Demo for robot arm

This is a demo of a robot arm for use in an Industry 4.0 talk.

Explanation

The aim is to show how a robot arm can be animated using two shafts and a gripper. This will then be extended to support a production line for filling a jar, screwing on a cap and packing it into a container.

The robot arm is composed from a static base with a joint for a shaft with a further joint for a shorter shaft with the gripper at the end that opens and closes. I draw these in reverse order, for the given joint angles and gripper setting.

I next need to figure out what the two joint angles should be to place the gripper at a desired position. Joint2 will be on a circular path around the gripper position. I can then draw a circle around Joint1 and find the intersection. There will usually be two such points, and I should select the one that involves the smallest motion for Joint1. I can then animate both joints to move from the current to desired position. This should involve speeding up and slowing down with a maximum speed for each joint.

Dave Raggett <dsr@w3.org>