Force reflecting haptic interface

• US 6,417,638 B1
• Filed: 07/16/1999
• Issued: 07/09/2002
• Est. Priority Date: 07/17/1998
• Status: Expired due to Term

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: SensAble Technologies, Inc. (3D Systems Corporation)
• Inventors: Goodwin, William A., Lohse, R. Michael, Andrew, Ziegler, Guy, Rodomista, Clive, Bolton, Massie, Thomas H.
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US09/356,119
• Time in Patent Office: 1,089 Days
• Field of Search: 318/560-696, 318/138, 33/1.L, 33/1.PT, 335/04, 414/729, 74/96, 74/892.2, 744/69, 901/15.3, 901/21.42, 901/23.2, 901/25.47, 250/231.13, 356/614, 324/162
• US Class Current: 318/560
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: G05B 2219/39024 Calibration of manipulator
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks

Abstract

A six degree of freedom force reflecting haptic interface includes three powered axes and three free axes, all of which are tracked so that the position of a user connection element in the work volume can be determined. The interface includes cable drives with polymer composite or metallic cables, automatic cable tensioning devices, and grounded actuator capstans. A nested hub and transfer drive provide a compact, weight balanced interface. User comfort and safety features are also provided.

Claims

1. An automatic workspace volume calibration method for use with a haptic interface, the calibration method comprising the steps of:

initializing a position of the haptic interface;

rotating a rotary element of the haptic interface;

tracking an angular orientation of the rotary element;

determining a home position for the rotary element; and

geometrically centering a user reference point in a workspace volume and a remote environment by comparing the angular orientation of the rotary element with respect to the home position of the rotary element.

2. The automatic workspace volume calibration method of claim 1, wherein an encoder is used to track the angular orientation of the rotary element.

3. The automatic workspace volume calibration method of claim 1, wherein a proximity switch is used to determine the home position of the rotary element.

4. The automatic workspace volume calibration method of claim 1, wherein a microswitch is used to determine the home position of the rotary element.

5. The automatic workspace volume calibration method of claim 1, wherein a potentiometer is used to track the angular orientation of the rotary element.

6. The automatic workspace volume calibration method of claim 1, wherein a cable coupled to the haptic interface transmits force to the rotary element.

7. The automatic workspace volume calibration method of claim 1, wherein a potentiometer is used to determine the home position of the rotary element.

8. A system for automatic workspace volume calibration of a haptic interface, comprising:

at least one rotary element;

at least one flag disposed on the at least one rotary element;

a user interface connection for moving the at least one rotary element through a range of motion thereof; and

means for determining angular orientation of the at least one flag to geometrically calibrate the work volume.

9. The system for automatic workspace volume calibration of a haptic interface of claim 8 further comprising:

a second flag disposed on the at least one rotary element and forming a gap between the at least one flag and the second flag; and

means for determining angular orientation of the second flag and the gap to geometrically calibrate the work volume.

10. The system for automatic workspace volume calibration of a haptic interface of claim 8 further comprising a cable coupled to the at least one rotary element to transmit force thereto.