A CAD Package for High-Speed Cam Design Based on Direct Multiple Shooting Optimal Control Techniques

2004 ◽  
Author(s):  
Sebastian Mennicke ◽  
Richard W. Longman ◽  
Meng-Sang Chew ◽  
Hans Georg Bock
Keyword(s):  
Optimal Control ◽  
High Speed ◽  
Optimality Criteria ◽  
Iterative Refinement ◽  
Valve Train ◽  
Design Stage ◽  
Multiple Shooting ◽  
Cam Design ◽  
Trade Offs ◽  
Highly Nonlinear

High-speed automotive valve train design requires realistic models of the valve train. However, this frequently results in highly nonlinear systems with discontinuities and constraints. Optimality criteria and trade-offs for the designs are frequently performed through a process of simulation and iterative refinement. This paper presents CamOE, a cam design optimization package based on direct multiple shooting optimal control theory, incorporating structured sequential quadratic programming. The code allows the designer to incorporate the constraints of importance and to consider and synthesize appropriate optimality criteria. This allows him or her to synthesize the cam profile at the design stage without resorting to a tedious trial-and-error design process. This paper presents CamOE as a software environment that permits rapid feedback to the designer through the process of numerical experiments in specifying criteria and constraints on the automotive valve train.

High Speed Automotive Cam Design Using Direct Multiple-Shooting Optimal Control Techniques

2004 ◽  
Author(s):  
Sebastian Mennicke ◽  
Richard W. Longman ◽  
Meng-Sang Chew ◽  
Hans Georg Bock
Keyword(s):  
Optimal Control ◽  
Contact Stress ◽  
High Speed ◽  
Numerical Solutions ◽  
Inequality Constraints ◽  
Optimization Procedure ◽  
Hertzian Contact ◽  
Design Stage ◽  
Multiple Shooting ◽  
Cam Design

Prior investigations have presented the use of optimal control theory in the design of high-speed cam follower systems. These investigations were constrained by the difficulty of numerical solutions of optimal control problems, and this limited the types of criteria investigated, the state inequality constraints considered, and the realism of the models used. In recent years numerical solution techniques based on direct multiple shooting and using specially structured sequential quadratic programming have become available. These are capable of handling complex optimization criteria and imposing state and control in-equality constraints. This paper investigates and illustrates the potential of such methods in revolutionizing high speed automotive cam design. Cam design is complicated by the number of partially competing criteria one is interested in. This work synthesizes an optimal cam design approach, considering a range of speeds, the area under the lift curve, Hertzian contact stress, vibrations and residual vibrations, energy loss, cam curvature, follower force, and contact stress. The paper illustrates how all of these criteria can be integrated into the optimization in the design stage. Since the polydyne method is not an optimization procedure, the resulting design is superior to polydyne design in all aspects considered.

Application of Optimal Control Theory to the Synthesis of High-Speed Cam-Follower Systems. Part 1: Optimality Criterion

1983 ◽  
Vol 105 (3) ◽  
pp. 576-584 ◽  
Author(s):  
M. Chew ◽  
F. Freudenstein ◽  
R. W. Longman
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Dynamic Response ◽  
Optimal Control Theory ◽  
High Speed ◽  
Integrated Approach ◽  
Optimization Criterion ◽  
Design Stage ◽  
Trade Offs ◽  
Cam Follower

The synthesis of the parameters governing the dynamic response of high-speed cam-follower systems ideally involves an integrated approach capable of carrying out the tradeoffs necessary to achieve optimum dynamic response in the design stage. These trade-offs involve a balance between the system characteristics at the output and at the cam-follower interface. In this investigation optimal-control theory has been demonstrated to be a useful tool in developing such a tradeoff. Part 1 describes the development of an optimization criterion while Part 2 describes the application of optimal-control theory to the evaluation of system parameters satisfying the optimization criterion.

scholarly journals Minimum Time Approach to Emergency Collision Avoidance by Vehicle Handling Inverse Dynamics

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Wang Wei ◽  
Bei Shaoyi ◽  
Yang Hui ◽  
Wang Yongzhi ◽  
Zhang Lanchun
Keyword(s):  
Optimal Control ◽  
Collision Avoidance ◽  
High Speed ◽  
Inverse Dynamics ◽  
Avoidance Performance ◽  
Control Object ◽  
Minimum Time ◽  
Driving Safety ◽  
Multiple Shooting ◽  
Vehicle Handling

Vehicle driving safety is the urgent key problem to be solved of automobile independent development while encountering emergency collision avoidance with high speed. And it is also the premise and one of the necessary conditions of vehicle active safety. A new technique of vehicle handling inverse dynamics which can evaluate the emergency collision avoidance performance is proposed. Based on optimal control theory, the steering angle input and the traction/brake force imposed by driver are the control variables; the minimum time required to complete the fitting biker line change is the control object. By using the improved direct multiple shooting method, the optimal control problem is converted into a nonlinear programming problem that is then solved by means of the sequential quadratic programming. The simulation results show that the proposed method can solve the vehicle minimum time maneuver problem, and can compare the maneuverability of two different vehicles that complete fitting biker line change with the minimum time and the correctness of the model is verified through real vehicle test.

Model-Based Optimal Control for Underwater Robotics

2010 ◽  
Author(s):  
Yingfeng Ji ◽  
Ryoichi S. Amano ◽  
Ronald A. Perez
Keyword(s):  
High Speed ◽  
Linear Control ◽  
Design Stage ◽  
Underwater Robotics ◽  
Fluid Forces ◽  
Nonlinear Properties ◽  
Highly Nonlinear ◽  
Control Technologies ◽  
The One ◽  
External Forces

It is always one of the most challenging problems to control an underwater robotics due to the complex external forces in an underwater environment. It is difficult to obtain an ideal control performance using linear control technologies due to highly nonlinear properties of system. A valid method of linearization for nonlinear system is provided in this study. Based on this linearized system, the linear control theories were therefore employed for the tracking control of underwater robotics. The panning and tilting motions of this underwater robotics can basically track two given sinusoidal references based on the simulation results. In order to achieve a high-speed manipulation of this underwater robotics, fluid forces have to be considered and modeled. A computational fluid dynamics (CFD) technology is adopted in order to obtain more precise hydrodynamic models for simulation at the design stage. Two torque models that represent the degree of freedoms (DOFs) of panning and tilting respectively have been developed using the CFD software. The dynamic model of this robotics used in this paper is the one by Ji, et al [1].

The Design of High-Speed Dwell-Rise-Dwell Cams Using Linear Quadratic Optimal Control Theory

1994 ◽  
Vol 116 (3) ◽  
pp. 867-874 ◽  
Author(s):  
B. C. Fabien ◽  
R. W. Longman ◽  
F. Freudenstein
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Optimal Control Theory ◽  
High Speed ◽  
Numerical Procedure ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Trajectory Sensitivity ◽  
Cam Design ◽  
Quadratic Optimal Control

This paper uses linear quadratic optimal control theory to design high-speed Dwell-Rise-Dwell (D-R-D) cams. Three approaches to D-R-D cam design are compared. In the first approach the cam is designed to be optimal at a fixed operating speed, i.e., a tuned cam design is obtained. In the second approach the cam profile is determined by minimizing a sum of quadratic cost functions over a range of discrete speeds, thus producing a cam-follower system which is optimal over a range of speeds. The third technique uses trajectory sensitivity minimization to design a cam which is insensitive to speed variations. All design methods are formulated as linear quadratic optimal control problems and solved using an efficient numerical procedure. It is shown that the design techniques developed can lead to cams that have significantly lower peak contact stress, contact force and energy loss when compared to a polydyne cam design. Furthermore, the trajectory sensitivity minimization approach is shown to yield cams that have lower residual vibration, over a range of speeds, when compared to a polydyne cam design.

scholarly journals Using optimal control to understand complex metabolic pathways

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Nikolaos Tsiantis ◽  
Julio R. Banga
Keyword(s):  
Optimal Control ◽  
Metabolic Pathways ◽  
Regulatory Networks ◽  
Complex Dynamics ◽  
Cost Benefit ◽  
Optimality Criteria ◽  
Enzyme Activation ◽  
Computational Framework ◽  
Trade Offs ◽  
Optimality Principles

Abstract Background Optimality principles have been used to explain the structure and behavior of living matter at different levels of organization, from basic phenomena at the molecular level, up to complex dynamics in whole populations. Most of these studies have assumed a single-criteria approach. Such optimality principles have been justified from an evolutionary perspective. In the context of the cell, previous studies have shown how dynamics of gene expression in small metabolic models can be explained assuming that cells have developed optimal adaptation strategies. Most of these works have considered rather simplified representations, such as small linear pathways, or reduced networks with a single branching point, and a single objective for the optimality criteria. Results Here we consider the extension of this approach to more realistic scenarios, i.e. biochemical pathways of arbitrary size and structure. We first show that exploiting optimality principles for these networks poses great challenges due to the complexity of the associated optimal control problems. Second, in order to surmount such challenges, we present a computational framework which has been designed with scalability and efficiency in mind, including mechanisms to avoid the most common pitfalls. Third, we illustrate its performance with several case studies considering the central carbon metabolism of S. cerevisiae and B. subtilis. In particular, we consider metabolic dynamics during nutrient shift experiments. Conclusions We show how multi-objective optimal control can be used to predict temporal profiles of enzyme activation and metabolite concentrations in complex metabolic pathways. Further, we also show how to consider general cost/benefit trade-offs. In this study we have considered metabolic pathways, but this computational framework can also be applied to analyze the dynamics of other complex pathways, such as signal transduction or gene regulatory networks.

Optimum Balancing of Combined Shaking Force, Shaking Moment, and Torque Fluctuations in High-Speed Linkages

1984 ◽  
Vol 106 (2) ◽  
pp. 242-251 ◽  
Author(s):  
T. W. Lee ◽  
C. Cheng
Keyword(s):  
High Speed ◽  
Optimization Technique ◽  
Integrated Approach ◽  
Optimization Techniques ◽  
Theoretical Development ◽  
Design Stage ◽  
Heuristic Optimization ◽  
Analytical Mechanics ◽  
Trade Offs ◽  
Shaking Moment

This paper presents an analytical and computer-aided procedure on the balancing of high-speed linkages. The method allows for the trade-offs necessary to achieve optimum dynamic response of the linkage in the design stage. These trade-offs involve a balance among the shaking force, the shaking moment, bearing reactions, and input-torque fluctuations by mass distribution of the links or counterweighting the linkage. Analytical mechanics and heuristic optimization techniques have been demonstrated to be useful tools in developing such a trade-off. The first part of this paper concerns the development of an optimality criterion in which an integrated approach is presented using both the Lagrangian and the Newtonian formulations, and consequently, a higher computational efficiency is achieved. Based on this theoretical development, the remainder of the paper focuses on the formulation of an optimization problem for linkage balancing and the solution of the problem by the Heuristic Optimization Technique of Lee and Freudenstein. The theory and computation are illustrated by numerical examples in the case of four-bar linkages.

Algorithm for optimal allocation of limited resources based on the game iteration method

2019 ◽  
pp. 89-99
Author(s):  
V. Ya. Vilisov
Keyword(s):  
Optimal Control ◽  
Linear Programming ◽  
Embedded Systems ◽  
Iterative Method ◽  
High Speed ◽  
Optimal Allocation ◽  
Software Implementation ◽  
Limited Resources ◽  
Matrix Game ◽  
Acceptable Accuracy

The article proposes an algorithm for solving a linear programming problem (LPP) based on the use of its representation in the form of an antagonistic matrix game and the subsequent solution of the game by an iterative method. The algorithm is implemented as a computer program. The rate of convergence of the estimates of the solution to the actual value with the required accuracy has been studied. The software implementation shows a high speed of obtaining the LPP solution with acceptable accuracy in fractions or units of seconds. This allows the use algorithm in embedded systems for optimal control.

scholarly journals Alternative Agri-Food Systems Under a Market Agencements Approach: The Case of Multifunctional Farming Activity in a Peri-Urban Area

Environments ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 61
Author(s):  
Maria Cecilia Mancini ◽  
Filippo Arfini ◽  
Federico Antonioli ◽  
Marianna Guareschi
Keyword(s):  
Urban Area ◽  
Food Systems ◽  
Food System ◽  
Large Body ◽  
Alternative Food ◽  
Design Stage ◽  
Alternative Food Networks ◽  
Alternative Food Systems ◽  
Design And Implementation ◽  
Trade Offs

(1) Background: A large body of literature is available on the environmental, social, and economic sustainability of alternative food systems, but not much of it is devoted to the dynamics underlying their design and implementation, more specifically the processes that make an alternative food system successful or not in terms of its sustainability aims. This gap seems to be particularly critical in studies concerning alternative food systems in urban and peri-urban agriculture (UPA). This paper explores how the design and implementation of multifunctional farming activity in a peri-urban area surrounding the city of Reggio Emilia in the Emilia-Romagna region of Italy impact the achievement of its sustainability aims. (2) Methods: The environmental, social, and economic components of this project are explored in light of the sociology of market agencements. This method brings up the motivations of the human entities involved in the project, the role played by nonhuman entities, and the technical devices used for the fulfillment of the project’s aims. (3) Results: The alternative food system under study lacked a robust design phase and a shared definition of the project aims among all the stakeholders involved. This ended in a substantial mismatch between project aims and consumer expectations. (4) Conclusions: When a comprehensive design stage is neglected, the threefold aim concerning sustainability might not be achievable. In particular, the design of alternative food systems must take into account the social environment where it is intended to be put in place, especially in UPA, where consumers often live in suburban neighborhoods wherein the sense of community is not strong, thus preventing them from getting involved in a community-based project. In such cases, hybridization can play a role in the sustainability of alternative food networks, provided that some trade-offs occur among the different components of sustainability—some components of sustainability will be fully achieved, while others will not.

scholarly journals Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4144
Author(s):  
Yatai Ji ◽  
Paolo Giangrande ◽  
Vincenzo Madonna ◽  
Weiduo Zhao ◽  
Michael Galea
Keyword(s):  
Power Density ◽  
High Speed ◽  
High Performance ◽  
Low Voltage ◽  
Electrical Machines ◽  
Design Stage ◽  
Switching Frequency ◽  
Special Focus ◽  
Electrical Machine ◽  
Engineering Approach

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.

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