Scalable motion control system
A control system includes a clustered architecture having a master controller, a central control section including one or more first remote controllers under direct control of the master controller, and a distributed control section including a cluster controller controlled by the master controller. The cluster controller controls the activities of one or more second remote controllers. Each of the first and second remote controllers are utilized to drive one or more axes.
1. A method of operating an axis of a control system comprising:
generating a trajectory for the axis in terms of a position, velocity, and acceleration for each point of a plurality of points on the trajectory;
calculating an inverse dynamic model accounting at least for dynamic cross-coupling of the axis to determine a gain value and a feedforward term for each point; and
grouping the position, velocity, acceleration, gain value, and feedforward term for each point into a communication frame.
2. The method of claim 1 , comprising interpolating between two consecutive frames to obtain an instantaneous position, instantaneous velocity, instantaneous feedforward term and instantaneous gain value utilized to control the axis.
3. A method of obtaining axis data, at a time of an event, for the method of operating an axis as in claim 1 , comprising:
buffering data at one or more axis nodes;
recording time information of a triggering event occurring at a triggering event node of the one or more axis nodes where the triggering event corresponds to a payload carried by an arm controlled by the one or more axis nodes;
sending the recorded time information to at least one predetermined axis node, of the one or more axis nodes, pre-determined for the triggering event; and
processing the buffered data from the at least one pre-determined axis node to determine a set of values at a time period indicated by the recorded time information.
4. The method of claim 3 , comprising sending the recorded time information to the one or more axis nodes.
5. The method of claim 4 , comprising processing the buffered data at the one or more axis nodes.
6. The method of claim 5 , further comprising sending the set of values to a node controller operating to control the one or more axis nodes.
7. The method of claim 3 , comprising sending the recorded time information to a node controller operating to control the one or more axis nodes.
8. The method of claim 7 , comprising sending the buffered data to the node controller and processing the buffered data at the node controller.
9. The method of claim 3 , comprising sending the recorded time information to the one or more axis nodes from the triggering event node.
10. The method of claim 4 , wherein sending the recorded time information to the one or more axis nodes comprises sending the recorded time information to a node controller operating to control the one or more axis nodes and then to the one or more axis nodes from the node controller.
11. The method of claim 3 , further comprising sending the set of values to a node controller operating to control the one or more axis nodes.
12. The method of claim 1 , further comprising:
calculating an operating parameter value defining a force value of an end effector of an axis in a first mode of axis operation that is different than a corresponding force value of the end effector in a second mode of axis operation;
generating a motion profile for an individual joint of the axis such that a motion profile for the end effector does not exceed the force value of the end effector in the first mode of axis operation.
13. The method of claim 12 , wherein the operating parameter value is a maximum velocity.
14. The method of claim 12 , wherein the operating parameter value is a maximum torque.
15. The method of claim 1 , further comprising:
calculating, with a controller, a velocity and a torque for a position of the axis;
calculating, with the controller, a predetermined first maximum time period during which an axis velocity may exceed the calculated velocity;
calculating, with the controller, a predetermined second maximum time period during which an axis torque may exceed the calculated torque;
disabling, with the controller, the axis if one or more of the first and second maximum time period is exceeded.
16. The method of claim 15 , comprising disabling the axis if the calculated velocity exceeds a predetermined maximum velocity.
17. The method of claim 16 , comprising disabling the axis if the calculated torque exceeds a predetermined maximum torque.
18. The method of claim 15 , comprising disabling the axis upon failure to receive a periodic communication from the axis.
19. The method of claim 15 , comprising disabling the axis upon failure to receive a periodic communication from an axis controller.
20. The method of claim 1 further comprising bringing the axis to a controlled stop comprising:
determining if power has been lost to a system including the axis;
setting a predetermined time period applying a mode of operation of the axis and applying a trajectory to the axis that brings the axis to a zero velocity within the predetermined time period where motion of the axis along the trajectory is coordinated with motion of another axis; and
removing power fro e axis at an end of the predetermined time period.
21. The method of claim 20 wherein the predetermined time period is determined by calculating a time remaining before power is lost to the axis.