Grip Force Control Using Vision-Based Tactile Sensor for Dexterous Handling

Watanabe, Norinao; Obinata, Goro

doi:10.1007/978-3-540-78317-6_12

Cited by 10 publications

(18 citation statements)

References 6 publications

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“…"Slippage" means these cases and the slippage degree can be defined as . With the stick ratio, we can prevent a grasped object from a shape deformation and slipping [1].…”

Section: A Stick Ratiomentioning

confidence: 99%

“…In order to obtain the slippage degree, we need to distinguish the two regions in the contact surface. The area ratio of the stick region to the total contact region is called as the stick ratio and defined by (1) where is the area of the stick region, and is the area of the contact region. The stick ratio is directly related to the friction coefficient.…”

Section: A Stick Ratiomentioning

confidence: 99%

“…The slippage degree on the sensor surface is determined by the stick ratio obtained from an analysis of the dot displacements [35]. We had shown an example of grip force control of robot fingers in [1], where the stick ratio was so that order that the contacted object does not slip on the sensor surface. Although the proposed method in [35] can be successfully applied in some ideal situations, the stick ratio was not well estimated in some situations; for an example, when the sensor's stick region contains deformation.…”

Section: Introductionmentioning

confidence: 99%

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Robust Slippage Degree Estimation Based on Reference Update of Vision-Based Tactile Sensor

2011

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In this paper, we propose a new slippage degree estimation method of a vision-based tactile sensor. The advantage of the vision-based tactile sensor is simultaneous acquisition of the slippage degree, a multidimensional force and a moment. A CCD camera captures the sensor surface which has regularly arrayed dots. The slippage degree on the sensor surface is determined by the stick ratio obtained from the displacements of dots in the captured images. In our previous work [1], the stick ratio was successfully applied to avoid slippage or the shape deformation of grasped objects. Based on the adaptive selection of the reference image and the compensation of the dot displacement, the proposed method in this study extends use of the previously developed algorithm, to dynamically complex but general situations as follows. First, the contact surface deforms after the macroscopic slippage or the slippage direction is changed. Second, the contact surface rotates with an applied moment. Third, the captured image is locally zoomed with a significant change of a grip force. A heuristic weighted average method is also proposed to decrease each dot's variation in the captured image. Usefulness of the proposed method is confirmed through experimental results.

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“…"Slippage" means these cases and the slippage degree can be defined as . With the stick ratio, we can prevent a grasped object from a shape deformation and slipping [1].…”

Section: A Stick Ratiomentioning

confidence: 99%

Section: A Stick Ratiomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Robust Slippage Degree Estimation Based on Reference Update of Vision-Based Tactile Sensor

2011

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“…If incipient slippage is detected, a robot can keep grasping an unknown object and prevent it from slipping, even if the mass and friction coefficients are unknown. Watanabe et al proposed a method to calculate and maintain appropriate grip force on an unknown object by feeding back the slippage degree, based on proportional control [28]. When the slippage degree indicates perfect sticking, increasing the grip force should be avoided because it may crush the object.…”

Section: Estimation Of Slippage Definition Of Stick Ratiomentioning

confidence: 99%

Acquisition of Contact Force and Slippage Using a Vision-Based Tactile Sensor with a Fluid-Type Touchpad for the Dexterous Handling of Robots

Ito¹,

Kim²,

Obinata³

2014

Adv Robot Autom

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This paper presents a new approach for estimating contact force and slippage by using a vision-based tactile sensor with a fluid-type touchpad for the dexterous handling of robots. The sensor consists of a CCD camera, LED lights, a transparent acrylic plate and a deformable touchpad. The sensor can obtain a variety of tactile information, such as the contact force, shape, contact region, position and orientation of an object in contact with the fluid-type touchpad. The previous method for measuring contact force requires extensive calculation; this paper proposes a new method based on lookup tables for measuring normal force, tangential force and moment, using a fluid-type touchpad. Additionally, we clarify the mechanism of slippage between a fluid-type touchpad and a contacted object. This mechanism is efficient for applying the proposed slippage estimation method to a fluid-type touchpad. The validation of the proposed methods is confirmed in the experimental results.

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“…Conductive polymer, containing conductive particles, was used for the pressure sensors which recognized pressure by detecting variation of the resistance [7,8]. Vision-based sensors monitor deformation of the object and deduce the pressure distribution applied [9,10]. An attempt was made to enhance the piezoresistive sensor sensitivity by placing a polymer thin film mimicking the epidermal ridge structures on a finger skin [11].…”

Section: Introductionmentioning

confidence: 99%

A Flexible Capacitive Sensor with Encapsulated Liquids as Dielectrics

2012

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Flexible and high-sensitive capacitive sensors are demanded to detect pressure distribution and/or tactile information on a curved surface, hence, wide varieties of polymer-based flexible MEMS sensors have been developed. High-sensitivity may be achieved by increasing the capacitance of the sensor using solid dielectric material while it deteriorates the flexibility. Using air as the dielectric, to maintain the flexibility, sacrifices the sensor sensitivity. In this paper, we demonstrate flexible and highly sensitive capacitive sensor arrays that encapsulate highly dielectric liquids as the dielectric. Deionized water and glycerin, which have relative dielectric constants of approximately 80 and 47, respectively, could increase the capacitance of the sensor when used as the dielectric while maintaining flexibility of the sensor with electrodes patterned on flexible polymer substrates. A reservoir of liquids between the electrodes was designed to have a leak path, which allows the sensor to deform despite of the incompressibility of the encapsulated liquids. The proposed sensor was microfabricated and demonstrated successfully to have a five times greater sensitivity than sensors that use air as the dielectric.

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Grip Force Control Using Vision-Based Tactile Sensor for Dexterous Handling

Cited by 10 publications

References 6 publications

Robust Slippage Degree Estimation Based on Reference Update of Vision-Based Tactile Sensor

Robust Slippage Degree Estimation Based on Reference Update of Vision-Based Tactile Sensor

Acquisition of Contact Force and Slippage Using a Vision-Based Tactile Sensor with a Fluid-Type Touchpad for the Dexterous Handling of Robots

A Flexible Capacitive Sensor with Encapsulated Liquids as Dielectrics

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