The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform

Miroslav Krstic - One of the best experts on this subject based on the ideXlab platform.

  • a single Forward Velocity control signal for stochastic source seeking with multiple nonholonomic vehicles
    Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 2014
    Co-Authors: Paul Frihauf, Miroslav Krstic
    Abstract:

    With a single stochastic extremum seeking control signal, we steer multiple autonomous vehicles, modeled as nonholonomic unicycles, toward the maximum of an unknown, spatially distributed signal field. The vehicles, whose angular velocities are constant and distinct, travel at the same Forward Velocity, which is controlled by the stochastic extremum seeking controller. To determine the vehicles’ Velocity, the controller uses measurements of the signal field at the respective vehicle positions and excitation based on filtered white noise. The positions of the vehicles are not measured. We prove local exponential convergence, both almost surely and in probability, to a small neighborhood near the source and provide a numerical example to illustrate the effectiveness of the algorithm. [DOI: 10.1115/1.4027577]

  • stochastic source seeking with multiple nonholonomic vehicles via a single Forward Velocity control signal
    ASME 2012 5th Annual Dynamic Systems and Control Conference joint with the JSME 2012 11th Motion and Vibration Conference, 2012
    Co-Authors: Paul Frihauf, Miroslav Krstic
    Abstract:

    With a single stochastic extremum seeking control signal, we steer multiple autonomous vehicles, modeled as nonholonomic unicycles, toward the maximum of an unknown, spatially distributed signal field. The vehicles, whose angular velocities are constant and distinct, travel at the same Forward Velocity, which is controlled by the stochastic extremum seeking controller. To determine the vehicles’ Velocity, the controller uses measurements of the signal field at the respective vehicle positions and excitation based on filtered white noise. The positions of the vehicles are not measured. We prove local exponential convergence, both almost surely and in probability, to a small neighborhood near the source and provide a numerical example to illustrate the effectiveness of the algorithm.Copyright © 2012 by ASME

  • Stochastic source seeking with tuning of Forward Velocity
    Proceedings of the 31st Chinese Control Conference, 2012
    Co-Authors: Paul Frihauf, Miroslav Krstic
    Abstract:

    Using the method of stochastic extremum seeking, we navigate an autonomous vehicle, modeled as a nonholonomic unicycle, towards the maximum of an unknown, spatially distributed signal field by measuring only the signal at the vehicle's position. The vehicle position is not measured. Keeping the angular Velocity constant, we control the Forward Velocity by designing a stochastic source seeking control law, which employs excitation based on filtered white noise rather than sinusoidal perturbations used in previous works. We prove local exponential convergence, both almost surely and in probability, to a small neighborhood near the source and provide numerical simulations to illustrate the effectiveness of the algorithm.

  • GPS denied source seeking for underactuated autonomous vehicles in 3D
    2008 IEEE International Conference on Robotics and Automation, 2008
    Co-Authors: Jennie Cochran, Nima Ghods, Antranik Siranosian, Miroslav Krstic
    Abstract:

    Extremum seeking has been successfully applied to source seeking for autonomous vehicles operating in two dimensions. In this paper we extend these results to vehicles operating in three dimensions. The extension is interesting for several reasons. First, there is the choice of vehicle models to consider, and second there is the question of what type of vehicle movement can be actuated. We present two control schemes which address these questions. The first scheme focuses on vehicles with a constant Forward Velocity and the ability to actuate pitch and yaw velocities. The second scheme explores vehicles which operate with a constant Forward Velocity and a constant pitch Velocity and which are capable of actuating only the roll Velocity. We present the vehicle models, details of the control schemes, and simulation results.

  • ICRA - GPS denied source seeking for underactuated autonomous vehicles in 3D
    2008 IEEE International Conference on Robotics and Automation, 2008
    Co-Authors: Jennie Cochran, Nima Ghods, Antranik Siranosian, Miroslav Krstic
    Abstract:

    Extremum seeking has been successfully applied to source seeking for autonomous vehicles operating in two dimensions. In this paper we extend these results to vehicles operating in three dimensions. The extension is interesting for several reasons. First, there is the choice of vehicle models to consider, and second there is the question of what type of vehicle movement can be actuated. We present two control schemes which address these questions. The first scheme focuses on vehicles with a constant Forward Velocity and the ability to actuate pitch and yaw velocities. The second scheme explores vehicles which operate with a constant Forward Velocity and a constant pitch Velocity and which are capable of actuating only the roll Velocity. We present the vehicle models, details of the control schemes, and simulation results.

Yasushi Ikei - One of the best experts on this subject based on the ideXlab platform.

  • tactile apparent motion on the torso modulates perceived Forward self motion Velocity
    IEEE Transactions on Haptics, 2016
    Co-Authors: Tomohiro Amemiya, Koichi Hirota, Yasushi Ikei
    Abstract:

    The present study investigated whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with an optical flow in peripheral vision enhances the perceived Forward Velocity of self-motion. A brief tactile motion stimulus consisted of four successive rows of vibration, and the interstimulus onset between the tactile rows was varied to change the Velocity of the tactile motion. The results show that the Forward Velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow ones, compared with optical flow alone or non-motion vibrotactile stimulation conditions. In addition, the effect with a temporal tactile rhythm without changing the stimulus location was smaller than that with spatiotemporal tactile motion, with the interstimulus onset interval to elicit a clear sensation of tactile apparent motion. These findings suggest that spatiotemporal tactile motion is effective in inducing a change in the perceived Forward Velocity of self-motion.

  • HCI (18) - Tactile Apparent Motion Presented from Seat Pan Facilitates Racing Experience
    Virtual Augmented and Mixed Reality. Designing and Developing Augmented and Virtual Environments, 2013
    Co-Authors: Tomohiro Amemiya, Koichi Hirota, Yasushi Ikei
    Abstract:

    When moving through the world, humans receive a variety of sensory cues involved in self-motion. In this study, we clarified whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with a car-racing computer game enhances the perceived Forward Velocity of self-motion. The experimental results show that the Forward Velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow ones, compared with only optical flow or non-motion vibrotactile stimulation conditions.

  • Perceived Forward Velocity increases with tactile flow on seat pan
    2013 IEEE Virtual Reality (VR), 2013
    Co-Authors: Tomohiro Amemiya, Koichi Hirota, Yasushi Ikei
    Abstract:

    We conducted a user study to clarify whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with an optical flow in peripheral vision enhances the perceived Forward Velocity of self-motion. A brief tactile motion stimulus consisted of four successive rows of vibration, and the inter-stimulus onset between the tactile rows was varied to change the Velocity of the tactile motion. The experimental results show that the Velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow tactile flows, compared with only optical flow or non-motion vibrotactile stimulation conditions.

  • Tactile flow on seat pan modulates perceived Forward Velocity
    2013 IEEE Symposium on 3D User Interfaces (3DUI), 2013
    Co-Authors: Tomohiro Amemiya, Koichi Hirota, Yasushi Ikei
    Abstract:

    We conducted a user study to clarify whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with an optical flow in peripheral vision enhances the perceived Forward Velocity of self-motion. A brief tactile motion stimulus consisted of four successive rows of vibration, and the inter-stimulus onset between the tactile rows was varied to change the Velocity of the tactile motion. The experimental results show that the Forward Velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow ones, compared with only optical flow or non-motion vibrotactile stimulation conditions. Furthermore, the tactile flow on the seat pan can be applied in a car-racing computer game and provide a perceptual change in Forward Velocity.

  • 3DUI - Tactile flow on seat pan modulates perceived Forward Velocity
    2013 IEEE Symposium on 3D User Interfaces (3DUI), 2013
    Co-Authors: Tomohiro Amemiya, Koichi Hirota, Yasushi Ikei
    Abstract:

    We conducted a user study to clarify whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with an optical flow in peripheral vision enhances the perceived Forward Velocity of self-motion. A brief tactile motion stimulus consisted of four successive rows of vibration, and the inter-stimulus onset between the tactile rows was varied to change the Velocity of the tactile motion. The experimental results show that the Forward Velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow ones, compared with only optical flow or non-motion vibrotactile stimulation conditions. Furthermore, the tactile flow on the seat pan can be applied in a car-racing computer game and provide a perceptual change in Forward Velocity.

Antranik Siranosian - One of the best experts on this subject based on the ideXlab platform.

  • GPS denied source seeking for underactuated autonomous vehicles in 3D
    2008 IEEE International Conference on Robotics and Automation, 2008
    Co-Authors: Jennie Cochran, Nima Ghods, Antranik Siranosian, Miroslav Krstic
    Abstract:

    Extremum seeking has been successfully applied to source seeking for autonomous vehicles operating in two dimensions. In this paper we extend these results to vehicles operating in three dimensions. The extension is interesting for several reasons. First, there is the choice of vehicle models to consider, and second there is the question of what type of vehicle movement can be actuated. We present two control schemes which address these questions. The first scheme focuses on vehicles with a constant Forward Velocity and the ability to actuate pitch and yaw velocities. The second scheme explores vehicles which operate with a constant Forward Velocity and a constant pitch Velocity and which are capable of actuating only the roll Velocity. We present the vehicle models, details of the control schemes, and simulation results.

  • ICRA - GPS denied source seeking for underactuated autonomous vehicles in 3D
    2008 IEEE International Conference on Robotics and Automation, 2008
    Co-Authors: Jennie Cochran, Nima Ghods, Antranik Siranosian, Miroslav Krstic
    Abstract:

    Extremum seeking has been successfully applied to source seeking for autonomous vehicles operating in two dimensions. In this paper we extend these results to vehicles operating in three dimensions. The extension is interesting for several reasons. First, there is the choice of vehicle models to consider, and second there is the question of what type of vehicle movement can be actuated. We present two control schemes which address these questions. The first scheme focuses on vehicles with a constant Forward Velocity and the ability to actuate pitch and yaw velocities. The second scheme explores vehicles which operate with a constant Forward Velocity and a constant pitch Velocity and which are capable of actuating only the roll Velocity. We present the vehicle models, details of the control schemes, and simulation results.

  • source seeking with non holonomic unicycle without position measurement and with tuning of Forward Velocity
    Systems & Control Letters, 2007
    Co-Authors: Chunlei Zhang, Nima Ghods, Antranik Siranosian, Dan Arnold, Miroslav Krstic
    Abstract:

    We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the non-holonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We employ periodic Forward–backward movement of the unicycle (implementable with mobile robots and some underwater vehicles but not with aircraft), where the Forward Velocity has a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of “drifting” towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies—one related to the angular Velocity of the unicycle and the other related to the probing frequency of extremum seeking.

  • Source seeking with non-holonomic unicycle without position measurement and with tuning of Forward Velocity
    Systems and Control Letters, 2007
    Co-Authors: Chunlei Zhang, Nima Ghods, Antranik Siranosian, Daniel Arnold, Miroslav Krstić
    Abstract:

    We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the non-holonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We employ periodic Forward-backward movement of the unicycle (implementable with mobile robots and some underwater vehicles but not with aircraft), where the Forward Velocity has a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of "drifting" towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies-one related to the angular Velocity of the unicycle and the other related to the probing frequency of extremum seeking. © 2006 Elsevier B.V. All rights reserved.

  • Source Seeking With Nonholonomic Unicycle Without Position Measurement---Part I: Tuning of Forward Velocity
    Proceedings of the 45th IEEE Conference on Decision and Control, 2006
    Co-Authors: Chunlei Zhang, Nima Ghods, Antranik Siranosian, Daniel Arnold, Miroslav Krstic
    Abstract:

    We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the nonholonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We have developed two control strategies - one which keeps the angular Velocity at a constant nonzero value and tunes the Forward Velocity, and the other which keeps the Forward Velocity at a constant positive value and tunes the angular Velocity. In this paper we present the former method, which is implementable with mobile robots and some underwater vehicles. In a future companion paper we will present the latter method, which is more suitable for aerial vehicles. Our approach in this paper employs periodic Forward-backward movement of the unicycle, with a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of "drifting" towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies - one related to the angular Velocity of the unicycle and the other related to the probing frequency of extremum seeking

Nima Ghods - One of the best experts on this subject based on the ideXlab platform.

  • GPS denied source seeking for underactuated autonomous vehicles in 3D
    2008 IEEE International Conference on Robotics and Automation, 2008
    Co-Authors: Jennie Cochran, Nima Ghods, Antranik Siranosian, Miroslav Krstic
    Abstract:

    Extremum seeking has been successfully applied to source seeking for autonomous vehicles operating in two dimensions. In this paper we extend these results to vehicles operating in three dimensions. The extension is interesting for several reasons. First, there is the choice of vehicle models to consider, and second there is the question of what type of vehicle movement can be actuated. We present two control schemes which address these questions. The first scheme focuses on vehicles with a constant Forward Velocity and the ability to actuate pitch and yaw velocities. The second scheme explores vehicles which operate with a constant Forward Velocity and a constant pitch Velocity and which are capable of actuating only the roll Velocity. We present the vehicle models, details of the control schemes, and simulation results.

  • ICRA - GPS denied source seeking for underactuated autonomous vehicles in 3D
    2008 IEEE International Conference on Robotics and Automation, 2008
    Co-Authors: Jennie Cochran, Nima Ghods, Antranik Siranosian, Miroslav Krstic
    Abstract:

    Extremum seeking has been successfully applied to source seeking for autonomous vehicles operating in two dimensions. In this paper we extend these results to vehicles operating in three dimensions. The extension is interesting for several reasons. First, there is the choice of vehicle models to consider, and second there is the question of what type of vehicle movement can be actuated. We present two control schemes which address these questions. The first scheme focuses on vehicles with a constant Forward Velocity and the ability to actuate pitch and yaw velocities. The second scheme explores vehicles which operate with a constant Forward Velocity and a constant pitch Velocity and which are capable of actuating only the roll Velocity. We present the vehicle models, details of the control schemes, and simulation results.

  • source seeking with non holonomic unicycle without position measurement and with tuning of Forward Velocity
    Systems & Control Letters, 2007
    Co-Authors: Chunlei Zhang, Nima Ghods, Antranik Siranosian, Dan Arnold, Miroslav Krstic
    Abstract:

    We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the non-holonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We employ periodic Forward–backward movement of the unicycle (implementable with mobile robots and some underwater vehicles but not with aircraft), where the Forward Velocity has a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of “drifting” towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies—one related to the angular Velocity of the unicycle and the other related to the probing frequency of extremum seeking.

  • Source seeking with non-holonomic unicycle without position measurement and with tuning of Forward Velocity
    Systems and Control Letters, 2007
    Co-Authors: Chunlei Zhang, Nima Ghods, Antranik Siranosian, Daniel Arnold, Miroslav Krstić
    Abstract:

    We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the non-holonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We employ periodic Forward-backward movement of the unicycle (implementable with mobile robots and some underwater vehicles but not with aircraft), where the Forward Velocity has a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of "drifting" towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies-one related to the angular Velocity of the unicycle and the other related to the probing frequency of extremum seeking. © 2006 Elsevier B.V. All rights reserved.

  • Source Seeking With Nonholonomic Unicycle Without Position Measurement---Part I: Tuning of Forward Velocity
    Proceedings of the 45th IEEE Conference on Decision and Control, 2006
    Co-Authors: Chunlei Zhang, Nima Ghods, Antranik Siranosian, Daniel Arnold, Miroslav Krstic
    Abstract:

    We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the nonholonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We have developed two control strategies - one which keeps the angular Velocity at a constant nonzero value and tunes the Forward Velocity, and the other which keeps the Forward Velocity at a constant positive value and tunes the angular Velocity. In this paper we present the former method, which is implementable with mobile robots and some underwater vehicles. In a future companion paper we will present the latter method, which is more suitable for aerial vehicles. Our approach in this paper employs periodic Forward-backward movement of the unicycle, with a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of "drifting" towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies - one related to the angular Velocity of the unicycle and the other related to the probing frequency of extremum seeking

Nikos G. Tsagarakis - One of the best experts on this subject based on the ideXlab platform.

  • IROS - From one-legged hopping to bipedal running and walking: A unified foot placement control based on regression analysis
    2015 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2015
    Co-Authors: Zhibin Li, Darwin G. Caldwell, Nikos G. Tsagarakis
    Abstract:

    This paper aims at developing a unified and adaptive foot placement control for legged robots. The locomotion control of legged robots can be classified into three parts as body height control, body attitude control, and Forward Velocity control. In our study, the body attitude is controlled at stance phase by the hip actuator, and the height is controlled by the motion of the stance leg. In this case, the foot placement has a nearly linear correlation with Forward Velocity. Hereby, a generic foot placement controller is developed to control the Forward Velocity based on the online linear regression analysis of their coupled correlation. Our proposed algorithm is capable of adjusting the control parameters automatically, and is featured by good adaptability and higher control accuracy that outperforms the empirical tuning. The very same controller is able to produce stable hopping with accurate Forward Velocity tracking even with unknown mass offset, as well as stable bipedal running and walking with accurate Velocity tracking.

  • From one-legged hopping to bipedal running and walking: A unified foot placement control based on regression analysis
    2015 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2015
    Co-Authors: Zhibin Li, Darwin G. Caldwell, Nikos G. Tsagarakis
    Abstract:

    This paper aims at developing a unified and adaptive foot placement control for legged robots. The locomotion control of legged robots can be classified into three parts as body height control, body attitude control, and Forward Velocity control. In our study, the body attitude is controlled at stance phase by the hip actuator, and the height is controlled by the motion of the stance leg. In this case, the foot placement has a nearly linear correlation with Forward Velocity. Hereby, a generic foot placement controller is developed to control the Forward Velocity based on the online linear regression analysis of their coupled correlation. Our proposed algorithm is capable of adjusting the control parameters automatically, and is featured by good adaptability and higher control accuracy that outperforms the empirical tuning. The very same controller is able to produce stable hopping with accurate Forward Velocity tracking even with unknown mass offset, as well as stable bipedal running and walking with accurate Velocity tracking.