| CPC G05B 19/0428 (2013.01) [B25J 5/007 (2013.01); B25J 9/12 (2013.01)] | 19 Claims |
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1. A system, comprising:
a mobile drive unit comprising a motorized wheel to propel the mobile drive unit, first and second sensors, and a motor having a rotor and a magnet, the motor coupled to the motorized wheel to control movements of the mobile drive unit around a warehouse environment comprising inventory holders, and the first and second sensors attached to the motor and configured to measure data associated with the magnet, the first and second sensors being homogeneous non-safety rated sensors;
a programmable logic device in communication with the first and second sensors and comprising first and second modules, each of the first and second modules configured to:
receive, from the first and second sensors, first and second data associated with the motor;
process the first and second data, the processing of the first and second data comprising determining a first set of characteristics associated with the motor; and
generate a fault status comprising the first set of characteristics,
wherein the programmable logic device is configured to compare first and second fault statuses from the respective first and second modules and generate a fault message based on the compared first and second fault statuses;
a safety controller comprising first and second processors, each of the first and second processors in communication with the programmable logic device and configured to:
receive, from the programmable logic device, the fault message and the first and second data associated with the motor;
process the first and second data, the processing of the first and second data comprising determining a second set of characteristics associated with the motor;
generate an output based on the second set of characteristics,
wherein the safety controller is configured to compare first and second outputs from the respective first and second processors and generate operating instructions based on the compared first and second outputs and the fault message, the operating instructions comprising data associated with the operation of the motor to control movements via the wheel of the mobile drive unit within the warehouse environment; and
a motor safety actuation controller configured to:
receive the operating instructions from the safety controller and navigating instructions from a non-safety subsystem;
prioritize the operating instructions from the safety controller that are based on the compared first and second outputs of the safety controller and the fault message from the programmable logic device; and
actuate, based on the prioritizing, the motor to safely guide the mobile drive unit while lifting an inventory holder and/or around the inventory holders within the warehouse environment.
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