Structured Adaptive Model Inversion Controller for Mars Atmospheric Flight

Restrepo, Carolina I.; Valasek, John

doi:10.2514/6.2007-6850

Cited by 2 publications

(5 citation statements)

References 15 publications

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“…The nonlinear, non real‐time simulation model of the Mars Ellipsled is developed using the mass properties, e.g. location, and aerodynamics provided in 5, as are the standard guidance equations and rotational equations of motion.…”

Section: Modeling Of Vehicle and Rcs Systemmentioning

confidence: 99%

“…Because dynamic inversion assumes perfect knowledge of all the system parameters which are used to solve for the control, but is approximate in the actual implementation due to inaccurate modeling of system parameters, in SAMI an adaptive controller is wrapped around the dynamic inversion to handle the uncertainties in system parameters. Specific to the Mars entry problem, Restrepo and Valasek in 5 conducted the modeling and SAMI adaptive control formulation for a potential planetary entry vehicle that has 18 discrete reaction control system (RCS) jets.…”

Section: Introductionmentioning

confidence: 99%

“…Second, fault‐tolerant control allocation for redundant discrete controls is used for the first time on a nonlinear plant, and a stability analysis is provided for quantized control of nonlinear, time‐varying systems. The third contribution is the demonstration of a fault‐tolerant control algorithm to a Mars entry vehicle with redundant discrete controls 5.…”

Section: Introductionmentioning

confidence: 99%

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Fault‐tolerant control allocation for Mars entry vehicle using adaptive control

Marwaha

Valasek

2011

Adaptive Control & Signal

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96M. MARWAHA AND J. VALASEK the concepts of feedback linearization, dynamic inversion, and structured model reference adaptive control. Because dynamic inversion assumes perfect knowledge of all the system parameters which are used to solve for the control, but is approximate in the actual implementation due to inaccurate modeling of system parameters, in SAMI an adaptive controller is wrapped around the dynamic inversion to handle the uncertainties in system parameters. Specific to the Mars entry problem, Restrepo and Valasek in [5] conducted the modeling and SAMI adaptive control formulation for a potential planetary entry vehicle that has 18 discrete reaction control system (RCS) jets.Another challenge during operation is recovery or tolerance in the case of actuator faults. Actuator faults can be due to any malfunction in the physical system or subsystem of the controller which results in its failure to perform as designed. The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required, with most application studies based upon aerospace systems [6]. Patton provides a thorough review of fault-tolerant control systems in [6]. When combined with adaptive control, control allocation algorithms provide the capability to recover from actuator faults. In their basic form control allocation algorithms are useful for finding solutions to meet the desired control objectives by delivering the desired moments [7]. Bodson provides a comprehensive survey of constrained, numerical-based optimization methods for control allocation in [8], and Page and Steinberg in [9] compare the closed and open-loop performance for 16 different control allocation approaches. Numerous linear control allocation algorithms are currently available. In [10] a faulttolerant control allocation scheme is introduced to handle actuator failures in discrete systems and is validated with a numerical example of a disturbance-free case. Tjonnas and Johansen [11] considers a dynamic approach by constructing actuator reference adaptive laws for over-actuated nonlinear time-varying systems. Shertzer et al. [12] discusses control allocation algorithms specifically in the context of next generation entry vehicles. Recently, Bolender and Doman have used a concept in which control allocation is used for aerodynamic surfaces, and dynamic inversion-based adaptive control is used for system identification, which helps in identifying any failure [13]. The control variable rates or moments are nonlinear functions of control positions. These schemes are applied to different aerovehicles and are shown to have good performance for continuous controls. However, this approach has not been applied to discrete controls, since they require a different allocation algorithm from aerodynamic surfaces [14].This paper introduces a novel use of fault-tolerant control allocation for discrete controls to nonlinear, time-varying systems. Specifically, we address the problem of discrete c...

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Section: Modeling Of Vehicle and Rcs Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fault‐tolerant control allocation for Mars entry vehicle using adaptive control

Marwaha

Valasek

2011

Adaptive Control & Signal

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“…Table I provides the thrust characteristics for all 18 jets. The nonlinear, non real-time simulation model of the Mars Ellipsled is developed using the mass properties, e.g. location, and aerodynamics provided in [5], as are the standard guidance equations and rotational equations of motion.…”

Section: Vehicle Modelmentioning

confidence: 99%

“…Second, faulttolerant control allocation for redundant discrete controls is used for the first time on a nonlinear plant, and a stability analysis is provided for quantized control of nonlinear, time-varying systems. The third contribution is the demonstration of a fault-tolerant control algorithm to a Mars entry vehicle with redundant discrete controls [5].…”

Section: Introductionmentioning

confidence: 99%

Fault Tolerant Control Allocation for Mars Entry Vehicle using Adaptive Control

Marwaha

Valasek

2008

AIAA/AAS Astrodynamics Specialist Conference and Exhibit

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Accurate and reliable control of planetary entry is a major challenge for planetary exploration vehicles. For Mars entry, uncertainties in atmospheric properties such as winds aloft and density pose a major problem for meeting precision landing requirements. Anticipated manned missions to Mars will also require levels of safety and fault tolerance not required during earlier robotic missions. This paper develops a nonlinear fault-tolerant controller specifically tailored for addressing the unique environmental and mission demands of future Mars entry vehicles. The controller tracks a desired trajectory from entry interface to parachute deployment, and has an adaptation mechanism that reduces tracking errors in the presence of uncertain parameters such as atmospheric density, and vehicle properties such as aerodynamic coefficients and inertias. This nonlinear control law generates the commanded moments for a discrete control allocation algorithm, which then generates the optimal controls required to follow the desired trajectory. The reaction control system acts as a non-uniform quantizer, which generates applied moments that approximate the desired moments generated by a continuous adaptive control law. If a fault is detected in the control jets, it reconfigures the controls and minimizes the impact of control failures or damage on trajectory tracking. It is assumed that a fault identification and isolation scheme already exists to identify failures. A stability analysis is presented, and fault tolerance performance is evaluated with non real-time simulation for a complete Mars entry trajectory tracking scenario using various scenarios of control effector failures. The results presented in the paper demonstrate that the control algorithm has a satisfactory performance for tracking a pre-defined trajectory in the presence of control failures, in addition to plant and environment uncertainties.

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Structured Adaptive Model Inversion Controller for Mars Atmospheric Flight

Cited by 2 publications

References 15 publications

Fault‐tolerant control allocation for Mars entry vehicle using adaptive control

Fault‐tolerant control allocation for Mars entry vehicle using adaptive control

Fault Tolerant Control Allocation for Mars Entry Vehicle using Adaptive Control

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