DC Servo Research Articles

A 1.8 $\mu$W 60 nV$/\surd$Hz Capacitively-Coupled Chopper Instrumentation Amplifier in 65 nm CMOS for Wireless Sensor Nodes

This paper presents a low-power precision instrumentation amplifier intended for use in wireless sensor nodes. It employs a capacitively-coupled chopper topology to achieve a rail-to-rail input common-mode range as well as high power efficiency. A positive feedback loop is employed to boost its input impedance, while a ripple reduction loop suppresses the chopping ripple. To facilitate bio-potential sensing, an optional DC servo loop may be employed to suppress electrode offset. The IA achieves 1 μV offset, 0.16% gain inaccuracy, 134 dB CMRR, 120 dB PSRR and a noise efficiency factor of 3.3. The instrumentation amplifier was implemented in a 65 nm CMOS technology. It occupies only 0.1 mm2 chip area (0.2 mm2 with the DC servo loop) and consumes 1.8 μA current (2.1 μA with the DC servo loop) from a 1 V supply.

Identification and control using MLP, Elman, NARXSP and radial basis function networks: a comparative analysis

This paper describes four neural networks multilayer perceptron (MLP) network, Elman network, NARXSP network and radial basis function (RBF) network. Neural networks are applied for identification and control of DC servo motor and benchmark nonlinear system. Number of epochs required and time taken to train the controller are shown in the form of bar plots for four neural networks. Levenberg-Marquardt algorithm is used for training the controller using neural network toolbox in MATLAB. Each neural network controller is run ten times. Their performances are compared for each run in terms of number of epochs required and time taken to train each controller for tracking a reference trajectory.

Design and experimental validation of UDE based controller--observer structure for robust input--output linearisation

In this work, uncertainty and disturbance estimation (UDE) technique is employed to robustify an input--output linearisation (IOL) controller. An IOL controller designed for a nominal system is augmented by the UDE estimated uncertainties to achieve robustness. In doing so, state dependent nonlinearities of the system are treated as a part of the uncertainties and thus, the controller does not require system states for its implementation. The resulting controller, however, needs derivatives of the output. To address the issue, a design of an observer that employs the UDE estimated uncertainties for robustness is proposed giving rise to the UDE based controller--observer structure. Closed loop stability of the overall system is established. The notable feature of the proposed design is that it neither requires accurate plant model nor system states or derivatives of output. Also the approach does not need any information about the uncertainty. To demonstrate the effectiveness, numerical simulation results of the proposed approach as applied to the wing-rock motion control problem are presented. Lastly, hardware implementation of the UDE based controller-observer structure for motion control of Quanser's DC servo motion control platform is carried out and it is shown that the proposed strategy offers a viable approach for designing implementable robust IOL controllers.

Control Algorithm Study for some Optical Tracking Measurement System with Low Mechanical Resonance Frequency

For some optical tracking measurement systems, because their size, weight and space structure are very strict restrictions, DC servo motors have to drive the loads through the several stages of gear transmission. For such a nonlinear controlled object, it is difficult to obtain acceptable control performance applying the traditional controller design method. In the paper, firstly, establish such a non-linear system dynamic model, and consider intelligent control algorithm to inhibit mechanical resonance effect for the control system performance. In order to achieve real-time control easily, the paper suggests a fuzzy numeric model with the self-regulating factor based on analytic expression for such a non-linear system. The result demonstrates that the fuzzy controller is very effective in applications. This work provides a new thought for a controller design to inhibit the low mechanical resonance frequency.

Genetic Algorithms: Concepts, Design for Optimization of Process Controllers

Genetic Algorithm is a search heuristic that mimics the process of evaluation. Genetic Algorithms can be applied to process controllers for their optimization using natural operators. This paper discusses the concept and design procedure of Genetic Algorithm as an optimization tool. Further, this paper explores the well established methodologies of the literature to realize the workability and applicability of genetic algorithms for process control applications. Genetic Algorithms are applied to direct torque control of induction motor drive, speed control of gas turbine, speed control of DC servo motor for the optimization of control parameters in this work. The simulations were carried out in simulink package of MATLAB. The simulation results show better optimization of hybrid genetic algorithm controllers than fuzzy standalone and conventional controllers.

2A2-L05 SMAアクチュエータを用いた蠕動運動による管内移動ロボット(特殊移動ロボット)

There are many various movements in the natural world. Peristalsis motion like an earthworm is useful to progress in any confined spaces. In this study, our purpose is development of earthworm robot which is useful to progress in the narrow pipe. An actuator of the earthworm robot was BioMetal Fiber (BMF series) which is one of the shape memory alloys. BMF, elongated at room temperature, becomes stiff and sharply contract when a current is fed through it. The mechanism of using BMF is lighter and smaller than any other mechanisms, such as DC motor, servo motor and air pressure.

The Design of Two-Wheel Mobile Platform Using Digital DC Servo Motor Based on CompactRIO

This paper describes some main design methods of the mechatronics system and control system of the self-balancing two-wheel mobile platform based on a CompactRIO embedded controller, two digital DC servo motors with two odometry encoders, etc. We use mechatronics-oriented virtual prototyping tools to design the mechatronics system using SolidWorks and LabVIEW. And we use fuzzy controller to control this mobile platform. Through several experiments of self-balancing, linear running, it was confirmed that the mobile platform could realize stable mobile motion in a flat surface environment by the fuzzy controller. Using these methods, we have designed a two-wheel mobile platform to keep itself balancing in order to carry something from someplace to another in the future. The two-wheel mobile platform has been manufactured successfully by CIMS & Robotics Center of Shanghai University. The self-balancing control software and the other software have been developed.

Design of a universal robot controller

The paper deals with a general purpose industrial robot controller. Due to the modules of the system is universal. It can be connected to several types of robots, even to CNC, turning-mill or other machines. It was connected to an Adept Scara robot successfully,experimental results will be presented. The basic element of the system is the EMC2 open source robot controller program, which runs in a realtime linux kernel. A PCI card creates the high speed connection between the EMC2 and the machine. DC servo amplifier, digital input and output module, teach pendant, and power electronics designed for the system. The system is RT-middleware (Robotics Technology Middleware)compatible. The RT-middleware is a common robot control platform, which can easily connect different robots to the same network for a common work.

MCU-Based Detection and Control System Design of a Kernel Hardness Tester

A novel kernel hardness tester was introduced in the paper, and the detection and control system was studied in detail. The stylus of the tester is forced into grain which placed in a container. The force which was acquired by a load cell and the displacement of the stylus which was measured by an optical encoder were used as a new hardness index. The core microcontroller unit (MCU) applied in the paper is STC89C52 to accomplish the data acquisition and the position control of a DC servo motor.

Multimedia Educational Material and Remote Laboratory for Sliding Mode Control Measurements

The paper presents a multimedia educational program of DC servo drives for distant learning with a special emphasis on sliding mode control. The program contains of three parts: animation, simulation and internet based measurement. The animation program explains the operation of DC motors, gives its time- and frequency-domain equations, transfer functions and the theoretical background necessary for controller design for DC servo motors. The simulation model of the DC servo motor and the controller can be designed by the students based on the animation program. The students can also test their controllers through the internet based measurement, which is the most important part from engineering point of view. After the measurements are executed, the students can download the measured data and compare them to the simulation results.

Servo Control Education Tool for Industrial Applications

In this study, a training set consisting of servo motors is designed to assist development of the students, especially who are in electrical, electronics and mechanical engineering, in industrial field. For this training set; three AC servo motors and one DC servo motor are used and four-axis control mechanism is generated. In order to control servo motors a special driving circuit is developed through which position and speed is controlled. These controls can be managed either via operating panel (touch panel) or via computer depending on user’s purpose. In addition, a local network based training software is developed, which involves theoretical information regarding servo motors and allows testing opportunity and observing animations. Thus, a practical, functional and also economical training set allowing students both to learn and to perform many applications that they might be introduced with industrial field is developed.

Position control of a dual-stage actuator

This paper describes the position control of a dual-stage actuator with piezoelectric actuator using self-sensing actuation. The dual-stage servo system consists of a coarse actuator and a fine actuator. A DC servo motor is used as the coarse actuator, and a piezoelectric actuator provides fine control. The position control of the dual-stage actuator us ing the dual feedback method and self-sensing is presented. Experimental results show the validity of the proposed control system

Control of an Embedded System via Internet

This paper presents our experience with a complete multimedia educational program of dc servo drives for distant learning. The program contains three parts: animation, simulation, and Internet-based measurement. The animation program helps to understand the operation of dc motors as well as its time- and frequency-domain equations, transfer functions, and the theoretical background necessary to design a controller for dc servo motors. The simulation model of the dc servo motor and the controller can be designed by the students based on the animation program. The students can also test their controllers through the Internet-based measurement, which is the most important part from an engineering point of view. Students can then perform various exercises such as programming the D/A and A/D cards in the embedded system and designing different types of controllers. First, a simple PI controller can be designed, but advanced students can also design more sophisticated controllers such as the sliding mode controller. After the measurements are executed, the students can download the measured data and compare them to the simulation results.

모델기반 설계를 이용한 이륜 도립진자 로봇의 임베디드 제어시스템

In this paper, embedded control system of segway robot using model based design is presented. Design of control program in embedded system can be implemented simply and easily by model based design method using MATLAB/SIMULINK. Segway robot is consisted of a NXT Mindstorms controller, two DC servo motors, a ultrasonic sensor, a gyro sensor, and a light sensor. It is a unstable nonlinear system and has a control problem of body pitch angle. So controller of segway robot is designed using state feedback LQR control. It is confirmed through design and experiment of controller that the model based design method, that is not depend on target processor, has merits compared with the text based design in aspects such as a program development, an error detection/modify, and an insight of software structure.

Optimal Design of the Fuzzy Sliding Mode Control for a DC Servo Drive

A new controller for the optimal speed control of a DC drive is presented in this paper. The controller employs a variant of fuzzy sliding mode, optimized by a genetic algorithm. Proposed controller has many advantages, such as satisfactory control performance under a wide range of operating conditions, a faster response than conventional controllers and suppressed chattering phenomenon. The simulations, experimental results, and comparative analysis verify the efficiency, excellent performance, and robustness of such a control in the case of a DC servomotor.

Sliding Mode Control with PID Tuning Technique: An Application to a DC Servo Motor Position Tracking Control

Problem statement: In this study, a combination of a classical Sliding Mode Control (SMC) and a PID tuning technique with low-pass filter is developed for a position tracking control of a DC servo motor. Approach: The DC servo motor will be used to adjust the throttle angle of the gasoline engine in our laboratory. To control the engine speed to be accurate, the servo motor position has to be controlled precisely. Results: Uncertainty and nonlinearity of the servo motor system can be surmounted by the sliding mode control while the system response can be fine adjusted via the PID gain tuning. A low-pass filter has been incorporated also in order to eliminate and limit amplification of noise due to differentiation in the PID algorithm. The stability of the control system is guaranteed by the Lyapunov stability theorem. The experimental results shown that, the proposed technique has good tracking performance compares to a PIDSMC and a conventional PID technique even without actuator model. Conclusion/Recommendations: However, the performance strongly depends on the specified control gain in PID portion and sliding function. Therefore, any self tuning control gain techniques should be developed further.

반송장치에서의 방향제어를 위한 DC모터와 STEP모터 제어기의 성능비교에 관한 연구

영구자석의 반발력을 이용한 반송장치에서 캐리어를 받아 다음 스테이션으로 방향을 전환해주기 위한 회전판의 제어를 수행하기 위한 제어기로서 적당한 모터의 선정을 위하여 두 가지 형태의 제어기를 만들고 이를 비교하여 최적의 제어기를 선정하고자 하였다. 즉 스텝모터를 사용한 마이크로스텝방식의 오픈루프 제어와 DC모터를 사용한 폐루프 제어방식의 DC서보 방향제어기를 설계하고 제작하였다. 이 두 방식의 방향제어기의 성능과 제어특성을 비교하였다.

Investigation on Skew Rotor Design for the Dc Servo Spindle Motor

This paper will investigate the effect of skew rotor structure for the DC servo spindle motor. Twelve commutation patterns are carefully illustrated to provide the pre-processing for the finite element analysis (FEA). The skew effect for the rotor design is discussed to assess the effect on current and torque. The FE A for each different rotating angle of the rotor is also discussed. By proper mechanical design of the skew angle for the rotor, it can be found that the current ripple and cogging torque waveforms can be made smoother. The cogging torque can be assessed by using FEA. Verification of the validity and feasibility of the technique is obtained from simulation and experimental results.

Application of Compound PID Control in the DC Servo Motor

Although the traditional PID controller is widely used in many fields, the system parameters varying and external disturbances existing in the DC servo system will cause large overshoot or poor stability. To improve the performance of the PID controller, a compound servo control system combining the conventional PID control and the fuzzy control is presented to meet the demand of a vehicular antenna servo system in this paper. Incorporating the fuzzy control and the conventional PID control, this paper presents a design method of the fuzzy PID controller that is based on the fuzzy tuning rules and formed by integrating two above control ideas. Simulation results are presented to show the efficiency of the proposed controller. The practical control effect shows that the control system that adopts the fuzzy PID controller has better performance than that of the traditional PID control system, and meets the performance requirements of the servo system.

Myoelectric Hand Prosthesis Force Control Through Servo Motor Current Feedback

This paper presents the prehension force closed-loop control design of a mechanical finger commanded by electromyographic signal (EMG) from a patient's arm. The control scheme was implemented and tested in a mechanical finger prototype with three degrees of freedom and one actuator, driven by arm muscles EMG of normal volunteers. Real-time indirect estimation of prehension force was assessed by measuring the DC servo motor actuator current. A model of the plant comprising finger, motor, and grasped object was proposed. Model parameters were identified experimentally and a classical feedback phase-lead compensator was designed. The controlled mechanical finger was able to provide a more accurate prehension force modulation of a compliant object when compared to open-loop control.