Dynamics and Control of Autonomous Space Vehicles and Robotics

Vepa, Ranjan

doi:10.1017/9781108525404

Cited by 8 publications

(7 citation statements)

References 134 publications

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“…The complete pose is found by accumulating the attitudes with alternate representations of the other vectors. It is demonstrated succinctly that the methodology may be applied, with minimal use of the dynamics, to actual space and aerial robotic manipulators attached to a vehicle in flight, a planetary rover (Vepa, 2019) or a robotic vehicle, where the attitude of the vehicle and the pose of the manipulator links or vehicle itself must be obtained. Apart from the simplicity, the fact they are non-dimensional implies that they could be used in variety of different physical solutions, by appropriate re-scaling.…”

Section: Discussionmentioning

confidence: 99%

Optimal Manoeuver Trajectory Synthesis for Autonomous Space and Aerial Vehicles and Robots

Vepa

2019

Towards Autonomous Robotic Systems

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In this paper the problem of the synthesis of optimal manoeuver trajectories for autonomous space vehicles and robots is revisited. It is shown that it is entirely feasible to construct optimal manoeuver trajectories from considerations of only the rigid body kinematics rather than the complete dynamics of the space vehicle or robot under consideration. Such an approach lends itself to several simplifications which allow the optimal angular velocity and translational velocity profiles to be constructed, purely from considerations of the body kinematic relations. In this paper the body kinematics is formulated, in general, in terms of the quaternion representation attitude and the angular velocities are considered to be the steering inputs. The optimal inputs for a typical attitude manoeuver is synthesized by solving for the states and co-states defined by a two point boundary value problem. A typical example of a space vehicle pointing problem is considered and the optimal torque inputs for the synthesis of a reference attitude trajectory and the reference trajectories are obtained.

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Section: Discussionmentioning

confidence: 99%

Optimal Manoeuver Trajectory Synthesis for Autonomous Space and Aerial Vehicles and Robots

Vepa

2019

Towards Autonomous Robotic Systems

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“…The HCW equations (Clohessy and Wiltshire [11]) assume that both the target body and the chaser satellite are in near locally circular orbits and that the relative perturbations acting on the chaser satellite relative to the target body are small. The HCW equations may be extended to include all the nonlinearities and Earth oblateness perturbations (Kuiack and Ulrich [12], Vepa [13]). The assumptions on which the derivation of the HCW linearized equations of relative motion is based, are quite restrictive and to initiate a change in both the change in the position and velocity of the satellite so it flies alongside or just behind the target body, the application of the continuous thrust should be done when the phase angle between the two is within certain acceptable limits.…”

Section: Of 17mentioning

confidence: 99%

“…When the closeness that can be determined by a single parameter, δ which must be relatively small and, δ = 2(x/r) + (ρ/r) 2 << 0.001,where x is the relative local vertical position coordinate of the spacecraft, r is the distance of the asteroid from the Sun and ρ is the relative distance of the spacecraft from the asteroid. (The derivation of this parameter is presented in Vepa [13]). In practice, however, for a satellite in circular co-planar orbit, with almost the same orbit radius as the asteroid, (ρ/r) 2 ≤ 0.05.…”

Section: Of 17mentioning

confidence: 99%

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Optimal Trajectory Synthesis for Spacecraft Asteroid Rendezvous

Vepa

Shaheed

2021

Symmetry

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Several researchers are considering the plausibility of being able to rapidly launch a mission to an asteroid, which would fly in close proximity of the asteroid to deliver an impulse in a particular direction so as to deflect the asteroid from its current orbit. Planetary motion, in general, and the motion of asteroids, in particular, are subject to planetary influences that are characterised by a kind of natural symmetry, which results in an asteroid orbiting in a stable and periodic or almost periodic orbit exhibiting a number of natural orbital symmetries. Tracking and following an asteroid, in close proximity, is the subject of this paper. In this paper, the problem of synthesizing an optimal trajectory to a NEO such as an asteroid is considered. A particular strategy involving the optimization of a co-planar trajectory segment that permits the satellite to approach and fly alongside the asteroid is chosen. Two different state space representations of the Hill–Clohessy–Wiltshire (HCW) linearized equations of relative motion are used to obtain optimal trajectories for a spacecraft approaching an asteroid. It is shown that by using a state space representation of HCW equations where the secular states are explicitly represented, the optimal trajectories are not only synthesized rapidly but also result in lower magnitudes of control inputs which must be applied continuously over extended periods of time. Thus, the solutions obtained are particularly suitable for low thrust control of the satellites orbit which can be realized by electric thrusters.

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“…The associated tracking problem, which involves tracking the complete state vector set point, must then be separately addressed. Typically this is done by using a barrier Lyapunov function as illustrated by Vepa [17].…”

Section: Simplified Formulation Of the Optimal Angular Rate Trajectormentioning

confidence: 99%

Optimal Trajectory Synthesis and Tracking Control for Spacecraft Large Attitude Manoeuvers

Vepa¹

2020

Advances in Spacecraft Attitude Control

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The classical approach to the problem of synthesizing an optimal attitude manoeuver trajectory, involves the use of the calculus of variations and the use Lagrange multipliers or co-states. The nonlinear large attitude manoeuver trajectory is controlled by a set of nonlinear evolving co-states. In this paper, following a review of the methodologies available for trajectory synthesis followed by tracking control, the optimal trajectory for a typical optimal attitude manoeuver is synthesized by solving for the states and co-states defined by a two point boundary value problem. Gravity gradient torques are included as a matter of course. Following the synthesis of the optimal attitude-rate trajectory, tracking control laws are synthesized by re-formulating the optimal control as a feedback law. The approximate linear tracking feedback controls are evaluated by relating the optimal state and costate vector by a linear relation. The control laws are synthesized numerically. The problem of optimal attitude orientation trajectory synthesis is also addressed. The methodologies are applied to typical sample problems and results are presented. Quantitative comparisons of the results of the methods are made to the results obtained by the application of other linear and nonlinear methods, to illustrate the key features of the methodologies.

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Dynamics and Control of Autonomous Space Vehicles and Robotics

Cited by 8 publications

References 134 publications

Optimal Manoeuver Trajectory Synthesis for Autonomous Space and Aerial Vehicles and Robots

Optimal Manoeuver Trajectory Synthesis for Autonomous Space and Aerial Vehicles and Robots

Optimal Trajectory Synthesis for Spacecraft Asteroid Rendezvous

Optimal Trajectory Synthesis and Tracking Control for Spacecraft Large Attitude Manoeuvers

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