Vibration of numerical control machine tool is measured and control a technology

  • Time:
  • Click:173
  • source:EDON CNC Machining
Be opposite as manufacturing industry of mould industry, aviation the demand of precision of treatment speed, treatment and exterior quality is higher and higher and the development of high speed processing technique, while if why machine speed higher in implementation,numerical control machine tool and robot manufacturer are faced with, assure to machine the task of precision and exterior quality. Generally speaking, the vibration of numerical control machine tool and shake have subtle but very clear distinction (if pursue 1) : Vibration is in what the low frequency of less than of electric machinery bandwidth moves to say normally, can be in maintain rigid structure undertake eliminate and be inhibitioned below changeless premise; The high frequency sports of bandwidth of prep above electric machinery says normally to shake, often need to undertake modification to rigid structure, the tigidity that raises machine achieves the goal that reduces vibration. The vibration of numerical control machine tool or robot can increase work handling time, reduce exterior quality even precision. Graph 1 vibration distinguishs the article to will accuse a machine tool to be with 5 number of axle with what shake exemple, key introduction is based on acceleration sensor to have oscillatory pilot new technology to machine tool of high speed numerical control. 1.

DAS (Direct Acceleration Sensor) use in acceleration sensor tradition inertial measure unit (IMU, inertial Measurement Unit) can undertake inertial and even oscillatory measurement. But, as a result of inertial the size that measures unit bigger, cost is higher and measure frequency range too narrow and use at numerical control machine tool and robot industry hard. Use DAS acceleration sensor to be able to get used to application of numerical control machine tool very well, it has measure compact (make an appointment with 100100x30 Mm) and measure frequency limits to be bordering on electric machinery frequency (make an appointment with 100 Hz) and take up the cost with numerical control overall machine tool is lesser (occupy about overall cost 5% ) wait for a characteristic. In the meantime, because use aether network (Ethernet) technology, the data of DAS acceleration sensor collects frequency to be 100 Mb/s about, can satisfy the higher demand with numerical control periodic to sampling system. On hardware structure, DAS acceleration sensor uses many planar and linear accelerometer to undertake permutation, can undertake the measurement of linear acceleration and angular acceleration, measurable number of axle amounts to 6. On software function, there is function of rich DAS API library in DAS acceleration sensor, can pass Ethernet UDP and simple client / server agreement and computer have news report, allow an user to develop a variety of application below Windows and Linux, complete relatively intricate work. Sensor of acceleration of graph 2 DAS 2.

Be based on test and verify of speed of TCP of estimation of DAS acceleration sensor to pass the DAS API library of acceleration sensor, the acceleration information of the acceleration sensor that can arrive to collecting undertakes Bayes estimation and sensor confluence algorithm undertake the estimation of speed of TCP of cutting tool center. Be opposite for sensor of acceleration of test and verify TCP speed is estimated effectiveness, undertake the experiment checks especially. Move in numerical control machine tool in, read the acceleration of TCP of cutting tool center through DAS acceleration sensor speed estimation undertakes in taking Orchestra motion to control platform, this estimated result and laser dog the outcome that appearance measures undertakes contrast, the effectiveness that already achieved test and verify to be based on speed of TCP of acceleration sensor estimation (if experimental model pursues 3) . Those who need an attention is, DAS acceleration sensor basically installs the around position in TCP of cutting tool center. Graph 3 when be based on test and verify of feasibility of speed of TCP of acceleration sensor estimation to carry out lozenge motion contrail in numerical control machine tool, pass speed of TCP of estimation of DAS acceleration sensor and laser to dog respectively appearance is online measure TCP speed, test condition is worth 7 M/s^2 for acceleration, add acceleration to be worth 80 M/s^3, undertake if pursue,the result contrasts 4 (blue line - estimation of acceleration sensor Bayes and shirt-sleeve algorithm, green line - use only rotate coder estimation speed, red line - the real rate that laser interferometer measures) . Graph 4 if graph of experimental earnings result is shown 4 times,be based on result of test and verify of feasibility of speed of TCP of acceleration sensor estimation, the TCP rate that uses estimation of acceleration sensor Bayes and shirt-sleeve and algorithmic estimation to reach is worth can the virtual campaign speed of TCP of relatively accurate reaction machine tool. Nextpage3.

The oscillatory control that uses acceleration sensor to have numerical control machine tool is current, great majority does not include effective vibration to control a function in system of general numerical control. Orchestra opens type to control systematic platform to be able to pass PC interface and system of general numerical control to have news report, measure DAS acceleration sensor information of gotten machine tool vibration to undertake handle and be compensatinged, convey to have oscillatory control to numerical control system. Among them, orchestra platform has of all kinds interface, the news report that can complete different hardware and sensor works, if rotate with DAS, electric machinery the interface of system of coder, general numerical control. Graph vibration of machine tool of 5 numerical control controls principle block diagram to be based on a graph the configuration of 5, in the light of door of frame type dragon treatment machine tool undertakes vibration controls systematic test and verify. Right now, DAS installation is near cutting tool center, if pursue 6. Control the effectiveness of plan for vibration of test and verify, have rectangular Ban gold according to following measure treatment: 1) standard checks, do not use vibration to dominate program: Be based on acceleration 4 M/s^2, add acceleration 50 M/s^3, treatment precision asks for ± 30 µm 2) tall trends checks, do not use vibration to dominate program: Be based on acceleration 7 M/s^2, add acceleration 125 M/s^3, treatment precision asks for ± 30 µm 3) tall trends checks, use vibration to dominate program: Be based on acceleration 7 M/s^2, add acceleration 125 M/s^3, treatment precision asks to be installation of sensor of acceleration of 6 DAS of graph of ± 30 µm to have 3 tests respectively at falling according to set condition near TCP, use laser dogs appearance undertakes to machining orbit real time is collected, attainable if pursue the experimental result of 7. Graph the relation of displacement of motion of the machine tool below condition of parameter of 7 different machine tools and time 4.

Conclusion from the graph can reach as follows in the experimental result of 7 conclusion: The acceleration that 1) raises a machine tool, add the dynamic performance such as acceleration, the vibration that can increase a machine tool affects treatment precision even. 2) uses the vibration that is based on acceleration sensor to dominate program, can go up in the base that improves performance of machine tool trends (acceleration increases 50% , add acceleration to increase 150%) , the treatment efficiency that improves a machine tool is amounted to 15% , improving exterior quality while do not reduce treatment precision. Final, the oscillatory control program that through collecting the measurement of acceleration sensor information controls the development below systematic platform in Orchestra is not reducing the premise that machines precision to fall, promote the treatment of numerical control machine tool efficiency and exterior quality. In the meantime, oscillatory control program also can apply at all sorts of industry robots, improve the dynamic character that its play in high speed motion. CNC Milling CNC Machining