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Author

Rathindranath Maiti

Other affiliations: Indian Institutes of Technology
Bio: Rathindranath Maiti is an academic researcher from Indian Institute of Technology Kharagpur. The author has contributed to research in topics: Epitrochoid & Harmonic drive. The author has an hindex of 11, co-authored 38 publications receiving 379 citations. Previous affiliations of Rathindranath Maiti include Indian Institutes of Technology.

Papers
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Journal ArticleDOI
TL;DR: In this article, a wave generator is proposed to drive flex gears of harmonic drives with fully conjugate gear pairs of purely involute profiles, where the cam profile is made of circular arcs at the two diametrically opposite contact zones and shifted elliptical curves for the other two zones.
Abstract: Consider commercially available harmonic drives or strain wave gearings (all patented designs). The tooth profiles of the mating pairs of teeth of the noncircular (pitch curve) flex gear and circular (pitch circle) ring gears are nearly conjugate and noninvolute. Evidently none of them offers ideal gear kinematics. In this paper, we propose a new wave generator (or cam) to drive flex gears of harmonic drives with fully conjugate gear pairs of purely involute profiles. The cam profile is made of circular arcs at the two diametrically opposite contact zones and shifted elliptical curves for the other two zones. The geometric construction is done in such a way that tip interference is properly avoided for both engagement and disengagement with nominally stubbed or full depth tooth involute gears. We develop the theory of geometric and gearing conditions. We have also built a physical model in order to verify the geometry of tooth interference and other relevant gearing kinematics.

53 citations

Journal ArticleDOI
01 Mar 2002
TL;DR: In this paper, the steady state and dynamic characteristics of a two-stage pressure relief valve with proportional solenoid control of the pilot stage are studied theoretically as well as experimentally in the MATLAB-SIMULINK environment.
Abstract: The steady state and dynamic characteristics of a two-stage pressure relief valve with proportional solenoid control of the pilot stage is studied theoretically as well as experimentally. The mathematical model is studied within the MATLAB-SIMULINK environment and the non-linearities have been considered via the use of appropriate SIMULINK blocks. The detailed modelling has resulted in a good comparison between simulation and measurement, albeit assumptions had to be made regarding the solenoid dynamic characteristic based upon practical experience. The use of this characteristic combined with additional dynamic terms not previously considered allows new estimations of internal characteristics to be made such as the damping flowrate. The overall dynamic behaviour has been shown to be dominated by the solenoid characteristic relating force to applied voltage.

45 citations

Journal ArticleDOI
TL;DR: In this article, an attempt has been made to examine the possibility of lowering the difference as much as possible in the internal-external involute gear pair with the help of simple gear corrections, and it is found that by addendum modification the tooth difference can be reduced, though not to unity, from their value with full depth gears.

37 citations

Journal ArticleDOI
TL;DR: In this article, a method of estimating the load shared by the multiple tooth pairs in contact is proposed, where the load distribution pattern in proportion to the tooth deformation is considered.
Abstract: A harmonic drive is a two gear epicyclic drive with a gear set of circular ring gear (RG), a flex rimmed external toothed gear (FG) and an oval cam. FG, with oval cam inside, takes non-circular gear shape encounters improper teeth mating with RG, having only two teeth difference. Consequently, interferences occur at several tooth pairs even at no load. These are inherent and obvious. Overcoming such interferences and further with applied load estimation of load sharing by tooth pairs poses a complex problem. In solving it, first, tooth stiffness of internal gear and external gear are derived in the present investigation. A method of estimating the load shared by the multiple tooth pairs in contact is proposed. The load distribution pattern in proportion to the tooth deformation is considered. Load shared by contacting tooth pairs is estimated and stresses in FG cup are found out using FEM. Finally, such results are compared with experimental results, which have good agreement.

34 citations

Journal ArticleDOI
TL;DR: In this article, a kinematic analysis has been carried out to investigate the pattern of rolling and sliding at the load transmitting (active) contact regions in rotary piston machines with modified epitrochoids.

29 citations


Cited by
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MonographDOI
John Watton1
27 Mar 2014
TL;DR: In this article, the authors present a reference text for fluid power control, which is an ideal reference for the practicing engineer and a textbook for advanced courses in fluid power Control, and discuss many exciting challenges facing the fluid power engineer, who now must have a broad skill set.
Abstract: This exciting new reference text is concerned with fluid power control. It is an ideal reference for the practicing engineer and a textbook for advanced courses in fluid power control. In applications in which large forces and/or torques are required, often with a fast response time, oil-hydraulic control systems are essential. They excel in environmentally difficult applications because the drive part can be designed with no electrical components and they almost always have a more competitive power/weight ratio compared to electrically actuated systems. Fluid power systems have the capability to control several parameters, such as pressure, speed, position, and so on, to a high degree of accuracy at high power levels. In practice there are many exciting challenges facing the fluid power engineer, who now must preferably have a broad skill set.

101 citations

Journal ArticleDOI
TL;DR: The developed PRV can make the clutch actuator system have a fast response and a high flow capacity simultaneously simultaneously and infers from the experimental results that the feedback control can lead to excellent control precision.
Abstract: Precision control of clutch pressure is critical in heavy-duty automatic transmission applications in which the fast response of the clutch actuator is required. A conventional clutch actuator system with a pressure-reducing valve (PRV) is not applicable in this kind of application due to the fact that a large transient flow and high output power for power-on shift are necessary. In this paper, a pilot-operated PRV is developed for heavy-duty automatic transmission systems. The developed PRV can make the clutch actuator system have a fast response and a high flow capacity simultaneously. The PRV utilizes a three-stage structure with a high-speed proportional solenoid valve (PSV) as the pilot stage to do the tradeoff between the valve response and the flow capacity. First, a linearized input–output dynamic analytical model for the clutch pressure control system is developed based on fluid dynamics. Then, the parameters are identified, and the model is validated by using experimental data. For the validated input–output model, both open- and closed-loop (feedback) pressure control strategies are designed and implemented in a test setup. It infers from the experimental results that the feedback control can lead to excellent control precision. The developed clutch actuator system is applicable for heavy-duty automatic transmissions.

70 citations

Proceedings ArticleDOI
TL;DR: In this article, the authors present geometric and kinematic aspects that constitute a premise to the modelling and simulation of gerotor lubricating oil pumps, and two approaches to modelling are presented.
Abstract: The paper presents geometric and kinematic aspects that constitute a premise to the modelling and simulation of gerotor lubricating oil pumps. With reference to a commercial oil pump two different modelling approaches of the pumping elements are addressed: the classical integralderivative approach and the new derivative-integral approach. The latter, based on volumes swept by vector rays, is easier to implement and requires less computer time at equal accuracy. Two approaches to modelling are also detailed that feature different reticulations of the pump and consequently involve a different number of ordinary differential equations (ODE). Depending on the extent and detail of expected informations, either 4 or N+2 ODE must be solved, N being the number of variable volume chambers in the pump. Finally, numerical results of the simulation code, developed in the AMESim environment, have been compared with experimental results presented elsewhere [4].

68 citations

Journal ArticleDOI
TL;DR: In this paper, a complete method to design tooth profile and its backlash assessment in harmonic drive is presented, where parametric equations are expressed for all segments of the DCTP.

62 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed an effective methodology for the fluid-dynamic design optimization of the sliding spool of a hydraulic proportional directional valve, where the goal is to minimize the flow force at a prescribed flow rate, so as to reduce the required opening force while keeping the operation features unchanged.
Abstract: This article proposes an effective methodology for the fluid-dynamic design optimization of the sliding spool of a hydraulic proportional directional valve: the goal is the minimization of the flow force at a prescribed flow rate, so as to reduce the required opening force while keeping the operation features unchanged. A full three-dimensional model of the flow field within the valve is employed to accurately predict the flow force acting on the spool. A theoretical analysis, based on both the axial momentum equation and flow simulations, is conducted to define the design parameters, which need to be properly selected in order to reduce the flow force without significantly affecting the flow rate. A genetic algorithm, coupled with a computational fluid dynamics flow solver, is employed to minimize the flow force acting on the valve spool at the maximum opening. A comparison with a typical single-objective optimization algorithm is performed to evaluate performance and effectiveness of the employed geneti...

60 citations