The reality gap, which often makes controllers evolved in simulation inefficient once transferred onto the physical robot, remains a critical issue in evolutionary robotics (ER). We hypothesize that this gap highlights a conflict between the efficiency of the solutions in simulation and their transferability from simulation to reality: the most efficient solutions in simulation often exploit badly modeled phenomena to achieve high fitness values with unrealistic behaviors. This hypothesis leads to the transferability approach, a multiobjective formulation of ER in which two main objectives are optimized via a Pareto-based multiobjective evolutionary algorithm: 1) the fitness; and 2) the transferability, estimated by a simulation-to-reality (STR) disparity measure. To evaluate this second objective, a surrogate model of the exact STR disparity is built during the optimization. This transferability approach has been compared to two reality-based optimization methods, a noise-based approach inspired from Jakobi's minimal simulation methodology and a local search approach. It has been validated on two robotic applications: 1) a navigation task with an e-puck robot; and 2) a walking task with a 8-DOF quadrupedal robot. For both experimental setups, our approach successfully finds efficient and well-transferable controllers only with about ten experiments on the physical robot.

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The Transferability Approach: Crossing the Reality Gap in Evolutionary Robotics

Parametric uncertainties and coupled nonlinear dynamics are inherent in quadrotor configuration and infer adaptive nonlinear approaches to be used for flight control system. Numerous adapt...

Nonlinear and Adaptive Intelligent Control Techniques for Quadrotor UAV – A Survey

Unmanned Aerial Vehicles (UAVs) offer a wide range of interesting military and commercial applications at reduced costs. A couple of their more interesting characteristics include: They are capable of hovering and flying at high and low speeds, and they can move in any direction and take off and land vertically. A very promising class of these vehicles comprises small vehicles that can be flown either indoor or outdoor and offer the possibility for near-area surveillance, crop dusting, precision farming [1], microwave autonomous copter systems for geological remote sensing as shown in [2], geographic studies, fire monitoring, security applications, search- and-rescue, and attack and rendezvous [3], [4]. However, challenging requirements in terms of size, weight, and maneuverability for these systems are presented in [5]. A type of aircraft with an important and significant potential is the so-called Quadrotor that is considered by most research studies as a promising UAV [6].

A survey on quadrotors: Configurations, modeling and identification, control, collision avoidance, fault diagnosis and tolerant control

This study includes altitude stabilization, hovering control any desired position and attitude control of quadrotor. Classically PD controller derived and applied to this system. Inverse dynamic control, feedback linearization control and sliding mode control methods have used to derive as nonlinear controllers. Linear and nonlinear control techniques applied to attitude control of this vehicle. Derived control methods have been performed using computer simulations and compared the results according to this study objective.

Attitude control of a quadrotor

Multirotors have received a great attention from researchers and the general public, as a platform on which various ideas can be easily demonstrated. This paper aims to provide background materials by categorizing various representations of multirotor dynamics and existing control approaches for multirotor control. First, many ways of expressing the translation and the attitude dynamics of a quadrotor UAV are described. Second, linear and nonlinear control laws are reviewed considerably. Finally, we show various types of flight test-beds configured for validating the controller. In experiments, the performance of linear and nonlinear controller are described.

Trajectory tracking control of multirotors from modelling to experiments: A survey

The present study addresses the issues concerning the developpment of a reliable assisted remote control for a four-rotor miniature aerial robot (known as quadrotor), guaranteeing the capability of a stable autonomous flight. The following results are proposed: after establishing a dynamical flight model as well as models for the rotors, gears and motors of the quadrotor, different nonlinear control laws are investigated for attitude and position control of the UAV. The stability and performance of feedback, backstepping and sliding mode controllers are compared in simulations. Finally, experiments on a newly implemented quadrotor prototype have been conducted in order to validate the theoretical analysis.

https://hal.archives-ouvertes.fr/hal-02987436/document

Patrick Adigbli

Papers

Nonlinear Attitude and Position Control of a Micro Quadrotor using Sliding Mode and Backstepping Techniques