Bang-bang Control Method Research Articles

Research of control method for pneumatic control of pneumatic microchips.

A novel composite control method for actuated chamber air pressure of pneumatic microfluidic chip via a three-way electromagnetic microvalve is presented in this paper. The purpose of the control methods is to improve air pressure controlling precision for pneumatic control. By using the Bang-Bang (on-off) controller for pneumatic control, the step-response time, air pressure steady-state accuracy, and air pressure fluctuations are performed with different maximum thresholds and minimum thresholds. Moreover, by using the k (proportional) plus PWM (Pulse-Width Modulation) control method for pneumatic control, the step-response time, air pressure steady-state accuracy, and air pressure fluctuations are performed with different carrier frequencies and carrier amplitudes. Both advantages and disadvantages of the two control methods are compared and analyzed based on the experimental data. According to the variable volume of the actuated chamber and the response characteristics of the three-way electromagnetic microvalve, the composite control method of the Bang-Bang plus k plus PWM is developed to control the actuated chamber air pressure. The experimental results show that when the absolute air pressure of the actuated chamber is set to 150kPa, the rising time is 69.3ms, which is about 8.0ms shorter than that of the k+PWM control method alone. The steady-state error is reduced from 0.90kPa to 0.65kPa, and the air pressure steady-state fluctuation is reduced from 1.60kPa to 0.90kPa, compared with the Bang-Bang control method alone.

Motorized smart pipette for handheld operation of a microfluidic blood plasma separator

Simple and institutionalized testing of circulating biomarkers is essential for rapid cancer diagnosis and prognosis. However, blood sample preparation typically requires time-consuming separation steps and bulky, costly equipment. Although microfluidic separators have been developed for rapid and simple blood separation, their fluidic accessories such as syringe pumps still need to be miniaturized at a lower price before translating the separators into clinical practice. Here, we present a motorized smart pipette as a portable, cost-effective, and controllable pumping tool that can generate stable and high-pressure conditions suitable for high-throughput microfluidic blood separators. The pumping technology is based on a miniature air pump and its feedback control using an open-source microcontroller board. We characterized the pumping performance (controllability and stability) of the proposed technology using a pressure divider and a bang-bang feedback control method in a range of flow rate (166.5–529.0 μL/min). Additionally, we demonstrated the clinical utility of the pumping technology by rapidly separating blood plasma from whole blood and successfully recovering cancer cell-derived exosomes spiked in blood. We achieved high-throughput (≈422.3 μL/min) and high-purity (≈99.8%) plasma separation without hemolysis, recovering ≈90.5% of cancer cell-derived exosomes spiked in blood. With the advantages of high usability and versatility, this method can potentially accelerate the widespread adoption and clinical translation of microfluidics-based liquid biopsy technologies.

Steering Quantum Dynamics of a Two-Qubit System via Optimal Bang-Bang Control

The optimization of control time for quantum systems has been an important field of control science attracting decades of focus, which is beneficial for efficiency improvement and decoherence suppression caused by the environment. Based on analyzing the advantages and disadvantages of the existing Lyapunov control, using a bang-bang optimal control technique, we investigate the fast state control in a closed two-qubit quantum system, and give three optimized control field design methods. Numerical simulation experiments indicate the effectiveness of the methods. Compared to the standard Lyapunov control or standard bang-bang control method, the optimized control field design methods effectively shorten the state control time and avoid high-frequency oscillation that occurs in bang-bang control.

Fast state transfer in closed quantum system based on the improved bang-bang control

Fast control of the state of quantum system is one of the robust control problems that often appear in practice, which is effective for decoherence suppression caused by the environment. In this paper, on the basis of an analysis of the advantages and disadvantages of the existing Lyapunov control, we propose three improved bang-bang control designs that are composed of the theory of bang-bang control and parameters optimization method and can solve fast control of the state transfer problem for quantum systems. Numerical simulation shows the effectiveness of the method for the problem of a closed two-level quantum system. Not only the decrease of Lyapunov function is fastened, the optimization of control time is realized and the coherence is protected, but also the high-frequency oscillation that occurs in bang-bang control is effectively avoided.

Low-cost feedback-controlled syringe pressure pumps for microfluidics applications.

Microfluidics are widely used in research ranging from bioengineering and biomedical disciplines to chemistry and nanotechnology. As such, there are a large number of options for the devices used to drive and control flow through microfluidic channels. Commercially available syringe pumps are probably the most commonly used instruments for this purpose, but are relatively high-cost and have inherent limitations due to their flow profiles when they are run open-loop. Here, we present a low-cost ($110) syringe pressure pump that uses feedback control to regulate the pressure into microfluidic chips. Using an open-source microcontroller board (Arduino), we demonstrate an easily operated and programmable syringe pump that can be run using either a PID or bang-bang control method. Through feedback control of the pressure at the inlets of two microfluidic geometries, we have shown stability of our device to within ±1% of the set point using a PID control method and within ±5% of the set point using a bang-bang control method with response times of less than 1 second. This device offers a low-cost option to drive and control well-regulated pressure-driven flow through microfluidic chips.

An offline predictive feedrate scheduling method for parametric interpolation considering the constraints in trajectory and drive systems

The ability of drive unit limits the velocity, acceleration, and jerk of the axis, and the process and tool path geometry constrain the feedrate, acceleration, and jerk of the trajectory. It is of great difficulty and importance to schedule a suitable feedrate profile to achieve the higher machining efficiency and satisfy all the constraints. Due to the complexity of the feedrate scheduling algorithm, this paper presents an offline predictive feedrate scheduling method considering the constraints of trajectory system and drive system. The constraints in the drive system are transformed to the trajectory system appropriately, which reduces the difficulty of feedrate scheduling. The one-dimensional high-order time-optimal problem is solved by a numerical calculation method according to the bang-bang control method. The predictive method is applied to find the switching points of the jerk. Then a time-optimal feedrate profile under all the constraints is obtained. Both simulations and experiments are carried out to prove the effectiveness of the proposed offline predictive feedrate scheduling method.

Bang-Bang Charge Control for LLC Resonant Converters

This paper proposes a Bang-Bang Charge Control (BBCC) method for LLC resonant converters. Instead of switching frequency control, the BBCC method utilizes the series resonant capacitor voltage level to trigger the MOSFETs' switching actions. Advantages of the proposed method include fast dynamic performance and simple implementations. Small-signal analysis shows that the loop bandwidth can achieve around 1/6 of the switching frequency in all operating conditions. Experimental results show that 5 to 25 A load step transients are completed within only seven switching cycles at both 400- and 300-V input-voltage conditions. Practical considerations are also discussed in detail.

The Research of PID and Bang-Bang Controllers Based on the dSPACE

This paper analyzes the PID and the Bang-Bang control methods. To compare the performance of these traditional algorithms, the speed control of a brushless DC drive system is implemented in real-time, using these two methods. The parameters in the controller can be adjusted by the hardware and the software to achieve the optimum performance of the closed-loop system. The experiment results proved that these two controllers have their own merit and defect according to the different steady-state performance and dynamic response respectively. It is concluded that the PID and the Bang-Bang controllers could be used in different applications.

The Analysis of Smart Car Guided by Electromagnetism

Nowadays, since there are many artificial intelligence techniques introduced into our daily life, which brings us much convenience, its a real hope that our transportation can be improved by artificial intelligence. In this article, a smart car with the detecting and following ability is introduced. The whole system is composed of the road track signal device; the electromagnetic sensor; the power source manage device; the engine drive device and the parking position detecting device. By using the PID, Bang-Bang and fuzz control methods, the smart car can collect the signal automatically and control the car moving effectively. When there are specially designed roads with electromagnetic field, our smart cars can automatically drive themselves.

A New Pulse Modulator for Solid Propellant Attitude Control Motors

Antimissile interceptors with the attitude control motors (ACM) were researched. For solid propellant ACM, a pulse frequency modulation scheme is proposed, which is based on conventional PWPF modulator. The modulator extends the application of modulation control method to solid propellant ACM, and integrates it with a feedback of thrust estimation which is decided by location and thrust interaction factors. The stability of the new modulator was analyzed by Lyapunov method and a stability margin was given. Simulations show that the stability margin is conservative, but acceptable. Interceptor simulations using the modulator indicate that this technique provides closer-to-linear actuation than conventional bang-bang thruster control methods.

Position Control with Parameter Adaptation for a Nano-Robotic Cell

This paper describes the development of a nano-assembly system, built up using linear piezo motors. The so-called nano-robotic cell is based on an X/Y manipulator, supported by three serving tables, movable within a Z axis, and a position controlled using two different types of a bang-bang control methods. The presented application has been developed as a stand-alone application with the LabVIEW Real Time software package, a PCI-7356 servo controller card and a TMCM-090 stepper driver. Our experiments focused on two major problems present during the construction of nano-robotic assembly cells. The first one is a nonlinear characteristic of a linear piezo motor, which makes the use of classical control methods very limited. The second problem appears when a nano-robotic cell needs a bigger working space and at the same time, production demands that the manipulator moves more often over longer distances. In order to position in nano-resolution, the motors have to run at higher resolutions with smaller speeds. Therefore, long distance moves slow down the entire production process. Experiments on this system have shown that positioning within the nano-scale is possible, using a simple control method such as the bang-bang control method. Although positioning using this method is possible, certain limitations and weaknesses exists, making this simple method useless in nano-scale if higher speeds and longer move distances are needed. Certain changes in the basic control algorithm are proposed, which will ensure that the bangbang control method becomes useful within higher speeds and over longer distances. All recommendations are supported and backed- up by practical experimental results.

Lyapunov 강인 안정성 조건을 이용한 강인 최적 뱅뱅 제어기

There are mainly two types of bang-bang controllers for nominal linear time-invariant (LTI) system. Optimal bang-bang controller is designed based on optimal control theory and suboptimal bang-bang controller is obtained by using Lyapunov stability condition. In this paper, the suboptimal bang-bang control method is extended to LTI system involving both control input saturation and structured real parameter uncertainties by using Lyapunov robust stability condition. Two robust optimal bang-bang controllers are derived by minimizing the time derivative of Lyapunov function subjected to the limit of control input. The one is developed based on the classical quadratic stability(QS), and the other is developed based on the affine quadratic stability(AQS). And characteristics of the two controllers are compared. Especially, bounds of parameter uncertainties which theoretically guarantee robust stability of the two controllers are compared quantitatively for 1DOF vibrating system. Moreover, the validity of robust optimal bang-bang controller based on the AQS is shown through numerical simulations for this system.

Bang-bang impact control using hybrid impedance/time-delay control

For stabilization of a robot manipulator upon collision with a stiff environment, a nonlinear bang-bang impact controller is developed. Under this control, a robot can successfully achieve contact tasks without changing the control algorithm or controller gains throughout all three modes: free space, transition and constrained motion. It uses a robust hybrid impedance/time-delay control algorithm to first absorb impact forces and stabilize the system. This control input alternates with zero when no environment force is sensed due to loss of contact. This alternation of control action repeats until the impact transient subsides and steady state is attained. After impact transient, the hybrid impedance/time-delay control algorithm is again utilized. This bang-bang control method provides stable interaction between a robot with severe nonlinear joint friction and a stiff environment, and achieves rapid response while minimizing force overshoots. During contact transition, we employ one simple control algorithm that switches only to zero and maintains the same gains, while other controllers use more than one control algorithm or different control gains. It is shown via experiments that overall performance is superior or comparable to more complicated existing impact force control techniques.

Reduction of Vortex Induced Vibration of a Tensioned Cable by Bang-Bang Control Method

The vortex induced vibration, generating on suspension bridge cables or high voltage lines are the most serious problems. Some authors have reported the effectiveness of both active and passive control methods in order to solve these vibration problems. However, most of them were focused on only the first order mode in-plane transverse vibration, and the high order mode vibration and out-of-plane vibration were not studied sufficiently. In this study, we experimentally examined the control of these out-of-plane and high order mode vibrations, which are induced by vortex. The experimental device was the most simple model consisting of single wire and one cylinder located on the middle part of the wire. For the vibration control of the system, we adopted the bang-bang control method, which nonlinearly varied the tension of the cable based on the Variable Structure System (VSS) theory.We experimentally employed the electrical magnetic actuator which can increase and decrease the tension from the initial value. As a result, we could reduce the now-induced vibration and confirmed the effectiveness of this control procedure. Additionally, the control effect of this method was confirmed by using Iwan model.

Vibration and Control of Axially Moving Crawler Used for Tracked Vehicles.

Recently, tracked vehicles are being equipped with a rubber crawler and they are used for leisure vehicles, snow machines, etc. With these applications, the resonance problems are common knowledge. The vibration characteristics of crawlers are experimentally examined. They have some resonance points caused by the differences in thickness of the crawler. These vibrations will make some noise and possibly cause system destruction. In order to analyze these vibrations, an approximate analytical model, which is based on the linear wave equation, including an effect of crawler velocity is introduced. Vibration characteristics are compared with exact solution and the experimental result. In order to suppress the resonance vibration, a bang-bang control method, which is part of the variable structure system control, is adopted. We experimentally and theoretically examined vibration and control of the crawler. As a result, that control method provides us the possibility of vibration suppression for the actual tracked vehicles.

Hybrid fuzzy control for electro-hydraulic active damping suspension

A new control scheme, the hybrid fuzzy control method, for active damping suspension system is presented. The scheme is the result of effective combination of the statistical optimal control method based on the statistical property of suspension system, with the bang-bang control method based on the real-time characteristics of suspension system. Computer simulations are performed to compare the effectiveness of hybrid fuzzy control scheme with that of optimal damping control, bang-bang control, and passive suspension. It takes the effects of time-variant factors into full account. The superiority of the proposed hybrid fuzzy control scheme for active damping suspension to the passive suspension is verified in the experiment study.

Two-state system driven by imperfect π pulses: an estimate of the error accumulation in bang-bang control methods

Two-state system driven by imperfect π pulses: an estimate of the error accumulation in bang-bang control methods

Two-state system driven by imperfect π pulses: An estimate of the error accumulation in bang-bang control methods

The evolution of a two-state system driven by a sequence of imperfect π pulses (with random phase or amplitude errors) is calculated. The resulting decreased fidelity is used to derive a plausible limit on the performance of ‘bang-bang’ control methods for the suppression of decoherence.

Frequency stabilization and measurements of 543 nm HeNe lasers

In this paper we report our investigations on the frequency stabilization and frequency measurements of 543 nm HeNe laser. It contains following four different works. (1) Using a metal laser tube we have built an iodine-stabilized 543 nm HeNe laser by the Frequency-Modulation (FM) spectroscopy. The signal-to-noise ratio of the hyperfine spectrum reached 2 × 10−12 at 1 s sampling time. (2) We have built a compact iodine-stabilized 543 nm HeNe laser system using the third-harmonic locking technique. Stability better than 1 × 10−12 for sampling time >1 s is obtained. We also suggest the b10 line for the future recommendation. (3) We constructed the Lamb-dip stabilized He-20Ne and He-22Ne lasers and measured their frequency stability, reproducibility, and absolute frequencies. The results suggest that the Lamb-dip stabilized lasers are appropriate for secondary wavelength standards. We have also deduced the isotope shift of Ne atom at 543 nm. (4) We have developed two two-mode stabilized 543 nm HeNe lasers using the bang-bang control method. The Allan variance is 1 × 10−11 at 1 s sampling time.

Vibration Reducing of Belt due to Bang-bang Feedback Control Method. 2nd Report, Experimental Analysis.

Belt driving systems applied to many kinds of equipment for industrial machinery encountered a vibration resonance problem due to the increase of the operational speed. To reduce this resonance vibration, we proposed parametric excitation feed-forward control using torque fluctuation. A drawback is not being able to apply it for multi-exciting sources. The alternative ideas were proposed in previous paper, which were bang-bang feedback control using sign function. That method were nonlinear control to fluctuate belt tension using bang-bang switching defined on displacement-velocity phase plane of detected belt vibration It was proved both theoretically and numerically that the methods were very effective to reduce transverse vibration of belt driving system. In order to confirm the control effect experimentally, a test device, which consisted of three pulleys (driving, idler and tension pulley), was established. As a result, this bang-bang feedback control is very effective and has many practical advantages for usage.