Papers by Przemyslaw Herman
Robust trajectory tracking control scheme using transformed velocities for asymmetric underactuated marine vehicles
Ocean Engineering
Applied Sciences
This paper considers a trajectory-tracking control algorithm for underactuated marine vehicles mo... more This paper considers a trajectory-tracking control algorithm for underactuated marine vehicles moving horizontally in which the current in the North-East-Down frame is constant. This algorithm is a modification of a control scheme based on the input-output feedback linearization method for which the application condition is that the vehicle is symmetric with respect to the left and right sides. The proposed control scheme can be applied to a fully asymmetric model, and, therefore, the geometric center can be different from the center of mass in both the longitudinal and lateral directions. A velocity transformation to generalized vehicle equations of motion was used to develop a suitable controller. Theoretical considerations were supported by simulation tests performed for a model with 3 degrees of freedom, in which the performance of the proposed algorithm was compared with that of the original algorithm and the selected control scheme based on a combination of backstepping and in...
Use of a nonlinear controller with dynamic couplings in gains for simulation test of an underwater vehicle model
International Journal of Advanced Robotic Systems, 2021
The article considers a method of examining the influence of dynamic couplings contained in the u... more The article considers a method of examining the influence of dynamic couplings contained in the underwater vehicle model on the movement of this vehicle. The method uses the inertia matrix decomposition and a velocity transformation if the fully actuated vehicle is described in the earth-frame representation. Based on transformed equations of motion, a controller including dynamic couplings in the gain matrices is designed. In the proposed method, the control algorithm is used for the test vehicle dynamics model taking into account disturbances. The approach is useful for simulating the model of an underwater vehicle and improving it, thus avoiding unnecessary experiments or planning them better. The procedure is shown for a full model of an underwater vehicle, and its usefulness is verified by simulation.
IEEE Robotics and Automation Letters, 2020
The paper presents a new, robust control algorithm for position trajectory tracking in a 3D space... more The paper presents a new, robust control algorithm for position trajectory tracking in a 3D space, dedicated to underactuated airships. In order to take into account real characteristics of such vehicles, and to reflect practically motivated constraints, the algorithm assumes a highly uncertain system dynamics model. The tracking problem is solved in a uniform way, without dividing it into subtasks considered in 2D spaces, thanks to the introduction of an auxiliary tracking error. The proposed controller is based on the sliding mode approach. Its stability is investigated using Lyapunov theorem. Numerical simulations are conducted in order to verify properties of a closed-loop system for a generic model of the airship. Performance of the control system is examined via experiments in various scenarios using a prototype airship. The obtained results indicate that the control objectives are satisfied in practice with a reasonable accuracy. Moreover, it is shown that the controller is robust to some bounded additive measurement perturbations and delays in the control loop.
Trajectory tracking control algorithm in terms of quasi-velocities for a class of vehicles
Mathematics and Computers in Simulation, 2019
Abstract This paper studies the problem of trajectory tracking control for a class of vehicles (u... more Abstract This paper studies the problem of trajectory tracking control for a class of vehicles (underwater vehicles, some horizontally moving vehicles, indoor airships). The control development is based on some velocity transformation arising from the inertia matrix decomposition, Lyapunov’s direct method and a non-adaptive nonlinear tracking controller in terms of the Generalized Velocity Components (GVC). In the nonlinear controller the control gains are strictly related to the vehicle dynamics (especially dynamical couplings). The general algorithm is presented for a 6 DOF vehicle. In the simulation two trajectories were tested. Moreover, one robustness test was done (corresponding to robustness issue considered in this work). The simulation results obtained for a full airship model show that the proposed control scheme guarantees satisfactory performance.
IFAC Proceedings Volumes, 2000
This paper presents new control algorithms for manipulators whose dynamics is expressed in terms ... more This paper presents new control algorithms for manipulators whose dynamics is expressed in terms of quasi-velocities (Jain and Rodriguez. 1995). Rob ot dynamic algorithms in terms of quasi-velocities are recursive in nature and consists of two recursions: one starts from a base of the mallipulator towards its tip alld the second in opposite direction. Both recursions are described by using vector-matrix notation. The considered algorithms allow to achie\'e end point of trajectory described in joint space of manipulator and in terms of quasi-velocities. The algorithms werp tested experimentally on a two degrees of freedom manipulator.
Robust tracking controller with constraints using generalized velocity components for manipulators
Transactions of the Institute of Measurement and Control, 2008
A proposed robust controller with torque constraints are presented in this article. It is shown t... more A proposed robust controller with torque constraints are presented in this article. It is shown that for a manipulator described in terms of the generalized velocity components (GVCs), given originally by Loduha and Ravani ( Transactions of the ASME Journal of Applied Mechanics 62, 216—22, 1995), one can use a simple control scheme, which guarantees position error tracking. Introducing GVCs, together with generalized joint positions, leads to first-order decoupling equations of motion instead of one second-order equation. Additionally, an interesting insight into the manipulator dynamics can be obtained. As opposed to the classical robust controller (Galicki, Studies in Automation and Information Technology 25, 83—93, 2000), the constraints in our algorithm are expressed in terms of quasi-moments. The performances of both controllers were compared on a 3-degree-of-freedom, 3-D Yasukawa-like robot.
Applied Sciences
This paper investigates the trajectory tracking control problem for underactuated underwater vehi... more This paper investigates the trajectory tracking control problem for underactuated underwater vehicles, for which a model is expressed in terms of quasi-velocities arising from the inertia matrix decomposition. The control approach takes into account non-modeled dynamics and external disturbances and is suitable for symmetric vehicles. It is shown that such systems can be diagonalized using inertial quasi-velocities (IQVs). The strategy consists of the velocity controller and two adaptive integral sliding mode control algorithms. The proposed approach, introducing velocity transformation and using backstepping methods and integral sliding mode control, allows trajectory tracking for vehicles in described models with symmetric inertia matrix. Proof of the stability of the closed system was carried out using IQV. The proposed scheme has been verified on two 3 DOF models of underwater vehicles with thruster limitations. A brief discussion of the results is also given.
Energies
This paper considers the issue of linear-quadratic regulator (LQR) design for nonlinear systems w... more This paper considers the issue of linear-quadratic regulator (LQR) design for nonlinear systems with the use of smooth state and input transformations. The proposed design methodology is considered in the stabilisation task of the Pendubot, which is based on the concept of feedback equivalent control systems. It turns out that it is possible to find a controller that ensures comparable dynamics of the closed-loop system in the vicinity of the set point regardless of the state-space representation adopted. In addition, the synthesis of suboptimal controllers according to the LQR strategy ensuring equal dynamics at the equilibrium point is presented. The properties of the studied controllers were investigated in a simulation environment and using experimental tests. The detailed forms of transformations and linear approximations given can be regarded as ready-made procedures that can be applied to stabilise similar mechanical systems in robotics.
Inertial Quasi-Velocity Based Controllers for a Class of Vehicles
Springer Tracts in Mechanical Engineering, 2022
Journal of the Franklin Institute, 2017
A global state feedback tracking controller for a class of vehicles, namely marine vehicles, hove... more A global state feedback tracking controller for a class of vehicles, namely marine vehicles, hovercrafts and indoor airships is considered in this paper. The control algorithm uses a velocity transformation of the vehicle equations of motion. It is shown that this algorithm is suitable for control of fully actuated systems and leads to fast response. This property arises from the fact that the dynamical couplings in the vehicle are taken into account in the control gain matrix. A Lyapunov-like function is proposed for the stability analysis of the system under the controller. The algorithms robustness issue is considered too. Numerical simulations are given to illustrate effectiveness of the approach.
Nonlinearity detection and reduction based on unnormalized quasi-velocities
CISM Courses and Lectures
In this paper an analysis concerning dynamical couplings between manipulator links is proposed. I... more In this paper an analysis concerning dynamical couplings between manipulator links is proposed. In order to detect nonlinearities we utilize equations of motion in terms of unnormalized quasi-velocities (UQV) introduced originally by Jain and Rodriguez (1995). Based on the equations some observations which are helpful for nonlinearity investigation and reduction were made. The presented strategy was tested by simulation on a 3 d.o.f. spatial manipulator.
Applied Sciences, 2022
In this work, an application of the trajectory tracking algorithm proposed in the literature for ... more In this work, an application of the trajectory tracking algorithm proposed in the literature for underactuated marine vehicles is presented. The main difference relies on that here the dynamics of the vehicle are expressed in terms of some quasi-velocities (QV). This fact has a double meaning. First of all, it is shown that using the QV, it is possible to control a vehicle in the absence of one variable because the works related to marine vehicles have only concerned fully actuated systems. In addition, a controller using QV provides information that gives some insight into vehicle dynamics and that is not available in classical equations of motion. The simulations done on two 3-DOF models of different underwater vehicles and using two desired trajectories show performance of the considered control strategy. A discussion of the presented control scheme and selected control approaches from recent years was also conducted, and the benefits of the proposed approach were pointed out.
Models of Airships
Springer Tracts in Mechanical Engineering, 2022
Velocity tracking control of AUVs in horizontal motion
2016 3rd Conference on Control and Fault-Tolerant Systems (SysTol), 2016
In the paper the problem of velocity tracking control of Autonomous Underwater Vehicles (AUVs) in... more In the paper the problem of velocity tracking control of Autonomous Underwater Vehicles (AUVs) in horizontal plane is considered. The proposed approach is based on transformed equations of motion and it allows one to apply the dynamical couplings in the control gain matrix. As a result, the dynamics of the vehicle is included into the control process what leads to fast system response. The stability of the system with the controller is done using the Lyapunov method. Effectiveness of the control algorithm is validated via simulations on a 3 DOF underwater marine vehicle model.
IQV Position and Velocity Tracking Control in Earth-Fixed Frame
Springer Tracts in Mechanical Engineering, 2022
IQV Velocity Tracking Control with Adaptive Term in Body-Fixed Frame
Springer Tracts in Mechanical Engineering, 2022
Models of Hovercrafts and Vehicles in Horizontal Motion
Springer Tracts in Mechanical Engineering, 2022
IQV Position and Velocity Tracking Control with Adaptive Term in Earth-Fixed Frame
Springer Tracts in Mechanical Engineering, 2022
Various Control Strategies
Springer Tracts in Mechanical Engineering, 2022
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Papers by Przemyslaw Herman