Cascade Control Research Articles

A PID-based control architecture for mobile robot path planning in greenhouses

This article presents a control strategy for an Ackermann mobile robot designed for greenhouse operation, based on a cascade control mechanism. It controls both, (i) an inner loop, based on PID, for two motors, and (ii) a classic Pure Pursuit control for the outer loop. In addition, a feedforward control strategy is proposed to address the issue of the natural variable terrain in greenhouses in southern Spain. Path following will be evaluated using a 2D model of the experimental greenhouse to obtain coordinates that will be assessed in simulation. Open-loop tests were conducted on a real agricultural robot prototype, AGRICOBIOT II, designed and built at the University of Almeria.

Path-Tracking Cascade Control of Hydraulic-Tracked Vehicles Based on Port-Controlled Hamiltonian Model

Path-Tracking Cascade Control of Hydraulic-Tracked Vehicles Based on Port-Controlled Hamiltonian Model

Robust cascade controller design for discrete minimum phase system using a novel data-driven virtual reference feedback tuning approach

Robust cascade controller design for discrete minimum phase system using a novel data-driven virtual reference feedback tuning approach

Robust cascade controller design for discrete minimum phase system using a novel data-driven virtual reference feedback tuning approach

Robust cascade controller design for discrete minimum phase system using a novel data-driven virtual reference feedback tuning approach

A General Design Methodology for Fractional Cascade Control Systems

A General Design Methodology for Fractional Cascade Control Systems

Analysis and design of PI-based controllers for the axes of European Solar Telescope

European Solar Telescope (EST) represents the largest European research infrastructure projected in the field of solar astrophysics. It is a 4-meter class solar telescope currently in the design phase. Within this phase, an essential objective is to analyze the control strategy of the telescope axes to achieve an accurate sun trajectory tracking. This paper presents a cascade control scheme based on proportional-integral (PI) controllers specifically designed for the elevation and azimuth axes of EST. The control strategy, which employs nested position-velocity loops, is devised to adeptly track the sun’s trajectory while mitigating wind impact. The controller tuning adheres to criteria of relative stability margins and bandwidth constraints using the state-space representation derived from Finite Element Model of the EST structure. An end-to-end dynamics model has been proposed to evaluate the performance of the control strategy during a ten-minute simulation. Results evidenced the convenience of the proposed controllers, highlighting wind as the main source of the control error (0.78 arcsec and 0.14 arcsec in azimuth and elevation axes, respectively) compared to the sun tracking error. Future control strategy enhancements should target the reduction of wind-induced effects to meet stringent image stability requirements.

Cascade motion control with synchronised saturation

This paper introduces an innovative motion control scheme tailored for traction systems, employing a cascade PI controller architecture. The internal loop regulates speed, and the external loop generates the necessary speed setpoint for position control. Two feedforward actions are strategically implemented in each loop to address potential disturbances and optimise overall performance. An inherent challenge in cascade control systems is the phenomenon known as windup, where integral components accumulate errors due to persistent disturbances or sudden changes in position reference. In order to mitigate this phenomenon, a control approach which integrates corresponding saturations for each loop and ensures synchronisation between them is developed. In this way, the external loop does not generate speed setpoints beyond physical thresholds during internal loop saturation. This strategic limitation prevents overly aggressive responses and eliminates undesired traction demands during saturation events. The proposed control scheme is validated through simulations that incorporate various disturbances, and the analysis of results confirms its suitability, showcasing improvements in the performance of such control schemes, especially in scenarios prone to windup.

POWERUP PASS MANAGEMENT SYSTEM

This article presents the demonstrator's own application framework for a BLDC motor drive. This demonstration is designed to fulfill the promises made by ST Microelectronics about the R3-PowerUP initiative. As a result, ST devices—particularly the STM32 ARM microcontroller—are employed primarily. The application structure, drivers and peripherals utilized, and the developed cascade control mechanism are all described in the paper. As a consequence, live variables acquired from the MCU are used to display the step responses of both control loops

Non-singular terminal sliding mode control for trajectory-tracking of a differential drive robot

This paper presents a trajectory control scheme for a non-holonomic differential drive mobile robot using the Non-singular Terminal Sliding Mode (NTSM) control method. The proposed approach, in fact, is a cascade control system scheme with the NTSM based dynamic controller at the internal loop which tracks the robot’s velocity quantities and a kinematic controller at the outer loop to regulate the robot’s position. In this manner, the control performance is robust to both disturbances and model’s uncertainties, as well as guarantees fast, finite-time convergence at better tracking precision. The simulation results demonstrate the merit of the anticipated control scheme.

Design of a Cascade Control Scheme for Unwinding Tension Based on RBF Network

Design of a Cascade Control Scheme for Unwinding Tension Based on RBF Network

Optimal Design of the Cascade Controller for Reheating Furnace by Taguchi Method

Optimal Design of the Cascade Controller for Reheating Furnace by Taguchi Method

ADVANCED AUTOMATIC SYSTEM FOR REMOTE CONTROL IN THE OIL AND GAS INDUSTRY

The purpose of this work is to design and implement a cascade control system of the level with the flow rate, with remote supervision, in an industrial type installation, located in the Laboratory of Measurement Techniques, Department of Automation, Computers and Electronics, within the Faculty of Mechanical and Electrical Engineering. The operating parameters of the installation are as follows: suction pressure: 0 – 2 bar; discharge pressure: 0 -10 bar; water flow: 0-30 m3/h; transported liquid: water. The automation system is structured on three hierarchical levels: level 1: the instrumentation mounted on the installation (transducers, signaling devices, etc.); level 2: includes the TGA System; level 3: constitutes the upper hierarchical level and includes the HMI (Human Machine Interface). The TGA system is a computerized system that ensures the monitoring, command and control functions of all the stand's component elements. It contains a programmable logic controller PLC 1214 – Siemens, which communicates via an Ethernet IP network with an operator interface and with the network of the Faculty of Mechanical and Electrical Engineering, which allows remote control of the installation. It also includes the protection system in case of failure, which involves stopping the rotating equipment, isolating the pipes by closing the control valve and alarming the operators. The HMI (Human Machine Interface) interface presents 3 options on the start page, from where the operator can select which application he wants to test: flow control loop application; level adjustment loop application; cascade adjustment loop application. The HMI equipment integrates SCADA functions, database update, evolution curves of analog quantities, sound and monitor alarm system, keyboard command, periodic records, event records, alarm records and technological schemes at the human-machine interface. The entire software is made in an open architecture, recommended by ISO norms. The PLC communicates in the network by adopting the protocol TCP/IP. An executable program used for the real-time application program was developed.

Cascade control of electrical drives of a pumping station based on an astatic fuzzy regulator

The article discusses the main features of cascade pressure control in a water supply system with a controlled and additional uncontrolled pumps. The disadvantages of the existing control systems are formulated and it is proposed to control the pump station electric drives using correction of speed of the controlled pump depending on the mode of operation of the uncontrolled pump. A simplified mathematical model of the pressure control loop was developed, with the representation of the switching on of the additional pump as a disturbance effect of an aperiodic behavior. At the same time, the control algorithm of the additional pump is described in the form of unequivocal nonlinearities based on single step and signature functions, which allows to significantly simplify its implementation in the case of using microprocessor devices. To reduce the impact of disturbances in transient operating modes, namely when the additional pump is switched on, it is proposed to use the speed correction component for the main pump in the control algorithm. To avoid the formation of a static error, it is suggested to use a pressure regulator with integral component. Next, a refined mathematical model in the MATLAB environment was developed and an investigation of system operation using proportional-integral-derivative controller of pressure main pump speed control was carried out. It was determined that using of correction component allows to increase the accuracy of pressure control, but does not allow to compensate the presence of transport delay and nonlinearities of the system. Therefore, as a pressure regulator of the hydraulic system output, a combined astatic fuzzy regulator based on a proportional-integral control algorithm is used. The main difference of such a regulator is the automatic change of the gain factor when the error changes, which prevents the occurrence of unstable modes with large coefficients of the open system. The developed fuzzy control system provides a lot of benefits, such as increasing the reliability of the water supply network, improving the performance of the water supply system for consumers, reducing the wear and tear of pumping equipment, and reducing electricity consumption, which is confirmed by the results of numerical modeling.

Analysis, Modeling and Cascade Operation of Wind Energy Fed Dual Active Bridge Converter Operating in Extended Phase Shift and Single Phase Shift Modes: A Comparative Study

In this work, cascade control of wind energy conversion System (WECS) fed Dual Active Bridge (DAB) converter is presented. The Permanent Magnet Synchronous Generator (PMSG) is used to feed the DAB. The real time wind speed data of Muppandal, Tamilnadu, India is fed to the PMSG. The DAB is operated in Extended Phase Shift (EPS) and Single-Phase Shift (SPS) control modes. An outer voltage controller in cascade with an inner current controller is used for closed loop operation of the DAB. The proposed controller is tested for small wind speed variations (13 m/s to 10 m/s) with a step load change and wide changes in wind speed (13 m/s to 8 m/s) accompanied with a step load change. DAB controls the power flow from the WECS to resistive load and its power carrying capability when controlled via the proposed controller is exhibited in the presented work. The proposed configuration controlled via the new cascade EPS controller draws lower power (100 Watts) and offers superior efficiency (85.10%) when compared with cascade SPS controlled microgrid configuration. The cascade controller is tested in MATLAB/Simulink environment and a prototype of DAB is developed in lab for which the cascade controller is tested through the TI-Piccolo-F280049 microcontroller.

Ultra-stable control near the EP in non-Hermitian systems and high-precision angular rate sensing applications.

In non-Hermitian systems, enhancing sensitivity under exceptional point (EP) conditions offers an ideal solution for reconciling the trade-off between sensitivity and size constraints in sensing applications. However, practical application is limited by undesired sensitivity to external fluctuations, noise, and errors in signal amplification synchronization. This paper presents a precisely controlled EP tracking and detection system (EPTDS) that achieves long-term rapid tracking and locking near the EP by constructing a second-order non-Hermitian optical sensing unit, employing an optical power adaptive control method, and utilizing a combinatorial demodulation-based dual-loop cascaded control (CDCC) technique to selectively suppress traditional noise at different frequencies. The system locking time is 10 ms, and in room temperature conditions, the output frequency error over 1 hour is reduced by more than 30 times compared to before locking. To assess its sensing capabilities, the EPTDS undergoes testing in a rotational experiment based on the Sagnac effect, with the output bias instability based on Allan deviation measured at 0.036 °/h. This is the best result for EP-enhanced angular rate sensing that we are aware of that has been reported. The EPTDS method can be extended to various sensing fields, providing a new path for transitioning non-Hermitian sensing from the laboratory to practical applications.

Cascade Control Method for Conducting Hybrid Simulation with Stiff Specimens

Cascade Control Method for Conducting Hybrid Simulation with Stiff Specimens

Puckered and JNK signaling in pioneer neurons coordinates the motor activity of the Drosophila embryo

Central nervous system organogenesis is a complex process that obeys precise architectural rules. The impact that nervous system architecture may have on its functionality remains, however, relatively unexplored. To clarify this problem, we analyze the development of the Drosophila embryonic Ventral Nerve Cord (VNC). VNC morphogenesis requires the tight control of Jun kinase (JNK) signaling in a subset of pioneer neurons, exerted in part via a negative feedback loop mediated by the dual specificity phosphatase Puckered. Here we show that the JNK pathway autonomously regulates neuronal electrophysiological properties without affecting synaptic vesicle transport. Manipulating JNK signaling activity in pioneer neurons during early embryogenesis directly influences their function as organizers of VNC architecture and, moreover, uncovers a role in the coordination of the embryonic motor circuitry that is required for hatching. Together, our data reveal critical links, mediated by the control of the JNK signaling cascade by Puckered, between the structural organization of the VNC and its functional optimization.

Double feedforward compensation for cascade control schemes

This paper addresses the problem of dealing with measurable disturbances in cascade control schemes. The combination of cascade and feedforward control algorithms is analyzed. The design of a static feedforward compensators control scheme to assist the controller in the rejection of measurable disturbances is a widely accepted solution in the literature. This article proposes a new solution by implementing two static feedforward controllers, one in the outer and other in the inner loop, as part of the cascade control scheme. The tuning rules for the feedforward compensators are proposed to enhance the process performance for the load disturbances rejection problem. Simulation examples demonstrate the advantages of the proposed solution by improving the process output performance while reducing the control effort. Moreover, the new solution is evaluated in simulation on two non-linear typical processes in chemical industry, a tank level control and concentration control in a Continuous Stirred Tank Reactor (CSTR).

Model predictive cascade control for resolving actuator saturation in human‐occupied vehicle trajectory tracking

SummaryA model predictive cascade controller is proposed in this article to resolve the actuator saturation problem of underwater human‐occupied vehicle (HOV) trajectory tracking. For the kinematic model, a grasshopper optimization‐based model predictive control (MPC) is developed to obtain control velocities with small fluctuations in allowable regions. Based on the desired velocities obtained from the improved kinematic control, the HOV dynamic model is used to generate the corresponding torques and forces using sliding mode control. With the control velocities and forces given by the cascade control strategy, the elimination of actuator saturation during the HOV trajectory tracking can be realized. The proposed controller is verified by simulations using a numerical example based on a four degrees of freedom (4‐DOFs) HOV.

Optimal analytical cascade control for FOPDT systems

This paper proposes a novel control strategy based on optimal Linear Quadratic Regulator (LQR) design applied to cascade systems with stable, integrative, and unstable First Order plus Dead-Time (FOPDT) outer loop models. The secondary (inner) and primary (outer) loop controller designs are performed using the Simplified Filtered Smith Predictor (SFSP). The optimal analytical design is derived from a novel strategy where the pole of the internal loop is placed so that the LQR criterion can be achieved with a simple tuning of the external loop. In contrast to related work, the secondary controller is designed using an SFSP control structure to nominally achieve optimal LQR performance and accelerated rejection of disturbances acting on the inner-loop process. To illustrate the usefulness of the proposed design, we evaluated the strategy in different scenarios, showing the optimality and performance of the analytical design.