Calculating the Inverse Kinematics

[CaptainMack]

Hi!

I’m trying to implement your code with my own built bot, I’ve tested the bot and it works. However, some of your code gives me problems, especially when it calculates the inverse kinematics

When calculating b with following code

var b = Math.acos((square(LENGTH1)+square(hypotenuse)-square(LENGTH2))/(2_LENGTH1_hypotenuse));

it returns a number above 1, but below 2, which causes Math.acos to return NaN

Can you see what’s wrong? I'm using following variables:

LENGTH1: 80mm
LENGTH2: 80mm

[ytham]

Hm, I'm not immediately sure what the problem might be, but you might want to try playing around with the MIN/MAX XYZ vars; they may be giving you NaNs. Otherwise try the default values and see if it works, then move then in small increments until you can isolate the issue.

On Oct 29, 2015, at 6:56 AM, Christian notifications@github.com wrote:

Hi!

I’m trying to implement your code with my own built bot, I’ve tested the bot and it works. However, some of your code gives me problems, especially when it calculates the inverse kinematics

When calculating b with following code

var b = Math.acos((square(LENGTH1)+square(hypotenuse)-square(LENGTH2))/(2LENGTH1hypotenuse));

it returns a number above 1, but below 2, which causes Math.acos to return NaN

Can you see what’s wrong? I'm using following variables:

LENGTH1: 80mm
LENGTH2: 80mm

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[CaptainMack]

It's funny, I've tried the default values and increase them (including setting min values to negative values) and it only gives me a number when I pull my hand towards myself - so the fingertips are approx. 5 centimeters from the front of the Leap Motion. I'll keep trying and see what I can make of it.

EDIT: Might have found the problem, will report back after I've tested it a bit more.

[ytham]

That's a little strange; the activation zone should be pretty in the middle and about 10-20 cm up

On Oct 29, 2015, at 7:29 AM, Christian notifications@github.com wrote:

It's funny, I've tried the default values and increase them (including setting min values to negative values) and it only gives me a number when I pull my hand towards myself - so the fingertips are approx. 5 centimeters from the front of the Leap Motion. I'll keep trying and see what I can make of it

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[CaptainMack]

Well, the leap motions Z and y values can be negative, so I tried untill I came to these values:

var MAX_Y = 105;
var MIN_Y = -105;
var MIN_Z = -105;
var MAX_Z = 105;

However, when hooking it up with the robot, it barely moves (I guess It's because the min and max values limits it quite much. Btw. I'm used the open-source MeArm robot build.

[ytham]

You might want to check if the servo values for the MeArm match up with
that of a regular servo. I feed in values from 0-180 into my arm; ensure
that values of 0-180, fed into your servos will move the servos on the arm
(I'm not familiar w/ MeArm).

As far as I know, z-values for leap start at 0 and cannot be negative.

On Thu, Oct 29, 2015 at 7:39 AM, Christian notifications@github.com wrote:

Well, the leap motions Z and y values can be negative, so I tried untill I
came to these values:

var MAX_Y = 105;
var MIN_Y = -105;
var MIN_Z = -105;
var MAX_Z = 105;

However, when hooking it up with the robot, it barely moves (I guess It's
because the min and max values limits it quite much. Btw. I'm used the
open-source MeArm robot build.

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