Motion control of a motion device

A trajectory generator for generating a trajectory to control the movement of a motion device, the trajectory generator comprising:

• i) a memory;
• and
• ii) a processor configured to execute computer-executable instructions stored on the memory, the processor configured to generate, in receipt of a commanded position, a motion control profile by:
• i) receiving a specification of the trajectory, the specification including a commanded position;
• ii) receiving at least one jerk constraint;
• and
• iii) generating a sequence of one or more trajectory segments based on the at least one jerk constraint, each of the one or more trajectory segments being a respective portion of the trajectory prescribing at least one of a jerk reference, an acceleration reference, a velocity reference and a position reference as a function of time;
• wherein the one or more trajectory segments of the sequence of trajectory segments is generated by applying a velocity transition algorithm including moving a magnitude of the velocity reference of the one or more trajectory segments in a given time to a desired final velocity reference, a difference between the desired final velocity reference and the velocity reference defining a velocity delta;
• wherein the velocity transition algorithm includes computing a peak acceleration having a magnitude being a function of the velocity delta;
• and
• wherein the at least one jerk constraint defines a plurality of constraints for generating a sequence of one or more trajectory segments, the plurality of constraints including:
• an acceleration constraint, and the generating the one or more trajectory segments is based on whether:
• i) a magnitude of the acceleration reference of the trajectory is substantially equal to a computed peak acceleration, and/or
• ii) the computed peak acceleration is smaller than or substantially equal to the acceleration constraint, and/or
• iii) the computed peak acceleration exceeds the acceleration constraint.

A load handling device comprising:

• a wheel assembly including a first and a second pair of wheels;
• a drive mechanism for driving the wheel assembly;
• and
• a controller connected to a drive mechanism and being configured to drive the wheel assembly according to the motion control profile generated by:
• i) receiving a specification of the trajectory, the specification including a commanded position;
• ii) receiving at least one jerk constraint;
• and
• iii) generating a sequence of one or more trajectory segments based on the at least one jerk constraint, each of the one or more trajectory segments being a respective portion of the trajectory prescribing at least one of a jerk reference, an acceleration reference, a velocity reference and a position reference as a function of time;
• wherein the one or more trajectory segments of the sequence of trajectory segments is generated by applying a velocity transition algorithm including moving a magnitude of the velocity reference of the one or more trajectory segments in a given time to a desired final velocity reference, a difference between the desired final velocity reference and the velocity reference defining a velocity delta;
• wherein the velocity transition algorithm includes computing a peak acceleration having a magnitude being a function of the velocity delta;
• and
• wherein the at least one jerk constraint defines a plurality of constraints for generating a sequence of one or more trajectory segments, the plurality of constraints including:
• an acceleration constraint, and the generating the one or more trajectory segments is based on whether:
• i) a magnitude of the acceleration reference of the trajectory is substantially equal to a computed peak acceleration, and/or
• ii) the computed peak acceleration is smaller than or substantially equal to the acceleration constraint, and/or
• iii) the computed peak acceleration exceeds the acceleration constraint.

A non-transitory computer medium having stored thereon computer-executable instructions that, in response to execution, cause a computer system to perform the operations of:

• i) receiving a specification of the trajectory, the specification including a commanded position;
• ii) receiving at least one jerk constraint;
• and
• iii) generating a sequence of one or more trajectory segments based on the at least one jerk constraint, each of the one or more trajectory segments being a respective portion of the trajectory prescribing at least one of a jerk reference, an acceleration reference, a velocity reference and a position reference as a function of time;
• wherein the one or more trajectory segments of the sequence of trajectory segments is generated by applying a velocity transition algorithm including moving a magnitude of the velocity reference of the one or more trajectory segments in a given time to a desired final velocity reference, a difference between the desired final velocity reference and the velocity reference defining a velocity delta;
• wherein the velocity transition algorithm includes computing a peak acceleration having a magnitude being a function of the velocity delta;
• and
• wherein the at least one jerk constraint defines a plurality of constraints for generating a sequence of one or more trajectory segments, the plurality of constraints including:
• an acceleration constraint, and the generating the one or more trajectory segments is based on whether:
• i) a magnitude of the acceleration reference of the trajectory is substantially equal to a computed peak acceleration, and/or
• ii) the computed peak acceleration is smaller than or substantially equal to the acceleration constraint, and/or
• iii) the computed peak acceleration exceeds the acceleration constraint.