regulation or control system set 1 210 can consist of a single sensor or multiple sensors providing a matrix of input values for further processing by the controller 200 moreover set 1 210 can be a device within the tool itself or represent input or signals derived from another source e g different tool previous logs for a wellbore shape measurement for example set 1 210 could be selected from any of the following types of sensors without departing from the spirit or intent of this disclosure a caliper measurement including multi armed caliper tools sonic tools ultrasonic tools or electromagnetic tools the data or signals detected schematically by set 1 210 are described as measurement 1 218 information given by set 1 210 typically this measurement is borehole shape including multi axis diameters but can be other measured physical characteristics as well this system also provides the ability to compare the data from actual measurement 218 with nominal values 214 inputted by the user of the system such as expected measurement or average of previous measurements these nominal conditions can be selected to describe correct tool operation or physical limits necessary for the tool operation the combination of these two signals or data streams in adding point 212 results in variation u03b5 1 224 constituting the difference between measurement 1 218 and nominal values 214 this value can be functionally proportional to wellbore diameter variation for example and without limitation accordingly variation u03b5 1 224 can represent borehole washouts formation collapse or unconsolidated wellbore wall casing tubing entry drilling diameter change diameter.