# US 9,751,153 B2 · Effort modulation for process control of friction stir operations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,153 B2 - Document ID: US9751153B2 - Status: Granted - Kind: B2 - Application number: 13/853,798 - Filed: 2013-03-29 - Published: 2014-07-24 - Granted: 2017-09-05 - Earliest claimed: 2012-03-30 - Assignees: Brigham Young University - Applicants: Brigham Young University - Inventors: Kenneth Alec Ross; Carl D. Sorensen - Web page: https://patentgrep.com/patent/US9751153B2 ## CPC - B23K 20/1235: {with temperature control during joining} - B23K 20/125: {Rotary tool drive mechanism} - G05B 19/188: {characterised by special applications and not provided for in the relevant subclasses, (e.g. making dies, filament winding)} - G05B 2219/49077: Control of feed and spindle, cutting speed - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract A system and method for making adjustments to output effort from a spindle driver using a multi-stage nested control loop of an active controller to provide constant power to a friction stir zone during a friction stir operation. Providing constant power facilitates temperature control within the friction stir zone and thereby improves the result of the operation such as a weld. ## Claims ### Claim 1 A method comprising: sensing a flow variable of a friction stir tool to a friction stir zone; and controlling, to a temperature setpoint and with an active controller, a temperature of the friction stir zone by adjusting a power provided by the friction stir tool to the friction stir zone, the controlling, to a power setpoint, the power provided by the friction stir tool to the friction stir zone being performed by controlling an output effort variable of a spindle driver that is used to drive the friction stir tool in response to the sensed flow variable feedback. ### Claim 2 (depends on 1) The method as defined in claim 1, wherein using the active controller to adjust power provided by the friction stir tool to a friction stir zone further comprises implementing a multi-stage nested control loop. ### Claim 3 (depends on 2) The method as defined in claim 2, wherein implementing the multi-stage nested control loop further comprises: 1) implementing an inner control loop to thereby maintain the power through sensing the flow variable of the friction stir tool and control of the output effort variable of the spindle driver; and 2) implementing an outer control loop that adjusts the power provided to thereby maintain the temperature for the friction stir zone. ### Claim 4 (depends on 3) The method as defined in claim 3, wherein controlling the output effort variable of the spindle driver further comprises controlling an input flow to the spindle driver. ### Claim 5 (depends on 3) The method as defined in claim 3, wherein controlling the output effort variable of the spindle driver further comprises controlling torque of the friction control tool. ### Claim 6 (depends on 3) The method as defined in claim 3, wherein controlling power provided by the friction stir tool to the friction stir zone comprises controlling the output effort variable of the spindle driver in response to changes in the flow variable of the friction stir tool, the flow variable comprising angular velocity of the friction stir tool. ### Claim 7 (depends on 1) The method as defined in claim 1, wherein controlling power provided by the friction stir tool to the friction stir zone comprises using spindle flow variable feedback, wherein power, the effort variable and the flow variable are related by the equation: P=e*f, wherein: P is power provided by the friction stir tool to the friction stir zone; e is the output effort variable of the spindle driver; and f is the flow variable of the friction stir tool. ### Claim 8 (depends on 7) The method as defined in claim 7, wherein maintaining the power through control of the output effort of the spindle driver further comprises increasing the output effort variable of the spindle driver in response to a decrease in the spindle flow variable. ### Claim 9 (depends on 7) The method as defined in claim 7, wherein maintaining the power through control of the output effort of the spindle driver further comprises decreasing the output effort variable of the spindle driver in response to an increase in the spindle flow variable. ### Claim 10 (depends on 3) The method of claim 3, wherein adjusting the power provided to thereby maintain the temperature for the friction stir zone comprises adjusting a reference power level to the inner control loop. ### Claim 11 A friction stir system comprised of: a friction stir tool; a spindle that is coupled to the friction stir tool; a spindle driver that is coupled to the spindle to thereby cause the friction stir tool to rotate; a sensor that senses a flow variable of the friction stir tool; an active controller for controlling operation of the friction stir tool, wherein the active controller controls a temperature, to a temperature setpoint, of a friction stir zone by adjusting a power provided by the friction stir tool to the friction stir zone, the active controller configured to control power, to a power setpoint, provided by the friction stir tool to the friction stir zone during friction stirring operations by controlling an output effort variable of the spindle driver that is used to drive the friction stir tool in response to the sensed flow variable feedback. ### Claim 12 (depends on 11) The system of claim 11 wherein using the active controller to adjust power provided by the friction stir tool to a friction stir zone further comprises implementing a multi-stage nested control loop. ### Claim 13 (depends on 12) The system of claim 12, wherein implementing the multi-stage nested control loop further comprises: 1) implementing an inner control loop to thereby maintain the power through sensing the flow variable of the friction stir tool and control of the output effort variable of the spindle driver; and 2) implementing an outer control loop that adjusts the power provided to thereby maintain the temperature for the friction stir zone. ### Claim 14 (depends on 13) The system of claim 13, wherein controlling the output effort variable of the spindle driver further comprises controlling an input flow to the spindle driver. ### Claim 15 (depends on 13) The system of claim 13, wherein controlling the output effort variable of the spindle driver further comprises controlling torque of the friction control tool. ### Claim 16 (depends on 13) The system of claim 13, wherein controlling power provided by the friction stir tool to the friction stir zone comprises controlling the output effort variable of the spindle driver in response to changes in the flow variable of the friction stir tool, the flow variable comprising angular velocity of the friction stir tool. ### Claim 17 (depends on 11) The system of claim 11, wherein controlling power provided by the friction stir tool to the friction stir zone comprises using spindle flow variable feedback, wherein power, the effort variable and the flow variable are related by the equation: P=e*f, wherein: P is power provided by the friction stir tool to the friction stir zone; e is the output effort variable of the spindle driver; and f is the flow variable of the friction stir tool. ### Claim 18 An active controller controlling operation of a friction stir tool to a friction stir zone, the active controller comprising: an inner control loop that controls power, to a power setpoint, provided by the friction stir tool to the friction stir zone by using sensed angular velocity of the friction stir tool to control torque of a spindle driver of the friction control tool, wherein power, the torque and the angular velocity are related by the equation: P=co*M, wherein: P is power provided by the friction stir tool to the friction control zone; M is the torque of the spindle driver; and co is the angular velocity of the friction stir tool; and an outer control loop that maintain a desired temperature, to a temperature setpoint, for the friction stir zone by using a sensed temperature to adjust the power provided by the friction stir tool to the friction stir zone.