Method and system for providing a tactile virtual reality and manipulator defining an interface device therefor

• US 5,459,382 A
• Filed: 06/09/1994
• Issued: 10/17/1995
• Est. Priority Date: 12/02/1992
• Status: Expired due to Term

• Current Assignee: Immersion Corporation
• Original Assignee: Cybernet Systems Corporation
• Inventors: Jacobus, Charles J., Taylor, Mark J., Riggs, Alan J.
• Primary Examiner(s): Ip, Paul
• Application Number:
  US08/257,070
• Time in Patent Office: 495 Days
• Field of Search: 318/560-646, 364/806, 364/146, 364/578, 901/3, 901/5, 901/7, 901/9, 901/15-23, 901/40-50, 414/730-735, 74/471 X, 395/80-99, 395/152, 395/161, 33/366, 33/377, 33/312, 33/313, 434/307, 434/43, 434/69
• US Class Current: 318/568.11
• CPC Class Codes: B25J 9/1689 Teleoperation
• CPC Class Codes: G05B 2219/35416 3-D joystick
• CPC Class Codes: G05B 2219/37396 Tactile feedback, operator feels reaction, force reflection
• CPC Class Codes: G05G 2009/04766 providing feel, e.g. indexing means, means to create counterforce
• CPC Class Codes: G05G 9/04737 with six degrees of freedom
• CPC Class Codes: G06F 2203/015 Force feedback applied to a joystick
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user

Abstract

An system and method for providing a tactile virtual reality to a user is present. The position and orientation of the user is utilized to generate a virtual reality force field. Forces are in turn generated on the user as a function of this force field. A six-axis manipulator is presented for providing a user interface to such a system. This manipulator provides a unique kinematic structure with two constant force springs which provide gravity compensation so that the manipulator effectively floats.

Claims

1. A method for providing a tactile virtual reality in response to a user position and orientation, the method comprising the steps of:

storing data representative of the virtual reality, including one or more virtual objects having virtual surfaces;

generating an electrical signal for each of a plurality of degrees of freedom of the user as a function of the user position and orientation in three-dimensional space;

synthesizing user velocity and acceleration from the electrical signals to determine user-applied force;

mapping the user position, orientation and applied force into the virtual reality to determine interactions between the user and any objects in the virtual reality;

generating at least one virtual reality force field in response to the interactions;

generating a force signal for each degree of freedom as a function of the force field; and

directing a tactile force on the user for each force signal, the generating tactile forces providing the tactile virtual reality.

2. The method of claim 1 wherein the number of degrees of freedom is six or more.

3. The method of claim 2 wherein the step of generating the electrical signals includes the step of sensing position and orientation of the user'"'"'s hand and wherein the tactile forces are directed to the user'"'"'s hand.

4. The method of claim 1, wherein the step of synthesizing user velocity and acceleration from the electrical signals to determine user-applied force includes the step of sampling the electrical signals at regular intervals to synthesize estimates of user velocity and acceleration.

5. The method of claim 1, further including the step of computing a torque contribution associated with each degree of freedom based upon user position, orientation and applied force to assist in determining the interaction between the user and any objects in the virtual reality.

6. The method of claim 5, further including the step of applying the torque contributions to a running sum of such contributions.

7. The method of claim 1, further including the step of generating an altered force field view by performing a mathematical transformation on the position and orientation data.

8. A system for providing a tactile virtual reality in response to a user position and orientation, the system comprising:

a six-axis interface device including an actuator for each axis of the device and a member movable by the user, the interface device being responsive to the position and orientation of the member to generate electrical signals representative of the position and orientation of the member; and

a programmed computer operative to;

store data representative of the virtual reality, including any virtual objects therewithin,

analyze the position and orientation of the member relative to the objects to determine any interaction therebetween,

generate at least one virtual reality force field in response to the interaction, and

generate a force signal for each axis of the device as a function of the force field, wherein the actuators are responsive to their respective force signals to provide a force to each axis of the device for creating the tactile virtual reality.

9. The system of claim 8 wherein the member includes switch means for disabling the actuators if the user breaks tactile contact with the member.

10. The system of claim 8 wherein the member includes a handle grippable by the user.

11. The system of claim 8 wherein the interface device further comprises an encoder coupled to each actuator for generating the corresponding electrical signals.

12. The system of claim 11 wherein the encoders are optical encoders.

13. The system of claim 8 wherein at least one virtual reality force field includes a mathematical function in the computer program.

14. The system of claim 8 wherein the virtual reality force field includes limits and stops implemented by the computer program.

15. The system of claim 8 wherein the means for generating is capable of generating a plurality of virtual reality force fields, and wherein the member includes a switch means for selecting one of the virtual reality force fields.

16. The system of claim 8 wherein the actuators are electric motors.

17. The system of claim 16 wherein the electric motors are back-drivable.

18. A locally self-contained system for providing a tactile virtual reality in response to a user position and orientation, comprising:

(a) a multi-axis, user-moveable member including an actuator and position sensor dedicated to each axis;

(b) an interface device in communication with each actuator and each position sensor, the interface device being operative to;

generate an electrical signal representative of the position and orientation of the member, and

activate one or more of the actuators in response to a received force signal;

(c) a programmed computer in communication with the interface device, the computer being programmed to perform the following functions;

receive an electrical signal from the interface device representative of the position and orientation of the member with respect to time,

determine a user-applied force to the member by synthesizing velocity and acceleration from the periodic position readings,

generate at least one virtual reality force field in response to the user-applied force,

generate a force signal as a function of the force field, and

output the force signal to the interface device.

19. The locally self-contained system of claim 18, wherein the actuator and position sensor associated with a particular axis are in physical communication with one another, enabling the superposition of translational displacement with force application, and angular displacement with torque, thereby permitting an arbitrary, programmed application of forces, torques and displacements to the member in any direction.