Modeling and Control of the Twisted String Actuation System

Palli, Gianluca; Natale, Ciro; May, Chris; Melchiorri, Claudio; Würtz, Thomas

doi:10.1109/tmech.2011.2181855

Cited by 156 publications

(84 citation statements)

References 14 publications

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“…This mechanism allows high speed bending when the reaction force at the fingertip is small, and at the same time, enables the fingertip force to gradually increase as the finger slows down due to a reaction from the external environment. The finger structure, however, cannot be applied to the extending motion of the joints, which results in disadvantages for practical movements required for dexterous manipulation [15], [16], [17].…”

Section: Related Workmentioning

confidence: 99%

Robotic joint design by agonist and antagonist arrangement with twisting small-diameter round-belts

Inoue

Yamamoto

Miyata

et al. 2015

2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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This paper develops a novel robotic joint mechanism by means of twisting a small-diameter round-belt, which enables slow movements of joint rotation unlike direct-drive actuator mechanisms. The actuator mechanism proposed in this manuscript is composed of two small-diameter round-belts located near the joint with opposite configurations. The two round-belts are twisted by DC motors placed on a motor stage, which can be activated by a step motor. This novel mechanism realizes movement of the robotic joint around its axis due to contraction forces generated by twisting both round-belts. That is, these round-belts act as agonist and antagonist actuators for the robotic joint, which give a human-like compliance to the rotational motion of the joint. Experimental results using the proposed one-link robot show that a high position resolution of the joint control can be achieved by increases and decreases in the amount of twisting. In addition, we clearly indicate a linear relationship between twisting and the joint angle of the robot. Finally, this paper reveals that the antagonistic twist-actuator system has a secondary role as a gear reducer that is capable of largely decreasing the velocity of joint movement.

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Section: Related Workmentioning

confidence: 99%

Robotic joint design by agonist and antagonist arrangement with twisting small-diameter round-belts

Inoue

Yamamoto

Miyata

et al. 2015

2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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“…The DEXMART Hand is also equipped with a wide set of sensors which comprise joint position sensors, tendon force sensors [20] and fingertip tactile sensors [6]. Moreover, the twisted string actuation concept [19] has been adopted for driving this robotic hand. As in the previous version, the maximum design simplification and reduction of the device's cost production and development has been held.…”

Section: The Dexmart Handmentioning

confidence: 99%

Mapping Grasps from the Human Hand to the DEXMART Hand by Means of Postural Synergies and Vision

Ficuciello

Palli

Melchiorri

et al. 2013

Experimental Robotics

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This work aims at defining a suitable postural synergies subspace for the DEXMART Hand from observation of human hand grasping postures. Previous works were carried out on a preliminary prototype (the UB Hand IV), without neither proprioceptive integrated sensors nor external sensors, by means of a joint-to-joint mapping technique. Using an RGB camera and depth sensor for 3D motion capture, the human hand palm pose and fingertip positions have been measured for a reference set of grasping postures. The proposed method for the determination of the synergies subspace is based on the kinematics mapping from the human hand to the robotic hand using data from experiments involving five subjects. The subjects' hand configurations have been mapped to the robotic hand by matching the hand pose and fingertip positions and applying a closed-loop inverse kinematic algorithm. Suitable scaling factors have been used to adapt the DEXMART Hand kinematics to the subjects' hand dimension. By means of Principal Component Analysis (PCA), the kinematic patterns of the first three predominant synergies have been computed and a brief comparison with the previous method and kinematics is reported. Finally, a synergy-based control strategy has been used for testing the efficiency of the grasp synthesis method

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“…Also impedance controlled twisted string actuators was reported, where researchers integrated a spring with a twisted string scheme and reported a position holding controller for both directions [21]. Mathematical modelling of the twisted string actuators were also presented in [22,23].…”

Section: Introductionmentioning

confidence: 99%

The UC Softhand: Light Weight Adaptive Bionic Hand with a Compact Twisted String Actuation System

2015

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Abstract:In this paper, we present the design and development of the UC-Softhand. The UC Softhand is a low cost, Bionic and adaptive hand that takes advantage of compliant joints. By optimization of the actuation strategy as well as the actuation mechanism, we could develop an anthropomorphic hand that embeds three actuators, transmission mechanisms, controllers and drivers in the palm of the hand, and weighs only 280 g, making it one of the lightest bionic hands that has been created so far. The key aspect of the UC Softhand is utilization of a novel compact twisted string actuation mechanism, that allows a considerable weight and cost reduction compared to its predecessor.

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Modeling and Control of the Twisted String Actuation System

Cited by 156 publications

References 14 publications

Robotic joint design by agonist and antagonist arrangement with twisting small-diameter round-belts

Robotic joint design by agonist and antagonist arrangement with twisting small-diameter round-belts

Mapping Grasps from the Human Hand to the DEXMART Hand by Means of Postural Synergies and Vision

The UC Softhand: Light Weight Adaptive Bionic Hand with a Compact Twisted String Actuation System

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