HAPTIC BASED MULTI-PURPOSE GRINDING SIMULATOR

Goal
Material removal operations such as polishing and grinding appear in a variety of fields. This projects aims at creating a haptic based simulator for these operations.

Abstract

Polishing and grinding operations are used in a variety of fields ranging from medical applications like dentistry and orthopedics, to machining operations on metals. These operations are labor-intensive and usually require high level of skill. It is not always viable or possible to train new operators directly on a real specimen for a variety of reasons. In the case of dentists for example, training would depend on the availability of a volunteer or on physical prototypes that are replicated using various artificial materials. Artificially created specimens that are most commonly used to train students are rarely able to simulate the feel of a real specimen that is often critical to the application. The recent onset of sophisticated haptic devices, capable of delivering precise and controllable forces has opened new avenues for the use of computer simulations to replicate these complicated tasks. In our research we aim to combine these new haptic technologies and ever growing computational power to produce training tools that are accurate, realistic and most importantly affordable.
A terrain modeling method called Heightmaps is used to replicate the surface roughness. In this method a digital image of the work piece is converted into a 3-D heightmap. Analyzing each pixel of the image relative to its surroundings and assigning it with a height leads to the creation of the heightmap that is imported into the haptic model. The surface roughness can now be felt using the PHANToM haptic device. Some screenshots of the process are shown below. A real-time analysis of the input forces, validated by the force model is used to modify the texture and enhance realism. This gives the user a sense of material removal. The rate of removal is governed by a variety of factors like input force and tool attributes like speed, depth of cut, etc.

Publications
[1] Balijepalli, A., Kesavadas, T., An Exploratory Haptic Based Robotic Path Planning and Training Tool, IEEE conference on Robotics and Automation, held May 11-15, 2002, Washington D.C.

[2] Balijepalli, A., Kesavadas, T., An Exploratory Haptic Based Manufacturing and Path-planning Tool, Symax Conference, January 7-8, IIT Madras, India.

[3] Balijepalli, A., Kesavadas, T., An Experimental Haptic Based Skill Training Simulator for Manufacturing Applications, ASME Winter Conference, to be held in November 2002, New Orleans, LA.

[4] Balijepalli, A., Kesavadas, T., A Haptic Based Virtual Grinding Tool, IEEE Virtual Reality Symposium 2003, to be held March 22-26, 2003, Los Angeles, CA.