ENCODING SYSTEM AND ENCODING METHOD

• US 20100260311A1
• Filed: 05/30/2009
• Published: 10/14/2010
• Est. Priority Date: 04/14/2009
• Status: Abandoned Application

• Current Assignee: Foxnum Technology Co., Ltd.
• Original Assignee: Foxnum Technology Co., Ltd.
• Inventors: CHEN, SHIH-CHANG, LIN, YOU-REN, CHEN, SHEN-AN, HORNG, RONG-HWANG, HUNG, RONG-CONG, LAI, YAW-SHEN
• Application Number:
  US12/475,507
• Publication Number:
  US 20100260311A1
• Time in Patent Office: Days
• US Class Current: 377/17
• CPC Class Codes: G01D 5/2448 Correction of gain, threshold, offset or phase control

Abstract

An encoding system includes an absolute encoder, a converter, a storage system, and a processor. The converter is connected between the absolute encoder and the storage system to determine amplitudes of two encoding waveforms from the absolute encoder when a motor rotates. The storage system determines an angle through which the motor rotates between a first time and a second time, according to the amplitudes of the two encoding waveforms.

Claims

1. An encoding system to measure an angle through which a motor rotates between a first time and a second time, the encoding system comprising:

a processor;

a storage system connected to the processor and storing one or more computerized instructions being executed by the processor;

an absolute encoder to output two encoding waveforms according to rotation of the motor at the first time and the second time;

a converter connected between the storage system and the absolute encoder, to determine amplitudes of the two encoding waveforms, and to output the amplitudes to the processor;

wherein the storage system comprises;

a data processing unit to store the amplitudes of the two encoding waveforms, store differences between absolute values of the amplitudes of the two encoding waveforms at the first time and the second time, store relationships of the amplitudes, store spaces of a coordinate system about the amplitudes of the two encoding waveforms at the first time and the second time, and store a function of each space;

a space determination unit to determine a coordinate point of the amplitudes of the two encoding waveforms at the first time and the second time according to the amplitudes of the two encoding waveforms at the first time and the second time; and

a position processing unit to record a number of each of the integrated encoding waveforms between the first time and the second time, determine a value S, and the angle which the motor rotates between the first time and the second time.

2. The encoding system of claim 1, wherein the two encoding waveforms are two sine waveforms or two cosine waveforms.

3. The encoding system of claim 1, wherein the data processing unit selects a corresponding function according to the space, and determines a first angle θ

and a second angle θ

at the first and second times, and values of L at the first and second times, according to a formula

L=N/2π

×

θ

, where N denotes a definition of the encoding system.

4. The encoding system of claim 1, wherein the position processing unit determines the value S according to a formula of S=L^Q+Z×

R−

L^P, wherein Z denotes the number of each of the integrated encoding waveforms between the first time and the second time, L^P denotes a value of L at the first time, L^Q denotes a value of L at the second time, R denotes a wavelength of each of the encoding waveforms, and the angle to which the motor rotates is (S/1000)*10°

.

5. The encoding system of claim 1, further comprising an amplitude adjuster connected between the converter and the storage system, wherein the amplitude adjuster adjusts the maximum amplitude of each of the encoding waveforms to be the same, and transmits the two encoding waveforms to the storage system.

6. The encoding system of claim 1, further comprising an offset adjuster connected between the converter and the storage, wherein the offset adjuster adjusts centerlines of the two encoding waveforms to be on a same line, and transmits the two encoding waveforms to the storage system, wherein a coordinate system for the amplitudes at each time of the two encoding waveforms is constructed by the offset adjuster.

7. The encoding system of claim 1, further comprising a converter circuit connected between the absolute encoder and the storage system, to convert the two encoding waveforms to two digital pulses, and transmit the two digital pulses to the storage system;

wherein the storage system further comprises a combination unit to combine the two digital pulses into a combined digital pulse, and the position recording unit is to record the pulse number of the combined digital pulse between the first time and the second time.

8. An encoding method to measure an angle through which a motor rotates between a first time and a second time, the encoding method comprising:

determining amplitudes of two encoding waveforms that a motor rotates between the first time and the second time, wherein a phase difference between the two encoding waveforms is 90 degrees;

transmitting the amplitudes to a storage system, wherein the storage system stores the amplitudes of the two encoding waveforms, stores differences between absolute values of amplitudes at the first time and the second time of the two encoding waveforms, store relationships of the amplitudes, stores spaces of a coordinate system for the amplitudes at the first time and the second time of the two encoding waveforms, and stores a function of each space, wherein the storage system stores one or more computerized instructions being executed by the processor;

determining which space is a coordinate point of the amplitudes of the two encoding waveforms at determined time;

recording a number of each of the integrated encoding waveforms between the first time and the second time, and determining a value S between the first time and the second time, and the angle to which the motor rotates between the first time and the second time.

9. The encoding method of claim 8, wherein the two encoding waveforms are two sine waveforms or two cosine waveforms.

10. The encoding method of claim 8, wherein determining the space and recording the number further comprising:

determining a first angle θ

at the first time and a second angle θ

at a second time, and values of L at the first and second time according to a formula of L=N/2π

×

θ

, N denotes a definition of the encoding system.

11. The encoding method of claim 8, wherein the value S between the first time and the second time is determined according to a formula of S=L_Q+Z×

R−

L_P, wherein L_P denotes a value of L at the first time, L_Q denotes a value of L at the second time, R denotes a wavelength of each, Z denotes the number of each of the integrated encoding waveforms between the first time and the second time.

12. The encoding method of claim 8, wherein determining amplitudes of two encoding waveforms at each time further comprises adjusting centerlines of the two encoding waveforms to be on a same line, and transmitting the two encoding waveforms to the storage system.

13. The encoding method of claim 8, further comprising, after determining amplitudes of two encoding waveforms at every time that the motor rotates, adjusting the maximum amplitude of each of the two encoding waveforms to be the same, and transmitting the two adjusted encoding waveforms to the storage system.

14. The encoding method of claim 8, wherein recording the number of each of the two encoding waveforms between the first time and the second time further comprises:

converting the two encoding waveforms to two digital pulses, and transmitting the two digital pulses to the storage system;

combining the two digital pulses to a combining pulse; and

recording a pulse number M of the combined digital pulse between the first time and the second time, and [M/4] is equal to Z, wherein [M/4] denotes an integer of M/4.