Control of Processing Machines with Redundant Actuators

A control system for controlling an operation of a processing machine including redundant actuators for jointly positioning a worktool along each axis of motion, comprising processor for executing components of the control system, wherein the components comprises:

• a trajectory generator for determining a reference trajectory defined in a spatial domain by points for positioning the worktool according to a processing pattern and defined in a time domain by a relative time for positioning the worktool on each point of the reference trajectory;
• a reference governor for selecting, from a set of points forming a segment of the reference trajectory to be processed for a period of time, a subset of points corresponding to a fraction of the period of time and expanding units of time separating subsequent points in the subset to produce a modified segment of the reference trajectory having the subset of points processed for the period of time, wherein the subset of points is selected based on a state of the processing machine and locations of the points in the set such that the redundant actuators are capable to position the worktool at each point in the subset within the period of time and are capable to maintain the worktool at a point in the subset after the period of time while satisfying constraints on motion of the redundant actuators;
• and
• a controller for determining control inputs for the redundant actuators using the modified segment of the reference trajectory.

A processing machine, comprising:

• redundant actuators for jointly positioning a worktool along each axis of motion, the redundant actuators include a fast actuator and a slow actuator, wherein a range of motion of the slow actuator is greater than a range of motion of the fast actuator, and wherein acceleration and velocity constraints of the fast actuator are greater than acceleration and velocity constraints of the slow actuator;
• a trajectory generator for determining spatial and time domains of a reference trajectory for positioning the worktool according to a processing pattern only with motion of an actuator having acceleration and velocity constraints of the fast actuator and unlimited range of the motion;
• a reference governor for modifying sequentially segments of the reference trajectory, such that the slow actuator is capable to process the modified segment of the reference trajectory within a period of time and is capable to maintain a position of the worktool around a point in the modified segment of the reference trajectory within the range of motion of the fast actuator for any time after the period of time;
• a predictive controller for determining a motion profile of the slow actuator for processing the modified segment within the period of time with an accuracy defined by the range of motion of the fast actuator;
• and
• a filter for determining a motion profile of the fast actuator based on a difference between the modified reference trajectory and the motion profile for the slow actuator.