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2020


Changes in Normal Force During Passive Dynamic Touch: Contact Mechanics and Perception
Changes in Normal Force During Passive Dynamic Touch: Contact Mechanics and Perception

Gueorguiev, D., Lambert, J., Thonnard, J., Kuchenbecker, K. J.

In Proceedings of the IEEE Haptics Symposium (HAPTICS), pages: 746-752, Washington, USA, March 2020 (inproceedings)

Abstract
Using a force-controlled robotic platform, we investigated the contact mechanics and psychophysical responses induced by negative and positive modulations in normal force during passive dynamic touch. In the natural state of the finger, the applied normal force modulation induces a correlated change in the tangential force. In a second condition, we applied talcum powder to the fingerpad, which induced a significant modification in the slope of the correlated tangential change. In both conditions, the same ten participants had to detect the interval that contained a decrease or an increase in the pre-stimulation normal force of 1 N. In the natural state, the 75% just noticeable difference for this task was found to be a ratio of 0.19 and 0.18 for decreases and increases, respectively. With talcum powder on the fingerpad, the normal force thresholds remained stable, following the Weber law of constant just noticeable differences, while the tangential force thresholds changed in the same way as the correlation slopes. This result suggests that participants predominantly relied on the normal force changes to perform the detection task. In addition, participants were asked to report whether the force decreased or increased. Their performance was generally poor at this second task even for above-threshold changes. However, their accuracy slightly improved with the talcum powder, which might be due to the reduced finger-surface friction.

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DOI [BibTex]

2020


DOI [BibTex]


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A Real-Robot Dataset for Assessing Transferability of Learned Dynamics Models

Agudelo-España, D., Zadaianchuk, A., Wenk, P., Garg, A., Akpo, J., Grimminger, F., Viereck, J., Naveau, M., Righetti, L., Martius, G., Krause, A., Schölkopf, B., Bauer, S., Wüthrich, M.

IEEE International Conference on Robotics and Automation (ICRA), 2020 (conference) Accepted

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Project Page PDF [BibTex]

Project Page PDF [BibTex]

2016


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Qualitative User Reactions to a Hand-Clapping Humanoid Robot

Fitter, N. T., Kuchenbecker, K. J.

In Social Robotics: 8th International Conference, ICSR 2016, Kansas City, MO, USA, November 1-3, 2016 Proceedings, 9979, pages: 317-327, Lecture Notes in Artificial Intelligence, Springer International Publishing, November 2016, Oral presentation given by Fitter (inproceedings)

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[BibTex]

2016


[BibTex]


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Designing and Assessing Expressive Open-Source Faces for the Baxter Robot

Fitter, N. T., Kuchenbecker, K. J.

In Social Robotics: 8th International Conference, ICSR 2016, Kansas City, MO, USA, November 1-3, 2016 Proceedings, 9979, pages: 340-350, Lecture Notes in Artificial Intelligence, Springer International Publishing, November 2016, Oral presentation given by Fitter (inproceedings)

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[BibTex]

[BibTex]


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Rhythmic Timing in Playful Human-Robot Social Motor Coordination

Fitter, N. T., Hawkes, D. T., Kuchenbecker, K. J.

In Social Robotics: 8th International Conference, ICSR 2016, Kansas City, MO, USA, November 1-3, 2016 Proceedings, 9979, pages: 296-305, Lecture Notes in Artificial Intelligence, Springer International Publishing, November 2016, Oral presentation given by Fitter (inproceedings)

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[BibTex]

[BibTex]


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Using IMU Data to Demonstrate Hand-Clapping Games to a Robot

Fitter, N. T., Kuchenbecker, K. J.

In Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, pages: 851 - 856, October 2016, Interactive presentation given by Fitter (inproceedings)

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[BibTex]

[BibTex]


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ProtonPack: A Visuo-Haptic Data Acquisition System for Robotic Learning of Surface Properties

Burka, A., Hu, S., Helgeson, S., Krishnan, S., Gao, Y., Hendricks, L. A., Darrell, T., Kuchenbecker, K. J.

In Proceedings of the IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems (MFI), pages: 58-65, 2016, Oral presentation given by Burka (inproceedings)

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Project Page [BibTex]

Project Page [BibTex]


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Equipping the Baxter Robot with Human-Inspired Hand-Clapping Skills

Fitter, N. T., Kuchenbecker, K. J.

In Proceedings of the IEEE International Symposium on Robot and Human Interactive Communication (RO-MAN), pages: 105-112, 2016 (inproceedings)

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[BibTex]

[BibTex]


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Comparison of vibro-acoustic performance metrics in the design and optimization of stiffened composite fuselages

Serhat, G., Basdogan, I.

In Proceedings of International Congress and Exposition of Noise Control Engineering (INTER-NOISE), Hamburg, Germany, August 2016 (inproceedings)

Abstract
In this paper, a comparison of preliminary design methodologies for optimization of stiffened, fiber-reinforced composite fuselages for vibro-acoustic requirements is presented. Fuselage stiffness properties are modelled using lamination parameters and their effect on the vibro-acoustic performance is investigated using two different approaches. First method, only considers the structural model in order to explore the effect of design variables on fuselage vibrations. The simplified estimation of the acoustic behavior without considering fluid-structure interaction brings certain advantages such as reduced modelling effort and computational cost. In this case, the performance metric is chosen as equivalent radiated power (ERP) which is a well-known criterion in the prediction of structure-born noise. Second method, utilizes coupled vibro-acoustic models to predict the sound pressure levels (SPL) inside the fuselage. ERP is calculated both for bay panels and fuselage section and then compared with the SPL results. The response surfaces of each metric are determined as a function of lamination parameters and their overall difference is quantified. ERP approach proves its merit provided that a sufficiently accurate model is used. The results demonstrate the importance of the simplifications made in the modelling and the selection of analysis approach in vibro-acoustic design of fuselages.

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[BibTex]

[BibTex]


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Reproducing a Laser Pointer Dot on a Secondary Projected Screen

Hu, S., Kuchenbecker, K. J.

In Proceedings of the IEEE International Conference on Advanced Intelligent Mechatronics (AIM), pages: 1645-1650, 2016, Oral presentation given by Hu (inproceedings)

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[BibTex]

[BibTex]


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Effect of Aspect Ratio and Boundary Conditions on the Eigenfrequency Optimization of Composite Panels Using Lamination Parameters

Serhat, G., Basdogan, I.

In Proceedings of the ASMO UK International Conference on Numerical Optimisation Methods for Engineering Design, pages: 160–168, Munich, Germany, July 2016 (inproceedings)

Abstract
Eigenfrequency optimization of laminated composite panels is a common engineering problem. This process mostly involves designing stiffness properties of the structure. Optimal results can differ significantly depending on the values of the model parameters and the metrics used for the optimization. Building the know-how on this matter is crucial for choosing the appropriate design methodologies as well as validation and justification of prospective results. In this paper, effects of aspect ratio and boundary conditions on eigenfrequency optimization of composite panels by altering stiffness properties are investigated. Lamination parameters are chosen as design variables which are used in the modeling of stiffness tensors. This technique enables representation of overall stiffness characteristics and provides a convex design space. Fundamental frequency and difference between fundamental and second natural frequencies are maximized as design objectives. Optimization studies incorporating different models and responses are performed. Optimal lamination parameters and response values are provided for each case and the effects of model parameters on the solutions are quantified. The results indicate that trends of the optima change for different aspect ratio ranges and boundary conditions. Moreover, convergence occurs beyond certain critical values of the model parameters which may cause an optimization study to be redundant.

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[BibTex]

[BibTex]


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Multi-objective optimization of stiffened, fiber-reinforced composite fuselages for mechanical and vibro-acoustic requirements

Serhat, G., Faria, T. G., Basdogan, I.

In Proceedings of AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, Washington, USA, June 2016 (inproceedings)

Abstract
In this paper, a preliminary design methodology for optimization of stiffened, fiber-reinforced composite fuselages for combined mechanical and vibro-acoustic requirements is presented. Laminate stiffness distributions are represented using the method called lamination parameters which is known to provide a convex solution space. Single-objective and multi-objective optimization studies are carried out in order to find optimal stiffness distributions. Performance metrics for acoustical behavior are chosen as maximum fundamental frequency and minimum equivalent radiated power. The mechanical performance metric is chosen as the maximum stiffness. The results show that the presented methodology works effectively and it can be used to improve load-carrying and acoustical performances simultaneously.

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DOI [BibTex]

DOI [BibTex]


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Deep Learning for Tactile Understanding From Visual and Haptic Data

Gao, Y., Hendricks, L. A., Kuchenbecker, K. J., Darrell, T.

In Proceedings of the IEEE International Conference on Robotics and Automation, pages: 536-543, May 2016, Oral presentation given by Gao (inproceedings)

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[BibTex]

[BibTex]


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Robust Tactile Perception of Artificial Tumors Using Pairwise Comparisons of Sensor Array Readings

Hui, J. C. T., Block, A. E., Taylor, C. J., Kuchenbecker, K. J.

In Proceedings of the IEEE Haptics Symposium, pages: 305-312, Philadelphia, Pennsylvania, USA, April 2016, Oral presentation given by Hui (inproceedings)

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[BibTex]

[BibTex]


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Data-Driven Comparison of Four Cutaneous Displays for Pinching Palpation in Robotic Surgery

Brown, J. D., Ibrahim, M., Chase, E. D. Z., Pacchierotti, C., Kuchenbecker, K. J.

In Proceedings of the IEEE Haptics Symposium, pages: 147-154, Philadelphia, Pennsylvania, USA, April 2016, Oral presentation given by Brown (inproceedings)

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[BibTex]

[BibTex]


Multisensory Robotic Therapy through Motion Capture and Imitation for Children with ASD
Multisensory Robotic Therapy through Motion Capture and Imitation for Children with ASD

Burns, R., Nizambad, S., Park, C. H., Jeon, M., Howard, A.

Proceedings of the American Society of Engineering Education, Mid-Atlantic Section, Spring Conference, April 2016 (conference)

Abstract
It is known that children with autism have difficulty with emotional communication. As the population of children with autism increases, it is crucial we create effective therapeutic programs that will improve their communication skills. We present an interactive robotic system that delivers emotional and social behaviors for multi­sensory therapy for children with autism spectrum disorders. Our framework includes emotion­-based robotic gestures and facial expressions, as well as tracking and understanding the child’s responses through Kinect motion capture.

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link (url) [BibTex]

link (url) [BibTex]


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Design and Implementation of a Visuo-Haptic Data Acquisition System for Robotic Learning of Surface Properties

Burka, A., Hu, S., Helgeson, S., Krishnan, S., Gao, Y., Hendricks, L. A., Darrell, T., Kuchenbecker, K. J.

In Proceedings of the IEEE Haptics Symposium, pages: 350-352, April 2016, Work-in-progress paper. Poster presentation given by Burka (inproceedings)

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Project Page [BibTex]

Project Page [BibTex]


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Psychophysical Power Optimization of Friction Modulation for Tactile Interfaces

Sednaoui, T., Vezzoli, E., Gueorguiev, D., Amberg, M., Chappaz, C., Lemaire-Semail, B.

In Haptics: Perception, Devices, Control, and Applications, pages: 354-362, Springer International Publishing, Cham, 2016 (inproceedings)

Abstract
Ultrasonic vibration and electrovibration can modulate the friction between a surface and a sliding finger. The power consumption of these devices is critical to their integration in modern mobile devices such as smartphones. This paper presents a simple control solution to reduce up to 68.8 {\%} this power consumption by taking advantage of the human perception limits.

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[BibTex]

[BibTex]


Effect of Waveform in Haptic Perception of Electrovibration on Touchscreens
Effect of Waveform in Haptic Perception of Electrovibration on Touchscreens

Vardar, Y., Güçlü, B., Basdogan, C.

In Haptics: Perception, Devices, Control, and Applications, pages: 190-203, Springer International Publishing, Cham, 2016 (inproceedings)

Abstract
The perceived intensity of electrovibration can be altered by modulating the amplitude, frequency, and waveform of the input voltage signal applied to the conductive layer of a touchscreen. Even though the effect of the first two has been already investigated for sinusoidal signals, we are not aware of any detailed study investigating the effect of the waveform on our haptic perception in the domain of electrovibration. This paper investigates how input voltage waveform affects our haptic perception of electrovibration on touchscreens. We conducted absolute detection experiments using square wave and sinusoidal input signals at seven fundamental frequencies (15, 30, 60, 120, 240, 480 and 1920 Hz). Experimental results depicted the well-known U-shaped tactile sensitivity across frequencies. However, the sensory thresholds were lower for the square wave than the sinusoidal wave at fundamental frequencies less than 60 Hz while they were similar at higher frequencies. Using an equivalent circuit model of a finger-touchscreen system, we show that the sensation difference between the waveforms at low fundamental frequencies can be explained by frequency-dependent electrical properties of human skin and the differential sensitivity of mechanoreceptor channels to individual frequency components in the electrostatic force. As a matter of fact, when the electrostatic force waveforms are analyzed in the frequency domain based on human vibrotactile sensitivity data from the literature [15], the electrovibration stimuli caused by square-wave input signals at all the tested frequencies in this study are found to be detected by the Pacinian psychophysical channel.

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vardar_eurohaptics_2016 [BibTex]

vardar_eurohaptics_2016 [BibTex]


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On the Effects of Measurement Uncertainty in Optimal Control of Contact Interactions

Ponton, B., Schaal, S., Righetti, L.

In The 12th International Workshop on the Algorithmic Foundations of Robotics WAFR, Berkeley, USA, 2016 (inproceedings)

Abstract
Stochastic Optimal Control (SOC) typically considers noise only in the process model, i.e. unknown disturbances. However, in many robotic applications involving interaction with the environment, such as locomotion and manipulation, uncertainty also comes from lack of precise knowledge of the world, which is not an actual disturbance. We analyze the effects of also considering noise in the measurement model, by devel- oping a SOC algorithm based on risk-sensitive control, that includes the dynamics of an observer in such a way that the control law explicitly de- pends on the current measurement uncertainty. In simulation results on a simple 2D manipulator, we have observed that measurement uncertainty leads to low impedance behaviors, a result in contrast with the effects of process noise that creates stiff behaviors. This suggests that taking into account measurement uncertainty could be a potentially very interesting way to approach problems involving uncertain contact interactions.

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link (url) [BibTex]

link (url) [BibTex]


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A Convex Model of Momentum Dynamics for Multi-Contact Motion Generation

Ponton, B., Herzog, A., Schaal, S., Righetti, L.

In 2016 IEEE-RAS 16th International Conference on Humanoid Robots Humanoids, pages: 842-849, IEEE, Cancun, Mexico, 2016 (inproceedings)

Abstract
Linear models for control and motion generation of humanoid robots have received significant attention in the past years, not only due to their well known theoretical guarantees, but also because of practical computational advantages. However, to tackle more challenging tasks and scenarios such as locomotion on uneven terrain, a more expressive model is required. In this paper, we are interested in contact interaction-centered motion optimization based on the momentum dynamics model. This model is non-linear and non-convex; however, we find a relaxation of the problem that allows us to formulate it as a single convex quadratically-constrained quadratic program (QCQP) that can be very efficiently optimized and is useful for multi-contact planning. This convex model is then coupled to the optimization of end-effector contact locations using a mixed integer program, which can also be efficiently solved. This becomes relevant e.g. to recover from external pushes, where a predefined stepping plan is likely to fail and an online adaptation of the contact location is needed. The performance of our algorithm is demonstrated in several multi-contact scenarios for a humanoid robot.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Inertial Sensor-Based Humanoid Joint State Estimation

Rotella, N., Mason, S., Schaal, S., Righetti, L.

In 2016 IEEE International Conference on Robotics and Automation (ICRA), pages: 1825-1831, IEEE, Stockholm, Sweden, 2016 (inproceedings)

Abstract
This work presents methods for the determination of a humanoid robot's joint velocities and accelerations directly from link-mounted Inertial Measurement Units (IMUs) each containing a three-axis gyroscope and a three-axis accelerometer. No information about the global pose of the floating base or its links is required and precise knowledge of the link IMU poses is not necessary due to presented calibration routines. Additionally, a filter is introduced to fuse gyroscope angular velocities with joint position measurements and compensate the computed joint velocities for time-varying gyroscope biases. The resulting joint velocities are subject to less noise and delay than filtered velocities computed from numerical differentiation of joint potentiometer signals, leading to superior performance in joint feedback control as demonstrated in experiments performed on a SARCOS hydraulic humanoid.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Stepping Stabilization Using a Combination of DCM Tracking and Step Adjustment

Khadiv, M., Kleff, S., Herzog, A., Moosavian, S. A. A., Schaal, S., Righetti, L.

In 2016 4th International Conference on Robotics and Mechatronics (ICROM), pages: 130-135, IEEE, Teheran, Iran, 2016 (inproceedings)

Abstract
In this paper, a method for stabilizing biped robots stepping by a combination of Divergent Component of Motion (DCM) tracking and step adjustment is proposed. In this method, the DCM trajectory is generated, consistent with the predefined footprints. Furthermore, a swing foot trajectory modification strategy is proposed to adapt the landing point, using DCM measurement. In order to apply the generated trajectories to the full robot, a Hierarchical Inverse Dynamics (HID) is employed. The HID enables us to use different combinations of the DCM tracking and step adjustment for stabilizing different biped robots. Simulation experiments on two scenarios for two different simulated robots, one with active ankles and the other with passive ankles, are carried out. Simulation results demonstrate the effectiveness of the proposed method for robots with both active and passive ankles.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Structured contact force optimization for kino-dynamic motion generation

Herzog, A., Schaal, S., Righetti, L.

In 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages: 2703-2710, IEEE, Daejeon, South Korea, 2016 (inproceedings)

Abstract
Optimal control approaches in combination with trajectory optimization have recently proven to be a promising control strategy for legged robots. Computationally efficient and robust algorithms were derived using simplified models of the contact interaction between robot and environment such as the linear inverted pendulum model (LIPM). However, as humanoid robots enter more complex environments, less restrictive models become increasingly important. As we leave the regime of linear models, we need to build dedicated solvers that can compute interaction forces together with consistent kinematic plans for the whole-body. In this paper, we address the problem of planning robot motion and interaction forces for legged robots given predefined contact surfaces. The motion generation process is decomposed into two alternating parts computing force and motion plans in coherence. We focus on the properties of the momentum computation leading to sparse optimal control formulations to be exploited by a dedicated solver. In our experiments, we demonstrate that our motion generation algorithm computes consistent contact forces and joint trajectories for our humanoid robot. We also demonstrate the favorable time complexity due to our formulation and composition of the momentum equations.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Balancing and Walking Using Full Dynamics LQR Control With Contact Constraints

Mason, S., Rotella, N., Schaal, S., Righetti, L.

In 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), pages: 63-68, IEEE, Cancun, Mexico, 2016 (inproceedings)

Abstract
Torque control algorithms which consider robot dynamics and contact constraints are important for creating dynamic behaviors for humanoids. As computational power increases, algorithms tend to also increase in complexity. However, it is not clear how much complexity is really required to create controllers which exhibit good performance. In this paper, we study the capabilities of a simple approach based on contact consistent LQR controllers designed around key poses to control various tasks on a humanoid robot. We present extensive experimental results on a hydraulic, torque controlled humanoid performing balancing and stepping tasks. This feedback control approach captures the necessary synergies between the DoFs of the robot to guarantee good control performance. We show that for the considered tasks, it is only necessary to re-linearize the dynamics of the robot at different contact configurations and that increasing the number of LQR controllers along desired trajectories does not improve performance. Our result suggest that very simple controllers can yield good performance competitive with current state of the art, but more complex, optimization-based whole-body controllers. A video of the experiments can be found at https://youtu.be/5T08CNKV1hw.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Step Timing Adjustement: a Step toward Generating Robust Gaits

Khadiv, M., Herzog, A., Moosavian, S. A. A., Righetti, L.

In 2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), pages: 35-42, IEEE, Cancun, Mexico, 2016 (inproceedings)

Abstract
Step adjustment for humanoid robots has been shown to improve robustness in gaits. However, step duration adaptation is often neglected in control strategies. In this paper, we propose an approach that combines both step location and timing adjustment for generating robust gaits. In this approach, step location and step timing are decided, based on feedback from the current state of the robot. The proposed approach is comprised of two stages. In the first stage, the nominal step location and step duration for the next step or a previewed number of steps are specified. In this stage which is done at the start of each step, the main goal is to specify the best step length and step duration for a desired walking speed. The second stage deals with finding the best landing point and landing time of the swing foot at each control cycle. In this stage, stability of the gaits is preserved by specifying a desired offset between the swing foot landing point and the Divergent Component of Motion (DCM) at the end of current step. After specifying the landing point of the swing foot at a desired time, the swing foot trajectory is regenerated at each control cycle to realize desired landing properties. Simulation on different scenarios shows the robustness of the generated gaits from our proposed approach compared to the case where no timing adjustment is employed.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]

2012


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Surgical Instrument Vibrations are a Construct-Valid Measure of Technical Skill in Robotic Peg Transfer and Suturing Tasks

Bark, K., Gomez, E. D., Rivera, C., McMahan, W., Remington, A., Murayama, K., Lee, D. I., Dumon, K., Williams, N., Kuchenbecker, K. J.

In Proc. Hamlyn Symposium on Medical Robotics, pages: 50-51, London, England, July 2012, Oral presentation given by Bark (inproceedings)

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[BibTex]

2012


[BibTex]


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Spectral Subtraction of Robot Motion Noise for Improved Vibrotactile Event Detection

McMahan, W., Kuchenbecker, K. J.

In Haptics: Perception, Devices, Mobility, and Communication: Proc. EuroHaptics, Part I, 7282, pages: 326-337, Lecture Notes in Computer Science, Springer, Tampere, Finland, June 2012, Oral presentation given by Kuchenbecker (inproceedings)

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[BibTex]

[BibTex]


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Refined Methods for Creating Realistic Haptic Virtual Textures from Tool-Mediated Contact Acceleration Data

Culbertson, H., Romano, J. M., Castillo, P., Mintz, M., Kuchenbecker, K. J.

In Proc. IEEE Haptics Symposium, pages: 385-391, Vancouver, Canada, March 2012, Poster presentation given by Culbertson (inproceedings)

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[BibTex]

[BibTex]


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VerroTouch: Detection of Instrument Vibrations for Haptic Feedback and Skill Assessment in Robotic Surgery

Gomez, E. D., Bark, K., McMahan, W., Rivera, C., Remington, A., Lee, D. I., Kuchenbecker, K. J.

In Proc. Annual Meeting of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), San Diego, California, USA, March 2012, Emerging Technology Poster presentation given by Gomez. Poster available at \href{http://thesagesmeeting.org/}{http://thesagesmeeting.org/} (inproceedings)

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[BibTex]

[BibTex]


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Using Accelerometers to Localize Tactile Contact Events on a Robot Arm

McMahan, W., Romano, J. M., Kuchenbecker, K. J.

In Proc. Workshop on Advances in Tactile Sensing and Touch-Based Human-Robot Interaction, ACM/IEEE International Conference on Human-Robot Interaction, Boston, Massachusetts, March 2012, Oral presentation given by McMahan (inproceedings)

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[BibTex]

[BibTex]


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Recreating the feel of the human chest in a CPR manikin via programmable pneumatic damping

Stanley, A. A., Healey, S. K., Maltese, M. R., Kuchenbecker, K. J.

In Proc. IEEE Haptics Symposium, pages: 37-44, Vancouver, Canada, March 2012, Oral presentation given by Stanley (inproceedings)

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[BibTex]

[BibTex]


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HALO: Haptic Alerts for Low-hanging Obstacles in White Cane Navigation

Wang, Y., Kuchenbecker, K. J.

In Proc. IEEE Haptics Symposium, pages: 527-532, Vancouver, Canada, March 2012, Poster presentation given by Kuchenbecker (inproceedings)

hi

[BibTex]

[BibTex]


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VerroTeach: Visuo-audio-haptic Training for Dental Caries Detection

Maggio, M. P., Parajon, R., Kuchenbecker, K. J.

In Proc. Annual American Dental Educator’s Association (ADEA) Conference, Orlando, Florida, 2012, Oral presentation given by Maggio (inproceedings)

hi

[BibTex]

[BibTex]


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Encoding of Periodic and their Transient Motions by a Single Dynamic Movement Primitive

Ernesti, J., Righetti, L., Do, M., Asfour, T., Schaal, S.

In 2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012), pages: 57-64, IEEE, Osaka, Japan, November 2012 (inproceedings)

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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A Data-Driven Method for Determining Natural Human-Robot Motion Mappings in Teleoperation

Pierce, R. M., Kuchenbecker, K. J.

In Proc. IEEE International Conference on Biomedical Robotics and Biomechatronics, pages: 169-176, Rome, Italy, 2012, Poster presentation given by Pierce (inproceedings)

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[BibTex]

[BibTex]


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Learning Force Control Policies for Compliant Robotic Manipulation

Kalakrishnan, M., Righetti, L., Pastor, P., Schaal, S.

In ICML’12 Proceedings of the 29th International Coference on International Conference on Machine Learning, pages: 49-50, Edinburgh, Scotland, 2012 (inproceedings)

am mg

[BibTex]

[BibTex]


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Low Bitrate Source-filter Model Based Compression of Vibrotactile Texture Signals in Haptic Teleoperation

Chaudhari, R., Çizmeci, B., Kuchenbecker, K. J., Choi, S., Steinbach, E.

In Proc. ACM Multimedia, pages: 409-418, Nara, Japan, 2012, Oral presentation given by {Chaudhari} (inproceedings)

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[BibTex]

[BibTex]


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Robotic Learning of Haptic Adjectives Through Physical Interaction

McMahon, I., Chu, V., Riano, L., McDonald, C. G., He, Q. (., Perez-Tejada, J. M., Arrigo, M., Fitter, N., Nappo, J., Darrell, T., Kuchenbecker, K. J.

In Proc. IROS Workshop on Advances in Tactile Sensing and Touch-based Human-robot Interaction, Vilamoura, Algarve, Portugal, 2012, Oral presentation given by McMahon (inproceedings)

hi

[BibTex]

[BibTex]


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Quadratic programming for inverse dynamics with optimal distribution of contact forces

Righetti, L., Schaal, S.

In 2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012), pages: 538-543, IEEE, Osaka, Japan, November 2012 (inproceedings)

Abstract
In this contribution we propose an inverse dynamics controller for a humanoid robot that exploits torque redundancy to minimize any combination of linear and quadratic costs in the contact forces and the commands. In addition the controller satisfies linear equality and inequality constraints in the contact forces and the commands such as torque limits, unilateral contacts or friction cones limits. The originality of our approach resides in the formulation of the problem as a quadratic program where we only need to solve for the control commands and where the contact forces are optimized implicitly. Furthermore, we do not need a structured representation of the dynamics of the robot (i.e. an explicit computation of the inertia matrix). It is in contrast with existing methods based on quadratic programs. The controller is then robust to uncertainty in the estimation of the dynamics model and the optimization is fast enough to be implemented in high bandwidth torque control loops that are increasingly available on humanoid platforms. We demonstrate properties of our controller with simulations of a human size humanoid robot.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Towards Associative Skill Memories

Pastor, P., Kalakrishnan, M., Righetti, L., Schaal, S.

In 2012 12th IEEE-RAS International Conference on Humanoid Robots (Humanoids 2012), pages: 309-315, IEEE, Osaka, Japan, November 2012 (inproceedings)

Abstract
Movement primitives as basis of movement planning and control have become a popular topic in recent years. The key idea of movement primitives is that a rather small set of stereotypical movements should suffice to create a large set of complex manipulation skills. An interesting side effect of stereotypical movement is that it also creates stereotypical sensory events, e.g., in terms of kinesthetic variables, haptic variables, or, if processed appropriately, visual variables. Thus, a movement primitive executed towards a particular object in the environment will associate a large number of sensory variables that are typical for this manipulation skill. These association can be used to increase robustness towards perturbations, and they also allow failure detection and switching towards other behaviors. We call such movement primitives augmented with sensory associations Associative Skill Memories (ASM). This paper addresses how ASMs can be acquired by imitation learning and how they can create robust manipulation skill by determining subsequent ASMs online to achieve a particular manipulation goal. Evaluation for grasping and manipulation with a Barrett WAM/Hand illustrate our approach.

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Template-based learning of grasp selection

Herzog, A., Pastor, P., Kalakrishnan, M., Righetti, L., Asfour, T., Schaal, S.

In 2012 IEEE International Conference on Robotics and Automation, pages: 2379-2384, IEEE, Saint Paul, USA, 2012 (inproceedings)

Abstract
The ability to grasp unknown objects is an important skill for personal robots, which has been addressed by many present and past research projects, but still remains an open problem. A crucial aspect of grasping is choosing an appropriate grasp configuration, i.e. the 6d pose of the hand relative to the object and its finger configuration. Finding feasible grasp configurations for novel objects, however, is challenging because of the huge variety in shape and size of these objects. Moreover, possible configurations also depend on the specific kinematics of the robotic arm and hand in use. In this paper, we introduce a new grasp selection algorithm able to find object grasp poses based on previously demonstrated grasps. Assuming that objects with similar shapes can be grasped in a similar way, we associate to each demonstrated grasp a grasp template. The template is a local shape descriptor for a possible grasp pose and is constructed using 3d information from depth sensors. For each new object to grasp, the algorithm then finds the best grasp candidate in the library of templates. The grasp selection is also able to improve over time using the information of previous grasp attempts to adapt the ranking of the templates. We tested the algorithm on two different platforms, the Willow Garage PR2 and the Barrett WAM arm which have very different hands. Our results show that the algorithm is able to find good grasp configurations for a large set of objects from a relatively small set of demonstrations, and does indeed improve its performance over time.

am mg

link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Probabilistic depth image registration incorporating nonvisual information

Wüthrich, M., Pastor, P., Righetti, L., Billard, A., Schaal, S.

In 2012 IEEE International Conference on Robotics and Automation, pages: 3637-3644, IEEE, Saint Paul, USA, 2012 (inproceedings)

Abstract
In this paper, we derive a probabilistic registration algorithm for object modeling and tracking. In many robotics applications, such as manipulation tasks, nonvisual information about the movement of the object is available, which we will combine with the visual information. Furthermore we do not only consider observations of the object, but we also take space into account which has been observed to not be part of the object. Furthermore we are computing a posterior distribution over the relative alignment and not a point estimate as typically done in for example Iterative Closest Point (ICP). To our knowledge no existing algorithm meets these three conditions and we thus derive a novel registration algorithm in a Bayesian framework. Experimental results suggest that the proposed methods perform favorably in comparison to PCL [1] implementations of feature mapping and ICP, especially if nonvisual information is available.

am mg

link (url) DOI [BibTex]

link (url) DOI [BibTex]

2009


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Image-Enabled Force Feedback for Robotic Teleoperation of a Flexible Tool

Lindsey, Q., Tenenholtz, N., Lee, D. I., Kuchenbecker, K. J.

In Proc. IASTED International Conference on Robotics and Applications, pages: 224-233, Boston, Massachusetts, November 2009, Oral presentation given by Lindsey (inproceedings)

hi

[BibTex]

2009


[BibTex]


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GPU Methods for Real-Time Haptic Interaction with 3D Fluids

Yang, M., Lu, J., Safonova, A., Kuchenbecker, K. J.

In Proc. IEEE International Workshop on Haptic Audio-Visual Environments and Games, pages: 24-29, Lecco, Italy, November 2009, Oral presentation given by Kuchenbecker (inproceedings)

hi

[BibTex]

[BibTex]


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The AirWand: Design and Characterization of a Large-Workspace Haptic Device

Romano, J. M., Kuchenbecker, K. J.

In Proc. IEEE International Conference on Robotics and Automation, pages: 1461-1466, Kobe, Japan, May 2009, Oral presentation given by \uline{Romano} (inproceedings)

hi

[BibTex]

[BibTex]


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Stiffness Discrimination with Visual and Proprioceptive Cues

Gurari, N., Kuchenbecker, K. J., Okamura, A. M.

In Proc. IEEE World Haptics Conference, pages: 121-126, Salt Lake City, Utah, USA, March 2009, Poster presentation given by Gurari (inproceedings)

hi

[BibTex]

[BibTex]


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Toward Tactilely Transparent Gloves: Collocated Slip Sensing and Vibrotactile Actuation

Romano, J. M., Gray, S. R., Jacobs, N. T., Kuchenbecker, K. J.

In Proc. IEEE World Haptics Conference, pages: 279-284, Salt Lake City, Utah, USA, March 2009, Poster presentation given by Romano, Gray, and Jacobs (inproceedings)

hi

[BibTex]

[BibTex]


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A High-Fidelity Ungrounded Torque Feedback Device: The iTorqU 2.0

Winfree, K. N., Gewirtz, J., Mather, T., Fiene, J., Kuchenbecker, K. J.

In Proc. IEEE World Haptics Conference, pages: 261-266, Salt Lake City, Utah, USA, March 2009, Poster presentation given by Winfree and Gewirtz (inproceedings)

hi

[BibTex]

[BibTex]


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Real-Time Graphic and Haptic Simulation of Deformable Tissue Puncture

Romano, J. M., Safonova, A., Kuchenbecker, K. J.

In Proc. Medicine Meets Virtual Reality, Long Beach, California, USA, January 2009, Poster presentation given by Romano (inproceedings)

hi

[BibTex]

[BibTex]