Method and module for measuring rotation and portable apparatus comprising the module

• US 8,655,620 B2
• Filed: 03/30/2011
• Issued: 02/18/2014
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: National Tsing Hua University
• Original Assignee: National Tsing Hua University
• Inventors: King, Chung-Ta, Lin, Chun-Yu, Chen, Chung-Tso
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US13/076,101
• Publication Number:
  US 20120173189A1
• Time in Patent Office: 1,056 Days
• Field of Search: 702/141
• US Class Current: 702/141
• CPC Class Codes: G06F 1/1694 the I/O peripheral being a single or a set of motion sensors for pointer control or gesture input obtained by sensing movements of the portable computer
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device

Abstract

The invention discloses a method and a module for measuring rotation and a portable apparatus comprising said module. The module of the present invention is adapted for measuring rotation of a target, and the module includes a first sensor, a second sensor and a processor. The first sensor is disposed at a first location of the target, for sensing a first centripetal acceleration and a first tangential acceleration when the target is rotated. The second sensor is disposed at a second location of the target, for sensing a second centripetal acceleration and a second tangential acceleration when the target is rotated. The processor is coupled to the first sensor and the second sensor, for receiving the first centripetal acceleration and the first tangential acceleration from the first sensor, receiving the second centripetal acceleration and the second tangential acceleration from the second sensor, and calculating the rotation angle of the target accordingly.

Claims

1. A rotation measuring module used to measure rotation of a target object, the rotation measuring module comprising:

a first sensor, installed at one first location of the target object so that when the target object is rotating, the first sensor senses a first centripetal acceleration and a first tangential acceleration;

a second sensor, installed at a second location of the target object so that when target object is rotating, the second sensor senses a second centrifugal acceleration and a second tangential acceleration; and

a processor, which is connected respectively to the first sensor and the second sensor so as to receive from the first sensor the first centripetal acceleration (a_C) and the first tangential acceleration (a_T), and to receive from the second sensor the second centrifugal acceleration and the second tangential acceleration;

meanwhile, the processor follows the following equation 1 and 2 to calculate respectively an angular velocity (ω

) and an angular acceleration (α

) of the first location and the second location;

2. The rotation measuring module of claim 1, wherein the processor will follow respectively the following equation 4 and 5 to calculate the distance (r₁) between the first location and the rotational center of the target object and the distance (r₂) between the second location and the rotational center of the target object:

3. The rotation measuring module of claim 1, further comprising at least one low pass filter disposed respectively among the first sensor and the second sensor and the processor.

4. The rotation measuring module of claim 1, wherein the first sensor, on at least two different time points and at the first location, will sense a first previous data and a next data, and the second sensor, on the at least two different time points and at the second location, will sense a second previous data and a second next data, and the processor will then compare a first difference value between the first previous data and the first next data, and then compare a second difference value between the second previous data and the second next data;

wherein when the first difference value is larger than one preset threshold value, the processor will then follow the second difference value to adjust the first next data, or when the second difference value is larger than the preset threshold value, the processor will then follow the first difference value to adjust the second next data.

5. The rotation measuring module of claim 1, wherein only when the first centripetal acceleration and/or the first tangential acceleration, and the second centrifugal acceleration and/or the second tangential acceleration is larger than the preset threshold value for a preset time, processor will then calculate the angular velocity, the angular acceleration and the rotational angle.

6. The rotation measuring module of claim 1, wherein the processor will follow the rotational angle to output a control signal.

7. A portable device comprising the rotation measuring module of claim 1, which is used to measure the rotation of the portable device.

8. The portable device of claim 7, wherein the processor will follow the rotational angle to output a control signal.

9. A rotation measuring method, which is applicable to measurement of rotation of a target object, and the rotation measuring method comprising the following steps:

(a) when the target object is rotating, sensing at one first location of the target object, a first centripetal acceleration and a first tangential acceleration by a first sensor, and sensing at the second location of the target object, a second centrifugal acceleration and a second tangential acceleration by a second sensor;

(b) receiving the first centripetal acceleration (a_c) and the first tangential acceleration (a_T), and the second centrifugal acceleration and the second tangential acceleration respectively by a processor;

(c) according to the following equation 1 and 2, calculating an angular velocity (ω

) and an angular acceleration (α

) of the first location and the second location respectively by the processor;

10. The rotation measuring method of claim 9, further comprising the following steps:

(e) the following equation 4 and 5 are based respectively to calculate the distance (r₁) between first location and the rotational center of the target object and the distance (r₂) between the second location and the rotational center of the target object;

11. The rotation measuring method of claim 9, further comprising the following steps:

(f) on at least two different time points and at the first location, first previous data and first next data is sensed, and a first difference value between the first previous data and the first next data is compared;

(g) on at least two different time points and at the second location, a second previous data and a second next data is sensed, and a second difference value is compared between the second previous data and the second next data; and

(h) when the first difference value is larger than a preset threshold value, the second difference value is based to adjust the first next data, or when the second difference value is larger than the preset threshold value, the first difference value is based to adjust the second next data.

12. The rotation measuring method of claim 9, wherein when the first centripetal acceleration and/or the first tangential acceleration, and the second centrifugal acceleration and/or the second tangential acceleration is larger than the preset threshold value for a preset time, steps (c) and (d) will be performed.