), a front magnetic pole (7) and a magnetic core assembly (8) are arranged in a housing (9), the front magnetic pole (7) and the housing (9 ) are in an attaching structure, and the coil assembly (10) is connected with a control member (35) According to the proportional control hydraulic valve structure, the response speed and the reliability of a solenoid valve are improved, and the applicability of the proportional control solenoid valve is wide The proportional control hydraulic valve structure can be simultaneously mounted in an engine cylinder head with a peripherally uniformly-distributed oil-way structure by replacing the front valve body portion

Sensorless V/f control with MRAS speed estimator for a five-phase induction machine under open-circuit phase faults

Abstract: This paper introduces a sensorless scalar controller with MRAS speed estimator based on simple Proportional Resonant PR controllers to provide a disturbance-free operation to a five-phase induction machine under phase open and based on optimal current control The machine speed is estimated using MRAS observer based on rotor flux (RF-MRAS) Under open phase, the torque-producing fundamental sequence current is used to estimate the required third sequence current components to ensure equal remaining healthy currents Two PR controllers are then used to determine the corresponding third sequence voltage components The used optimization criterion ensures maximum fundamental torque, minimum torque ripples, and equal line currents The proposed controller is verified using a 15hp prototype machine for both dynamic and steady-state cases

Combined active damping with adaptive current control for converters with LCL filters

Abstract: This paper proposes a grid side current control technique for Pulse Width Modulated converters connected to the grid through LCL filters. The system is modeled in order to allow the implementation of a multi-loop control strategy. The inner loop is designed for active damping using the classical approach of feeding back the capacitor voltage or current to implement a Proportional plus Derivative or a Proportional controller, respectively. The outer loop is designed for the compensation of parametric uncertainties and disturbances by means of a Model Reference Adaptive Controller. The adaptive behavior allows to easily design the outer controller despite de presence of the inner one.

Static and Dynamic Characteristic Simulation of Feed System Driven by Linear Motor in High Speed Computer Numerical Control Lathe

Abstract: In order to design the feed system of high speed Computer Numerical Control (CNC) lathe, the static and dynamic characteristics of feed system driven by linear motor in high speed CNC lathe were analyzed. The slide board was taking as the main moving part of the feed system, and the guide rail was the main support component of the linear motor feed system. The mechanical structure static stiffness of feed system is researched through the slide board statics analysis. The simulation results show that the maximum deformation of the slide board occurs in the middle of the slide board where the linear motor is placed. The linear motor feed system control model was established based on analysis of high-speed linear feed system control principle, and the linear motor feed system transfer function was established, and servo dynamic stiffness factors were analyzed. The control parameters of the servo system and actuating mechanism parameters of feed system on the effect of the linear motor servo dynamic stiffness were analyzed using MATLAB software. The simulation results show that the position loop proportional gain, speed loop proportional gain and speed loop integral response time are the biggest influence factors on servo dynamic stiffness. The displacement response is reduced under the cutting interference force step inputting, the servo dynamic stiffness is increased, the number of system oscillation is also reduced, and the system tends to be stable. DOI: http://dx.doi.org/10.11591/telkomnika.v11i7.2813 Full Text: PDF

Mechanism for synchronized motion between two humans in mutual tapping experiments: Transition from alternative mode to synchronization mode

Abstract: We performed mutual tapping experiments between two humans to investigate the conditions required for synchronized motion. A transition from an alternative mode to a synchronization mode was discovered under the same conditions as when a subject changed from a reactive mode to an anticipation mode in single tapping experiments. The experimental results suggest that the cycle time for each tapping motion is tuned by a proportional control that is based on synchronization errors and cycle time errors. As the tapping frequency increases, a mathematical model based on feedback control in the sensory-motor closed loop predicts a discrete transition of the mode as the gain factors of the proportional control decrease. The conditions for synchronization are shown as a consequence of the coupled dynamics based on the next feedback loop in the sensory-motor system.