Calculation of control sequences for machine tool axes represented by numerical impulse response | |
| Author | Kamonwan Tanta-ngai |
| Call Number | AIT Thesis no.ISE-03-08 |
| Subject(s) | Machine-tools Numerical control Frequency response (Electrical engineering) |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineer, School of Advanced Technologies |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ISE-03-08 |
| Abstract | Motion control in NC kernel generates jerk, acceleration, velocity and position reference signals for machine tool axes. The present day principle of feedforward control impresses these reference signals with as little delay as possible assuming rigid machine axes. However, the flexibility of the drive train may result in an excitation of mechanical oscillations. Since these resonance frequencies are not considered in the contemporary control algorithms, a novel feedforward control technique has been investigated that considers the natural frequencies of the mechanical system. For this purpose the frequency response of the system has been measured. A generalized averaging procedure has been applied to reduce the noise being superimposed upon the measurement signals. By means of a Discrete Inverse Fourier Transform the impulse response of the system has been identified. Subsequently, a stable acceleration feed forward signal based upon inverted convolution has been calculated from the left shifted impulse response. An alternative approach is to use the Least Squares method to identify the discrete transfer function of the mechanical plant. Since unstable zeros of the transfer function cause unstable reference signals, their conjugate complex reciprocals are used for the poles of the feedforward algorithm. The effectiveness of this novel feedforward technique has been evaluated in combination with a balanced velocity feedforward and a balanced position control. |
| Year | 2003 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ISE-03-08 |
| Type | Thesis |
| School | School of Advanced Technologies (SAT) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Afzulpurkar, Nitin V.; |
| Examination Committee(s) | Manukid Parnichkun; Bohez, Erik L.J. ; |
| Scholarship Donor(s) | Siemens AG; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2003 |