The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform

Takashi Tsubouchi - One of the best experts on this subject based on the ideXlab platform.

  • Planning of scooping position and Approach Path for loading operation by wheel loader
    Proceedings of the 22nd International Symposium on Automation and Robotics in Construction, 2005
    Co-Authors: Shigeru Sarata, Yossewee Weeramhaeng, Takashi Tsubouchi
    Abstract:

    Our group developed a method for planning of scooping point and Approach Path as a part of our ongoing research on autonomous loading operation of wheel loader at construction sites. The planning of scooping position and direction is obtained through processing pile model. The pile model represents shape and volume of the pile, changes of shape and volume by scooping, and falling behavior accompanied scooping. Scooping direction should be perpendicular to slope of the pile to avoid unbalance of resistance force around the center line of the bucket. The resistance force imposed on the bucket is estimated using the pile model and bucket trajectory model. The scooping direction with least unbalance of resistance force is selected. V shape Path between the scooping position and the loading position to dump track is composed of straight lines and clothoid curves. For given scooping position and loading position, the Path with the least length is produced by the proposed planning method using optimization by Lagrange multiplier. For selection of the next scooping point, V shape Paths for candidate of scooping points are planned by proposed method.

  • ICRA - Approach Path Generation to Scooping Position for Wheel Loader
    Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1
    Co-Authors: Shigeru Sarata, Yossewee Weeramhaeng, Takashi Tsubouchi
    Abstract:

    Our group developed a method of Path generation for wheel loaders as part of our ongoing research on the autonomous loading operation of wheel loaders at surface mines and construction sites. The Path connecting the present vehicle position and scooping position consists of clothoid curves and straight lines. Each line segment is optimized in a Path generation procedure. A simplified model of the pile shape and bucket trajectory is used to determine the scooping direction based on an estimation of the resistance force applied on the bucket during the scooping motion. We applied the proposed method in an experimental model. A stereo-vision system was used to measure the shape of the pile and the scooping direction that imposed the least moment on the bucket was selected as the scooping position. This method generates an appropriate Path for the wheel loader.

Changdon Kee - One of the best experts on this subject based on the ideXlab platform.

  • Fully Automatic Taxiing, Takeoff and Landing of a UAV only with a Single-Antenna GPS Receiver
    2008
    Co-Authors: Am Cho, Sanghyo Lee, Dongkeon Kim, Jihoon Kim, Changdon Kee
    Abstract:

    [Abstract] This paper deals with automatic takeoff and landing of a UAV using a single antenna GPS receiver only. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single -antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic landing and takeoff on the runway. In addition to GPS receiver , only an airspeed sen sor is added because the velocity relative to the air is very important during landing and takeoff. For a fixed wing aircraft, the attitude information called as pseudo -attitudes can be estimated from the measurements of a single -antenna GPS receiver under the assumption of coordinated flight . From linearized equations of motions around the steady state, LQR controllers f or takeoff and landing are buil t. In particular, for the flare control, the controller that controls the pitch, altitude and airspeed of a UAV is designe d. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. The flight test results show that a single -ante nna GPS receiver can be used as a main sensor for a backup or a low -cost control system of UAVs.

  • Fully automatic taxiing, takeoff and landing of a UAV based on a single-antenna GNSS receiver
    IFAC Proceedings Volumes, 2008
    Co-Authors: Am Cho, Sanghyo Lee, Bosung Kim, Noha Park, Dongkeon Kim, Jihoon Kim, Changdon Kee
    Abstract:

    This paper presents fully automatic control of an unmanned aerial vehicle (UAV) from taxiing and takeoff to landing based on a single-antenna GPS receiver. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single-antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic taxiing, landing and takeoff on the runway. For a fixed wing aircraft, under the assumption of coordinated flight, the attitude information called as pseudo-attitudes can be estimated from the measurements of a single-antenna GPS receiver. Therefore full state variables for the automatic control can be obtained from single-antenna GPS receiver. In addition to GPS receiver, only an airspeed sensor is added because the velocity relative to the air is very important during landing and takeoff. The forward velocity is replaced with the airspeed obtained from Pitot tube. From linearized equations of motions around the steady state, LQR controllers for takeoff and landing are built. In particular, the flare controller that controls the pitch, altitude and airspeed of a UAV is designed. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. Based on flight test results, a single-antenna GPS receiver can be used as a main sensor for a backup or a low-cost control system of UAVs

  • Fully automatic taxiing, takeoff and landing of a UAV using a single-antenna GPS receiver only
    ICCAS 2007 - International Conference on Control Automation and Systems, 2007
    Co-Authors: Am Cho, Sanghyo Lee, Bosung Kim, Noha Park, Dongkeon Kim, Sujin Choi, Jihoon Kim, Boram Lee, Changdon Kee
    Abstract:

    This paper presents automatic taxiing, takeoff and landing of a UAV based on a single-antenna GPS receiver. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single-antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic taxiing, landing and takeoff on the runway. For a fixed wing aircraft, under the assumption of coordinated flight, the attitude information called as pseudo-attitudes can be estimated from the measurements of a single-antenna GPS receiver. So full state variables for the automatic control can be obtained from single-antenna GPS receiver. In addition to GPS receiver, only an airspeed sensor is added because the velocity relative to the air is very important during landing and takeoff. The forward velocity is replaced with the airspeed obtained from Pitot tube. From linearized equations of motions around the steady state, LQR controllers for takeoff and landing are built, m particular, the flare controller that controls the pitch, altitude and airspeed of a UAV is designed. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. Based on flight test results, a single-antenna GPS receiver can be used as a main sensor for a backup or a low-cost control system of UAVs.

  • Fully Automatic Taxiing, Takeoff and Landing of a VAV using a Single-Antenna GPS Receiver only
    2007
    Co-Authors: Am Cho, Sanghyo Lee, Bosung Kim, Noha Park, Dongkeon Kim, Changdon Kee, Sujin Choi, Jihoon Kim, Boram Lee, Gnss Lab
    Abstract:

    This paper presents automatic taxiing, takeoff and landing of a UAV based on a single-antenna GPS receiver. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single-antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic taxiing, landing and takeoff on the runway. For a fixed wing aircraft, under the assumption of coordinated flight, the attitude information called as pseudo-attitudes can be estimated from the measurements of a single-antenna GPS receiver. So full state variables for the automatic control can be obtained from single-antenna GPS receiver. In addition to GPS receiver, only an airspeed sensor is added because the velocity relative to the air is very important during landing and takeoff The forward velocity is replaced with the airspeed obtained from Pitot tube. From linearized equations of motions around the steady state, LQR controllers for takeoff and landing are built. In particular, the flare controller that controls the pitch, altitude and airspeed of a UAV is designed. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. Based on flight test results, a single-antenna GPS receiver can be used as a main sensor for a backup or a low-cost control system ofUAVs

Igor Gilitschenski - One of the best experts on this subject based on the ideXlab platform.

  • Free LSD: Prior-Free Visual Landing Site Detection for Autonomous Planes
    arXiv: Robotics, 2018
    Co-Authors: Timo Hinzmann, Thomas Stastny, Cesar Cadena, Roland Siegwart, Igor Gilitschenski
    Abstract:

    Full autonomy for fixed-wing unmanned aerial vehicles (UAVs) requires the capability to autonomously detect potential landing sites in unknown and unstructured terrain, allowing for self-governed mission completion or handling of emergency situations. In this work, we propose a perception system addressing this challenge by detecting landing sites based on their texture and geometric shape without using any prior knowledge about the environment. The proposed method considers hazards within the landing region such as terrain roughness and slope, surrounding obstacles that obscure the landing Approach Path, and the local wind field that is estimated by the on-board EKF. The latter enables applicability of the proposed method on small-scale autonomous planes without landing gear. A safe Approach Path is computed based on the UAV dynamics, expected state estimation and actuator uncertainty, and the on-board computed elevation map. The proposed framework has been successfully tested on photo-realistic synthetic datasets and in challenging real-world environments.

  • Free LSD: Prior-Free Visual Landing Site Detection for Autonomous Planes
    IEEE Robotics and Automation Letters, 2018
    Co-Authors: Timo Hinzmann, Thomas Stastny, Cesar Cadena, Roland Siegwart, Igor Gilitschenski
    Abstract:

    Full autonomy for fixed-wing unmanned aerial vehicles (UAVs) requires the capability to autonomously detect potential landing sites in unknown and unstructured terrain, allowing for self-governed mission completion or handling of emergency situations. In this letter, we propose a perception system addressing this challenge by detecting landing sites based on their texture and geometric shape without using any prior knowledge about the environment. The proposed method considers hazards within the landing region such as terrain roughness and slope, surrounding obstacles that obscure the landing Approach Path, and the local wind field that is estimated by the on-board EKF. The latter enables applicability of the proposed method on small-scale autonomous planes without landing gear. A safe Approach Path is computed based on the UAV dynamics, expected state estimation and actuator uncertainty, and the on-board computed elevation map. The proposed framework has been successfully tested on photo-realistic synthetic datasets and in challenging real-world environments.

Shigeru Sarata - One of the best experts on this subject based on the ideXlab platform.

  • Planning of scooping position and Approach Path for loading operation by wheel loader
    Proceedings of the 22nd International Symposium on Automation and Robotics in Construction, 2005
    Co-Authors: Shigeru Sarata, Yossewee Weeramhaeng, Takashi Tsubouchi
    Abstract:

    Our group developed a method for planning of scooping point and Approach Path as a part of our ongoing research on autonomous loading operation of wheel loader at construction sites. The planning of scooping position and direction is obtained through processing pile model. The pile model represents shape and volume of the pile, changes of shape and volume by scooping, and falling behavior accompanied scooping. Scooping direction should be perpendicular to slope of the pile to avoid unbalance of resistance force around the center line of the bucket. The resistance force imposed on the bucket is estimated using the pile model and bucket trajectory model. The scooping direction with least unbalance of resistance force is selected. V shape Path between the scooping position and the loading position to dump track is composed of straight lines and clothoid curves. For given scooping position and loading position, the Path with the least length is produced by the proposed planning method using optimization by Lagrange multiplier. For selection of the next scooping point, V shape Paths for candidate of scooping points are planned by proposed method.

  • ICRA - Approach Path Generation to Scooping Position for Wheel Loader
    Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 1
    Co-Authors: Shigeru Sarata, Yossewee Weeramhaeng, Takashi Tsubouchi
    Abstract:

    Our group developed a method of Path generation for wheel loaders as part of our ongoing research on the autonomous loading operation of wheel loaders at surface mines and construction sites. The Path connecting the present vehicle position and scooping position consists of clothoid curves and straight lines. Each line segment is optimized in a Path generation procedure. A simplified model of the pile shape and bucket trajectory is used to determine the scooping direction based on an estimation of the resistance force applied on the bucket during the scooping motion. We applied the proposed method in an experimental model. A stereo-vision system was used to measure the shape of the pile and the scooping direction that imposed the least moment on the bucket was selected as the scooping position. This method generates an appropriate Path for the wheel loader.

Am Cho - One of the best experts on this subject based on the ideXlab platform.

  • Fully Automatic Taxiing, Takeoff and Landing of a UAV only with a Single-Antenna GPS Receiver
    2008
    Co-Authors: Am Cho, Sanghyo Lee, Dongkeon Kim, Jihoon Kim, Changdon Kee
    Abstract:

    [Abstract] This paper deals with automatic takeoff and landing of a UAV using a single antenna GPS receiver only. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single -antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic landing and takeoff on the runway. In addition to GPS receiver , only an airspeed sen sor is added because the velocity relative to the air is very important during landing and takeoff. For a fixed wing aircraft, the attitude information called as pseudo -attitudes can be estimated from the measurements of a single -antenna GPS receiver under the assumption of coordinated flight . From linearized equations of motions around the steady state, LQR controllers f or takeoff and landing are buil t. In particular, for the flare control, the controller that controls the pitch, altitude and airspeed of a UAV is designe d. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. The flight test results show that a single -ante nna GPS receiver can be used as a main sensor for a backup or a low -cost control system of UAVs.

  • Fully automatic taxiing, takeoff and landing of a UAV based on a single-antenna GNSS receiver
    IFAC Proceedings Volumes, 2008
    Co-Authors: Am Cho, Sanghyo Lee, Bosung Kim, Noha Park, Dongkeon Kim, Jihoon Kim, Changdon Kee
    Abstract:

    This paper presents fully automatic control of an unmanned aerial vehicle (UAV) from taxiing and takeoff to landing based on a single-antenna GPS receiver. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single-antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic taxiing, landing and takeoff on the runway. For a fixed wing aircraft, under the assumption of coordinated flight, the attitude information called as pseudo-attitudes can be estimated from the measurements of a single-antenna GPS receiver. Therefore full state variables for the automatic control can be obtained from single-antenna GPS receiver. In addition to GPS receiver, only an airspeed sensor is added because the velocity relative to the air is very important during landing and takeoff. The forward velocity is replaced with the airspeed obtained from Pitot tube. From linearized equations of motions around the steady state, LQR controllers for takeoff and landing are built. In particular, the flare controller that controls the pitch, altitude and airspeed of a UAV is designed. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. Based on flight test results, a single-antenna GPS receiver can be used as a main sensor for a backup or a low-cost control system of UAVs

  • Fully automatic taxiing, takeoff and landing of a UAV using a single-antenna GPS receiver only
    ICCAS 2007 - International Conference on Control Automation and Systems, 2007
    Co-Authors: Am Cho, Sanghyo Lee, Bosung Kim, Noha Park, Dongkeon Kim, Sujin Choi, Jihoon Kim, Boram Lee, Changdon Kee
    Abstract:

    This paper presents automatic taxiing, takeoff and landing of a UAV based on a single-antenna GPS receiver. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single-antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic taxiing, landing and takeoff on the runway. For a fixed wing aircraft, under the assumption of coordinated flight, the attitude information called as pseudo-attitudes can be estimated from the measurements of a single-antenna GPS receiver. So full state variables for the automatic control can be obtained from single-antenna GPS receiver. In addition to GPS receiver, only an airspeed sensor is added because the velocity relative to the air is very important during landing and takeoff. The forward velocity is replaced with the airspeed obtained from Pitot tube. From linearized equations of motions around the steady state, LQR controllers for takeoff and landing are built, m particular, the flare controller that controls the pitch, altitude and airspeed of a UAV is designed. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. Based on flight test results, a single-antenna GPS receiver can be used as a main sensor for a backup or a low-cost control system of UAVs.

  • Fully Automatic Taxiing, Takeoff and Landing of a VAV using a Single-Antenna GPS Receiver only
    2007
    Co-Authors: Am Cho, Sanghyo Lee, Bosung Kim, Noha Park, Dongkeon Kim, Changdon Kee, Sujin Choi, Jihoon Kim, Boram Lee, Gnss Lab
    Abstract:

    This paper presents automatic taxiing, takeoff and landing of a UAV based on a single-antenna GPS receiver. In this paper, inertial sensors such as gyros and accelerometers are not used at all to show the full potential of a single-antenna GPS receiver based attitude determination system. DGPS is implemented to give high accuracy position information for automatic taxiing, landing and takeoff on the runway. For a fixed wing aircraft, under the assumption of coordinated flight, the attitude information called as pseudo-attitudes can be estimated from the measurements of a single-antenna GPS receiver. So full state variables for the automatic control can be obtained from single-antenna GPS receiver. In addition to GPS receiver, only an airspeed sensor is added because the velocity relative to the air is very important during landing and takeoff The forward velocity is replaced with the airspeed obtained from Pitot tube. From linearized equations of motions around the steady state, LQR controllers for takeoff and landing are built. In particular, the flare controller that controls the pitch, altitude and airspeed of a UAV is designed. During flight tests, the aircraft taxies and takes off the runway, follows the predefined waypoint Path, and then lands on the runway along the curved Approach Path, all fully automatically. Based on flight test results, a single-antenna GPS receiver can be used as a main sensor for a backup or a low-cost control system ofUAVs