Haptic manipulation of virtual mechanisms from mechanical CAD designs

Abstract

A haptic display system is presented for manipulating virtual mechanisms derived from a mechanical CAD design. Links are designed and assembled into mechanisms using Utah's Alpha.1 CAD system, and are then manipulated with a Sarcos Dextrous Arm Master. Based on the mechanism's kinematics and the virtual grasp, the motion of the master is divided into motion of the mechanism and constraint violation.The operator expen"ences the dynamic forces from the mechanism plus constraint forces.

Haptic Rendering of Topological Constraints to Users Manipulating Serial Virtual Linkages

“…1. In this figure, and ÚØ are the impedance of the device and of the VT, respectively, Ë scales the two force channels (from the device to the VE and vice-versa), and , ÒÚ , and Ô are the hand, the VE, and the coordination force 1 …”

“…A main challenge is the need to compute the dynamics and the interactions of the virtual objects at guaranteed speeds of the order of hundreds of Hz. This computational requirement poses difficulties for the rendering of haptic interaction between a user and a virtual environment through a linkage and only a very few examples [1], [2], [3], [4] have been reported. Nevertheless, potential applications such as virtual CAD prototyping, medical simulators for orthopedics, or animation require users to be provided with convincing force feedback while they manipulate virtual linkages.…”

“…Existing research has developed application-specific [1] and generalpurpose [2], [3], [4], [5] haptic rendering techniques that address the first two factors. In [1], [2], and [4] the main concern is the efficient simulation of the linkage dynamics. Physically-based models for linkage contact and collision are developed in [3] and [5].…”

Real-time rigid body simulation based on volumetric penalty method

“…Therefore, haptic interfaces help natural manipulation of virtual object and extend application area of virtual world. For example, Nahvi et al [1] created simple mechanism in the virtual world to aid the design process. In their system, the user can manipulate the mechanism with a haptic interface.…”

Haptic aided design: a case study

“…For example, [1] describes a haptic interface coupled with CAD software, allowing the operator to both see and feel geometrical shapes and dynamics forces. In the work described by [2], the author formulated inverse kinematics and inverse dynamics equations involved in simulating open chain mechanisms and single closed chain mechanisms. [3] describes a formulation for force calculation in a virtual mechanism manipulation system to simulate the mechanics of two-finger grasping.…”