scholarly journals Hull Shape Actuation for Speed Regulation in an Underwater Vehicle

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Levi DeVries ◽  
Michael D. M. Kutzer ◽  
Archie Bass ◽  
Rebecca Richmond
Keyword(s):  
Spatial Scales ◽  
Autonomous Underwater Vehicles ◽  
Major Axis ◽  
Great Promise ◽  
Control Input ◽  
Vehicle Speed ◽  
Semi Major Axis ◽  
Modeling And Control ◽  
Speed Regulation ◽  
And Control

Abstract Autonomous underwater vehicles (AUVs) have shown great promise in fulfilling surveillance, scavenging, and monitoring tasks. Traditional gliders and streamlined AUVs are designed for long-term operational efficiency in expansive environments but are limited in cluttered spaces due to their shape and control authority; agile AUVs can penetrate cluttered or sensitive environments but are limited in operational endurance at large spatial scales. This paper presents the dynamic modeling and control design of an underwater hull capable of actuating its shape morphology. The prototype hull incorporates flexible, buckled fiberglass ribs to ensure a rigid shape that is actuated by modulating the length of the body’s semi-major axis. We represent the vehicle shape using a single control input actuating the vehicle’s length-to-diameter ratio. Hydrodynamic modeling of the flexible hull suggests that dynamic shape actuation can modulate the mass and drag properties of the hull to improve control of the vehicle’s forward speed. Using tools from nonlinear control theory, this paper presents the derivation of a shape-actuating autonomous control algorithm regulating the vehicle speed to a time-varying reference speed, subject to the actuator limits. The theoretical control results are illustrated using numerical simulations of the vehicle model.

Design, Modeling, and Experimental Drag Characterization of a Bio-Inspired, Shape-Adapting Underwater Vehicle

2018 ◽  
Author(s):  
Levi D. DeVries ◽  
Michael D. M. Kutzer ◽  
Rebecca E. Richmond ◽  
Archie C. Bass
Keyword(s):  
Spatial Scales ◽  
Autonomous Underwater Vehicles ◽  
Major Axis ◽  
Underwater Vehicle ◽  
Great Promise ◽  
Hydrodynamic Drag ◽  
Control Input ◽  
Semi Major Axis ◽  
Generative Modeling

Autonomous underwater vehicles (AUVs) have shown great promise in fulfilling surveillance, scavenging, and monitoring tasks, but can be hindered in expansive, cluttered or obstacle ridden environments. Traditional gliders and streamlined AUVs are designed for long term operational efficiency in expansive environments, but are hindered in cluttered spaces due to their shape and control authority; agile AUVs can penetrate cluttered or sensitive environments but are limited in operational endurance at large spatial scales. This paper presents the prototype testbed design, modeling, and experimental hydrodynamic drag characterization of a novel self-propelled underwater vehicle capable of actuating its shape morphology. The vehicle prototype incorporates flexible, buckled fiberglass ribs to ensure a rigid shape that can be actuated by modulating the length of the semi-major axis. Tools from generative modeling are used to represent the vehicle shape by using a single control input actuating the vehicles length-to-diameter ratio. By actuating the length and width characteristics of the vehicle’s shape to produce a desired drag profile, we derive the feasible speeds achievable by shape actuation control. Tow-tank experiments with an experimental proto-type suggest shape actuation can be used to manipulate the drag by a factor between 2.15 and 5.8 depending on the vehicle’s operating speed.

Modeling and Control of a Rotary Crane

1985 ◽  
Vol 107 (3) ◽  
pp. 200-206 ◽  
Author(s):  
Y. Sakawa ◽  
A. Nakazumi
Keyword(s):  
Feedback Control ◽  
Equilibrium State ◽  
Open Loop ◽  
The State ◽  
Control Input ◽  
Loop Control ◽  
Modeling And Control ◽  
Control Scheme ◽  
Rotary Crane ◽  
And Control

In this paper we first derive a dynamical model for the control of a rotary crane, which makes three kinds of motion (rotation, load hoisting, and boom hoisting) simultaneously. The goal is to transfer a load to a desired place in such a way that at the end of transfer the swing of the load decays as quickly as possible. We first apply an open-loop control input to the system such that the state of the system can be transferred to a neighborhood of the equilibrium state. Then we apply a feedback control signal so that the state of the system approaches the equilibrium state as quickly as possible. The results of computer simulation prove that the open-loop plus feedback control scheme works well.

scholarly journals Modeling and Control of Crane Overload Protection During Marine Lifting Operation Based on Model Predictive Control

2017 ◽  
Author(s):  
Zhengru Ren ◽  
Roger Skjetne ◽  
Zhen Gao
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Pid Controller ◽  
Degrees Of Freedom ◽  
Multiple Shooting ◽  
Control Input ◽  
Lumped Mass ◽  
Modeling And Control ◽  
Overload Protection ◽  
And Control

This paper deals with a nonlinear model predictive control (NMPC) scheme for a winch servo motor to overcome the sudden peak tension in the lifting wire caused by a lumped-mass payload at the beginning of a lifting off or a lowering operation. The crane-wire-payload system is modeled in 3 degrees of freedom with the Newton-Euler approach. Direct multiple shooting and real-time iteration (RTI) scheme are employed to provide feedback control input to the winch servo. Simulations are implemented with MATLAB and CaSADi toolkit. By well tuning the weighting matrices, the NMPC controller can reduce the snatch loads in the lifting wire and the winch loads simultaneously. A comparative study with a PID controller is conducted to verify its performance.

scholarly journals Modeling of Autonomous Underwater Vehicles with Multi-Propellers Based on Maximum Likelihood Method

2020 ◽  
Vol 8 (6) ◽  
pp. 407
Author(s):  
Feiyan Min ◽  
Guoliang Pan ◽  
Xuefeng Xu
Keyword(s):  
Maximum Likelihood ◽  
Controller Design ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Likelihood Method ◽  
Hydrodynamic Characteristics ◽  
Identification Algorithm ◽  
Modeling And Control ◽  
Good Convergence ◽  
And Control

The hydrodynamic characteristics of multi-propeller autonomous underwater vehicles (AUV) is usually complicated and it is difficult to obtain an accurate mathematical model. A modeling method based on CFD calculation and maximum likelihood identification algorithm is proposed for this problem. Firstly, rough hydrodynamic parameters of AUV hull are obtained by CFD calculation. Secondly, on the basis of rough parameters, a maximum likelihood identification algorithm is proposed to adjust the parameters and improve the model precision. Besides, the method to improve the convergence of identification algorithm is analyzed by considering the characteristics of AUV model structure. Finally, the identification algorithm and identification results were validated with experimental data. It was found that this method has good convergence and adaptability. In particular, the identification results of turning force and torque parameters are highly consistent in different identification experiments, which indicates that this method can well extract the maneuvering characteristics of AUVs, thus contributing to the controller design of AUVs. The research of this paper has potential application for the modeling and control of multi-propeller AUVs.

Frequency Domain Uncertainty Modeling and Quantification of the Laser Metal Deposition Process

2016 ◽  
Author(s):  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers
Keyword(s):  
Frequency Domain ◽  
Uncertainty Modeling ◽  
Deposition Process ◽  
Metal Deposition ◽  
Great Promise ◽  
Laser Metal Deposition ◽  
Modeling And Control ◽  
Metal Parts ◽  
Modeling Uncertainties ◽  
And Control

Additive Manufacturing (AM) is a growing class of manufacturing processes where parts are fabricated by repeated addition of material. Many of these processes show great promise for the production of complex, functional parts for use in critical applications. One such process, Laser Metal Deposition (LMD), uses a laser and a coaxial blown metal powder source to produce functional metal parts. However, it has been demonstrated that the LMD process possesses complex two-dimensional dynamics which, when not appropriately accounted for in the modeling and control stages, can lead to build failures. Additionally, even when the two-dimensionality of the process is accounted for, modeling and process uncertainties can lead to degraded performance or instability. Here, in the context of a control oriented model of the LMD process developed previously, process and modeling uncertainties are modeled and quantified in the frequency domain.

Dynamic Modeling and Control of a Ball-Joint-Like Variable-Reluctance Spherical Motor

1996 ◽  
Vol 118 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Kok-Meng Lee ◽  
Ronald B. Roth ◽  
Zhi Zhou
Keyword(s):  
Dynamic Modeling ◽  
Rotor Dynamics ◽  
Inverse Model ◽  
Control Input ◽  
Forward Dynamics ◽  
Modeling And Control ◽  
Spherical Motor ◽  
Variable Reluctance ◽  
Robot Wrist ◽  
And Control

Examination of existing joint designs for robot wrist applications has indicated that a spherical wrist motor offers a major performance advantage in trajectory planning and control as compared to the popular three-consecutive-rotational joint wrist. The tradeoff, however, is the complexity of the dynamic modeling and control. This paper presents the dynamic modeling and the control strategy of a three degree-of-freedom (DOF) variable-reluctance (VR) spherical motor which presents some attractive possibilities by combining pitch, roll, and yaw motion in a single joint. The spherical motor dynamics consist of the rotor dynamics and a torque model. The torque model is described as a function of coil excitations and a permeance model in terms of the relative position between the rotor and the stator. Both the forward dynamics which determine the rotor motion as a result of activating the electromagnetic coils and the inverse model which determines the coil excitations required to generate the desired torque are derived in this paper. The solution to the forward dynamics of the spherical motor is unique, but the inverse model has many solutions and therefore an optimization is desired. Experimental results verifying the dynamic model are presented. The control of a VR spherical motor consists of two parts; namely, the control of the rotor dynamics with the actuating torque as system input, and the determination of the optimal electrical inputs for a specified actuating torque. The simulation results and implementation issues in determining the optimal control input vectors are addressed. It is expected that the resulting analysis will serve as a basis for dynamic modeling, motion control development, and design optimization of the VR spherical motor.

Modeling and Control of a Hybrid Opposed Piston Engine

2021 ◽  
Author(s):  
Joseph Drallmeier ◽  
Jason B. Siegel ◽  
Robert Middleton ◽  
Anna G. Stefanopoulou ◽  
Ashwin Salvi ◽  
...  
Keyword(s):  
Exchange Process ◽  
Tracking Error ◽  
Control Input ◽  
Hybrid Architecture ◽  
Electric Motors ◽  
Linear Quadratic ◽  
Modeling And Control ◽  
1D Model ◽  
Gas Exchange Process ◽  
And Control

Abstract This paper presents the modeling and control of an opposed piston (OP) engine in a novel hybrid architecture. The OP engine was selected for this work due to the inherent thermody-namic benefits and the balanced nature of the engine. The typical geartrain required on an OP engine was exchanged for two electric motors, significantly reducing friction and decoupling the crankshafts. By using the motors to control the crankshaft motion profiles, this configuration introduces capabilities to dynamically vary compression ratio, combustion volume, and scavenging dynamics. To realize these opportunities, a model of the system capturing the instantaneous engine dynamics is essential along with methodology to regulate the crankshaft’s rotational dynamics utilizing the electric motors. The modeling presented here couples a 1D model capturing the gas exchange process during scavenging and a 0D model of the crankshaft dynamics and the heat release profile due to combustion. With the use of this model, a linear quadratic controller with reference feedforward was designed to track the crankshaft motion trajectory. Experimental results are used to validate the model and controller performance. These results highlight the sensitivity to model uncertainty at points with high cylinder pressure, leading to large differences in control input near minimum volume. The proposed controller is, however, still able to maintain tracking error for crankshaft position below ± 1 degree.

scholarly journals AUV Trajectory Tracking Models and Control Strategies: A Review

2021 ◽  
Vol 9 (9) ◽  
pp. 1020
Author(s):  
Daoliang Li ◽  
Ling Du
Keyword(s):  
Trajectory Tracking ◽  
Tracking Control ◽  
Reference Model ◽  
Control Strategies ◽  
Autonomous Underwater Vehicles ◽  
Trajectory Tracking Control ◽  
Open Problems ◽  
Modeling And Control ◽  
Motion System ◽  
And Control

Autonomous underwater vehicles (AUVs) have been widely used to perform underwater tasks. Due to the environmental disturbances, underactuated problems, system constraints, and system coupling, AUV trajectory tracking control is challenging. Thus, further investigation of dynamic characteristics and trajectory tracking control methods of the AUV motion system will be of great importance to improve underwater task performance. An AUV controller must be able to cope with various challenges with the underwater vehicle, adaptively update the reference model, and overcome unexpected deviations. In order to identify modeling strategies and the best control practices, this paper presents an overview of the main factors of control-oriented models and control strategies for AUVs. In modeling, two fields are considered: (i) models that come from simplifications of Fossen’s equations; and (ii) system identification models. For each category, a brief description of the control-oriented modeling strategies is given. In the control field, three relevant aspects are considered: (i) significance of AUV trajectory tracking control, (ii) control strategies; and (iii) control performance. For each aspect, the most important features are explained. Furthermore, in the aspect of control strategies, mathematical modeling study and physical experiment study are introduced in detail. Finally, with the aim of establishing the acceptability of the reported modeling and control techniques, as well as challenges that remain open, a discussion and a case study are presented. The literature review shows the development of new control-oriented models, the research in the estimation of unknown inputs, and the development of more innovative control strategies for AUV trajectory tracking systems are still open problems that must be addressed in the short term.

Optimum Pressure Control of Molten Metals for Casting Production Using a Novel Greensand Mold Press Casting Method

2010 ◽  
Vol 457 ◽  
pp. 453-458
Author(s):  
Kazuhiko Terashima ◽  
Ryosuke Tasaki ◽  
Yoshiyuki Noda ◽  
Kunihiro Hashimoto ◽  
Junichi Iwasaki ◽  
...  
Keyword(s):  
Pressure Control ◽  
Control Input ◽  
Molten Metals ◽  
Key Factors ◽  
Optimum Pressure ◽  
Modeling And Control ◽  
Casting Technique ◽  
Sequential Control ◽  
Novel Method ◽  
And Control

This paper presents a novel method of sand mold press casting. In this process, molten metal is poured into a drag mold, and then the cope mold is placed on top of the drag mold, and the two molds are matched. The mold design for casting, the pouring control and the velocity control of the press have been previously clarified as key factors in the manufacture of sound products. This paper presents methods for modeling and control of the molten metal’s pressure for novel sand press casting technique. Substituting detailed information for the complex mold shape, the poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the sequential control algorithm based on the construction of an inverse system comprised of a sequential switching from higher to lower speed. The effectiveness of adaptive press casting is demonstrated by using CFD model simulations.

Sign in / Sign up

Export Citation Format

Share Document