MPC-BASED AUTONOMOUS DRIVING CONTROL WITH LOCALIZED PATH PLANNING FOR OBSTACLE AVOIDANCE AND NAVIGATING SIGNALIZED INTERSECTIONS

Connected and autonomous vehicles are becoming the major focus of research for the industry and academia in the automotive field. Many companies and research groups have demonstrated the advantages and the requirement of such technology to improve the energy efficiency of vehicles, decrease the number of crash and road accidents, and control emissions. This research delves into improving the autonomy of self-driving vehicles by implementing localized path planning algorithms to introduce motion control for obstacle avoidance during uncertainties. Lateral path planning is implemented using the A* algorithm combined with piecewise Bezier curve generation which provides an optimum trajectory reference to avoid a collision. Model Predictive Control (MPC) is used to implement longitudinal and lateral control of the vehicle. The data from vehicle-to-everything (V2X) communication infrastructure is used to navigate through multiple signalized intersections. Furthermore, a new method of developing Advanced Driver Assistance Systems (ADAS) algorithms and vehicle controllers using Model-In-the-Loop (MIL) testing is explored with the use of PreScan®. With PreScan®, various traffic scenarios are modeled and the sensor data are simulated by using physics-based sensor models, which are fed to the controller for data processing and motion planning. Obstacle detection and collision avoidance are demonstrated using the presented MPC controller. The results of the proposed controller and the scope of the future work conclude the research

Neural Network based Controller for High Speed Vehicle following Predetermined Path

The actual integration of automated control systems in vehicles such as Anti-lock Braking Systems (ABS) or Traction Control System (TCS) has proved to increase road safety and improve driver's comfort. Since most of the accidents are attributed to the fault of the driver, automated control systems in vehicle safety technology may dramatically better road safety by improving driver's performance. This thesis presents an enhanced and improved autonomous intelligent cruise control systems with obstacle collision avoidance integrated with path following/lane keeping. Obstacle collision avoidance is the ability to avoid obstaclesthat are in the vehicle's path, without causing damage to the obstacle or vehicle. Path following/lane keeping is the ability to follow the vehicle's path and keeping in its lane, as accurately as possible. The idea is to have a vehicle that drives by itself and avoids obstacles in the real world. Every instant, the vehicle decides by itself how to modify its direction according to its environment. This thesis demonstrates Gaussian functions and multi-objective cost function employed alongside with the Neural Network and optimal preview controller for control of the position of the vehicle to move while avoiding collision with obstacles. Each obstacle is represented independent of the others as a bell-shaped hump by the Gaussian functions which serve as an obstacle recognition system. Multi-objective cost function is formed for the planning strategy to generate, evaluate and select plans so that the vehicle can select which direction to move. Neural Network and optimal preview steering control are utilized to control a full linear steering model of a vehicle so as to increase path following accuracy. Optimal preview control is capable to portray the driver's vision of the path and process the knowledge while Neural Network controller has the ability to 'learn' from past errors and adjust the network to obtain specific target output. In this thesis, a MATLAB simulation environment was created to simulate the ability of a vehicle to avoid obstacles that are in the vehicle's path. Simulated obstacle avoidance has confirmed the capability of a vehicle to precisely avoid collision with obstacles while traveling on high speed along its predetermined path. i

Control of Outdoor Robots at Higher Speeds on Challenging Terrain

This thesis studies the motion control of wheeled mobile robots. Its focus is set on high speed control on challenging terrain. Additionally, it deals with the general problem of path following, as well as path planning and obstacle avoidance in difficult conditions. First, it proposes a heuristic longitudinal control for any wheeled mobile robot, and evaluates it on different kinematic configurations and in different conditions, including laboratory experiments and participation in a robotic competition. Being the focus of the thesis, high speed control on uneven terrain is thoroughly studied, and a novel control law is proposed, based on a new model representation of skid-steered vehicles, and comprising of nonlinear lateral and longitudinal control. The lateral control part is based on the Lyapunov theory, and the convergence of the vehicle to the geometric reference path is proven. The longitudinal control is designed for high speeds, taking actuator saturation and the vehicle properties into account. The complete solution is experimentally tested on two different vehicles on several different terrain types, reaching the speeds of ca. 6 m/s, and compared against two state-of-the-art algorithms. Furthermore, a novel path planning and obstacle avoidance system is proposed, together with an extension of the proposed high speed control, which builds up a navigation system capable of autonomous outdoor person following. This system is experimentally compared against two classical obstacle avoidance methods, and evaluated by following a human jogger in outdoor environments, with both static and dynamic obstacles. All the proposed methods, together with various different state-of-the-art control approaches, are unified into one framework. The proposed framework can be used to control any wheeled mobile robot, both indoors and outdoors, at low or high speeds, avoiding all the obstacles on the way. The entire work is released as open-source software

Simultaneous Local Motion Planning and Control, Adjustable Driving Behavior, and Obstacle Representation for Autonomous Driving

The evolving autonomous driving technology has been attracting significant research efforts in both academia and industry because of its promising potentials. Eliminating the human intervention in driving will drastically improve the road safety and will create more mobility freedom for the humankind. Decision-making system in autonomy pipeline is the last module that interacts directly with the surrounding environment. Typical decision-making systems perform a variety of tasks including local motion planning, obstacle avoidance, and path-following in a sequential manner. An alternative approach is to perform these tasks simultaneously to obtain faster decision-making actions. This thesis focuses on designing an optimization-based simultaneous controller that performs obstacle avoidance, local motion planning, and vehicle control on roads regardless of their orientation while following a target path, and also incorporates adjustable driving behavior. Firstly, a decision-making scheme that enables autonomous driving for long trips while expanding the usage of the available computational resources and ensuring obstacle avoidance functionality is proposed. The proposed scheme utilizes a parallel architecture for local motion planning and control layers to increase time efficiency. In addition, a novel feasibility-guaranteed lane change and double lane change planners are introduced for path planning and obstacle avoidance. Finally, an online parameterized curve generator is proposed and integrated with a recently developed path-following controller. Next, a nonlinear model predictive control (NMPC) scheme is developed for the path-following control of autonomous vehicles. In addition, a dual-objective cost function which is composed of a regulation part and an economic part is introduced. By tuning the weights of this cost, a driving behavior can be implemented; two different driving behaviors are designed, namely, energy-efficient and sport driving modes. Finally, a kinematic bicycle model is used for predicting the vehicle motion while a longitudinal motion dynamic model is used for estimating the energy consumption. Finally, a novel representation framework for static maps and obstacles based on Fourier Series is proposed. The framework relies on Complex Fourier Series analysis to reduce the computation time and outputs mathematical equations to describe the shape of the considered object. Furthermore, two methods were proposed, namely; offline method and online method. The offline method is used to create accurate representations for static maps and most common obstacles an ego vehicle may encounter. The online method is used to model the free space around the vehicle when dealing with uncertain environments. The proposed contributions fill significant gaps in the autonomous driving problem. All the proposed work is tested and validated using numerical simulations and some experiments. The results show the effectiveness of the proposed contributions

AutonoVi: Autonomous Vehicle Planning with Dynamic Maneuvers and Traffic Constraints

We present AutonoVi:, a novel algorithm for autonomous vehicle navigation that supports dynamic maneuvers and satisfies traffic constraints and norms. Our approach is based on optimization-based maneuver planning that supports dynamic lane-changes, swerving, and braking in all traffic scenarios and guides the vehicle to its goal position. We take into account various traffic constraints, including collision avoidance with other vehicles, pedestrians, and cyclists using control velocity obstacles. We use a data-driven approach to model the vehicle dynamics for control and collision avoidance. Furthermore, our trajectory computation algorithm takes into account traffic rules and behaviors, such as stopping at intersections and stoplights, based on an arc-spline representation. We have evaluated our algorithm in a simulated environment and tested its interactive performance in urban and highway driving scenarios with tens of vehicles, pedestrians, and cyclists. These scenarios include jaywalking pedestrians, sudden stops from high speeds, safely passing cyclists, a vehicle suddenly swerving into the roadway, and high-density traffic where the vehicle must change lanes to progress more effectively.Comment: 9 pages, 6 figure

Fault-tolerant formation driving mechanism designed for heterogeneous MAVs-UGVs groups

A fault-tolerant method for stabilization and navigation of 3D heterogeneous formations is proposed in this paper. The presented Model Predictive Control (MPC) based approach enables to deploy compact formations of closely cooperating autonomous aerial and ground robots in surveillance scenarios without the necessity of a precise external localization. Instead, the proposed method relies on a top-view visual relative localization provided by the micro aerial vehicles flying above the ground robots and on a simple yet stable visual based navigation using images from an onboard monocular camera. The MPC based schema together with a fault detection and recovery mechanism provide a robust solution applicable in complex environments with static and dynamic obstacles. The core of the proposed leader-follower based formation driving method consists in a representation of the entire 3D formation as a convex hull projected along a desired path that has to be followed by the group. Such an approach provides non-collision solution and respects requirements of the direct visibility between the team members. The uninterrupted visibility is crucial for the employed top-view localization and therefore for the stabilization of the group. The proposed formation driving method and the fault recovery mechanisms are verified by simulations and hardware experiments presented in the paper

Fuzzy Logic Path Planning System for Collision Avoidance by an Autonomous Rover Vehicle

Systems already developed at JSC have shown the benefits of applying fuzzy logic control theory to space related operations. Four major issues are addressed that are associated with developing an autonomous collision avoidance subsystem within a path planning system designed for application in a remote, hostile environment that does not lend itself well to remote manipulation of the vehicle involved through Earth-based telecommunication. A good focus for this is unmanned exploration of the surface of Mars. The uncertainties involved indicate that robust approaches such as fuzzy logic control are particularly appropriate. The four major issues addressed are: (1) avoidance of a single fuzzy moving obstacle; (2) back off from a dead end in a static obstacle environment; (3) fusion of sensor data to detect obstacles; and (4) options for adaptive learning in a path planning system

Navigation, localization and stabilization of formations of unmanned aerial and ground vehicles

A leader-follower formation driving algorithm developed for control of heterogeneous groups of unmanned micro aerial and ground vehicles stabilized under a top-view relative localization is presented in this paper. The core of the proposed method lies in a novel avoidance function, in which the entire 3D formation is represented by a convex hull projected along a desired path to be followed by the group. Such a representation of the formation provides non-collision trajectories of the robots and respects requirements of the direct visibility between the team members in environment with static as well as dynamic obstacles, which is crucial for the top-view localization. The algorithm is suited for utilization of a simple yet stable visual based navigation of the group (referred to as GeNav), which together with the on-board relative localization enables deployment of large teams of micro-scale robots in environments without any available global localization system. We formulate a novel Model Predictive Control (MPC) based concept that enables to respond to the changing environment and that provides a robust solution with team members' failure tolerance included. The performance of the proposed method is verified by numerical and hardware experiments inspired by reconnaissance and surveillance missions

Model Predictive Control for Autonomous Driving Based on Time Scaled Collision Cone

In this paper, we present a Model Predictive Control (MPC) framework based on path velocity decomposition paradigm for autonomous driving. The optimization underlying the MPC has a two layer structure wherein first, an appropriate path is computed for the vehicle followed by the computation of optimal forward velocity along it. The very nature of the proposed path velocity decomposition allows for seamless compatibility between the two layers of the optimization. A key feature of the proposed work is that it offloads most of the responsibility of collision avoidance to velocity optimization layer for which computationally efficient formulations can be derived. In particular, we extend our previously developed concept of time scaled collision cone (TSCC) constraints and formulate the forward velocity optimization layer as a convex quadratic programming problem. We perform validation on autonomous driving scenarios wherein proposed MPC repeatedly solves both the optimization layers in receding horizon manner to compute lane change, overtaking and merging maneuvers among multiple dynamic obstacles.Comment: 6 page