Showing papers on "Guidance system published in 2014"

Generalized Model Predictive Static Programming and Angle-Constrained Guidance of Air-to-Ground Missiles

Abstract: A new generalized model predictive static programming technique is presented for rapidly solving a class of finite-horizon nonlinear optimal control problems with hard terminal constraints. Two key features for its high computational efficiency include one-time backward integration of a small-dimensional weighting matrix dynamics, followed bya static optimization formulation that requires only a static Lagrange multiplier to update the control history. It turns out that under Euler integration and rectangular approximation of finite integrals it is equivalent to the existing model predictive static programming technique. In addition to the benchmark double integrator problem, usefulness of the proposed technique is demonstrated by solving a three-dimensional angle-constrained guidance problem for an air-to-ground missile, which demands that the missile must meet constraints on both azimuth and elevation angles at the impact point in addition to achieving near-zero miss distance, while minimizing the lateral acceleration demand throughout its flight path. Simulation studies include maneuvering ground targets along with a first-order autopilot lag. Comparison studies with classical augmented proportional navigation guidance and modern general explicit guidance lead to the conclusion that the proposed guidance is superior to both and has a larger capture region as well.

A Biologically Inspired, Vision-based Guidance System for Automatic Landing of a Fixed-wing Aircraft

Abstract: We describe a guidance system for achieving automatic landing of a fixed-wing aircraft in unstructured outdoor terrain, using onboard video cameras. The system uses optic flow information for sensing and controlling the height above the ground, and information on the horizon profile, also acquired by the vision system for stabilizing roll and controlling pitch, and additionally, if required, for the control and stabilization of yaw and flight direction. At low heights, when optic flow is unreliable, stereo information is used to guide descent close to touchdown. While rate gyro information is used to augment attitude stabilization in one of the designs, this is not mandatory and it can be replaced by visual information. Smooth, safe landings are achieved with a success rate of 92.5%. The system does not emit active radiation and does not rely on any external information such as a global positioning system or an instrument landing system.

Guidance for human navigation using a vibro-tactile belt interface and robot-like motion planning

Abstract: We present a navigation guidance system that guides a human to a goal point with a tactile belt interface and a stationary laser scanner. We make use of ROS local navigation planner to find an obstacle-free path by modeling the human as a non-holonomic robot. Linear and angular velocities to keep the ’robot’ on the path are dynamically calculated, which are then converted to vibrations and applied by the tactile belt. We define directional and rotational vibration patterns and evaluate which ones are suitable for guiding humans. Continuous patterns for representing directions had the least average angular error with 8.4◦, whereas rotational patterns were recognized with near-perfect accuracy. All patterns had a reaction time slightly more than 1 seconds. The person is tracked in laser scans by fitting an ellipse to the torso. Average tracking error is found to be 5cm in position and 14◦ in orientation in our experiments with 23 people. Best tracking results was achieved when the person is 2.5m away and is facing the sensor or the opposite way. The human control system as a whole is successfully demonstrated in a navigation guidance scenario.

Real-time urban traffic amount prediction models for dynamic route guidance systems

Abstract: The route guidance system (RGS) has been considered an important technology to mitigate urban traffic congestion. However, existing RGSs provide only route guidance after congestion happens. This reactive strategy imposes a strong limitation on the potential contribution of current RGS to the performance improvement of a traffic network. Thus, a proactive RGS based on congestion prediction is considered essential to improve the effectiveness of RGS. The problem of congestion prediction is translated into traffic amount (i.e. the number of vehicles on the individual roads) prediction, as the latter is a straightforward indicator of the former. We thereby propose two urban traffic prediction models using different modeling approaches. Model-1 is based on the traffic flow propagation in the network, while Model-2 is based on the time-varied spare flow capacity on the concerned road links. These two models are then applied to construct a centralized proactive RGS. Evaluation results show that (1) both of the proposed models reduce the prediction error up to 52% and 30% in the best cases compared to the existing Shift Model, (2) providing proactive route guidance helps reduce average travel time by up to 70% compared to providing reactive one and (3) non-rerouted vehicles could benefit more from route guidance than rerouted vehicles do.

Nonlinear Autopilot Design for an Asymmetric Missile Using Robust Backstepping Control

Abstract: This paper deals with the design of a robust nonlinear controller for a highly maneuverable missile. Stabilization and tracking are achieved, exploiting a detailed nonlinear model of the six-degree-of-freedom, nonminimum phase, uncertain, and time-varying dynamics of a non-axial-symmetric air-to-air tail-controlled missile. A robust backstepping approach is applied to the multi-input/multi-output model to achieve both bank-to-turn and skid-to-turn maneuvers. Control objectives consist of following the reference signals in angle of attack, sideslip, and bank angle produced by the external guidance system, in order to pursue highly agile maneuvers. Uncertain terms, mostly due to aerodynamic coefficients and dynamic pressure, are suitably limited by bounding functions constructed using experience, a priori knowledge on system behavior, and a bit of conservatism. Robust sigmoidlike control functions are then used to dominate in size the uncertain terms. The whole control system is shown to be practically-robu...

Analytical Hierarchy Process Using Fuzzy Inference Technique for Real-Time Route Guidance System

Abstract: This paper focuses on an optimum route search function in the in-vehicle routing guidance system. For a dynamic route guidance system (DRGS), it should provide dynamic routing advice based on real-time traffic information and traffic conditions, such as congestion and roadwork. However, considering all these situations in traditional methods makes it very difficult to identify a valid mathematical model. To realize the DRGS, this paper proposes the analytical hierarchy process (AHP) using a fuzzy inference technique based on the real-time traffic information. This AHP-FUZZY approach is a multicriterion combination system. The nature of the AHP-FUZZY approach is a pairwise comparison, which is expressed by the fuzzy inference techniques, to achieve the weights of the attributes. The hierarchy structure of the AHP-FUZZY approach can greatly simplify the definition of a decision strategy and explicitly represent the multiple criteria, and the fuzzy inference technique can handle the vagueness and uncertainty of the attributes and adaptively generate the weights for the system. Based on the AHP-FUZZY approach, a simulation system is implemented in the route guidance system, and the process is analyzed.

Parking Guidance System Based on ZigBee and Geomagnetic Sensor Technology

Abstract: Concerning the phenomenon that common parking service could not satisfy the increasing demand of the private vehicle owners, an intelligent parking guidance system based on Zig Bee network and geomagnetic sensors was designed. Real-time vehicle position and related traffic information were collected by geomagnetic sensors around parking lots and updated to center server via Zig Bee network. On the other hand, out-door Liquid Crystal Display screens controlled by center server can display information of available parking places. In this paper, guidance strategy was divided into four levels, which could provide clear and effective information to drivers. The experimental results prove that the distance detection accuracy of geomagnetic sensors was within 0.4m, and the lowest package loss rate of the wireless network in the range of 150m is 0%. This system can provide solution for better parking service in intelligent cities.

Arbitrary-Order Sliding-Mode-Based Homing-Missile Guidance for Intercepting Highly Maneuverable Targets

Abstract: This paper investigates the development and implementation of a new homing-missile guidance system for intercepting highly maneuverable targets using arbitrary features of the homogeneous high-order sliding-mode controllers and observers. The concept of this guidance system involves artificially increasing the orders of controllers and observers to enhance accuracy and robustness of future interceptors. Two advanced guidance laws, that is, augmented proportional navigation law and direct collision or hit-to-kill law, are considered to construct acceleration-based and velocity-based attractive sliding manifolds, respectively; and high-order robust exact differentiators are used to compute high-order time derivatives of these manifolds. Real-time estimation of target maneuver from measurements using these differentiators is also considered. The resulting guidance laws are implemented in computer simulation using nonlinear interceptor dynamics and engagement kinematics. The results prove that the guidance sy...

Collision-Avoidance Framework for Small Fixed-Wing Unmanned Aerial Vehicles

Abstract: C OLLISION avoidance is of vital importance to the autonomous flight of unmanned aerial vehicles (UAVs). This especially is true for small UAVs flying at low heights, which usually encounter a large number of mostly static obstacles. Due to a limited knowledge of the environment and small computing power, collision-avoidance algorithms need to rely on little information while being computationally efficient. Guidance laws are one way of tackling such difficulties. There are various approaches to both static [1–3] and moving obstacles [4–7] that are mostly based on the collision cone approach [8,9]. Often, collision avoidance is achieved by tracking an aimpoint at a safe distance from the obstacle, using a homing guidance law [2– 5]. Some authors have derived explicit avoidance laws by limiting their considerations to a plane, defined by the relative geometry between the vehicle and the obstacle [1,7]. The main issue of most of these approaches is that they are designed to avoid only one obstacle at a time, which can be insufficient in obstacle-cluttered environments. A further problem is that primary mission objectives are not fully considered or even completely ignored during avoidance,which may cause trajectories to be far from optimal. This work is concerned with developing an algorithm that keeps a certain safety distance while passing an arbitrary number of possibly moving but nonmaneuvering obstacles. Starting from a threedimensional collision cone condition, input–output linearization is used to design a suitable nonlinear guidance law. The remaining design parameters are determined considering convergence and performance properties of the closed guidance loop. Then, the guidance framework is developed in terms of a constrained optimization problem that can avoid multiple obstacles simultaneously while incorporating other mission objectives. Aimpoint-based approaches [2–5] rely on choosing the most dangerous threat, and thus tend to oscillate or get trapped in symmetric or nearly symmetric situations. The main contribution of the presented algorithm is that it solves this problem by simultaneously avoiding all obstacles using inequality constraints. For cases when collision avoidance is not the only objective, the use of distinct avoidance/guidance modes has been proposed [1,2]. However, this does not ensure that avoidance trajectories comply with other requirements. Thus, the second contribution of the proposed guidance framework is that it can handle this difficulty by permanently considering further mission objectives in its objective function.

Swarm-based path-following for cooperative unmanned surface vehicles

Abstract: This article proposes a swarm-based path-following guidance system for an autonomous marine multi-vehicle system. In particular, a team of unmanned surface vehicles is required to converge to and navigate along a desired reference path, while at the same time aggregating and maintaining a range-based formation configuration. First, a separate description is given for a swarm methodology, initially developed for small ground mobile robots and exploited to aggregate the robot team, and a virtual target–based path-following guidance system developed for unmanned surface vehicles, exploited to drive not the single vehicles but the robot formation as a whole. Then, the integration of the two proposed methodologies is reported and proven, in order to guarantee the feasibility and stability of the overall guidance framework. Simulative results are proposed to validate the effectiveness of the proposed methodology and to evaluate the system performances.

Performing Surface Treatments Using an Automated Guided Vehicle

Abstract: A low-profile, automated guided vehicle (AGV) performs surface treatments over large areas of a structure having limited access, such as an aircraft underbelly. The AGV includes a movable gantry provided with automated robot. The robot has interchangeable end effectors for carrying out the surface treatments. Travel of the AGV relative to structure is controlled by a ground guidance system.

Navigation and Guidance System Architectures for Small Unmanned Aircraft Applications

Abstract: Two multisensor system architectures for navigation and guidance of small Unmanned Aircraft (UA) are presented and compared. The main objective of our research is to design a compact, light and relatively inexpensive system capable of providing the required navigation performance in all phases of flight of small UA, with a special focus on precision approach and landing, where Vision Based Navigation (VBN) techniques can be fully exploited in a multisensor integrated architecture. Various existing techniques for VBN are compared and the Appearance-Based Navigation (ABN) approach is selected for implementation. Feature extraction and optical flow techniques are employed to estimate flight parameters such as roll angle, pitch angle, deviation from the runway centreline and body rates.

Autonomous and automatic landing method and system

Abstract: A system and method are disclosed for automatic landing of an aircraft on a landing runway, including an on-board video camera intended to take images of the ground, image processor to extract from these images visual features of the landing runway, guidance system determining guidance commands of the aircraft to bring it into a nominal approach plane and to align it with the axis of the landing runway, from the respective positions of the visual features of the landing runway, in at least one of the images, where the guidance commands are supplied to a flight control computer.

Guidance for Autonomous Precision Landing on Atmosphereless Bodies

Abstract: Two key technologies that will likely fly on next-generation planetary landers are hazard detection and avoidance (HDA) and vision-based navigation. The purpose of HDA is to make previously unsafe landing sites accessible by future vehicles, and to increase the safe landing probability overall. Vision-based navigation will enable to target specific landing sites more precisely and also plays an important role for HDA. This paper formulates requirements on the guidance system that derive from the needs of these new systems. After the introduction of a reference mission scenario with HDA and vision-based navigation inthe-loop, an extensive literature survey of the state-of-the-art in approach-phase guidancealgorithms is presented. This presents the methods under the angle of HDA-compatibility. The sheer number of papers mentioned here leads to the conclusion that trade-offs are challenging. It is recommended to do a down-selection from the papers presented here, and do a performance-based trade study for the particular test case under consideration with a few candidates. As an example, E-Guidance is presented for a Mercuryand a Moon-landing scenario. Because the results differ dramatically, it is concluded that it is essential to perform trade-offs on the actual mission scenario under study, and that trades cannot merely be based on references in the literature. Because the proposed E-Guidance method is not satisfyingly robust, it is a goal for future research to improve upon this.

Reverse Engineering of a Fixed Wing Unmanned Aircraft 6-DoF Model for Navigation and Guidance Applications

Abstract: A method for deriving the parameters of a six-degree-of-freedom (6-DoF) aircraft dynamics model by adopting reverse engineering techniques is presented. The novelty of the paper is the adaption of the 6-DoF Aircraft Dynamics Model (ADM) as a virtual sensor integrated in a low-cost navigation and guidance system designed for small Unmanned Aircraft (UA). The mass and aerodynamic properties of the JAVELIN UA are determined with the aid of an accurate 3D scanning and CAD processing. For qualitatively assessing the calculated ADM, a trajectory with high dynamics is simulated for the JAVELIN UA and compared with that of a published 6-DoF model of the AEROSONDE UA. Additionally, to confirm the validity of the approach, reverse engineering procedures are applied to a published CAD model of the AEROSONDE UA aiding to the calculation of the associated 6-DoF model parameters. A spiral descent trajectory is generated using both the published and calculated parameters of the AEROSONDE UA and a comparative analysis is performed that validates the methodology. The accurate knowledge of the ADM is then utilized in the development of a virtual sensor to augment the UA navigation and guidance system in case of primary navigation sensor outages.

A Context-Aware-Based Audio Guidance System for Blind People Using a Multimodal Profile Model

Abstract: A wearable guidance system is designed to provide context-dependent guidance messages to blind people while they traverse local pathways. The system is composed of three parts: moving scene analysis, walking context estimation and audio message delivery. The combination of a downward-pointing laser scanner and a camera is used to solve the challenging problem of moving scene analysis. By integrating laser data profiles and image edge profiles, a multimodal profile model is constructed to estimate jointly the ground plane, object locations and object types, by using a Bayesian network. The outputs of the moving scene analysis are further employed to estimate the walking context, which is defined as a fuzzy safety level that is inferred through a fuzzy logic model. Depending on the estimated walking context, the audio messages that best suit the current context are delivered to the user in a flexible manner. The proposed system is tested under various local pathway scenes, and the results confirm its efficiency in assisting blind people to attain autonomous mobility.

A novel approach for trajectory tracking of UAVs

Abstract: Purpose – The purpose of this paper is to present a novel approach for trajectory tracking of UAVS. Research on unmanned aircraft is constantly improving the autonomous flight capabilities of these vehicles to provide performance needed to use them in even more complex tasks. The UAV path planner (PP) plans the best path to perform the mission. This is a waypoint sequence that is uploaded on the flight management system providing reference to the aircraft guidance, navigation and control system (GNCS). The UAV GNCS converts the waypoint sequence in guidance references for the flight control system (FCS) that, in turn, generates the command sequence needed to track the optimum path. Design/methodology/approach – A new guidance system (GS) is presented in this paper, based on the graph search algorithm kinematic A* (KA*). The GS is linked to a nonlinear model predictive control (NMPC) system that tracks the reference path, solving online (i.e. at each sampling time) a finite horizon (state horizon) open loo...

Real-time simulation platform for airport activity area monitoring guidance system

Abstract: The invention discloses a real-time simulation platform for an airport activity area monitoring guidance system. The real-time simulation platform comprises an airport activity area multisensory target simulation system, a flight attitude calculation and data conversion module, a simulation cockpit seat, a recording and playback module, a three-dimensional scene generation platform, a computer cluster graphic processing system and a large screen high definition projected display system. Data of the airport activity area multisensory target simulation system are processed through the airport activity area monitoring guidance system and then output to the flight attitude calculation and data conversion module for flight attitude calculation and format conversion, graph segmentation is carried out through simulation of the three-dimensional scene generation platform and the computer cluster graphic processing system, and ultimately the data are displayed through the large screen high definition projected display system. The real-time simulation platform can meet the simulation requirements of multiple airport activity area monitoring systems, seamless splice pictures are displayed with high definition, and the simulation degree is high.

RPAS navigation and guidance systems based on GNSS and other low-cost sensors

Abstract: A new navigation system for small size Remotely Piloted Aircraft Systems (RPAS) is presented, which is based on Global Navigation Satellite System (GNSS), Micro-Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU), Vision Based Navigation (VBN) and other low-cost avionics sensors. The objective of this research is to design a compact, lightweight and relatively inexpensive Navigation and Guidance System (NGS) capable of providing the required navigation performance in all phases of flight of a small RPAS, with a special focus on precision approach and landing, where VBN techniques can be fully exploited in a multisensory integrated architecture. Additionally, the potential of carrier-phase GNSS for Attitude Determination (GAD) is explored and a six-degree-of-freedom (6-DoF) Aircraft Dynamics Model (ADM) is adopted to compensate for the MEMS-IMU sensor shortcomings in high-dynamics attitude determination tasks. The NGS data fusion architectures investigated are based on Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) approaches. After introducing the key hardware and software features of the NGS, the system performance is evaluated in a small RPAS integration scheme (i.e., AEROSONDE RPAS platform) by exploring a representative cross-section of this RPAS operational flight envelope, including a variety of high dynamics maneuvers and CAT-I to CAT-III precision approach tasks. The performance evaluation shows that the position and attitude accuracies of the proposed integrated navigation and guidance systems are compatible with the Required Navigation Performance (RNP) specified in the various RPAS flight phases, including precision approach down to CAT-II.

Adapting haptic guidance authority based on user grip

Abstract: Haptic guidance systems support the operator in task execution using additional forces on the input device. Scaling of the guidance forces determines the control authority of the support system. As task complexity may vary, one level of the guidance scaling may be insufficient, and adaptation of the control authority may be helpful. The available literature mostly proposed to adapt the authority based on external cues (e.g. actual performance or safety) and the user had no direct way to modulate the desired level of support. In this paper we investigated a variable authority guidance scheme based on the user grip force. During a user study (with 8 subjects) we explored two opposite approaches to trade the control authority (i.e. increasing or decreasing guidance force magnitude with increased user grip). To simulate increased task difficulty and imperfections of the haptic guidance system, at random times either an unpredictable force disturbance was added or subjects were presented with incorrect guidance. While the performance differences between the fixed- and the variable-authority schemes were not significant, the "decreasing guidance with increased user grip" scheme allowed to substantially reduce the user control effort (steering force), especially when the guidance system was incorrect. The presented method essentially provides additional control over the guidance system without reducing the performance.

A traffic surveillance and guidance system

Abstract: A traffic surveillance and guidance system comprising a traffic server system is disclosed. The traffic server is configured to receive and update and record data of geographical positions of registered road users, and wherein each registered road user is registering a replaceable and modifiable geometrically shaped model of a field of view representing the respective road users observation space and observation ability of possible traffic incidents around geographical positions the respective road users are located on at any time.

A self stabilizing platform

Abstract: There exist mechanical devices for which it is important to retain a constant position, or a constant direction regardless of their space fitting. Classic applications of such systems include a camera stabilization in moving systems, a platform stabilization for mobile guidance systems, or other special cases. For this and other cases, it is appropriate to use the now widespread and relatively accurate MEMS gyroscopes and accelerometers. Their consumption and size are negligible and can be used right from the smallest models or toys. This paper reports on a particular solution build on the sensor MPU6050 and its parameters that can scan 6DOF (3 × 3 accelerometer + gyroscope). In real conditions this task is not trivial, since the signals of these sensors are quite noisy and influenced by other variables such as reaction speed, inertia, and accuracy of data interpretation, sensor drift and others. Self-stabilizing platforms can be of great use especially in the automotive, aviation, marine, robotics, aerospace as well as in everyday life.