This paper investigates the synthesis of a spatial stiffness matrix using simple line springs. A new algorithm is developed, which enables the selection of constituent springs based on their positions and directions. The constraining space of the line springs is then investigated. It is shown that an isotropic stiffness matrix, in general, can be split into the sum of two rank-3 stiffness matrices. The three line springs of the first matrix can be selected to pass through any arbitrary points in space, while the three line springs of the second stiffness matrix lie on a quadric surface, which is usually a hyperboloid of one sheet.

Investigates the stiffness and kinematics of an object grasped by multiple elastic fingers. The derivation is based on the work of Svinin (1995), but derived with the approach of minimization of energy and using Montana's (1989) equations of contact model. The result gives a closed form expression of object stiffness in terms of contact finger stiffness, contact locations and contact point curvatures.

Dextrous manipulation is an important issue in the study of multifingered robotic hands. Determining the contact velocities in dextrous manipulation with rolling contact is the key problem. We propose a coordinated manipulation scheme in which the contact velocities are determined by tactile sensor feedback. We address coordinated motion generation which maintains or improves the grasp quality in dextrous manipulation. We implement several experiments using the HKUST three-fingered robotic hand. The experimental results illustrate the effectiveness of the proposed scheme.

Capacitive tactile sensors are constructed and installed to the fingers of the HKUST hands for measurement of position, force and direction of principle curvature of contact point. The hardware and software for signal processing are designed such that the contact information is sent to the motion control computer in real time. Experiments in rolling and sliding contact motions are then performed for testing the functionality of the tactile sensing system in motion control. The measurement of contact velocities obtained from the sensor is also compared with that calculated from the theoretical contact equations. This paper describes the tactile sensing system and the experimental result in contact motion control.