Accepted Manuscripts

Stephanie Bonadies, Neal Smith, Nathan Niewoehner, Andrew Lee, Alan M Lefcourt and S. Andrew Gadsden
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038504
Farming and agriculture is an area that may benefit from improved use of automation in order to increase working hours and improve food quality and safety. In this paper, a commercial robot was purchased and modified, and crop row navigational software was developed, to allow the ground-based robot to autonomously navigate a crop row setting. A proportional-integral-derivative (PID) controller and a fuzzy logic controller were developed to compare the efficacy of each controller based on which controller navigated the crop row more reliably. Results of the testing indicate that both controllers perform well, with some differences depending on the scenario.
TOPICS: Control equipment, Safety, Robots, Fuzzy logic, Fuzzy control, Testing, Computer software, Food products, Navigation
Hayder M. Abdulridha and Zainab A. Hassoun
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038492
In this study, a control system was designed to control the robot's movement (The Mitsubishi RM-501 robot manipulator) based on the Quantum Neural Network (QNN). A proposed method was used to solve the inverse kinematics in order to determine the angles values for the arm's joints when it follows through any path. The suggested method is the QNN algorithm. The forward kinematics was derived according to Devavit-Hartenberg representation. The dynamics model for the arm was modelled based on Lagrange method. The dynamic model is considered to be a very important step in the world of robots. In this study, two methods were used to improve the system response. In the first method, the dynamic model was used with the traditional PID controller to find its parameters (Kp, Ki, Kd) by using Ziegler Nichols method. In the second method, the PID parameters were selected depending on QNN without the need to a mathematical model of the robot manipulator. The results show a better response to the system when replacing the traditional PID controller with the suggested controller.
TOPICS: Design, Artificial neural networks, Manipulators, Control equipment, Kinematics, Dynamic models, Dynamics (Mechanics), Control systems, Robots, Algorithms
Mohamed Shaltout, Zheren Ma and Dongmei Chen
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038490
Motivated by the reduction of overall wind power cost, considerable research effort has been focused on enhancing both efficiency and reliability of wind turbines. Maximizing wind energy capture while mitigating fatigue loads has been one of the main goals for control design. Recent developments in remote wind speed measurement systems (e.g. LIDAR) have paved the way for implementing advanced control algorithms in the wind energy industry. In this paper, a LIDAR-assisted economic model predictive control framework with a real-time adaptive approach is presented to achieve the aforementioned goal. First the formulation of a convex optimal control problem is introduced, with linear dynamics and convex constraints that can be solved globally. Then, an adaptive approach is proposed to reject the effects of model-plant mismatches. The performance of the developed control algorithm is compared to that of a standard wind turbine controller, which is widely used as a benchmark for evaluating new control designs. Simulation results show that the developed controller can reduce the tower fatigue load with minimal impact on energy capture. For model-plant mismatches, the adaptive controller can drive the wind turbine to its optimal operating conditions while satisfying the optimal control objectives.
TOPICS: Predictive control, Wind turbines, Control equipment, Fatigue, Stress, Optimal control, Wind energy, Control algorithms, Simulation results, Wind power, Measurement systems, Design, Dynamics (Mechanics), Wind velocity, Reliability
Mingxuan Sun, He Li and Yanwei Li
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038488
Fractional uncertainties are involved in many practical systems. Currently, there are lack of research results about such general class of nonlinear systems, in the context of learning control. This paper presents a Lyapunov-synthesis approach to repetitive learning control, being unified due to the use of the direct parametrization and adaptive bounding techniques. To effectively handle fractional uncertainties, the estimation method for such uncertainties is elaborated to facilitate the controller design and convergence analysis. Its novelty lies in the less requirement for the knowledge about the system undertaken. Unsaturated- and saturated-learning algorithms are respectively characterized, by which both the boundedness of the variables in the closed-loop system undertaken and the asymptotical convergence of the tracking error are established. Experimental results are provided to verify the effectiveness of the presented learning control.
TOPICS: Design, Uncertainty, Control equipment, Algorithms, Nonlinear systems, Closed loop systems, Errors
Yan-an Gao and Qing shan Yang
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038489
The lateral excessive sway motion caused by pedestrian traffic has attracted great public attention in the past decades years. However, the theories about exploring the effect of pedestrian on the lateral dynamic properties of structure are scarce. The new contribution of this paper is that a new pedestrian-structure system is proposed for exploring the effect of human on structural dynamic properties based on a sway assumption. Study shows that pedestrian deteriorates the natural frequency of structure and improves structural damping. The influence tendencies of pedestrian on structure can be supported by measurements. The further parametric study shows that the changes of human dynamic parameters have some evident impacts on structural dynamic performances. For example, the increase of leg damping can trigger an improvement of structural damping capacity. In addition, the walking step frequency closing structural harmonic natural frequency can incur the worst response. The increase of step width deteriorates lateral vibration and structural frequency, but can slightly improve structural damping. One of essential reasons influencing structural lateral dynamic properties is the dynamic human system including body mass, damping, stiffness and its motion behavior such as step frequency. This theory is proposed to analyze how pedestrian alter the lateral dynamic performances on those sensitive structures such as the footbridges or stadium bleachers. For example, how the variation of step width influences the change of natural frequency of structure.
TOPICS: Vibration, Excitation, Damping, Structural dynamics, Stiffness, Traffic
Prasanth Kandula and Lili Dong
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038493
When a parallel-plate electrostatic actuator (ESA) is driven by a voltage source, a pull-in instability limits the range of displacement to one-third of the gap between plates. In this paper, a nonlinear active disturbance rejection controller (NADRC) is originally developed on ESA. Our control objectives are stabilizing and increasing the displacement of an ESA to 99.99% of its full gap. Most of the reported controllers in literature are based on linearized models of the ESAs, and depend on detailed model information of them. However, the ESA is inherently nonlinear, and has model uncertainties due to the imperfections of micro-fabrication and packaging. The NADRC consists of a nonlinear extended state observer (NESO) and a feedback controller. The NESO is used to estimate system states and unknown nonlinear dynamics for the ESA. Therefore, it doesn't require accurate model. We simulate the NADRC on a nonlinear ESA in the presences of external disturbance, system uncertainties and noise. The simulation results verify the effectiveness of the controller by successfully extending the travel range of ESA beyond pull-in point. They also demonstrate that the controller is robust against both disturbance and parameter variations, and has low sensitivity to measurement noise. Furthermore, the stability for the NADRC with NESO is theoretically proved.
TOPICS: Stability, Control equipment, Noise (Sound), Plates (structures), Displacement, Electrostatic actuators, Feedback, Microactuators, Microfabrication, Simulation results, State estimation, Nonlinear dynamics, Packaging, Uncertainty
Saeed Pezeshki, Mohammadali Badamchizadeh, Amir Rikhtegar Ghiasi and Sehraneh Ghaemi
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038491
This paper concerns the problems of stability and robust model reference tracking control for a class of switched nonlinear systems with input delay under asynchronous switching. By proposing a new Lyapunov-Krasovskii functional, and using free-weighting matrices and average dwell time technique, new input-to-state stability conditions are derived in terms of linear matrix inequalities under a certain delay bound. Then, robust model reference tracking control problem is studied based on the proposed Lyapunov-Krasovskii functional; Finally a kind of state feedback control law which guarantees robust model reference tracking performance is proposed. Illustrative examples are presented to demonstrate the efficacy and feasibility of results.
TOPICS: Nonlinear systems, Delays, Tracking control, Stability, Linear matrix inequalities, State feedback
Jun-Wei Wang and Chang-Yin Sun
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038374
This paper extends the framework of Lyapunov–Krasovskii functional to address the problem of exponential stabilization for a class of linear distributed parameter systems with continuous differentiable time-varying delay and a spatiotemporal control input, where the system model is described by parabolic partial differential-difference equations (PDdEs) subject to homogeneous Neumann or Dirichlet boundary conditions. By constructing an appropriate Lyapunov–Krasovskii functional candidate and using some inequality techniques (e.g., spatial integral form of Jensen's inequalities and vector-valued Wirtinger's inequalities), some delay–dependent exponential stabilization conditions are derived, and presented in terms of standard linear matrix inequalities (LMIs). These stabilization conditions are applicable to both slow-varying and fast-varying time delay cases. The detailed and rigorous proof of the closed-loop exponential stability is also provided in this paper. Moreover, the main results of this paper are reduced to the constant time delay case and extended to the stochastic time-varying delay case, and also extended to address the problem of exponential stabilization for linear parabolic PDdE systems with a temporal control input. Numerical simulation results of two examples show the effectiveness and merit of the main results.
TOPICS: Distributed parameter systems, Delays, Linear matrix inequalities, Spatiotemporal phenomena, Boundary-value problems, Stability, Computer simulation
Nripen Mondal, Binod Kumar Saha, Rana Saha and Dipankar Sanyal
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038377
A simple perturbation flow model is formulated and validated by a rigorous computational fluid dynamics (CFD) study for designing a counterbalanced vertical-axis aerostatic thrust bearing. The flow model of the orifice at the entry of the stator manifold involves natural transition between the choked and free flows. While the air distribution network of holes in the stator and one air gap at the inner radius of the stator constitute the fixed part, the variable part is comprised of two air gaps at the top and bottom of the stator interconnected by the inner air gaps. The top and the inner gaps receive air by a circular array of holes. While the basic flow of the perturbation model is taken as steady corresponding to fixed air gaps, the transient effect is captured by a squeezing flow due to the variations of the top and bottom gaps. The overall flow including that in the network is assumed as compressible and isothermal. This model has been validated through a transient axi-symmetric CFD study using dynamic meshing and the coupled lifting dynamics of the payload. The validated model has been used to find the appropriate counterbalancing, the orifice diameter, the air gap sizes and the location of the air holes feeding the top gap. This clearly shows the worth of the model for carrying out an extensive design analysis that would have been very costly and even unachievable for small gaps that would occur during system transients.
TOPICS: Thrust, Transients (Dynamics), Bearing design, Modeling, Flow (Dynamics), Stators, Computational fluid dynamics, Design, Dynamics (Mechanics), Manifolds, Thrust bearings
Tianheng Feng, Inho Kim and Dongmei Chen
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038388
Drillstring vibration can cause fatigue failure of the drillpipe, premature wear of the bit, and a decreased drilling efficiency; therefore, it is important to accurately model the drillstring and bottomhole assembly (BHA) dynamics for vibration suppression. The dynamic analysis of directional drilling is more important, considering its wide application and the advantage of increasing drilling and production efficiencies; however, the problem is complex because the large bending can bring nonlinearities to drillstring vibration and the interaction with the wellbore can occur along the entire drillstring. To help manage this problem, this paper discusses a dynamic finite element method (FEM) model to characterize directional drilling dynamics by linearizing the problem along the well's central axis. Additionally, the rig force and drillstring/wellbore interaction are modeled as a boundary condition to simulate realistic drilling scenarios. The proposed modeling framework is verified using comparisons with analytical solutions and literatures. The utility of the proposed model is demonstrated by analyzing the dynamics of a typical directional drillstring.
TOPICS: Dynamic modeling, Drill strings, Drilling, Dynamics (Mechanics), Vibration, Finite element methods, Dynamic analysis, Modeling, Vibration suppression, Boundary-value problems, Wear, Manufacturing, Fatigue failure
Technical Brief  
Saeid Bashash
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038390
This paper investigates the optimal coordination of multiple interacting HVAC appliances in buildings such as air conditioners and refrigerators, in time-varying electricity pricing environments. Each load is modeled as a first order differential equation with a binary (ON-OFF) switching control function. An energy cost minimization problem is then formulated with weighted penalties on the temperature deviation from the desired setpoint and the control input fluctuation. Using the dynamic programming method, the cost-optimal trajectories are computed, indicating pre-cooling of the loads in anticipation of the electricity price peak period. Moreover, the loads are desynchronized in the presence of local renewable generation to maximize the on-site consumption of the local energy. The presented results provide useful insights for the development of predictive and rule-based control policies for optimal energy management in buildings.
TOPICS: Structures, Stress, HVAC equipment, Differential equations, Dynamic programming, Air conditioners, Energy management, Temperature, Cooling
Technical Brief  
Toru Namerikawa, Yasuhiro Kuriki and Ahmed Mohammed Khalifa
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038375
In this article, we consider cooperative control issues for a multi-unmanned aerial vehicle (UAV) system. We propose a cooperative formation control strategy with unidirectional network connections between UAVs. Our strategy is to apply a consensus-based algorithm to the UAVs so that they can cooperatively fly in formation. First, we show that UAV models on the horizontal plane and in the vertical direction are expressed as a fourth- and second-order system, respectively. Then, we show that the stability discriminants of the multi-UAV system on the horizontal plane and in the vertical direction are expressed as polynomials. For a network structure composed of bidirectional or unidirectional network connections under the assumption that the network has a directed spanning tree, we provide conditions for formation control gains such that all roots of the polynomials have negative real parts in order for the UAVs to asymptotically converge to the positions for a desired formation by using the generalized Routh stability criterion. The proposed control algorithms are validated through simulations, and experiments are performed on multiple commercial small UAVs to validate the proposed control algorithm.
TOPICS: Stability, Simulation, Algorithms, Engineering simulation, Aircraft, Polynomials, Routh–Hurwitz stability criterion, Unmanned aerial vehicles, Control algorithms
Technical Brief  
Meryem Deniz, Alper Bayrak, Enver Tatlicioglu and Erkan Zergeroglu
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038373
In this study, the design of a smooth robust velocity observer for a class of uncertain nonlinear mechatronic systems is presented. The proposed velocity observer does not require a priori knowledge of the upper bounds of the uncertain system dynamics and introduces time-varying observer gains for uncertainty compensation. Practical stability of the velocity observation error is ensured via Lyapunov-type stability analysis. Experimental results obtained from Phantom Omni haptic device are presented to illustrate the performance of the proposed velocity observer.
TOPICS: Dynamics (Mechanics), Stability, Design, Uncertain systems, Errors, Uncertainty, PHANToM Omni
Technical Brief  
Yuan Yao, Yapeng Yan, Zhike Hu and Kang Chen
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038389
We put forward the motor active flexible suspension and investigate its dynamic effects on the high-speed train bogie. The linear and nonlinear hunting stability are analyzed using a simplified 8 degrees of freedom bogie dynamics with partial state feedback control. The active control can improve the function of dynamic vibration absorber of the motor flexible suspension in a wide frequency range, thus increasing the hunting stability of the bogie at high speed. Three different feedback state configurations are compared and the corresponding optimal motor suspension parameters are analyzed with the multi-objective optimal method. In addition, the existence of the time-delay in the control system and its impact on the bogie hunting stability are also investigated. The results show that the three control cases can effectively improve the system stability and the optimal motor suspension parameters in different cases are different. The direct state feedback control can reduce corresponding feed state's vibration amplitude. Suppressing the frame's vibration can significantly improve the running stability of bogie. However, suppressing the motor's displacement and velocity feedback are equivalent to increasing the motor lateral natural vibration frequency and damping, separately. The time-delay over 10 ms in control system reduces significantly the system stability. At last, the effect of preset value for getting control gains on the system linear and nonlinear critical speed is studied.
TOPICS: Engines, Motors, Trains, Stability, Control systems, Vibration, Delays, Feedback, State feedback, Displacement, Dynamics (Mechanics), Vibration absorbers, Oscillating frequencies, Degrees of freedom, Damping
Shengtao Li, Xiaomei Liu and Xiaoping Liu
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038342
Transient stability is the key problem for reliable and secure planning under the new deregulated market conditions. By using immersion and invariance (I&I) method, a nonlinear coordinated generator excitation and steam-valve controller is designed to improve transient stability of power systems. The proposed coordinated immersion and invariance controller can assure power angle stability, voltage and frequency regulations, when a large disturbance occurs on the transmission line or a small perturbation to mechanical power. Compared with the Lyapunov method, the proposed method does not need to construct a Lyapunov energy function. Some numerical simulations are used to validate the proposed controller. Simulation results show that the nonlinear coordinated I&I controller has better control performance than the existing coordinated passivation controller (CPC).
TOPICS: Power systems (Machinery), Valves, Steam, Excitation, Control equipment, Stability, Transients (Dynamics), Computer simulation, Generators, Lyapunov methods, Regulations, Simulation results, Transmission lines
Matthew Williams, Justin Koeln, Herschel Pangborn and Andrew Alleyne
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038341
The current trend of electrification in modern aircraft has driven a need to design and control onboard power systems that are capable of meeting strict performance requirements while maximizing overall system efficiency. Model-based control provides the opportunity to meet the increased demands on system performance, but the development of a suitable model can be a difficult and time-consuming task. Due to the strong coupling between systems, control-oriented models should capture the underlying physical behavior regardless of energy domain or time-scale. This paper seeks to simplify the process of identifying a suitable control-oriented model by defining a scalable and broadly applicable approach to generating graph-based models of thermal, electrical, and turbomachinery aircraft components and systems. Subsequently, the process of assembling component graphs into a dynamical system graph that integrates multiple energy domains is shown. A sample electrical and thermal management system is used to demonstrate the capability of a graph model at matching the complex dynamics exhibited by nonlinear and empirically-based simulation models.
TOPICS: Aircraft, Turbomachinery, System efficiency, Simulation models, Thermal management, Dynamics (Mechanics), Power systems (Machinery), Design, Dynamic systems
Ghulam Murtaza, Aamer Iqbal Bhatti and Qadeer Ahmed
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038299
The efficiency of the spark ignition (SI) engine degrades while working at part loads. It can be optimally dealt with a slightly different thermodynamic cycle termed as an Atkinson cycle. It can be implemented in the conventional SI engines by incorporating advanced mechanisms as variable valve timing (VVT) and variable compression ratio (VCR). In this research, a control framework for the Atkinson cycle engine with flexible intake valve load control strategy is designed and developed. The control framework based on extended mean value engine model (EMVEM) of the Atkinson cycle engine is evaluated in the view of fuel economy for the standard NEDC, FUDS and FHDS driving cycles. In this context, the authors have already proposed a controloriented EMVEM model of the Atkinson cycle engine with variable intake valve actuation. To demonstrate, the potential benefits of the VCR Atkinson cycle VVT engine, for the various driving cycles, in the presence of auxiliary loads and uncertain road loads, its EMVEM model is simulated by using a precisely tuned controller having similar specifications as that of the conventional gasoline engine. The simulation results point towards the significant reduction in engine part load losses and improvement in the thermal efficiency over the wide operating range. Consequently, considerable enhancement in the fuel economy of the VCR Atkinson cycle VVT engine is achieved over conventional Otto cycle engine during the NEDC, FUDS and FHDS driving cycles.
TOPICS: Design, Atkinson cycle engines, Cycles, Engines, Stress, Valves, Gasoline engines, Fuel efficiency, Corporate average fuel economy, Thermodynamic cycles, Ignition, Roads, Simulation results, Thermal efficiency, Spark-ignition engine, Control equipment, Compression
Ben S. Petschel, Kianoosh Soltani Naveh and P. R. McAree
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038267
The Kalman filter has a long history of use in input deconvolution where it is desired to estimate structured inputs or disturbances to a plant from noisy output measurements. However, little attention has been given to the the convergence properties of the deconvolved signal, in particular the conditions needed to estimate inputs and disturbances with zero bias. The paper draws on ideas from linear systems theory to understand the convergence properties of the Kalman filter when used for input deconvolution. The main result of the paper is to show that, in general, unbiased estimation of inputs using a Kalman filter requires both an exact model of the plant and an internal model of the input signal. We show that for unbiased estimation, an identified sub-block of the Kalman filter that we term the plant model input generator must span all possible inputs to the plant and that the robustness of the estimator with respect to errors in model parameters depends on the eigen-structure of this sub-block. We give estimates of the bias on the estimated inputs/disturbances when the model is in error. The results of this paper provide insightful guidance in the design of Kalman filters for input deconvolution.
TOPICS: Design, Errors, Filters, Generators, Kalman filters, Linear systems, Robustness, Signals
Yan Gu, Bin Yao and C. S. George Lee
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038268
This paper focuses on the development of a model-based feedback controller to realize high versatility of fully actuated planar bipedal robotic walking. To conveniently define both symmetric and asymmetric walking patterns, we propose to use the left and the right legs for gait characterization. In addition to walking pattern tracking error, a biped's position tracking error in Cartesian space is included in the output function in order to enable high-level task planning and control such as multi-agent coordination. A feedback controller based on input-output linearization and proportional-derivative control is then synthesized to realize exponential tracking of the desired walking pattern as well as the desired global position trajectory. Sufficient stability conditions of the hybrid time-varying closed-loop system are developed based on the construction of multiple Lyapunov functions. In motion planning, a new method of walking pattern design is introduced, which decouples the planning of global motion and walking pattern. Finally, simulation results on a fully actuated planar biped showed the effectiveness of the proposed walking strategy.
TOPICS: Robotics, Control equipment, Errors, Feedback, Path planning, Simulation results, Construction, Trajectories (Physics), Design, Closed loop systems, Stability
Mohammed A. Hassan, Michael R. Habib, Rania A. Abul Seoud and Abdel M. Bayoumi
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4038243
Condition monitoring and fault diagnostics in rotorcraft have significant effect on improving safety level and reducing operational and maintenance costs. In this paper, a new method is proposed for fault detection and diagnoses of AH-64D (Apache helicopter) tail rotor drive shaft problems. The proposed method depends on decomposing signal into different frequency ranges using mother wavelet. The most informative part of the vibration signal is then determined by calculating Shannon entropy of each part. Bispectrum is calculated for this part to investigate quadratic nonlinearities in this segment. Then, search algorithm is used to extract minimum number of indicative features from the bispectrum which are then fed to classification algorithms. In order to quantitatively evaluate the proposed method, six classification algorithms is compared against each other such as fine K- nearest neighbor (KNN), cubic KNN, quadratic discriminant analysis, linear support vector machine (SVM), Gaussian SVM and neural network. Comparison criteria include accuracy, precision, sensitivity, F score, true alarm, and error classification accuracy (ECA). The proposed method is verified using real-world vibration data collected from a dedicated AH-64D helicopter tail-rotor drive-train research test bed. The proposed algorithm proves its ability in finding minimum number of indicative features and classifying the shaft faults with superior performance.
TOPICS: Wavelets, Algorithms, Support vector machines, Rotors, Vibration, Signals, Artificial neural networks, Condition monitoring, Errors, Flaw detection, Trains, Maintenance, Safety, Entropy

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