Master Motor Research Articles

Position Tracking for Multi-Channel Double-Crystal Monochromator Scanning Based on Iterative Learning Control

As a core component of the X-ray absorption fine structure spectroscopy (XAFS) system, the multi-channel double-crystal monochromator (DCM) can improve the time resolution of the system significantly. In contrast to the conventional single-channel DCM, the multi-channel DCM includes more pairs of crystals that are located separately in the master and slave motor axis with the same driving direction. However, a mismatched parallelism in the pitch direction, which can result from the manual mounting operation between the two separated crystals, directly affects the performance of the flux and the angular stability of the monochromatic beam. This poses a significant challenge to the precision position tracking of this system. In this paper, the mounting errors were translated into repetitive errors in the slave motor when the master motor was rotated at a constant velocity. Therefore, the iterative learning control (ILC) was considered in order to improve the tracking accuracy of the slave motor motion. The zero-magnitude error controller (ZMETC) was used to calculate the learning function to accelerate the convergence of the control inputs, and the convergence conditions of the control signal and error were also given. To validate the effectiveness of the proposed method, comparative experiments were performed on the motor motion platform. Experimental results indicated that the ILC effectively decreased the parallelism errors of the multi-channel DCM under various trajectories by comparing them with feedback controllers and the ZMETC, respectively.

Double machine vibration synchronization system based on GA-PID

Aiming at the problem that it is difficult to realize the synchronization of motor speed under the electromechanical coupling condition of DC motor and vibrating mass in double machine drive vibration system, the PID parameters of DC motor are optimized by using master-slave control mode and genetic algorithm. Firstly, the electromechanical coupling model of the vibration system is established, and the differential equation of motion of the system is obtained by using Lagrange equation; Using master-slave control structure and genetic PID control algorithm, a controller based on master motor speed difference and slave motor phase difference is designed; The MATLAB/Simulink simulation model is established to verify the effectiveness of the control system. The experimental results show that the genetic PID algorithm based on master-slave control structure can better realize the synchronous control of dual machine driven vibration system. The research content can provide a theoretical basis for the design, control and application of this type of vibration system.

Design of Sliding-Mode Speed Controller With Active Damping Control for Single-Inverter Dual-PMSM Drive Systems

In this article, a novel sliding mode speed controller is proposed for the parallel operation of dual permanent magnet synchronous motors (PMSMs) with a single inverter. For this operation, the vector control method is applied to the master motor drive and the open-loop control mode is employed for the slave one. If the load torques of two motors are different, oscillations in the speed of the slave motor will occur due to the difference in the rotor positions. Therefore, a damping control that can suppress these oscillations is required for the stable operation. The proposed controller consists of a speed controller for the master PMSM and a damping controller for the stable operation of two motors, designed based on sliding-mode control theory. With this nonlinear controller, robust control performance can be obtained for parameter mismatch of two motors. The feasibility of the proposed control scheme has been verified by simulation and experimental results.

Phase Synchronization Control of Two Eccentric Rotors in the Vibration System with Asymmetric Structure Using Discrete‐Time Sliding Mode Control

Control synchronization of two eccentric rotors (ERs) in the vibration system with the asymmetric structure is studied to make the vibration system obtain the maximum excited resultant force and the driven power. Because this vibration system is essentially an underactuated system, a decoupling strategy for the control goal of the same phase motion between two ERs is proposed to reduce the order of state equation of the vibration system. According to the master‐slave control scheme, the complex control objects are converted into the velocity control of the master motor and the phase control of the slave motor. Considering the self‐adjusting of the vibration system as interference, controllers of the velocity and the phase difference are designed by applying the discrete‐time sliding mode control, which is proved by Lyapunov theory. A vibration machine is designed for evaluating the performance of the proposed controllers. Two control schemes are presented: controlling one motor and controlling two motors, and two group experiments are achieved to investigate the dynamic coupling characteristic of the vibration system in the state of control synchronization. The experimental results show that control synchronization is an effective and feasible technology to remove the limitation of vibration synchronization.

Novel Design of Master Manipulator for Robotic Catheter System

This paper presents a new master manipulator applied to robotic systems for arrhythmia ablation. The manipulator is designed to implement the concept of two different master-slave teleoperation controls in the clinical application. One is the conventional control between the master and catheter-handle in the slave site and the other is catheter tip manipulation corresponding the master motion. For the purpose, the master has six degrees of freedom (DOF) and consists of three main components: a spherical mechanism for rotational motion of 2-DOF, 3-RRR planar parallel mechanism with 3-DOF, and counter-weight lifting mechanism for the vertical movement. Two mechanisms except the lifting mechanism are parallel chains and structurally more complicated. Therefore, their forward kinematics are analyzed, and workspaces are simulated. To evaluate the applicability for robotic catheter systems, the manipulator prototype was tested for its smoothness, workspace, and teleoperation performance. The subjects in the smoothness test reported no considerable friction and jerk in free movement in the three-dimensional space as shown in the recorded curves. The workspace test shows the actual workspace is similar to the simulated one except some structural constraints in the 3-RRR mechanism. For the last test, a robotic catheter teleoperation system with a slave robot and the software structure for the robotic catheter control system with electrical connection of each component were built. The result performed by five different users shows the motion of the slave robot well tracks that of the master device with small average errors and time delay that are acceptable in robotic catheter teleoperation systems.

Robust Cooperative Positioning Control of Composite Nested Linear Switched Reluctance Machines With Network-Induced Time Delays

This paper addresses the robust cooperative positioning control for the networked composite nested linear switched reluctance machines (LSRMs) with network-induced sensor-to-controller and controller-to-actuator time delays and uncertain motor parameters. In complex industrial processes, considering the spatio-temporal cooperative nested movement relationship of a master motor and a slave motor nested on the master one, and the inevitable motor parameters identification errors, the robust cooperative positioning control method is proposed based on the networked control method. In order to realize long distance movement and complementary close movement for industrial requirements, the composite nested LSRMs over communication networks are modeled as a Markov time-delay system with the motor parameters uncertainties. The stability conditions and the robust positioning controller design method for the composite nested LSRMs are obtained by using Lyapunov theory and the inequality technique. Several groups of experimental tests are presented to verify the effectiveness and practicability of the proposed robust cooperative positioning control method for the networked composite nested LSRM control systems.

Master-Slave Control of an Intention-Actuated Exoskeletal Robot for Locomotion and Lower Extremity Rehabilitation

In this paper, a master-slave control system is proposed and applied in an intention-actuated exoskeletal robot to assist user locomotion and lower extremity rehabilitation simultaneously. In particular, to increase users’ sense of participation, the motion of the exoskeleton and the wheelchair, which is denoted as slave motion in this study, is actuated by the user’s intention, which is denoted as master motion and thus makes patients feel that they are moving the wheelchair. This master-slave motion control system can help to eliminate patients’ fear of medical apparatus and instruments. The bicycling motion actuated by one motor is implemented to realize the rehabilitation motion exercise. Experimental results validate a position-force control strategy for the exoskeleton motors, and show that the proposed method can help users to move around and to exercise their legs simultaneously and effectively.

The Study of Parallel Synchronous Operation in Permanent Linear Synchronous Motor

In recently, permanent magnet type linear motors (PM-LSM) which could control high speed have attracted attention in the industrial field. Our laboratory is focusing on conveyance system. In the loading and unloading of the luggage of the transport system, the mover to move repeatedly to "stop-and-go". This operation occurs each time to move the respective processing sections. This work leads to a reduction of transport efficiency. Therefore, we propose parallel synchronous drive. This method synchronizes the mover of the two LSMs. Because both movers in the synchronized state are the same inertia, luggage may be moved without the movers stop. Main line of the motor called “master motor” and another motor called “slave motor”. The master motor’s position is passed Slave motor and parallel synchronous drive is run. This paper reports a parallel synchronous drive method for transportation system of PM-LSM.

Power Balance of Starting Process for Pipe Belt Conveyor Based on Master-Slave Control

An output power imbalance usually occurs in the driving motor of pipe belt conveyor due to the load disturbance and a variety of environmental interferences. This paper focuses on the operating condition of pipe belt conveyor where the head and tail with inclined angle are equipped with a motor separately. The discrete element method is used to propose a discrete model of the pipe belt conveyor, and its simulation model is established in the AMESim. According to the direct torque control method for the three-phase asynchronous motor, the principles for controlling the balance of dual-motor power are analyzed. A master-slave control strategy is proposed, where the master motor is controlled using a speed-given strategy and the slave motor is controlled using a torque-given strategy. A simulation model is built for the dual-motor driven system in the MATLAB-Simulink. After establishing a correlation between parameters through VS2010, a joint simulation model was established for the control system of the pipe belt conveyor. Simulation analysis and field test of the starting process are performed. Results of comparison with the traditional master-slave control strategy demonstrate the ability of the proposed method to balance the master-slave motor power of the pipe belt conveyor more effectively.

The Design of Multi-Motor Synchronous Monitoring System Based on IOT

In order to improve the quality of network monitoring, the monitoring design of the multi-motor synchronization control system based on IOT was present. In the paper IOT technology was adopted. The server part was completed on PC. And the client system was implemented on Android smart phone platform. And the motor control parameters were saved in text mode. Various parameters of multi motor synchronous system were monitored in text and graphics on Android smart phone. The parameter changes of the master motor speed and the tension were monitored on-line and shown in data curve mode. Users could browse in real time by mobile phone. Users could use manual / automatic two control methods to implement real-time control on the system. The communication parameters were stored in SQLite database. Socket network communication based on message notification was used in the system. More and more experiments showed that: The monitoring system was cost-effective, and good real-time performance. And the same time the system was quickly, low demand on the network, and easy to use.

Multiple‐Frequency Controlled Synchronization of Two Homodromy Eccentric Rotors in a Vibratory System

Multifrequency controlled synchronization of two homodromy eccentric rotors is investigated. The vibrating screen with two rotors is a typical underactuated system. So, the model of the vibrating screen is converted to a synchronization motion problem. Firstly, the mechanical‐electromagnetic coupling dynamical model of the vibrating system is established. And then the fuzzy PID method is used for the two motors which are based on the master‐slave control strategy. The slave motor uses the method of the phase ratio to trace the master motor and achieve the synchronous motion. Through the simulation, the two rotors cannot reach the state of multifrequency self‐synchronization. And, then, it is realized by multifrequency controlled synchronization. The article presents the motion trails of the vibrating system between one and two times and realizes the zero phase difference after each period. Finally, some experiments are used to verify the accuracy and effectiveness of the conclusion in the simulation and analysis of the feature of the movement tracks.

Position domain nonlinear PD control for contour tracking of robotic manipulator

Abstract Contouring control is most important in machining applications to ensure the quality of the final product. In this paper, the contouring control problem for a multi-dof robotic manipulator is studied, and a nonlinear PD (NPD) control law is proposed in position domain and applied to contour tracking control. To develop the position domain control system, the robotic motions are viewed as the combination of a master motion, controlled in time domain, and slave motions controlled in position domain. The master motion is used as a reference for the slave motions, and the slave motions are controlled by the developed NPD and synchronized with the master motion so that a good contour tracking performance can be achieved. Stability analysis is conducted based on the Lyapunov theory for the developed position domain NPD control. Linear and nonlinear contour tracking problems are simulated and compared with existed PD controllers. It is demonstrated that the position domain NPD control can achieve much better contour tracking performance compared with the counterparts in time domain and the linear PD-type position domain control. Furthermore, the proposed NPD controller is much efficient for nonlinear contour tracking problems.

Unifying Representations and Large-Scale Whole-Body Motion Databases for Studying Human Motion

Large-scale human motion databases are key for research questions ranging from human motion analysis and synthesis, biomechanics of human motion, data-driven learning of motion primitives, and rehabilitation robotics to the design of humanoid robots and wearable robots such as exoskeletons. In this paper we present a large-scale database of whole-body human motion with methods and tools, which allows a unifying representation of captured human motion, and efficient search in the database, as well as the transfer of subject-specific motions to robots with different embodiments. To this end, captured subject-specific motion is normalized regarding the subject's height and weight by using a reference kinematics and dynamics model of the human body, the master motor map (MMM). In contrast with previous approaches and human motion databases, the motion data in our database consider not only the motions of the human subject but the position and motion of objects with which the subject is interacting as well. In addition to the description of the MMM reference model, we present procedures and techniques for the systematic recording, labeling, and organization of human motion capture data, object motions as well as the subject–object relations. To allow efficient search for certain motion types in the database, motion recordings are manually annotated with motion description tags organized in a tree structure. We demonstrate the transfer of human motion to humanoid robots and provide several examples of motion analysis using the database.

直列接続型マスタ・スレーブアクチュエータの力覚可変の一方法（機械構成品の変更をせず力の比率を変更する方法）

In recent years, surgical robots have come into wider use. These robots do not yet provide a force sense to the surgeon, but such force sense will be necessary on the next generation of surgical robots. When the slave motor needs to generate a larger or smaller driving force than the master motor, mechanical gearing is normally used. This leads to large mechanical losses. A small force sensed at the slave cannot be transmitted back to the master. We have proposed a master-slave system of the series connection type that generates a force sense using conventional bilateral control. However, when linking together motors of different output power, the allowable current of the small power output motor is insufficient to drive the large power output motor. We now propose a method that combines a motor with a shunt resistor. If a resistor is connected to a motor in parallel, the allowable circuit current increases, removing the current limitation and increasing the circuit current. This approach also allows the variable force to be sensed by changing the shunt resistor. We experimentally confirmed the effectiveness of the proposed method. In this paper, the principles of using a shunt resistor for changing the force sense are explained, and our experimental results are presented.

Parallel Sensorless Speed Control using Flux-axis Current for Dual SPMSMs Fed by a Single Inverter

This paper proposes a sensorless speed control algorithm for parallel-connected dual Surface-mounted Permanent Magnet Synchronous Motors (SPMSMs) fed by a single inverter. For stable parallel operation of synchronous motors with a single inverter, each motor has to be constantly kept in the synchronization state regardless of load torque. If the master motor with the larger load is controlled, the synchronous state will be maintained. Therefore, detection of the master motor is essential. Conventionally, the master motor is determined by comparing the rotor position error from the relation between the back-EMF for torque angle and the flux position; consequently, the position sensor is deemed essential for finding the rotor position. The parallel sensorless speed control method proposed in this paper uses no position sensor, instead it compares the flux-axis current from the connection between the back-EMF for torque angle and current in unbalanced load conditions. The results of simulation and experiment conducted verify the efficacy of the proposed method.

Research on Power Balance Control of Multi-Motor Driving Belt Conveyor System Based on Controlled Transmission Device

According to the existing problems of driving equipment for belt conveyor, a novel design scheme of controlled transmission which uses hydraulic transmission system driving worm gear to control the output speed of planetary gear mechanism is proposed. The control strategy of multi-motor drive power balance which adopts master-slave structure is designed. The master driver adopts speed closed-loop control with current limiting and the slave drivers adopt power closed-loop control. The given power signal of slave pulley is decided by the master motor. The control system offers multiple communication interfaces which enable the belt conveyor to integrate in coal mine information platform and realize information resource sharing. The controlled transmission device and its power balance control system have characteristics of compact, reliable and high efficiency.

Speed Synchronization System of Master-Slave Motor Based on Repetitive Control

In the wrapping process of magnet wire, as the haulage speed of master motor varies periodically, it is difficult for slave wrapping motor to track master motor due to the mechanical resonance, which destabilizes the wrapping pitch. In the proposed system, the synchronization speed control scheme of master-slave motor based on repetitive control compensation is employed. In the process of control, real-time spectrum analysis of the haulage speed is given, which can be used to adjust the parameters of wrapping speed controller adaptively with the acquired characteristic information of the mechanical resonant. Simulation shows that wrapping speed can track haulage speed well in the proposed system, and the maximum tracking synchronous deviation can be reduced to 56% of that in the system without repetitive control.

The Research of Servo Motor Control Strategies for the Mobile Gantry Milling Machine

It is known for the traditional milling machine in operation at low speed and efficiency. This paper describes the research of servo motor control strategies for the mobile gantry milling machine. The principles of AC servo motor dynamics, master-slave servo control, and adaptive-neuro fuzzy inference system based on controller are illustrated. Using these strategies when the master servo motor is interference by the external signal, the reference speed of the slave servo motor can follow just like the master motor. Finally the mechanical coupling can be eliminated and the mechanical damage can be avoided.

Synchronous Controller for Dual Servo Motor in Servo Press

This study shows the results of double servomotors synchronization controller (SC) for Mirco-precision servo press. Two systems are used in this study, one is the master motor and another is the slave motor. Each system is designed separately. Also, it is necessary to use the synchronous controller to minimize the synchronization error and the motion command is transmitted simultaneously to two motors. The control system for the master motor includes a feedback controller (FB) and a zero phase error tracking controller (ZPET). For the slave motor, only velocity is controlled. The feedback controller is a cascade control structure, velocity and position controller. It can make the output follows the command. In order to reduce synchronized motion error, two servomotors are synchronized by the SC. The results of simulation reveal that the performance of the overall control system is improved compare to open loop, the synchronous position error between two sliders were less than 4μmm.

Positioning system with backlash compensation by twin motor cooperative control (Evaluation of rectilinear motion mechanism installed planetary gear speed reducer)

Backlash occurs in gear drive systems that are used with machine tools and transport mechanisms. The problem with backlash is that it reduces positioning accuracy and tends to cause vibrations. In this paper, a twin-motor drive method that compensates for backlash by master-slave control is adopted. In full-closed loop control of master motor, the position is controlled by using a linear scale mounted externally which detects the machine position directly and feeds it back, whereas in semi-closed loop control of slave motor, the position is determined by using a rotary encoder mounted inside the motor which detects the motor position directly and feeds it back. An integral control factor on the master motor is required to minimized positioning errors when using a combination of semi-closed loop control (slave motor) and full-closed loop control (master motor), and a P ( proportional ) control system without I ( integral ) control factor neither on position nor velocity control is adopted as the slave motor's semi-closed loop control system, allowing the slave motor for a follow-up control after the master motor and to compensate for and eliminate mechanical backlash. We confirmed the effectiveness of this control method by simulation and experiment. Slave motor locates itself and master motor into final position by automatically adjusting the gap between itself and the master motor. At final positioning, the phase between main motor and slave motor is automatically controlled to compensate for the backlash upon positioning. It is shown that this method improves the positioning accuracy of the system.