Papers by Luis Govinda García Valdovinos
Control of a hybrid glider (Kay Juul H) with regulation of roll: Preliminary results in real time
This paper describes the mechanical considerations, electronic architecture and the control strat... more This paper describes the mechanical considerations, electronic architecture and the control strategies of an Autonomous Underwater Vehicle (AUV) Kay Juul H. Real time experiments for pitch and roll control are presented. The applied control technique was the sliding PID control, which main advantages are: second order sliding mode control, model free control and avoids the chattering effect. Satisfactory real time results were obtained for pitch and roll regulation. The contribution of this work is the use of the Sliding PID control in a hybrid glider, this nonlinear control technique has been used in many complex systems including underwater ROVs (Remotely Operated Vehicle).
Sensors
Unmanned underwater vehicles perform inspection and maintenance tasks in complex and changing env... more Unmanned underwater vehicles perform inspection and maintenance tasks in complex and changing environments. Some of these tasks require synchronous navigation of multiple vehicles, which is challenging. This paper proposes a synchronous navigation scheme for two BlueROV2 underwater vehicles for a coordinated multi-vehicle task. In the proposed scheme, the vehicles perform the collaborative task of grasping, transporting, and releasing an object. In this scheme, no vehicle-to-vehicle communication is required. A model-free second-order sliding mode controller with finite-time convergence is used to accomplish this task. The controller’s convergence time is user-defined and does not depend on the physical or hydrodynamic parameters of the vehicle, unlike the other finite-time controllers found in the literature. Simulation experiments were conducted to verify the controller’s performance, including high ocean currents as external disturbances. Comparisons were made with two state-of-t...
Sensors
The use of autonomous underwater vehicles (AUVs) has expanded in recent years to include inspecti... more The use of autonomous underwater vehicles (AUVs) has expanded in recent years to include inspection, maintenance, and repair missions. For these tasks, the vehicle must maintain its position while inspections or manipulations are performed. Some station-keeping controllers for AUVs can be found in the literature that exhibits robust performance against external disturbances. However, they are either model-based or require an observer to deal with the disturbances. Moreover, most of them have been evaluated only by numerical simulations. In this paper, the feasibility of a model-free high-order sliding mode controller for the station-keeping problem is validated. The proposed controller was evaluated through numerical simulations and experiments in a semi-Olympic swimming pool, introducing external disturbances that remained unknown to the controller. Results have shown robust performance in terms of the root mean square error (RMSE) of the vehicle position. The simulation resulted i...
2020 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 2020
In this paper, an evolutionary General Type-2 Radial Basis Function Neural Network (GT2-RBFNN) fo... more In this paper, an evolutionary General Type-2 Radial Basis Function Neural Network (GT2-RBFNN) for trajectory planning in Remotely Operated underwater Vehicles (ROVs) is suggested. The GT2-RBFNN is used as a datadriven learning system to orient the current position of an ROV in underwater environments. To determine the parameters of GT2-RBFNN, Galactic Swarm Optimisation (GSO) was implemented. A BlueROV2 and a squared water container of 2.5m ⇥ 2.5m ⇥ 3.5m were employed to run all experiments. To control the ROV position, a sensory system that consists of a compass, a micro data sonar, a ping sonar and a pressure sensor was integrated. First, a Proportional Derivative fuzzy controller was implemented to control the depth and yaw positions of the ROV. Secondly, the GT2-RBFNN was applied to discriminate between two different types of contours, i.e. corners and walls in order to follow an obstacle-free trajectory. To compare the efficiency of the GT2-RBFNN, a number of learning techniques that are based on Extreme Learning Machine (ELM) and evolutionary optimisation were implemented. Based on our results, a high trade-off between model simplicity and low computational burden are provided by the GT2-RBFNN.
Sensors, 2022
Several control strategies have been proposed for the trajectory tracking problem of Autonomous U... more Several control strategies have been proposed for the trajectory tracking problem of Autonomous Underwater Vehicles (AUV). Most of them are model-based, hence, detailed knowledge of the parameters of the robot is needed. Few works consider a finite-time convergence in their controllers, which offers strong robustness and fast convergence compared with asymptotic or exponential solutions. Those finite-time controllers do not permit the users to predefine the convergence time, which can be useful for a more efficient use of the robot’s energy. This paper presents the experimental validation of a model-free high-order Sliding Mode Controller (SMC) with finite-time convergence in a predefined time. The convergence time is introduced by the simple change of a time-base parameter. The aim is to validate the controller so it can be implemented for cooperative missions where the communication is limited or null. Results showed that the proposed controller can drive the robot to the desired ...
Proceedings of the 6th International Conference on Informatics in Control, Automation and Robotics, 2009
Bilateral teleoperation system are prone to instability coming out from the time-delay introduced... more Bilateral teleoperation system are prone to instability coming out from the time-delay introduced by the indeterministic communication channel. This problem has been subject of intensive research under the assumption of non-equal master-slave teleoperators, however, what are the implications of dynamically similar teleoperation system (DSTS), is there simpler stability relationship and trade offs among several involved system and feedback parameters? When we consider a linear DSTS system, there arises the question whether there is analytically any advantage, as it was observed heuristically in several experiments . In this paper, the stability analysis of such system is reported under an impedance control scheme when the delay is considered constant but unknown. by applying the Llewellyn's and Raisbeck's criteria, it is found and explicit and straightforward relationships between the dynamic and kinematic scaling and the stability of the system. This result explicitly suggests clearly guidelines among key factors, such as time delay, desired velocities and feedback gains in terms of the scaling parameters, arises a clear advantage when dealing with dynamically similar systems. This explains why the transparency of the teleoperation system is improved by augmenting/reducing the dynamic/kinematic scaling factor, for given desired frequency, time delay and feedback gains. Simulations and preliminary experimental results illustrate different cases subject to a number of conditions, which can be very useful to design a physical teleoperation system. A preliminary mechatronics design is presented.
Design, Modeling and Control of a Micro AUV
OCEANS 2018 MTS/IEEE Charleston, 2018
This work describes the development, control and testing of a low cost Micro Autonomous Underwate... more This work describes the development, control and testing of a low cost Micro Autonomous Underwater Vehicle, named AR2D2. The main objective of this work is to apply a nonlinear PD controller to stabilize vehicle attitude and position, by using an Inertial Measurement Unit and a low-cost ultrasonic device. The stability of close loop system with the nonlinear PD controller is proven using a Lyapunovs theory. Therefore, the performance of the micro AUV is validated by simulation and real-time experiments.
Applied Sciences, 2021
Several strategies to deal with the trajectory tracking problem of Unmanned Underwater Vehicles a... more Several strategies to deal with the trajectory tracking problem of Unmanned Underwater Vehicles are encountered, from traditional controllers such as Proportional Integral Derivative (PID) or Lyapunov-based, to backstepping, sliding mode, and neural network approaches. However, most of them are model-based controllers where it is imperative to have an accurate knowledge of the vehicle hydrodynamic parameters. Despite some sliding mode and neural network-based controllers are reported as model-free, just a few of them consider a solution with finite-time convergence, which brings strong robustness and fast convergence compared with asymptotic or exponential solutions and it can also help to reduce the power consumption of the vehicle thrusters. This work aims to implement a model-free high-order sliding-mode controller and synthesize it with a time-base generator to achieve finite-time convergence. The time-base was included by parametrizing the control gain at the sliding surface. N...
Proceedings of the 14th International Conference on Informatics in Control, Automation and Robotics, 2017
Autonomous Underwater Gliders (AUG) have become a very useful and cheap tool to sample the ocean'... more Autonomous Underwater Gliders (AUG) have become a very useful and cheap tool to sample the ocean's environment compared with oceanographic ships to perform the same task. AUGs can glide along the ocean up to a specific depth thanks to their aerodynamic shape, wings and rudders, and a buoyancy-driven system composed of a bladder and an eccentric movable mass that modifies the net buoyancy and the pitch/roll angles of the vehicle, respectively. One of the main concerns of glider's pilots is to understand and/or predict the behaviour of the glider when it is affected by ocean currents under the water. In this paper, an interactive virtual simulator for motion analysis of underwater gliders is given. The simulator considers the online solution of the full nonlinear hydrodynamics of a well-known glider. The virtual simulator is a tool that will help technicians and pilots to increase their training process, to carry out performance analysis of new control schemes and validation of new glider's models before the physical construction.
Proceedings of the 14th International Conference on Informatics in Control, Automation and Robotics, 2017
This paper presents the design, construction and control of an Unmanned Surface Vessel (USV) alon... more This paper presents the design, construction and control of an Unmanned Surface Vessel (USV) along with a ROV (Remotely Operated Vehicle) system, called USV-ROV system. These systems are mainly used for underwater inspection of shallow water structures, such as: ports, bridges bases and platforms. The USV-ROV, developed at CIDESI-Mexico, has been designed for academic purposes. This paper describes the Surface Control Unit (SCU), the ROV and the USV, including: electronics architecture, data managing, sensors, actuators and mechanical design considerations. USV and ROV control strategies preliminary results are presented. Real time experiments are shown for: USV heading control, and ROV depth and heading control. The goal of this paper is to present preliminary results of a coordinated USV-ROV system, desgined for the development of inspection and surveillance techniques accroding to the marine and submarine application; however, these techniques are not commercially available and have to be developed with an open architecture system like the presented here.
Sensors, 2018
This work describes the modeling, control and development of a low cost Micro Autonomous Underwat... more This work describes the modeling, control and development of a low cost Micro Autonomous Underwater Vehicle (μ-AUV), named AR2D2. The main objective of this work is to make the vehicle to detect and follow an object with defined color by means of the readings of a depth sensor and the information provided by an artificial vision system. A nonlinear PD (Proportional-Derivative) controller is implemented on the vehicle in order to stabilize the heave and surge movements. A formal stability proof of the closed-loop system using Lyapunov’s theory is given. Furthermore, the performance of the μ-AUV is validated through numerical simulations in MatLab and real-time experiments.
Applied Sciences, 2020
Development of Autonomous Underwater Vehicles (AUVs) has permitted the automatization of many tas... more Development of Autonomous Underwater Vehicles (AUVs) has permitted the automatization of many tasks originally achieved with manned vehicles in underwater environments. Teams of AUVs designed to work within a common mission are opening the possibilities for new and more complex applications. In underwater environments, communication, localization, and navigation of AUVs are considered challenges due to the impossibility of relying on radio communications and global positioning systems. For a long time, acoustic systems have been the main approach for solving these challenges. However, they present their own shortcomings, which are more relevant for AUV teams. As a result, researchers have explored different alternatives. To summarize and analyze these alternatives, a review of the literature is presented in this paper. Finally, a summary of collaborative AUV teams and missions is also included, with the aim of analyzing their applicability, advantages, and limitations.
Sensors, 2019
Proposed in this paper is a model-free and chattering-free second order sliding mode control (2nd... more Proposed in this paper is a model-free and chattering-free second order sliding mode control (2nd-SMC) in combination with a backpropagation neural network (BP-NN) control scheme for underwater vehicles to deal with external disturbances (i.e., ocean currents) and parameter variations caused, for instance, by the continuous interchange of tools. The compound controller, here called the neuro-sliding control (NSC), takes advantage of the 2nd-SMC robustness and fast response to drive the position tracking error to zero. Simultaneously, the BP-NN contributes with its capability to estimate and to compensate online the hydrodynamic variations of the vehicle. When a change in the vehicle’s hydrodynamics occurs, the 2nd-SMC may no longer be able to compensate for the variations since its feedback gains are tuned for a different condition; thus, in order to preserve the desired performance, it is necessary to re-tune the feedback gains, which a cumbersome and time consuming task. To solve ...
Impedance-based sliding mode control for nonlinear teleoperators under constant time delay
2016 IEEE Conference on Control Applications (CCA), 2016
New technological advancements in the communication channel of time delay teleoperation systems h... more New technological advancements in the communication channel of time delay teleoperation systems have attracted a lot of attention, which have produced recently new control schemes, under a variety of conditions, including unknown (either constant or varying) time delay and parametric uncertainty. In this paper, a well-known model free, exact differentiator, is used to estimate the full state along with a chattering free second order sliding mode controller to guarantee robust impedance tracking under constant, but unknown, time delay of nonlinear multi-degree of freedom (n - DOF) robots. In addition, a new nominal reference is tailored in order to introduce a change of coordinates in the slave closed-loop dynamics. Experimental results, that validate the predicted behavior, are presented and discussed using the Phantom Premium 1.0 as the master robot and the Catalyst-5 virtual model as the slave robot, whose dynamics is solved online.
Sensors, 2016
For decades, PID (Proportional + Integral + Derivative)-like controllers have been successfully u... more For decades, PID (Proportional + Integral + Derivative)-like controllers have been successfully used in academia and industry for many kinds of plants. This is thanks to its simplicity and suitable performance in linear or linearized plants, and under certain conditions, in nonlinear ones. A number of PID controller gains tuning approaches have been proposed in the literature in the last decades; most of them off-line techniques. However, in those cases wherein plants are subject to continuous parametric changes or external disturbances, online gains tuning is a desirable choice. This is the case of modular underwater ROVs (Remotely Operated Vehicles) where parameters (weight, buoyancy, added mass, among others) change according to the tool it is fitted with. In practice, some amount of time is dedicated to tune the PID gains of a ROV. Once the best set of gains has been achieved the ROV is ready to work. However, when the vehicle changes its tool or it is subject to ocean currents, its performance deteriorates since the fixed set of gains is no longer valid for the new conditions. Thus, an online PID gains tuning algorithm should be implemented to overcome this problem. In this paper, an auto-tune PID-like controller based on Neural Networks (NN) is proposed. The NN plays the role of automatically estimating the suitable set of PID gains that achieves stability of the system. The NN adjusts online the controller gains that attain the smaller position tracking error. Simulation results are given considering an underactuated 6 DOF (degrees of freedom) underwater ROV. Real time experiments on an underactuated mini ROV are conducted to show the effectiveness of the proposed scheme.
Higher order sliding mode based impedance control for dual-user bilateral teleoperation under unknown constant time delay
2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015
This paper presents a dual-user teleoperation scheme to perform a collaborative task using n-DOF ... more This paper presents a dual-user teleoperation scheme to perform a collaborative task using n-DOF nonlinear manipulators as masters and slave. Impedance controllers for the manipulators are implemented in order to achieve a desired dynamic behavior depending on the user's necessities. Furthermore, a sliding mode controller is introduced to cope with the time delay in the communication channels and the uncertainty in the slave. Since the slave teleoperator is in contact with a rigid environment, the slave controller requires a free of chattering control strategy, which makes first order sliding mode teleoperation control unsuitable. Then a higher order sliding mode based impedance controller is proposed to guarantee robust impedance tracking under constant, but unknown time delay. Therefore, a position scaling factor is incorporated to deal with the different workspaces among masters and slave. The validity of the proposed control scheme is demonstrated via experimentation on a 3-DOF dual-user teleoperation system. While the haptic devices Phantom Premium 1.0A and a Phantom Omni are used as masters, a virtual industrial manipulator Catalyst-5 is used as slave. The dual-user system is tested not only in presence of constant unknown time delay in each of the communication channels but also in free and constrained motion regime.
Bilateral Cartesian sliding PID force/position control for tracking in finite time of master-slave systems
2006 American Control Conference, 2006
ABSTRACT
Observer-based Higher-Order Sliding Mode Impedance Control of Bilateral Teleoperation under Constant Unknown Time Delay
2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2006
Sliding mode control has been used extensively in robotics to cope with parametric uncertainty an... more Sliding mode control has been used extensively in robotics to cope with parametric uncertainty and hard nonlinearities, in particular for time-delay teleoperators, which have gained gradual acceptance due to technological advancements. However, since the slave teleoperator is in contact to a rigid environment, the slave controller requires a free of chattering control strategy, thus making first order sliding mode teleoperation
5-DOF manipulator simulation based on MATLAB-Simulink methodology
2010 20th International Conference on Electronics Communications and Computers (CONIELECOMP), 2010
This work presents a novel simulation methodology applied to a 5-DOF manipulator. The work includ... more This work presents a novel simulation methodology applied to a 5-DOF manipulator. The work includes mathematical modeling of the direct, inverse and differential kinematics as well as the dynamics of the manipulator. The method implements the path following in the 3D space and uses the Matlab-Simulink approach. Several paths were tested to verify the method. This methodology can be used
2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005
Visual servoing of constrained dynamical robots has not yet met a formal treatment. Also, notices... more Visual servoing of constrained dynamical robots has not yet met a formal treatment. Also, notices that due technological constraints, this tasks is done slowly at velocity reversals, thus dynamic friction arises, which complicates even more the problem. In this paper, a new adaptive scheme for visual servoing of constrained robots subject to dynamic friction is proposed. An image-based control is introduced to produce simultaneous convergence of the constrained visual position and the contact force between the end-effector and the constraint surface. Camera and robot parameters are considered uncertain. This new approach is based on a new formulation of the orthogonalization principle used in force control, coined here visual orthogonalization principle. This allows, under the framework of passivity, to yield a synergetic scheme that fuses camera, encoder and force sensor signals. Simulations results are presented and shows that image errors and force errors converge despite uncertainties of friction model.
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Papers by Luis Govinda García Valdovinos