Control device and method for setting upper and lower limit curves for one or more tools arranged to apply fasteners

A system comprising:

• one or more tools arranged to apply fasteners in a production process;
• and
• a control device configured to, in a production configuration process:
• obtain a set of trace data for a plurality of test fastening application operations performed by at least one of said one or more tools on one type of joint, the trace data including, for each fastener application operation, values indicative of application force versus values indicative of displacement or time or a derivative thereof;
• from said set of trace data, derive maximum values (Tmax) indicative of application force, or the derivative thereof, for each one of a plurality of the values (α) indicative of displacement or time, and calculate a first polynomial based on these maximum values;
• from said set of trace data, derive minimum values (Tmin) indicative of application force, or the derivative thereof, for each one of a plurality of the values (α) indicative of displacement or time, and calculate a second polynomial based on these minimum values;
• based on said first polynomial, set an upper limit curve;
• and
• based on said second polynomial, set a lower limit curve;
• in the production process following said production configuration process:
• determine that a fastener application operation performed by any one of said one or more tools is not okay (NOK) if at least some of its trace data exceeds the upper limit curve and/or falls below the lower limit curve.

A method for a control device for one or more tools arranged to apply fasteners in a production process, the method comprising,

• in a production configuration process:
• obtaining a set of trace data for a plurality of test fastening application operations performed by at least one of said one or more tools on one type of joint, the trace data including, for each fastener application operation, values indicative of application force versus values indicative of displacement or time or a derivative thereof;
• from said set of trace data, deriving maximum values indicative of application force, or the derivative thereof, for each one of a plurality of the values indicative of displacement or time, and calculating a first polynomial based on these maximum values;
• from said set of trace data, deriving minimum values indicative of application force, or the derivative thereof, for each one of a plurality of the values indicative of displacement or time, and calculating a second polynomial based on these minimum values;
• based on said first polynomial, setting an upper limit curve;
• and
• based on said second polynomial, setting a lower limit curve;
• in the production process following said production configuration process:
• determining that a fastener application operation performed by any one of said one or more tools is not okay (NOK) if at least some of its trace data exceeds the upper limit curve and/or falls below the lower limit curve.

A computer program product for a control device for one or more tools arranged to apply fasteners in a production process, wherein said computer program product comprising computer instructions to cause the control device to perform the following operations:

• in a production configuration process:
• obtaining a set of trace data for a plurality of test fastening application operations performed by at least one of said one or more tools on one type of joint, the trace data including, for each fastener application operation, values indicative of application force versus values indicative of displacement or time or a derivative thereof;
• from said set of trace data, deriving maximum values indicative of application force, or the derivative thereof, for each one of a plurality of the values indicative of displacement or time, and calculating a first polynomial based on these maximum values;
• from said set of trace data, deriving minimum values indicative of application force, or the derivative thereof, for each one of a plurality of the values indicative of displacement or time, and calculating a second polynomial based on these minimum values;
• based on said first polynomial, setting an upper limit curve;
• and
• based on said second polynomial, setting a lower limit curve;
• and
• in the production process following said production configuration process:
• determining that a fastener application operation performed by any one of said one or more tools is not okay (NOK) if at least some of its trace data exceeds the upper limit curve and/or falls below the lower limit curve.