Design and Integration of a Novel 6-DOF Human-Computer Interaction DeviceZhouming Tang and Shahram Payandeh

zta3@sfu.ca, shahram@cs.sfu.ca Experimental Robotics Laboratory, School of Engineering Science

US Patent NO: US 11/792,244

iV QW=

Aim to examine the forward and inverse kinematic models of the haptic device

Design, development and applications of haptic devices have been gaining momentum for the past 15 years. Typically, most developments have been carried-out and studied at universities. Some of these designs were then licensed to interested companies or has been commercialized through spin-off companies. The current commercial companies and their associated haptic products are listed below:

1 2 3[1,0,0] ; [0,1,0] ; [0,0,1]T T TV V V∗ ∗ ∗= = =

State-of-the-art and the prevailing market condition

6sin( )θ

Kinematic and force Correspondenceexperiments and results

• To integrate the proposed haptic device with the modules of the virtual simulation product, which has been developed in the experimental robotics laboratory, Simon Fraser University and can be accessed on line at (ViTEn, http://web.ensc.sfu.ca/research/erl/ViTEn/)

Kinematic Correspondence

1θ

LIST OF JOINT ANGLES AT THE THREE SELECTED SAMPLES ( ISRECORDED AT THE 1ST SAMPLE, IS RECORDED AT THE 1500TH

SAMPLE AND IS RECORDED AT THE 2500TH SAMPLE)1S

2θ 3θ 4θ 5θ 6θ

1S

2S

3S

2S3S

42.19

64.14

35.33

47.76

59.65

27.64

45

42.03

49.57

13.65−

28.74−

59.6−

81.49−

78.23−

87.42−

0

42.37−

95.41−

Corresponding forward kinematic results:

' '

1 26 6

0 1 0 0.15 0.89 0.44 0.07 94.810.16 0 0.99 5.9 0.13 0.41 0.9 83.93

,0.99 0 0.16 272.02 0.42 0.8 0.43 232.58

0 0 0 1 0 0 0 1

W WS ST T

− − − − − − − − − = =

− − −

'

36

0.96 0.17 0.2 75.620.08 0.9 0.41 136.440.25 0.38 0.89 178.28

0 0 0 1

WST

− − − − =

−

Force Correspondence

Six experiments are designed, each of which takes the desired force or torque value at the stylus as input, determines the corresponding six actuator joint torques and renders the force feedback accordingly.

The direction errors between the desire and actual force or torque vectors are denoted by . The values of these angles are and

1,..., 6ϕ ϕ4.29 ,6.91 ,7.85 ,11.43 ,2.11 1.32

Preliminary results of interaction with virtual environment

The above pictures describe the virtual environment and the scene when user manipulates the device. The stiffness of the virtual object is set to be 1 N/mm, and the haptic control loop is operated under 1 KHz.

The picture located at the bottom left is desired force at the stylus while the picture located at the bottom right is the actual measured force during the experiment by using the ATI Nano25 F/T sensor

Future Works• Improve the reliability of the force feedback

• Conduct user studies to make sure the proposed device can provide sufficient accuracy for the surgical training application

• Integrate the proposed haptic device with the modules of the virtual simulation product, which has been developed in the experimental robotics laboratory, Simon Fraser University

Objectives• To develop a working prototype of a novel six degree of freedom (DOF) force feedback (haptic) device allowing feedback along all six DOF

• To develop a mathematical model which can map the magnitude of the joint angle readings of the device to the position and orientation of the handle part of the device

• To communicate through an I/O servo-control interface with the computational platform where a representation of the haptic device and its virtualenvironment can graphically created

• To establish a mathematical model which can determine the torque of each individual joint based on the desired force/torque at the handle

Sensable Technology

Xitact Quanser Haption

Force Dimention MPB

• Hybrid robot design••

•

•

Design descriptions

Combines the spherical and serial configurationsCombination of active and passive components of spherical parallel mechanismIntroduction of a passive spherical joint at the center of rotationThe design of serial configuration and the interconnection between spherical parallel configuration and serial configuration

Overall key features:1) Location for the actuators (away from the moving platform);2) Location of the actuators of the serial robot on the moving platform; 3) Support of the weight and the interaction forces through the passive joint