Integrated control of a multi-fingered hand and arm using proximity sensors on the fingertips

Abstract

In this study, we propose integrated control of a robotic hand and arm using only proximity sensing from the fingertips. An integrated control scheme for the fingers and for the arm enables quick control of the position and posture of the arm by placing the fingertips adjacent to the surface of an object to be grasped. The arm control scheme enables adjustments based on errors in hand position and posture that would be impossible to achieve by finger motions alone, thus allowing the fingers to grasp an object in a laterally symmetric grasp. This can prevent grasp failures such as a finger pushing the object out of the hand or knocking the object over. Proposed control of the arm and hand allowed correction of position errors on the order of several centimeters. For example, an object on a workbench that is in an uncertain positional relation with the robot, with an inexpensive optical sensor such as a Kinect, which only provides coarse image data, would be sufficient for grasping an object.

A Review of Tactile Information: Perception and Action Through Touch

“…Pretouch is the ability to detect objects and their surfaces before contacting with them. A pretouch sensor can provide a robot with the relative geometrical relation to an object [37] , which is valuable for the robot's planners [38], [39] and controllers [40], [41], [42]. With the distance, the robot can roughly estimate the object's shape and position before making contact.…”

Integrated control of a multiple-degree-of-freedom hand and arm using a reactive architecture based on high-speed proximity sensing

“…In order to eliminate the delay time in the feedback loop, we developed a system that controls the hand and the arm with one controller and uses simple feedback control (details of the control are described in Section 8 and details of the system are described in Section 9.1). The hand controller used in our architecture was proposed in Koyama et al (2013) and the arm controller was proposed in Koyama et al (2016). This article provides more background on the connection between the sensor outputs and the kinematics of the fingers, and presents more position adjustment and grasping results based on the integrated control system.…”

“…Therefore, we use the arm tip position control so that the grasping posture is symmetrical between at least two fingers. The control law was proposed in Koyama et al (2016). In this article, we give further details of the control laws with kinematics of the robot.…”

High-Speed High-Precision Proximity Sensor for Detection of Tilt, Distance, and Contact

“…According to assumption 3), the distance is almost same value in a short time t. The emission frequency of the LEDs, ω, dominates the time change of the photo-current. The time change of the photo-current is approximated by equation (2).…”

“…We have developed a method of non-contact position control of fingers by mounting Resistor Network Structure Proximity Sensor on the fingertips of a robot hand [1]. We also developed an integrated control method for a multi-degree-offreedom hand and arm using the sensor [2]. In our grasping strategy, first the approximate position of the object is detected by a vision sensor, and then the hand adjusts the grasping position and posture automatically by feedback from the proximity sensor and finally grasps the object.…”