A method for determining lubricant consumption by a transmission mechanism, to be implemented by a sensing system which includes a computing device, the transmission mechanism being disposed on a machine tool, being provided with an amount of lubricant, and operating at an operational speed, the transmission mechanism including a ball screw which includes a screw rod and a screw nut, the screw rod formed with a screw groove on a surface of the screw rod, the operational speed being a rotational speed of the ball screw, the method comprising steps of:
- a) estimating, by the computing device, a total operational physical quantity based on the operational speed and a predetermined first predictive model which corresponds to the amount of lubricant and which represents a correspondence relationship between the operational speed and the total operational physical quantity, the total operational physical quantity resulting from operation of the transmission mechanism at the operational speed while consuming the amount of lubricant and being a sum of individual operational physical quantities each of which results from one occurrence of action performed by the transmission mechanism;
- b) estimating, by the computing device based on the total operational physical quantity estimated in step a) and one of the individual operational physical quantities, a total operational count representing a total number of occurrences of the action that the transmission mechanism is estimated to perform during operation of the transmission mechanism at the operational speed to consume the amount of lubricant;
- c) by the computing device, receiving from the machine tool, actuation information associated with actuation of the transmission mechanism to operate within a time period, and calculating based on the actuation information, a partial operational count representing a number of occurrences of the action that the transmission mechanism has performed within the time period;
- and
- d) calculating, by the computing device based on the partial operational count and the total operational count estimated in step b), a ratio between an amount of lubricant consumption within the time period and the amount of lubricant,
- wherein in step a), the total operation physical quantity is one of an aggregate surface area of the screw groove that is an aggregation of surface areas of the screw groove covered by passages of the screw nut on the screw rod for the operation of the transmission mechanism operating at the operation speed to consume the amount of lubricant, an aggregate length of the screw groove that is an aggregation of lengths of routes traveled by the screw nut along the screw groove for the operation of the transmission mechanism operating at the operation speed to consume the amount of lubricant, and an aggregate translational distance that is an aggregation of straight line distances, each between a start and an end of a corresponding one of the passages of the screw nut on the screw rod for a corresponding one of the occurrences of action, for the operation of the transmission mechanism operating at the operation speed to consume the amount of lubricant,
- wherein the total operational count thus estimated is equal to the total operational physical quantity thus estimated divided by a single one of the individual operational physical quantities.