Apples

 The Nature's Bounty challenge has apples, and what the apples should look like and how we get them off the 'tree' is of interest. 

I've posted a picture of the apple picker idea, but it is just an outline.

This bit is about that jaw on the picker and how it might work with different apple shapes.

Some thoughts on apples, spherical or otherwise, The pictures show two designs of apples for the PiWars 2022 Nature’s Bounty challenge, one spherical and one made up of intersecting circles, together with some apple picker ideas. The apples have a maximum diameter of 40mm, the minimum gap between apple and trunk for the topmost apple is 10mm.

 

A.     This is a spherical apple with plain grippers. The grippers hold the apple at only one position each forming an axle about which the apple can rotate. The grippers have to apply sufficient force to ensure that enough friction is generated at the touch pints to grip the apple. The apple can be held by any point on the gripper, reducing the need for accuracy.

B.     This is a spherical apple with parallel bar grippers. The apple is held at four points and cannot rotate. The force required to hold the apple is much less than A as there is some support for the apple provided by the lower gripper arm, but significant accuracy is required to position the gripper. The gripper requires less space to operate than plain grippers.

C.     This is a spherical apple with a finger gripper. The apple is held at 8 points and cannot rotate. The force required to hold the apple is much less than A as there is some support for the apple provided by the lower gripper arms. The apple can be gripped at multiple points reducing the need for accuracy.

D.    This is a spherical apple with a modified gripper. The apple is held over a continuous area and cannot rotate. Significant accuracy is required to position this gripper and the size of the gripper may be too large to be able to grip the top apple on the tree due to the gap between apple and tree trunk.

E.      This is an apple made of intersecting circles with plain grippers. The grippers hold the apple at only one position each forming an axle about which the apple can rotate. The grippers have to apply sufficient force to ensure that enough friction is generated at the touch points to grip the apple. The apple can be held by any point on the gripper, reducing the need for accuracy. The apple is lighter than the spherical apple so the gripper requires less force.

F.       This is an apple made up of intersecting circles and parallel bar gripper. The apple is held at four points and cannot rotate. The force required to hold the apple is much less as there is some support for the apple provided by the lower gripper arm, but significant accuracy is required to position the gripper. The gripper requires less space to operate than plain grippers.

G.     This is an apple made up of intersecting circles and finger gripper. The apple is held at 8 points and cannot rotate. The force required to hold the apple is much less as there is some support for the apple provided by the lower gripper arms, but significant accuracy is not required to position the grippe, as with F.

H.    This is an apple made up of intersecting circles and a plain gripper. The gripper can apply a force over a wide area, provided it is positioned with a small amount of accuracy, and while the apple can rotate, this may be limited by the position of the gripper. There is some increase in torque on the gripper due to holding the apple away from the centre of gravity.

I.          This is an apple made up of intersecting circles with plain grippers, but the apple is rotated 45 degrees. The apple is held at 4 points and cannot rotate. The apple can be held at any point on the gripper vertically, but the gripper must extend beyond the far edge of the apple.

J.       This is an apple made up of intersecting circles and a parallel bar gripper, the apple is rotated 45 degrees. The apple is held at 8 points and cannot rotate. Significant accuracy is required to ensure that the gripper locates both vertically and horizontally. The gripper requires less space to operate than plain grippers.

K.    This is an apple made up of intersecting circles and a finger gripper, the apple is rotated 45 degrees. The apple is held at 16 points and cannot rotate. Significant accuracy is not required as with J.

L.       This is an apple made up of intersecting circles and a modified gripper, the apple is rotated 45 degrees. The apple is held over a continuous area and cannot rotate. There is a degree of self-alignment in the gripper but does require some basic accuracy. The gripper may be too large to be used with the topmost apple, as with gripper C.