About Novint FalconAbout Novint Falcon

Novint Falcon : 3-DOF, Impedance type Haptic Device.

Mechanism used is modified delta mechanism.

Cost : 150$ only…..

Performance : Varies from device to device, due to cheap motors, cheap encoders etc. But really cheap device for any beginner to start his/her research work.

Cool device to play games and have real force feedback.

Courtesy of :http://www.terminally-incoherent.com/

Our Initial GoalsOur Initial Goals

To improve the performance of the device by implementing Gravity and Friction Compensation.

How far have we How far have we reached?reached?We did implemented the Gravity

Compensation, by computing it’s Kinematics, calculating COM, forming Jacobian Matrix, calculating the masses and then calculating & giving the force output to the device.

We already have the dynamics calculated for the device.

ApproachApproachInitially, we proceeded with the paper on :Delta robot: inverse, direct, and intermediate Jacobians by M Lo´pez1, E Castillo, G Garcı´a, and A Bashir

We computed Kinematics using this paper.

Fig. Original Delta Mechanism

Courtesy of:http://journals.pepublishing.com/content/8w134w1h7r3p7rj2/fulltext.pdf

Calculating COM

Calculating Moment of Calculating Moment of Inertia using Bifilar Inertia using Bifilar Pendulum MethodPendulum Method

MoviesMoviesWithout Gravity CompensationWith Gravity Compensation

The major turnaround!!!The major turnaround!!! We later on, found online a Ph.D.

Thesis Report of R.E. Stamper on “A Three Degree of Freedom Parallel Manipulator

with Only Translational Degrees of Freedom”.

We found that the work what we were trying to do was already done way back!!!

Gravity and Friction Compensation both were already done.

Further ModificationsFurther ModificationsWe made few modifications in

our original Inverse Kinematic Equations, based on modified delta mechanism.

Jacobian Matrix and Gravity Compensation implemented from the Phd Paper with further modifications.

How were we same??How were we same??

Fig. Modified Delta Mechanism used in the Phd paper

Courtesy of:www.thg.ru

Courtesy of:http://libnifalcon.wiki.sourceforge.net/space/showimage/PhD_97-4.pdf

How were we different??How were we different??Assumptions being made.Falcon mechanism is different,

than the Thesis Paper in two ways.

Direction of Gravity ForceDirection of Gravity

Force

Courtesy of :http://www.terminally-incoherent.com/

Courtesy of :http://libnifalcon.wiki.sourceforge.net/space/showimage/PhD_97-4.pdf

Goals being modified!!!Goals being modified!!!

Building a 5-DOF device using 2-Falcons.

Alternative available in the Alternative available in the MarketMarket

Courtesy of :www.quanser.blogspot.com

Quanser HD^2 High-Definition Haptic Device.

It’s an 5-DOF Device.

Cost : $70,000...Courtesy of:www.trafficcomplex.com

What can be the cheaper What can be the cheaper alternative???alternative???

Build an 5-DOF Haptic Device using two Falcons.

Cost : 320$ [2 Falcons + $20]

Performance : Improved by our Gravity Compensation.

Courtesy of:upload.wikimedia.org

SoftwareSoftwareOpen Source software available

at www.chai3d.org. Chai3d Beta Version 2.0Visual Studio 2003 or above is

required.OpenGl & Microsoft SDk are

required.Latest Novint Drivers from

www.novint.com.

Future GoalsFuture GoalsImplementing Friction

Compensation, to make device feel much better.

Make the current code more efficient.

Make new virtual environments.

Information about DEMOInformation about DEMOGravity Compensation working

for the New 5-DOF Device.Few Virtual Environments to

interact.

Thank You.Thank You.

Any Questions???Any Questions???

Courtesy of :www.crewelive08.com

Computing Inverse Computing Inverse KinematicsKinematics float theta33_1 = acos((px*sin(phi_1)/bb + py*cos(phi_1)/bb)); float theta33_2 = acos((px*sin(phi_2)/bb + py*cos(phi_2)/bb)); float theta33_3 = acos((px*sin(phi_3)/bb + py*cos(phi_3)/bb)); float theta22_1 = acos((( A_1 * A_1)+(B_1 * B_I)-(a*a) -(alpha_1*alpha_1))/

(2.0 * a * alpha_1)); float theta22_2 =acos((( A_2 * A_2)+(B_2 *B_2) -(a* a) -(alpha_2*alpha_2))/

(2.0 * a* alpha_2)); float theta22_3 =acos((( A_3 * A_3)+(B_3 * B_3) -(a*a) - (alpha_3*alpha_3))/

(2.0 *a* alpha_3)); double theta11_1 = atan2( ((B_1 * A_1) - (EE_1 * a) - (EE_1 * DD_1)) / ((A_1 *

a) - ( EE_1 * B_1) + (DD_1 * A_1)) , ((B_1 * B_1) - ((a + DD_1)*(a + DD_1))) / ((EE_1 * B_1) - ( A_1 * ( a + DD_1))) );

double theta11_2 = atan2( ((B_2 * A_2) - (EE_2 * a) - (EE_2 * DD_2)) / ((A_2 * a) - ( EE_2 * B_2) + (DD_2 * A_2)) , ((B_2 * B_2) - ((a + DD_2)*(a + DD_2))) / ((EE_2 * B_2) - ( A_2 * ( a + DD_2))) );

double theta11_3 = atan2( ((B_3 * A_3) - (EE_3 * a) - (EE_3 * DD_3)) / ((A_3 * a) - ( EE_3 * B_3) + (DD_3 * A_3)) , ((B_3 * B_3) - ((a + DD_3)*(a + DD_3))) / ((EE_3 * B_3) - ( A_3 * ( a + DD_3))) );

Computing JacobianComputing Jacobian

Computing Gravity Computing Gravity CompensationCompensation

ChartChart