Design and Development of a General Purpose 7 DOF Haptic Device

A seven degree-of-freedom (DOF) haptic device has been developed with applications towards robot-assisted minimally invasive surgery. The device consists of four degrees of force feedback (X, Y, Z, and grasping) capability and seven degrees of freedom for positioning capability. The haptic device is a closed kinematic chain with two halves (user interface and spatial mechanism) connected by a universal joint. Kinematic analysis of the haptic device has been developed with the particular goal of computing the slave robot position and the end point configuration of the laparoscopic tool. Additionally, the achievable workspace of the mechanism has been calculated based on the motion of each half of the device. Friction modeling and its compensation has also been presented to enable higher transparency of the haptic device.