Massimo Guiggiani - Academia.edu (original) (raw)

Papers by Massimo Guiggiani

Proceedings. IEEE/RSJ International Workshop on Intelligent Robots and Systems '. (IROS '89) 'The Autonomous Mobile Robots and Its Applications, 1989

In this paper the conceptual motivations and the implementation of a robotic leg-ankle-foot syste... more In this paper the conceptual motivations and the implementation of a robotic leg-ankle-foot system are presented. The system has been designed to serve as a testbed for investigating sonic basic problems of sensorbased legged locomotion. The leg is also cxpccted to be a module of a future four-or six-legged walking machine.

Volume 7: 10th International Power Transmission and Gearing Conference, 2007

ABSTRACT This paper outlines a systematic methodology for finding the machine setting corrections... more ABSTRACT This paper outlines a systematic methodology for finding the machine setting corrections required to obtain a predesigned ease-off surface in spiral bevel and hypoid gear teeth. The problem is given a nonlinear least squares formulation which, however, is highly prone to numerical instabilities. The Levenberg–Marquardt algorithm with a trust region strategy turned out to be quite effective and robust to obtain feasible solutions. The proposed method was tested on lengthwise crowning, profile crowning and spiral angle correction. In all cases, the goal was achieved with very high accuracy, in a few iterations and, remarkably, with different sets of machine parameters.

Volume 4: 9th International Power Transmission and Gearing Conference, Parts A and B, 2003

ABSTRACT Based on a recently developed geometric approach to the theory of gearing that does not ... more ABSTRACT Based on a recently developed geometric approach to the theory of gearing that does not make use of any reference systems [1], this paper presents some useful relations between the geometric properties of the enveloping surface and those of its envelope. Treating vectors as such, that is without expressing their components in any reference systems, it is possible to obtain compact expressions for the coefficients of the first and second fundamental forms of the envelope surface. These coefficients show to be central in the determination of the contact matrix between mating surfaces. Moreover, since this approach is coordinate free, it is valid regardless of the reference frame actually employed to perform calculations and allows a, hopefully, clearer understanding of the roles played by the intrinsic geometric properties of the enveloping surface, the relative position of the gear axes and the gear ratio.

Proceedings of the Winter Simulation Conference 2014, 2014

ABSTRACT

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2005

In the literature, some methods for curvature analysis of gears can be found, apparently very dif... more In the literature, some methods for curvature analysis of gears can be found, apparently very different from one another. This article presents a comparison of three approaches to stress their similarities or differences and field of application: the classic one by Litvin, its development by Chen and another one proposed by Wu and Luo and revisited by the present authors. All these methods are re-examined and expressed in a new form by means of a new approach to the theory of gearing that employs vectors and tensors. An extension of the relative motion is also considered, assuming translating axes of the gear pair and modified roll.

Mechanism and Machine Theory, 2006

In the first part, the alternative formulation of the theory of gearing presented in [F. Di Pucci... more In the first part, the alternative formulation of the theory of gearing presented in [F. Di Puccio, M. Gabiccini, M. Guiggiani, Alternative formulation of the theory of gearing, Mechanism and Machine Theory 40 (5) (2005) 613-637] is generalized to cope with the case of modified roll and translating axes of the mating surfaces, that is with a setting typical of some computer numerically controlled (CNC) machine. The peculiarity of the proposed approach is that it always deals with vectors as such, thus avoiding the need of a chain of reference systems, necessary when components are used as in the traditional method. It results in a more compact and clearer formulation. In the second part the proposed approach is applied to obtain the normal curvatures and geodesic torsions of two conjugate surfaces in a way that fully exploits the rigid-body relative motions involved in gear generation. In order to prove the ease of use and effectiveness of the proposed approach, the curvature analysis of a spiral bevel pinion generated on a CNC face-milling machine is performed.

Mechanism and Machine Theory, 2005

In this paper the theory of gearing is presented by means of a new approach that does not need re... more In this paper the theory of gearing is presented by means of a new approach that does not need reference systems. All equations are written in terms of vectors and therefore are valid regardless of the reference system actually employed. The overall formulation becomes more compact and clearer. As an example, the proposed approach is applied to the generation of spiral bevel gears. To actually perform all calculations, only one reference system is required, thus avoiding the chain of reference systems typical of the traditional approach.

Meccanica, 2007

In this paper an innovative joint for the transmission of motion between parallel and incident ax... more In this paper an innovative joint for the transmission of motion between parallel and incident axes is presented. It is made up of two frontal pinwheels with cylindrical pins. The kinematics in case of parallel axes is discussed in detail. It is shown that, quite surprisingly, it may behave in many different ways, depending on the value of the center distance between the two axes. A systematic way to analyze the joint kinematics is provided.

Journal of Mechanical Design, 2013

ABSTRACT Tooth surface modifications are small, micron-level intentional deviations from perfect ... more ABSTRACT Tooth surface modifications are small, micron-level intentional deviations from perfect involute geometries of spur and helical gears. Such modifications are aimed at improving contact pressure distribution, while minimizing the motion transmission error to reduce noise excitations. In actual practice, optimal modification requirements vary with the operating torque level, misalignments, and manufacturing variance. However, most gear literature has been concerned with determining optimal flank form modifications at a single design point, represented by fixed, single load and misalignment values. A new approach to the design of tooth surface modifications is proposed to handle such conditions. The problem is formulated as a robust design optimization problem, and it is solved, in conjunction with an efficient gear contact solver (LDP), by a direct search, global optimization algorithm aimed at guaranteeing global optimality of the obtained micro-geometry solutions. Several tooth surface modifications can be used as micro-geometry design variables, including profile, lead, and bias modifications. Depending on the contact solver capabilities, multiple performance metrics can be considered. The proposed method includes the capability of simultaneously and robustly handling several conflicting design objectives. In the present paper, peak contact stress and loaded transmission error amplitude are used as objective functions (to be minimized). At the end, two example optimizations are presented to demonstrate the effectiveness of the proposed method.

Journal of Mechanical Design, 2008

This paper presents a new systematic method for identifying the values of the machinetool setting... more This paper presents a new systematic method for identifying the values of the machinetool settings required to obtain flank form modifications in hypoid gears. The problem is given a nonlinear least-squares formulation, and it is solved by the Levenberg-Marquardt method with a trust-region strategy. To test the method, the same ease-off topography was obtained by means of very different sets of machine-tool settings, including a set of only kinematic parameters and a highly redundant set of 17 parameters. In all cases, the goal was achieved in a few iterations, with residual errors well below machining tolerances and, even more importantly, with realistic values of all parameters. Therefore, significant improvements in practical gear design can be achieved by employing the overall proposed procedure.

Journal of Mechanical Design, 2011

ABSTRACT Micro-geometry optimization has become an important phase of gear design that can remark... more ABSTRACT Micro-geometry optimization has become an important phase of gear design that can remarkably enhance gear performance. For spiral bevel and hypoid gears, micro-geometry is typically represented by ease-off topography. The optimal ease-off shape can be defined as the outcome of a process where generally conflicting objective functions are simultaneously minimized (or maximized), in the presence of constraints. This matter naturally lends itself to be framed as a multi-objective optimization problem. This paper proposes a general algorithmic framework for ease-off multi-objective optimization, with special attention to computational efficiency. Its implementation is fully detailed. A simulation model for loaded tooth contact analysis is assumed to be available. The proposed method is tested on a face-hobbed hypoid gear set. Three objectives are defined: maximization of mechanical efficiency, minimization of loaded transmission error, minimization of maximum contact pressure. Bound constraints on the design variables are imposed, as well as a nonlinear constraint aimed at keeping the loaded contact pattern inside a predefined allowable contact region. The results show that the proposed method can obtain optimal ease-off topographies that significantly improve the basic design performances. It is also evident that the method is general enough to handle geometry optimization of any gear type.

Journal of Mechanical Design, 2009

ABSTRACT Systematic optimization of the tooth contact pattern under load is an open problem in th... more ABSTRACT Systematic optimization of the tooth contact pattern under load is an open problem in the design of spiral bevel and hypoid gears. In order to enhance its shape and position, gear engineers have been assisted by numerical tools based on trial-and-error approaches, and/or they have been relying on the expertise of skilled operators. The present paper proposes a fully automatic procedure to optimize the loaded tooth contact pattern, with the advantage of eventually reducing design time and cost. The main problem was split into two identification subproblems: first, to identify the ease-off topography capable of optimizing the contact pattern; second, to identify the machine-tool setting variations required to obtain such ease-off modifications. Both of them were formulated and solved as unconstrained nonlinear optimization problems. In addition, an original strategy to quickly approximate the tooth contact pattern under load was conceived. The results obtained were very satisfactory in terms of accuracy, robustness, and computational speed. They also suggest that the time required to optimize the contact pattern can be significantly reduced compared with typical time frames. A sound mathematical framework ensures results independent of the practitioner's subjective decision-making process. By defining a proper objective function, the proposed method can also be applied to affect other contact properties, such as to improve the motion graph or to decrease the sensitivity of the transmission to assembly errors. Furthermore, it can be easily adapted to any gear drive by virtue of its systematic and versatile nature. [DOI: 10.1115/1.3013844]

Journal of Mechanical Design, 2010

This paper presents an automatic procedure to optimize the loaded tooth contact pattern of face-m... more This paper presents an automatic procedure to optimize the loaded tooth contact pattern of face-milled hypoid gears with misalignments varying within prescribed ranges. A two-step approach is proposed to solve the problem: in the first step, the pinion tooth microtopography is automatically modified to bring the perturbed contact patterns (as the assembly errors are varied within the tolerance limits) match a target area of the tooth while keeping them off the edges; in the second step, a subset of the machine-tool settings is identified to obtain the required topography modifications. Both steps are formulated and solved as unconstrained nonlinear optimization problems. While the general methodology is similar to the one recently proposed by the same authors for the optimization at nominal conditions, here, the robustness issues with respect to misalignment variations are considered and directly included in the optimization procedure: no a posteriori check for robustness is therefore required. Numerical tests show that nominally satisfactory and globally robust hypoid pairs can be designed by a direct process and within a unified framework, thus avoiding tiresome trial-and-error loops.

Journal of Mechanical Design, 2012

ABSTRACT In this paper we set out to investigate the performances of some of the algorithms propo... more ABSTRACT In this paper we set out to investigate the performances of some of the algorithms proposed in the gear literature for identifying the machine-settings required to obtain predesigned gear tooth surface topographies, or needed to compensate for flank form deviations of real teeth. For the ease of comparison, the problem is formulated as a nonlinear least-squares minimization, and the most widely employed algorithms are derived as particular cases. The algorithms included in the analysis are: (i) one-step methods; (ii) iterative methods; (iii) iterative methods with step control. The performance index is devised in their ability of returning practical solutions in the presence of: (i) strong model nonlinearities, (ii) ill-conditioning of the sensitivity matrix, (iii) demanding topographic shapes purposely selected. Instrumental here is an original classification of topographic modifications as either “simple” or “complex”, based on the SVD analysis of the sensitivity matrix. On the basis of the numerical tests documented, iterative techniques with step control seem the most convenient, due to reliability and robustness of the solutions produced. The generation process here considered is face-milling of hypoid gears, even though the methodology is general enough to cope with any gear cutting method requiring only some minor technical changes.

Journal of Applied Mechanics, 1992