System and method for controlling movers in an independent cart system during heavy traffic

A method for controlling movers in a linear drive system, wherein the linear drive system includes a track and a plurality of movers operative to travel along the track, the method comprising the steps of:

• driving a first mover along the track with a controller responsive to a first motion command wherein the first motion command includes a desired location;
• detecting heavy traffic along the track with the controller as the first mover is travelling along the track, wherein the heavy traffic is detected when the first motion command is interrupted and the mover is commanded to stop at a position other than the desired location;
• responsive to detecting the heavy traffic:
• generating a second motion command for the first mover to resume travel to the desired location;
• and
• driving the first mover responsive to the second motion command.

A system for controlling movers in a linear drive system, comprising:

• a track, wherein the track is divided into a plurality of blocks;
• at least a first mover and a second mover operative to travel along the track;
• a position feedback system configured to generate a first position feedback signal, corresponding to a present location of the first mover, and a second position feedback signal, corresponding to a present location of the second mover;
• and
• a controller operative to:
• control operation of the first mover responsive to a first motion command, wherein the first motion command defines a desired position for the first mover upon completion of the first motion command;
• sequentially assign at least one first block to the first mover between the present location and the desired position of the first mover responsive to the first motion command, each first block selected from the plurality of blocks;
• identify at least one second block assigned to the second mover or reserved for movement between the first mover and the second mover, each second block selected from the plurality of blocks;
• when the at least one first block to be assigned to the first mover is the same as the at least one second block, interrupt the first motion command and command the mover to stop at a position other than the desired position;
• detect the heavy traffic when the first motion command is interrupted;
• and
• control operation of the first mover responsive to a second motion command to resume travel to the desired position after detecting the heavy traffic.