Flatness-based MPC for underactuated surface vessels in confined areas

Helling, Simon; Lutz, Max; Meurer, Thomas

doi:10.1016/j.ifacol.2020.12.1831

Cited by 13 publications

(7 citation statements)

References 22 publications

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“…3b. The vessel is subject to disturbances induced by wind similar to [4] and an Extended Kalman Filter is used to estimate the system states. The different evading behaviors depending on the obstacle formulation are shown in Fig.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…The ellipsoidal approach also fails to take into account the geometry of the controlled vessel. Consequently, a more flexible approach is to approximate obstacles as CSG functions as in, e.g., [4] or convex polygons which can be studied in combination with a fundamental concept in collision-avoidance, namely, the signed distance function. This can be expressed as…”

Section: Introductionmentioning

confidence: 99%

“…The realized input for the entire simulation is depicted in Fig.3b. The vessel is subject to disturbances induced by wind similar to[4] and an Extended Kalman Filter is used to estimate the system states. The different evading behaviors depending on the obstacle formulation are shown in Fig.4for the obstacle that has already been passed in the snapshot…”

mentioning

confidence: 99%

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On the Dual Implementation of Collision-Avoidance Constraints in Path-Following MPC for Underactuated Surface Vessels

Helling

Roduner

Meurer

2021

2021 American Control Conference (ACC)

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A path-following collision-avoidance model predictive control (MPC) method is proposed which approximates obstacle shapes as convex polygons. Collision-avoidance is ensured by means of the signed distance function which is calculated efficiently as part of the MPC problem by making use of a dual formulation. The overall MPC problem can be solved by standard nonlinear programming (NLP) solvers. The dual signed distance formulation yields, besides the (dual) collisionavoidance constraints, norm, and consistency constraints. A novel approach is presented that combines the arising norm equality with the dual collision-avoidance inequality constraints to yield an alternative formulation reduced in complexity. Moving obstacles are considered using separate convex sets of linearly predicted obstacle positions in the dual problem. The theoretical findings and simplifications are compared with the often-used ellipsoidal obstacle formulation and are analyzed with regard to efficiency by the example of a simulated path-following autonomous surface vessel during a realistic maneuver and AIS obstacle data from the Kiel bay area.

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Section: Simulation Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Dual Implementation of Collision-Avoidance Constraints in Path-Following MPC for Underactuated Surface Vessels

Helling

Roduner

Meurer

2021

2021 American Control Conference (ACC)

Self Cite

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“…Exploitation of differential flatness, as introduced by [18] allows for a drastic reduction of decision variables when applying a direct method to a dynamic optimization problem, compare also [19]. As already discussed in [11] the known flat parametrization of the dynamic model ( 2) for the underactuated case, i.e., τ v = 0, shows singularities [20] such that in the following the flat parametrization of the fully actuated dynamic model is used and τ v = 0 is imposed later by setting the corresponding bounds in (7a) or ( 9), respectively, to zero.…”

Section: Numerical Implementationmentioning

confidence: 98%

“…The differential flatness property of the 3DOF vessel model considered in this work is also exploited in [11], where the flat outputs are directly parametrized using polynomial curve segments (B-splines) in order to attain a NLP for the task of vessel control in constrained areas. The flatness based direct method used in this work however is closely related to the concept presented in [12] with the application of time optimal trajectory generation for a gantry crane, which builds on the idea of parametrizing the highest derivative of the flat output as previously suggested by, e.g., [13], [14].…”

Section: Introductionmentioning

confidence: 99%

Optimal Trajectory Planning and Model Predictive Control of Underactuated Marine Surface Vessels using a Flatness-Based Approach

Lutz

Meurer

2021

2021 American Control Conference (ACC)

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This paper demonstrates a refined approach to solving dynamic optimization problems for underactuated marine surface vessels. To this end the differential flatness of a mathematical model assuming full actuation is exploited to derive an efficient representation of a finite dimensional nonlinear programming problem, which in turn is constrained to apply to the underactuated case. It is illustrated how the properties of the flat output can be employed for the generation of an initial guess to be used in the optimization algorithm in the presence of static and dynamic obstacles. As an example energy optimal point to point trajectory planning for a nonlinear 3 degrees of freedom dynamic model of an underactuated surface vessel is undertaken. Input constraints, both in rate and magnitude as well as state constraints due to convex and non-convex obstacles in the area of operation are considered and simulation results for a challenging scenario are reported. Furthermore, an extension to a trajectory tracking controller using model predictive control is made where the benefits of the flatness based direct method allow to introduce nonuniform sample times that help to realize long prediction horizons while maintaining short term accuracy and real time capability. This is also verified in simulation where additional disturbances in the form of environmental disturbances, dynamic obstacles and parameter mismatch are introduced.

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A collision avoidance algorithm with intention prediction for inland waterways ships

Tran,

Johansen,

Negenborn

2023

IFAC-PapersOnLine

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Flatness-based MPC for underactuated surface vessels in confined areas

Cited by 13 publications

References 22 publications

On the Dual Implementation of Collision-Avoidance Constraints in Path-Following MPC for Underactuated Surface Vessels

On the Dual Implementation of Collision-Avoidance Constraints in Path-Following MPC for Underactuated Surface Vessels

Optimal Trajectory Planning and Model Predictive Control of Underactuated Marine Surface Vessels using a Flatness-Based Approach

A collision avoidance algorithm with intention prediction for inland waterways ships

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