CNC system dial handwheel signal processing method

Abstract: The working principle dial hand wheel, dial hand wheel for which the existence of problems in the application of numerical control system, designed a structured dial handwheel phase circuit and the filter circuit,
Effectively eliminates signal interference dial hand wheel, hand wheel dial pulse signal properly recorded, and achieved good results in practice.
Keywords: hand wheel, phase, to shake, CNC system, dial hand wheel, hand wheel helm, steering wheel, steering hand wheel, steering gear steering wheel

Introduction In the numerical control system, the tool fretting piece of the knife, the follower table, machine tool origin correction, etc. These functions are usually achieved through handwheel operation of this function to the machine operator to bring a lot of convenience, so that the hand wheel on the NC machine is widely used. But when the handwheel slightly wavering, prone to shake, causing the output pulse allowed, leading to machine malfunctions, ranging from causing workpiece scrapped, while endangering the personal safety of the operator, so the machining process, precision and reliability is particularly important. Author in the actual application of numerical control systems, summary test a method of structured dial handwheel signal processing.
1 hand wheel works hand wheel, also known as the manual pulse generator, which is essentially an incremental encoder is a photoelectric position control element. Figure 1 shows the operating principle of the handwheel, the case, the grating disc and the axis of rotation at the same speed in the hand wheel rotation, after detecting device composed by the light emitting element, which is turned into a position angle size and direction contain pulse sequence information, under program control can drive CNC machine tool axis. Each rotation of the hand wheel 90b, a difference of scale obtained with a set of phase A, B signal, dial handwheel signals. Forward rotation, A-phase leads Phase B 90b, when inverted, B phase leads A phase 90b.
2 handwheel handwheel signal processing output signal processing circuit has discrete components, are many ways of ASIC, microcontroller, programmable logic devices. But for the purposes of multi-axis CNC system, the use of discrete components to perform a sequence encoder signals including hand signals, including wheel, you will need more components, resulting in complex structure, increasing power consumption, decreased stability and other shortcomings. Now often used complex programmable logic device CPLD to implement the handwheel signal discriminator phase filter function. Dial hand wheel hand wheel signal given the signal processing circuit diagram, which consists of a phase, to shake circuit, delay circuit, 16 reversible counter constituting the output buffer and a data bus. The following be described for the function of each part of the circuit.
2.11 phase phase circuit circuit principle role is to get the direction of rotation of the handwheel, produce the counter direction signal. Works seen by a hand wheel, in each signal cycle, A and B signals pulse signal pulse difference 90b.
2.12 handwheel signal phase, Debouncers designed to eliminate interference due to various factors which led to clutter the output pulse with a hand wheel to ensure the reliability and validity of the output signal, the counter must be carried out before deglitched. Generally use two methods to improve the ability to filter out the clutter: First, when using a Schmitt trigger input pole, by a Schmitt trigger waveform shaping ability to filter out clutter; second is to use a multi-stage delay methods to accomplish filtering. Similarly, the phase can also be used common methods: D flip-flops and gate circuits. These methods are relatively simple to implement, but the anti-interference ability. Based dial handwheel signal above analysis, in order to better achieve the handwheel signal phase discriminator filter work, we use a state machine plus sign discriminating approach. Through trial and error in the actual work, and that the use of this approach to achieve the handwheel phase, to shake the work, is better than the conventional method. Dial handwheel signals from the apparent: rotating a scale, the ideal situation is A, B signal combining a total of four states, when the forward, state BA is: 00y 01y 11y 10; When reversing, BA status: 00y 10y11y 01. In order to facilitate the description, so that S1 = 00, S2 = 01, S4 = 11, S3 = 10, the handwheel dial hand wheel signal given state transition diagram, dial handwheel signals FP and FN as a forward and reverse correspondence flag state, after completing a previous state to the next transition, the corresponding bit. If the dial hand wheel forward signal state transition diagram or reverse four consecutive complete state, there are a pulse output, namely Q = 1, and predetermined positive direction of rotation, the direction signal D = 1, then the anti-D = 0. The following items are hand wheel will be divided signal state transition diagram and use CPLD realization to illustrate the dial handwheel signal design process.
The current state is S1 when:
(1) If the previous state of S1, set forward flag FP = 0001, FN = 0001, then Q = 0;
(2) If the previous state of S3, and FP = 1111, then Q = 1, D = 1, the hand wheel forward one notch;
(3) If the previous state of S2, and FN = 1111, then Q = 1, D = 0, the handwheel reverse a scale;
(4) If the previous state is S4, this state is inactive, the reset FP = 0001, FN = 0001, Q = 0, the handwheel interference signal over, not counting.
The current state is S2 when:
(1) If the previous state is S4, and FN = 0111, then set FN = 1111, FP is cleared, the handwheel signal to convert from S4 state to state S2, belonging to a cycle of intermediate process, the hand wheel scale has not occurred change, Q = 0;
(2) If the previous state of S1, and FP = 0001, then set FP = 0011, FN is cleared, the handwheel signal to convert from S1 to S2 state status, the results above;
(3) If the previous state of S3, this state is inactive, the reset FP = 0001, FN = 0001, Q = 0, the handwheel interference signal over, not counting.
When the current state is S4:
(1) If the previous state of S3, and FN = 0011, then set FN = 0111, FP is cleared, the handwheel signal to convert from state S3 to S4 state, belonging to a cycle of intermediate process, the hand wheel scale has not occurred change, Q = 0;
(2) If the previous state of S2, and FP = 0011, then set FP = 0111, FN is cleared, the handwheel signal S2 to complete the transition from state to state S4, belonging to a cycle of intermediate process, the hand wheel scale has not occurred change, Q = 0;
(3) If the previous state of S1, this state is inactive, the reset FP = 0001, FN = 0001, Q = 0, the handwheel interference signal over, not counting.
When the current state is S3:
(1) If the previous state of S1, and FN = 0001, then set FN = 0011, FP is cleared, the handwheel signal to convert from S1 to S3 state status, belonging to a cycle of intermediate process, the hand wheel scale has not occurred change, Q = 0;
(2) If the previous state is S4, and FP = 0111, then set FP = 1111, FN is cleared, the handwheel signal to convert from S3 S4 state to state, are in the middle of a period, the handwheel scale has not occurred change, Q = 0;
(3) If the previous state of S2, this state is inactive, the reset FP = 0001, FN = 0001, Q = 0, the handwheel interference signal over, not counting.
2.13 dial handwheel signal delay circuit known works by the up-down counter, before the counting, first determine the direction in which you can use the D flip-flop so that the hand wheel pulse signal direction retardation than one clock cycle.
Conclusions This paper proposed and implemented Diamond Blunt state recognition based on wavelet packet analysis and SVM, the dial handwheel signal results showed that:
Acoustic emission signals (1) Dresser process of passivation of diamond pen is sensitive, can be used to determine the passive state diamond pen, and adjust or replace the diamond pen.
(2) Identification of Diamond Dresser Blunt, Dresser acoustic emission signals when concentrated in the high frequency part, three layers wavelet packet decomposition extract the energy of each frequency band, can effectively eliminate noise, feature quantity reflects Wheel Dull .
(3) the use of RBF kernel of SVM passivated identification at dial handwheel sample signal is not the case still get a good recognition results than BP network has a higher recognition rate. In summary, the wavelet packet decomposition and SVM based method for Diamond Blunt have better results than traditional methods, this method has some application in the field of mechanical fault diagnosis. Thus, the volume of glazing robot workspace is V = P360 (R2m ax - R2m in) (H1m ax - H1m in) (bmax - bm in)
Summary for the glazing process and dial handwheel signal process requirements typical sanitary ceramic products, determined glazing robot design principles, the following conclusions:
(1) the robot may glazing of five degrees of freedom articulated robot;
(2) According to the typical ceramic sanitary products (ie the size of the one-piece toilet are selected corresponding limit), dial handwheel signals can determine the structure of the size of various parts of the robot glazing;
When the structure size (3) the actual design of glazing robot operation margin should also consider the robot;
Work space (4) it is a closed figure robot glazing area from four arcs, and then multiplied by the distance moved along the y-axis.
Role 2.14 16 reversible counter 16 reversible counter is to record the positive and negative direction of displacement of the handwheel pulses; the direction of the signal phase after as the forward and reverse count determination to go through the filter, clean signal delay after counting pulse. The role of buffer output buffer 215 is to prevent internal signal and external bus collision, protecting the external bus.
3 Conclusion In this paper, the concept dial hand wheel signal processing state machine introduced, effectively eliminates jitter when the handwheel slightly swaying caused by the direction of the signal and provide accurate count pulse reversible counter, to ensure correct numerical control system handwheel count. I have used this method to achieve HDL language and used in numerical control system, accurate handwheel operation, to achieve the desired results. The method also highly versatile, can be used to handle the dial handwheel signal incremental encoder and grating signal.