General Information

A fundamental part of interpolated motion control is blending of (buffered) consecutive motion commands on an axes group. Without blending the TCP of an axes group moves towards the commanded position, decelerates and comes to standstill exactly at the commanded position. The following buffered motion command doesn’t become active until now. Obviously the axes group has to accelerate again. In many applications a different behaviour of the TCP is desired and one wants to concatenate movements without stopping.

Reasons for this are:

• Reduction of the process cycle time (e.g. pick and place)
• Generate a smoother movement in order to reduce the mechanical stress
• Some applications demand a constant Velocity of the TCP (e.g. applying glue, painting, welding, etc.)

All this can be achieved by different types of blending. Common to all types of blending is a modification of the origi-nal path, resulting in a smooth trajectory without corners.

Blending of motion commands in interpolated motion control differs from blending of motion commands on single axes. With single axes the commanded position is always reached. Just the velocity at the time when the commanded position is reached (or passed) can be changed according to the input parameter BufferMode.

With interpolated motion control several types of blending can be thought of, depending on the application and proc-ess. Therefore new types of blending have to be introduced for interpolated motion control.

The input parameter for blending might vary due to the kind of interpolation method applied. So this input is ABB specific.

The type of inserted curve that modifies the original path (the ‘contour curve’) is not part of this specification and can be defined by the ABB specific input parameter for blending.

Trajectories and process of Velocity in principle of two consecutive motion commands in three modes