References of "Muralidharan, Vivek 50044609"
     in
Bookmark and Share    
Full Text
See detailDeparture and Trajectory Design Applications using Stretching Directions
Muralidharan, Vivek UL; Howell, Kathleen C.

Scientific Conference (2021, August)

Stable or nearly stable orbits do not always possess well-distinguished manifold structures that assist in departing from or arriving onto the orbit. Generally, for potential missions, the orbits of ... [more ▼]

Stable or nearly stable orbits do not always possess well-distinguished manifold structures that assist in departing from or arriving onto the orbit. Generally, for potential missions, the orbits of interest are nearly stable to reduce the possibility of rapid departure. The stable nature of these orbits also serves as a drawback for insertion or departure from the orbit. The Near Rectilinear Halo Orbits (NRHOs) and the Distant Retrograde Orbits (DROs) offer some potential long-horizon trajectories for exploration missions. The current investigation focuses on leveraging the stretching direction as a tool for departure and trajectory design applications. The magnitude of the state variations along the maximum stretching direction is expected to grow rapidly and, therefore, offers information for efficient departure from the orbit. Similarly, the maximum stretching in reverse time, enables arrival with a minimal maneuver magnitude. [less ▲]

Detailed reference viewed: 98 (3 UL)
Full Text
See detailStretching Directions in Cislunar Space: Stationkeeping and an Application to Transfer Trajectory Design
Muralidharan, Vivek UL

Doctoral thesis (2021)

The orbits of interest for potential missions are stable or nearly stable to maintain long-term presence for conducting scientific studies and to reduce the possibility of rapid departure. Near ... [more ▼]

The orbits of interest for potential missions are stable or nearly stable to maintain long-term presence for conducting scientific studies and to reduce the possibility of rapid departure. Near Rectilinear Halo Orbits (NRHOs) offer such stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon regime, the L1 and L2 NRHOs are proposed as long-horizon trajectories for cislunar exploration missions, including NASA's upcoming Gateway mission. These stable or nearly stable orbits do not possess well-distinguished unstable and stable manifold structures. As a consequence, existing tools for stationkeeping and transfer trajectory design that exploit such underlying manifold structures are not reliable for orbits that are linearly stable. The current investigation focuses on leveraging stretching direction as an alternative for visualizing the flow of perturbations in the neighborhood of a reference trajectory. The information supplemented by the stretching directions are utilized to investigate the impact of maneuvers for two contrasting applications; the stationkeeping problem, where the goal is to maintain a spacecraft near a reference trajectory for a long period of time, and the transfer trajectory design application, where rapid departure and/or insertion is of concern. Particularly, for the stationkeeping problem, a spacecraft incurs continuous deviations due to unmodeled forces and orbit determination errors in the complex multi-body dynamical regime. The flow dynamics in the region, using stretching directions, are utilized to identify appropriate maneuver and target locations to support a long lasting presence for the spacecraft near the desired path. The investigation reflects the impact of various factors on maneuver cost and boundedness. For orbits that are particularly sensitive to epoch time and possess distinct characteristics in the higher-fidelity ephemeris model compared to their CR3BP counterpart, an additional feedback control is applied for appropriate phasing. The effect of constraining maneuvers in a particular direction is also investigated for the 9:2 synodic resonant southern L2 NRHO, the current baseline for the Gateway mission. The stationkeeping strategy is applied to a range of L1 and L2 NRHOs, and validated in the higher-fidelity ephemeris model. For missions with potential human presence, a rapid transfer between orbits of interest is a priority. The magnitude of the state variations along the maximum stretching direction is expected to grow rapidly and, therefore, offers information to depart from the orbit. Similarly, the maximum stretching in reverse time, enables arrival with a minimal maneuver magnitude. The impact of maneuvers in such sensitive directions is investigated. Further, enabling transfer design options to connect between two stable orbits. The transfer design strategy developed in this investigation is not restricted to a particular orbit but applicable to a broad range of stable and nearly stable orbits in the cislunar space, including the Distant Retrograde Orbit (DROs) and the Low Lunar Orbits (LLO) that are considered for potential missions. Examples for transfers linking a southern and a northern NRHO, a southern NRHO to a planar DRO, and a southern NRHO to a planar LLO are demonstrated. [less ▲]

Detailed reference viewed: 59 (22 UL)
Full Text
See detailOrbit Maintenance Strategy for Earth-Moon Halo Orbits
Muralidharan, Vivek UL; Howell, Kathleen C.

Scientific Conference (2021, February)

The L1 and L2 Near Rectilinear Halo Orbits (NRHOs) are proposed long horizon trajectories for cislunar exploration missions. Due to unmodeled forces as well as orbit determination errors in this ... [more ▼]

The L1 and L2 Near Rectilinear Halo Orbits (NRHOs) are proposed long horizon trajectories for cislunar exploration missions. Due to unmodeled forces as well as orbit determination errors in this dynamically sensitive region, the spacecraft deviates from the desired path. The current investigation focuses on an extended analysis of an impulsive stationkeeping technique to maintain the spacecraft near a long horizon virtual reference orbit. The dynamics in the halo orbit region are explored to identify suitable maneuver and target locations for stationkeeping. Furthermore, phasing constraints are incorporated to maintain spacecrafts on orbit where position and velocity states are sensitive to epoch time. [less ▲]

Detailed reference viewed: 20 (0 UL)
Full Text
See detailStationkeeping in Earth-Moon Near Rectilinear Halo Orbits
Muralidharan, Vivek UL; Howell, Kathleen C.

Scientific Conference (2020, August)

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon ... [more ▼]

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon regime, the L2 NRHOs offer candidate trajectories for the upcoming Gateway mission. The spacecraft, however, incurs continuous deviations due to unmodeled forces and orbit determination errors in this dynamically sensitive region. The current investigation focuses on a technique to maintain the spacecraft near a virtual reference orbit despite these uncertainties. For the stationkeeping scheme, flow dynamics in the region are utilized to categorically identify appropriate maneuver and target locations. The investigation reflects the impact of various factors on maneuver cost and efficacy. Additional feedback control is applied for phasing constraints. [less ▲]

Detailed reference viewed: 30 (3 UL)
Full Text
Peer Reviewed
See detailTracking neighboring quasi-satellite orbits around Phobos
Muralidharan, Vivek UL; Weiss, Avishai; Kalabic, Uros

in IFAC-PapersOnLine (2020, July)

We consider the orbital maintenance problem on a quasi-satellite orbit about the Martian moon, Phobos. The orbit is computed using a high-fidelity ephemeris model so that the major sources of disturbances ... [more ▼]

We consider the orbital maintenance problem on a quasi-satellite orbit about the Martian moon, Phobos. The orbit is computed using a high-fidelity ephemeris model so that the major sources of disturbances are due to measurement error. Two types of orbit maintenance schemes are considered. The first is based on asymptotically tracking the desired trajectory and the second is based on stabilizing to the manifold of trajectories that share the same Jacobi constant as the reference trajectory. The latter can be done because trajectories with the same Jacobi constant are in the neighborhood of one another. The results show that the trajectory-tracking scheme has lower fuel consumption when tracking must be precise and that the approach of stabilizing to a manifold has better fuel consumption at the expense of tracking. [less ▲]

Detailed reference viewed: 25 (0 UL)
Full Text
See detailControl Strategy for Long-Term Station-keeping on Near-Rectilinear Halo Orbits
Muralidharan, Vivek UL; Weiss, Avishai; Kalabic, Uros

Scientific Conference (2020, January)

This work considers the control of a spacecraft in indefinite near-rectilinear halo orbit about the Earth-Moon L2. For indefinite station-keeping, it is important to minimize fuel consumption, while ... [more ▼]

This work considers the control of a spacecraft in indefinite near-rectilinear halo orbit about the Earth-Moon L2. For indefinite station-keeping, it is important to minimize fuel consumption, while allowing for occasional transfer to a new orbit. The control scheme therefore consists of two components: the first component is the tracking of the nominal NRHO and the second component is an orbit correction maneuver between NRHO trajectories. The nominal NRHO is computed using a multiple-shooting technique that takes into account all forces on the spacecraft whose magnitude is larger than the dominant disturbance forces caused by navigational error. The tracking component is a linear-quadratic regulation scheme that rejects disturbances caused by orbit determination error, using a Lyapunov sublevel set that models the state covariance generated using sequential Kalman filter. The orbit correction maneuver is computed to minimize fuel costs. [less ▲]

Detailed reference viewed: 51 (1 UL)
Full Text
See detailOrbit Maintenance Strategies for Sun-Earth/Moon Libration Point Missions: Parameter Selection for Target Point and Cauchy-Green Tensor Approaches
Muralidharan, Vivek UL

Bachelor/master dissertation (2017)

The libration point orbits in the Sun-Earth/Moon system are formed by concurrent gravitational influences by various celestial bodies, originating in a nonlinear dynamical regime. Coupled with the ... [more ▼]

The libration point orbits in the Sun-Earth/Moon system are formed by concurrent gravitational influences by various celestial bodies, originating in a nonlinear dynamical regime. Coupled with the unstable nature of the orbit, the impact of any perturbations are expected to increase rapidly. The feasibility of a flow-based, Cauchy-Green tensor control strategy for station-keeping is examined. An orbit consistent with the mission objectives is selected for examination. The station-keeping process is stochastic, thus Gaussian random errors are introduced for simulation. The evolution of a velocity perturbation over time is monitored, beyond which the attainable state in the accessible region nearest to the target state is employed as a feedback to compute the necessary full, three-component corrective maneuver. The application and appropriateness of single axis control maneuvers for orbit maintenance are also evaluated. The selection procedure for certain parameters such as tolerances and weighting values are developed to incorporate the available dynamical information, yielding a versatile and straightforward strategy. Weighting matrices within the target point approach are effective in influencing the station-keeping costs as well as size and direction of maneuvers. Moreover, selection of appropriate tolerance values in the application of the Cauchy-Green tensor exploits the dominant stretching direction of the perturbation magnitude to inform the maneuver construction process. The work is demonstrated in the context of the upcoming Aditya-1 mission to a Sun-Earth/Moon L1 halo orbit for solar observations and the James Webb Telescope to a Sun-Earth/Moon L2 halo orbit for astronomy. [less ▲]

Detailed reference viewed: 31 (0 UL)
Full Text
Peer Reviewed
See detailDesign of Mechanically Actuated Aerodynamic Braking System on a Formula Student Race Car
Muralidharan, Vivek UL; Balakrishnan, Abhijith; Vardhan, Vinit et al

in Journal of the Institution of Engineers (India): Mechanical Engineering Division (2017), 99

Every second in a racing competition counts the performance of a team against the other. Many innovative and sophisticated techniques are being employed to overcome loses in time and add to the ... [more ▼]

Every second in a racing competition counts the performance of a team against the other. Many innovative and sophisticated techniques are being employed to overcome loses in time and add to the performance of the vehicle. Especially in a car racing challenge there is more freedom to install these innovative systems to empower the car to maximum efficiency due to availability of more space. At the global spectrum there are few events which encourage such innovations. Formula Student Racing competitions are one of the global events organized by the Society of Automotive Engineers of different countries which gives opportunity to university students to build and race formula style cars. Like any other racing competitions in this high octane event having an inch over their opponents is always an advantage. Not just better acceleration and high velocities but also good deceleration is required to excel in the competition. Aerodynamic braking system is utilizing the aerodynamic drag force to create high deceleration. This mechanism can be installed on any car with spoilers with minimum modification. Being a student event great amount of care needs to be given to the safety concerns of the driver [less ▲]

Detailed reference viewed: 96 (1 UL)
Full Text
Peer Reviewed
See detailDesign optimization of front and rear aerodynamic wings of a high performance race car with modified airfoil structure
Muralidharan, Vivek UL; Balakrishnan, Abhijith; Kumar, Suresh Y.

in 2015 International Conference on Nascent Technologies in the Engineering Field (ICNTE) (2015, January)

Formula Student Racing competitions are international events organized by Society of Automotive Engineers globally at various Formula SAE Circuits. Teams comprising of college students worldwide thrive to ... [more ▼]

Formula Student Racing competitions are international events organized by Society of Automotive Engineers globally at various Formula SAE Circuits. Teams comprising of college students worldwide thrive to build a Formula style race car to compete at these events. In this high octane racing event every team tries to have an inch over their opponents by reducing lap timings. The best way for minimal lap timings is better performance along the straights and a good cornering. It becomes difficult for cars to get good traction when traveling at high speeds as well as they need to reduce their speeds drastically to take sharp corners. To maximize the performance of team NITK Racing car for such events an aerodynamic wings package at the front and the rear is proposed which produces sufficient down-force when accelerating in the straights as well as allowing sharp corners at relatively higher speeds. Being a student based competition intense amount of care is given to the safety precautions. Cars having sharp corners and protrusions are liable to be disqualified and hence the wing tip needs to be modified in order to satisfy the safety rules of the competition. [less ▲]

Detailed reference viewed: 29 (0 UL)
Full Text
Peer Reviewed
See detailDesign and Analysis of a Tubular Space Frame Chassis of a High Performance Race Car
Kumar M P, Prajwal; Muralidharan, Vivek UL; G, Madhusudhana

in International Journal of Research in Engineering and Technology (2014), 03(02),

Formula Student Racing competitions are held at various Formula SAE circuits globally. Students from different colleges worldwide thrive to build a Formula style race car to compete at these events. In ... [more ▼]

Formula Student Racing competitions are held at various Formula SAE circuits globally. Students from different colleges worldwide thrive to build a Formula style race car to compete at these events. In lieu to the competition rules and regulations it is important to design the chassis of the car with utmost priority. The major challenge posed is to design and fabricate a light weight car without compromising on the safety of the driver. The car has to be rigidly fabricated at minimal expense. The work in this paper is based on the team NITK Racing’s Car; the DICV NR XIV. This paper showcases various methods of material selection, design optimization techniques and Finite element analysis (FEA) using ANSYS. The basic design is based on the anthropological data of the specified human (95th percentile male) allowing fast ingress and egress from the car. Following the final design selection the static structural analysis of the car was done and the consequent results have been plotted. The entire design and analysis process is based on FSAE 2013 rule book and knowledge of designing and manufacturing yesteryear’s car. [less ▲]

Detailed reference viewed: 34 (0 UL)