Papers by Keyword: Digital Control System

Abstract: A digital closed-loop control system with all digital phase locked loop (ADPLL) is designed and optimized, in order to improve the bias stability and transient response of the gyroscope. The nonlinear mathematical models for the closed-loop amplitude and phase control system are established. The linearization method is applied to analyze the nonlinear models. The control parameters of the drive loop are optimized. The experimental results show that the phase deviation between the demodulation reference signal of the drive loop and the sense signal is less than 0.25° in the temperature range from-40°C to 60°C, within 0.15° of the variation. At room temperature, the overshoot amount of the gyroscope control system is 4.5% with setting time of 0.12s. The bias stability is 1.45°h. Compared to the analog control scheme, the digital control system has advantages of short setting time, small overshoot, short phase locked time, large locked range, high phase precision, etc.

Abstract: Based on Nios II embedded processor control module, a digital control system was designed for wire feeding control of gas tungsten arc welding(GTAW). In the control system FPGA wave module is used to control the movement of the DC servo motor, and the digital control of pulsed wire feeder for GTAW was achieved. One and the same control module with Nios II embedded processor is used to control the wire feeder and the welding power source. Thus, the current parameter of pulsed welding arc can be obtained and used directly for controlling the speed of wire feeding. At last, the experiment results are provided to verify the validity.

Abstract: Aiming at the low automation level and the non-completeness of the fault diagnosis technology for the band sawing products in China and in our province, this paper studied the digital control system based on extracting the flutter amplitude characteristics of the band saw blades in real time, developed the adjustable device which clears the sticky chips between the saw teeth based on the brush friction change according to the inclination angle Φ between the brush disk and the saw blade, and designed the state recognition system for the hydraulic oil circuits of the sawing machine based on detecting real-timely the oil temperature, pressure, flow rate and hydraulic cylinders displacement and transmitting wirelessly. So it can improve the grade, efficiency, reliability and service life for the band sawing machine.

Abstract: Aiming at the lower performance, accuracy and efficiency of the existing motion control process for the traditional broaching machine, the paper studies the high-performance dual-hydraulic synchronous servo drive control technology. The synchronous electro-hydraulic servo system forms the closed loop control by the detection and feedback of the output quantity. It eliminates and restrains largely the influence of the adverse factors to obtain the high-precision synchronous driving performance. The numerical control system based on the real-time error compensation and the intelligent control to the auxiliary machinery is developed. It is used for the CNC broaching machine to make the steady-state synchronous displacement error of the double cylinders be ≤ 0.5mm.

Abstract: This paper proposes an improved design of micro-machined tuning fork gyroscope (M-TFG) to better decouple the cross talk between the driving and sensing directions and to increase resolution. By employing dual-folds spring suspension, the drive mode and the sense mode are mechanically decoupled. Through careful layout design of the location of the dual-folds spring suspension and the drive combs, the mechanical coupling effect is further decreased by isolating the unwanted excitation from detection. The peripheral circuit is also the important part to realize the function of the gyro system. Since the analog circuit has some inherent shortcomings, which has limited the accuracy of the gyro. In this paper, a digital control system for micro-comb is introduced.

Abstract: In this paper, the design and implementation of a 12/10 poles 6-phase switched reluctance generator (SRG) drive system for hybrid electric vehicles (HEVs) is investigated. Firstly, the principle of the SRG, its control parameters and operation characteristics are analyzed. Then, according to the requirements of the SRG using as an integrated starter generator for HEVs, an optimized switch angle position with current chopping control method is proposed to regulate the SRG power output. In order to improve the charge performance and extend the service life, the lead-acid battery group uses a two-stage charge mode, which is realized by two digital power regulators of the SRG. After that, an experimental system is set up and the controller's internal circuit is described. At last, the proposed SRG drive system is verified by experimental results.

Abstract: Unreliable and inflexible analog control systems of fatigue test stands applied in laboratories are being replaced by systems enabling easy development and implementation of new test ideas. This paper presents a digital control system applied in the fatigue test stand SHM 250b. It is based on a new electronic system and the I/O board RT-DAQ4/PCI with the software Matlab/Simulink used for communication with the board. The control system for the fatigue test stand SHM 250b gives the possibility of performing fatigue tests under controlled strain ε(t), stress σ(t) and energy parameter W(t) which is calculated from the stress and strain signals. The applied control system is now used, depending on the performed fatigue tests, and can be developed for specific needs of material strength analysis.

Abstract: This paper presents a two-channel digital control system for the hydraulic stand MZPK 100 designed for fatigue tests of cruciform specimens under biaxial tension-compression. In the past, the fatigue test stand MZPK 100 was provided with unreliable analog control power cubicles. Application of the computer with an analog and digital input-output signal path board, Matlab/Simulink software and a new control box equipped with the necessary electronic subassemblies (responsible for proper switching of the hydraulic supplier, command electrovalves, conditioning of signals from sensors and so on) enables replacement of the old analog system by a new two-channel digital control system. Nowadays, it is easy to modify the control system to different requirements of material tests because the hardware (electronic) solutions have been simplified, and the software has a friendly Simulink interface. Such an approach allows for the implementation of different control algorithms, e.g. PID, adaptive, and fuzzy logic etc. Moreover, this paper presents a description of how to keep the center of the specimen static under a controlled force that is being applied by four independent actuators.