Implementation of Real-Time Machining Process Control Based on Fuzzy Logic in a New STEP-NC Compatible System

Abstract

Implementing real-time machining process control at shop floor has great significance on raising the efficiency and quality of product manufacturing. A framework and implementation methods of real-time machining process control based on STEP-NC are presented in this paper. Data model compatible with ISO 14649 standard is built to transfer high-level real-time machining process control information between CAPP systems and CNC systems, in which EXPRESS language is used to define new STEP-NC entities. Methods for implementing real-time machining process control at shop floor are studied and realized on an open STEP-NC controller, which is developed using object-oriented, multithread, and shared memory technologies conjunctively. Cutting force at specific direction of machining feature in side mill is chosen to be controlled object, and a fuzzy control algorithm with self-adjusting factor is designed and embedded in the software CNC kernel of STEP-NC controller. Experiments are carried out to verify the proposed framework, STEP-NC data model, and implementation methods for real-time machining process control. The results of experiments prove that real-time machining process control tasks can be interpreted and executed correctly by the STEP-NC controller at shop floor, in which actual cutting force is kept around ideal value, whether axial cutting depth changes suddenly or continuously.

STEP-NC-Compliant Implementation to Support Mixed-Control Technologies Applied to Stone-Processing Machines Based on Industrial Automation Standards

“…In this case, the post-processing carried out by the implementer is restricted to converting the machining specification to a called sequence of those blocks [47,48]. The second case (Figure 4, route C), which allows more continual intervention, employs FIFO axes technology, a motion control functionality for feeding the NC with external position or velocity values cyclically in a first-in, first-out order [15,49]. On routes A and B in Figure 4, it is still the controller that is in charge of interpolation between specific points.…”

Simulative investigation of hybrid force and position control for electromechanical feed axes in production machines

“…Tsai et al 8 proposed a fuzzy adaptive control strategy to the problem of cutting force control in high‐speed milling operations. A dynamic threshold‐based fuzzy adaptive control algorithm for hard‐sphere grinding processes was introduced by Li et al 9 Hu et al 10 presented an adaptive control algorithm based on fuzzy logic and embedded the controller in the software computerized numerical control (CNC) kernel to improve the real‐time performance of machining process control. The combination of artificial techniques with adaptive force control in milling operations was discussed by Zuperl et al 11 The feed rate is adjusted on‐line with a feed‐forward neural control scheme to maintain a constant cutting force despite the variations in cutting conditions.…”