Move from Point A to B with given steps

.Net Add-on Programming
1

Hi,

I’m trying to implement a function in C# which move each joint from an initial position A to a target position B, using a step by step movement. Steps are defined as how much the joint should be altered to reach the point B.

Consider joint zero going from A (-150º) to B (30º). The difference between A to B is 120º, with a 20º increment, the joint zero should be incremented in 6 steps. But it goes from minus to plus and I can’t just sum up 20º to the original position A.

Any available code or information how to achieve this would be very appreciated. I’m very thankful in advance,

 

André Castro.

2

The distance between A and B is 180º.

B - A = 30 - (-150) = 180

So some C# to calculate the interpolated values based on a resolution is thus:

public static List<double> InterpolateBetween(double start, double end, int steps)
{
    List<double> positions = new List<double>();
    double delta = end - start;
    double increment = delta / (double)steps;
    for (int i = 1; i <= steps; i++)
    {
        double position = start + ((double)i * increment);
        positions.Add(position);
    }

    return positions;
}

 

Which, passing in arguments of -150, 30 and 9, givens the list:

-130

-110

-90

-70

-50

-30

-10

10

30

3

Hey, @90jb12,

you’re right, my mistake :expressionless:

Thank you for the provided snippet, this should solve the issue. Yet I guess we should take the absolute value from delta, in case we have a start position positive and the end negative.

Eg.:

A= 150 and B=-30

B – A = -30 -150 = -180

double delta = Math.Abs(end - start);

Cheers!

André Castro.

 

4

Not entirely!

If that was the case, it would increment in the wrong direction. Allowing delta to be a negative, makes sure the increment calculation goes in the correct direction:

double position = start + ((double)i * increment);

If delta; and subsequently increment, are only allowed to be positive, this would happen:

170, 190, 210… etc

When increment is negative however, it goes: 130, 90, 70, 50… etc

 

Hope this helps!

5

Now I see it crearly. Thanks a lot, mate!