Mitsubishi Electric Research Laboratories, Inc.

Abraham Goldsmith

Stefano Di Cairano

Uros Kalabic

William Yerazunis

Scott Bortoff

Jay E Thornton

John C Barnwell, Iii

Vijay Shilpiekandula

William T Vetterling

Yebin Wang

Alan Sullivan

Ankush Chakrabarty

Yuri A Ivanov

Zhaojian Li

Tsz-Chun Michael Chiu

Anantaram Varatharajan

A cascaded controller for controlling a kinetic three-phase synchronous machine comprises a current control circuitry and an active power control circuitry operatively coupled with the current controller circuitry. The current control circuitry is configured to regulate a magnitude of inrush stator current for a stator of the kinetic three-phase synchronous machine by producing a first voltage control signal causing a flow of active power in the kinetic three-phase synchronous machine. The active power control circuitry is configured to produce a second voltage control signal to reduce the active power to zero, based on the first voltage control signal. The second voltage control signal controls a phase angle of the inrush stator current such that the stator current vector is oriented to align with a magnet axis of the rotor.

Systems and methods for reactive power injection based flying start of synchronous machines

A system for generating a G-code for controlling an operation of a laser-cutting machine to cut parts from a sheet of material, upon receiving cutting data specifying a cutting order of parts and a cutting order of edges of each part, tests the parts for potential distortions and generates a G-code to avoid the potential distortion. For testing a current part, the system detects a potential distortion when the final edge of the current part is adjacent to an edge of a previously cut part scheduled for cutting before the current part according to the cutting order of parts. The system modifies the cutting order to select the modified cutting order for which the final edge is not adjacent to any edge of any previously cut part.

System and method for detecting and correcting laser-cutting distortion

A method and a system for fault detection and removal in a distributed computing system, implemented as a permissioned blockchain network, is disclosed. The method fault detection comprising compiling and executing a smart contract common for all nodes of the permissioned blockchain network. The smart contract is configured to perform at least one operation from a series of operations comprising: (1) appending transactions including logs indicative of exchanging of messages between the nodes of permissioned blockchain network, (2) detecting malicious behavior of a node in reaching a consensus, and (3) revoking the access of the node upon detecting the malicious behavior. Further, once malicious behavior (and corresponding malicious node) is detected, a consensus is reached between the networked computers of the permissioned blockchain network, by executing a distributed computing program.

Blockchain-based accountable distributed computing system

A system for controlling an operation of a machine subject to state constraints in continuous state space of the machine and subject to control input constraints in continuous control input space of the machine is provided. The apparatus includes an input interface to accept data indicative of a state of the machine, a memory configured to store an optimization problem for computing the safety margin of a state and action pair satisfying the state constraints and a control policy mapping the state of the machine within a control invariant set (CIS) to a control input satisfying the control input constraints, and a processor configured to iteratively perform a reinforcement learning (RL) algorithm to jointly control the machine and update the control policy.

Constraint adaptor for reinforcement learning control

A control system for controlling an operation of a processing machine positioning a worktool according to a processing pattern to machine a workpiece. A memory to store a reference trajectory defined in a spatial domain by a sequence of points for positioning the worktool and defined in a time domain by a relative time for positioning the worktool on each point of the reference trajectory. A sensor to determine a state of the processing machine. A reference governor to iteratively process the reference trajectory over a receding horizon including multiple windows of points, and analytically update the relative time for positioning the worktool for some points of the reference trajectory within the receding horizon to satisfy constraints on the operation of the processing machine having the state. A controller to control the operation of the processing machine using control inputs causing the worktool to track the updated reference trajectory.

Receding horizon reference governor

A laser processing system includes redundant actuators positioning a laser spot on a workpiece. The system determines a first trajectory of the first actuator minimizing motion of the first actuator that positions the second actuator such that each point of the reference trajectory is within a range of the second actuator and determines a second trajectory of the second actuator based on a difference between the reference trajectory and the first trajectory. For each axis of control, the system determines an envelope centered on the reference trajectory with a width not greater than the range of the second actuator and determines shortest trajectory traversing the envelope along the time domain to produce the first trajectory. Hence, the first trajectory includes a set of straight segments satisfying the constraints defined by the shape of the envelope. The system includes controllers for control the motion of redundant actuators.

System and method for controlling redundant actuators with different dynamics

An operation of a processing machine with redundant actuators is controlled according to a reference trajectory by 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. The subset of points is selected 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 the last point of the subset after the period of time while satisfying constraints on motion of the redundant actuators. The constraints on motion are selected based on the mode of operation of the processing machine. The segment of the reference trajectory is modified in the time domain and the control inputs for controlling the motion of the redundant actuators are determined using the modified segment of the reference trajectory.

Operation aware control of processing machine with redundant actuators

A method for controlling a system using an explicit model predictive control (EMPC) evaluates, with respect to a state of the system, each inequality in a set of inequalities defining a set of regions of a state space of the system to produce a set of Boolean results. At least some of the inequalities are evaluated concurrently, and a size of the set of Boolean results equals a size of the set of inequalities. The method determines a region including the state by applying a Boolean function to elements of the set of Boolean results corresponding to inequalities forming boundaries of the region and determines a control for the system based on the state and a gain associated with the region. At least some Boolean functions are applied to corresponding elements concurrently after all elements in the set of Boolean results are evaluated.

System and method for explicit model predictive control

An operation of a processing machine with redundant actuators is controlled according to a reference trajectory by 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. The subset of points is selected 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 the last point of the subset after the period of time while satisfying constraints on motion of the redundant actuators. The segment of the reference trajectory is modified in the time domain and the control inputs for controlling the motion of the redundant actuators are determined using the modified segment of the reference trajectory.

Control of processing machines with redundant actuators

A method calibrates a laser processing machine by commanding a scan head to direct a laser beam to a desired position, then senses an actual position of the laser beam directly using a position sensitive detector (PSD) after the scan head is positioned. A relative position between the scan head and PSD is altered using one or more linear actuators. A position feedback loop is closed around the linear actuators so that the relative position of the laser beam on the PSD is reduced to zero. The actual position of the laser spot is then measured indirectly by encoders attached to linear axes of the laser processing machine. The actual position is stored in a memory. An error is determined as a difference between the desired position and the actual position. Compensation coefficients are determined from the error and stored for later use during operation of the laser processing machine.

System and method for calibrating laser processing machines

A system for calibrating a laser cutting machine includes a calibration plate arranged to simulate a workpiece; a first quad photodiode (QPD) and a second QPD for converting light including an image of a portion of a surface of the calibration plate into a plurality of electrical signals, wherein the first and the second QPDs are positioned to receive the light propagated from the surface of the calibration plate through the optical path of the laser beam; and a control system for calibrating the laser cutting machine based on the plurality electrical signals.

System and method for calibrating laser cutting machines

A laser cutting machine includes a platform and a motion system. The motion system includes a first prismatic joint facilitating a first motion of the platform along a first direction and a second prismatic joint facilitating a second motion of the platform along a second direction. A galvano arranged on the platform, such that a motion of the platform causes a motion of the galvano, the galvano including a first mirror, wherein a third motion of the first mirror positions the laser beam along a third direction, and a second mirror, wherein a fourth motion of the second mirror positions the laser beam along a fourth direction. A control module controls concurrently the motion system and the galvano, such that a position of the laser beam on the workpiece is a vector sum of the first motion, the second motion, the third motion, and the fourth motion.

Laser cutting machine

A network in an environment includes passive sensors with associated sensor identification numbers. A set of active badges with associated badge identification numbers, wherein each badge is associated with an object, and wherein a particular sensor broadcasts a packet in response to detecting a particular object, wherein the packet includes the sensor identification number and a time, and only if the particular object is associated with a particular badge then the badge appends the badge identification number to the packet and broadcasts the appended packet, and the particular sensor receives and rebroadcasts the appended packet for further processing to passively and actively monitor the environment.

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Boston, MA, United States of America

Abraham Goldsmith