Force measurement device and force measurement method

Abstract

A force measurement device for an object under test includes a test unit; a motor coupled to the test unit; a processor coupled to the motor; and a memory coupled to the processor for storing program code that instructs the processor to execute a force measurement method, the force measurement method including the motor controlling the test unit to press the object under test with a measured force; receiving a first measured current from the motor in response to pressing the object under test; and determining a feedback force of the object under test based on the first measured current.

Description

[Technical Field]

[0001] This invention relates to a force measurement device and a force measurement method, and more particularly to a force measurement device and a force measurement method that uses measuring current to evaluate force. [Previous Technology]

[0002] In computer applications, there is a frequent need to measure the feedback force of a test object, such as the feedback force of keyboard keys or the feedback force of different areas of a touchpad. Please refer to Figure 1, which is a schematic diagram of a conventional force measurement device 1. The conventional force measurement device 1 includes a motor 10, a test unit 20, and a load unit 30. The load unit 30 is mounted on the test unit 20. The motor 10 drives the test unit 20 and the load unit 30 to press a test object (DUT) along a first direction, and the load unit 30 can measure the feedback force of the test object DUT. However, mounting the load unit 30 on the test unit 20 requires the cost of fixtures and installation time. In this situation, simplifying the force measurement device has become a goal pursued by the industry. [Summary of the Invention]

[0003] One of the main objectives of this invention is to provide a force measurement device and a force measurement method to solve the above-mentioned problems.

[0004] The present invention provides a force measurement device for a test object, comprising a test unit; a motor coupled to the test unit; a processor coupled to the motor; and a memory coupled to the processor for storing program code that instructs the processor to execute a force measurement method, the force measurement method comprising: the motor controlling the test unit to press the test object with a measurement force; receiving a first measurement current from the motor in response to pressing the test object; and determining a feedback force of the test object based on the first measurement current.

[0005] The present invention provides a force measurement method for a test object, comprising: a test unit controlled by a motor pressing the test object; receiving a first measurement current in response to pressing the test object; and determining a feedback force of the test object based on the first measurement current.

Implementation Method

[0007] Certain terms are used in the specification and subsequent claims to refer to specific components. It will be understood by those skilled in the art that hardware manufacturers may use different names to refer to the same component. This specification and subsequent claims do not distinguish components by differences in name, but by differences in function. The term "comprising" as used throughout this specification and subsequent claims is an open-ended term and should be interpreted as "comprising but not limited to". Furthermore, the term "coupled" here includes any direct and indirect electrical connection means. Therefore, if a first device is described as coupled to a second device, it means that the first device can be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices or connection means.

[0008] Please refer to Figure 2, which is a schematic diagram of a force measurement device 2 according to an embodiment of the present invention. The force measurement device 2 includes a motor 10, a testing unit 20, a processor 40, and a memory 50. The motor 10 drives the testing unit 20 to press a test object (DUT) along a first direction, causing the DUT to generate a feedback force on the testing unit 20 and the motor 10. The feedback force, after being transmitted to the motor 10, affects the operation of the motor 10, causing a change in the driving current of the motor 10. In one embodiment, the motor 10 drives the testing unit 20 to press the DUT along the first direction. The processor 40 is coupled to the motor 10 and the memory 50. The memory 50 stores a program code used to instruct the processor 40 to execute a force measurement method to determine the response of the DUT to the feedback force of the motor 10 and the testing unit 20 based on the change in the driving current of the motor 10. It should be noted that the force measurement device 2 is derived from the force measurement device 1, so the same components are represented by the same symbols.

[0009] The force measurement method for the force measuring device 2 can be summarized as a process 3, as shown in Figure 3. Process 3 includes the following steps:

[0010] Step S300: Start.

[0011] Step S302: The test unit 20 is controlled by the motor 10 to press the test object DUT with a measuring force.

[0012] Step S304: Receive the first measurement current of the motor 10 in response to pressing the test object DUT.

[0013] Step S306: Determine the feedback force of the DUT based on the first measured current.

[0014] Step S308: End.

[0015] According to process 3, in steps S302 and S304, the motor 10 controls the test unit 20 to press the object under test (DUT) with a measuring force, and the processor 40 receives the first measuring current from the motor 10 in response to pressing the DUT. In one embodiment, the first measuring current may be the driving current of the motor 10, or it may be the change in the driving current of the motor 10, but it is not limited thereto. In step S306, the processor 40 determines the feedback force of the DUT based on the first measuring current. In short, the force measuring device 2 determines the feedback force of the DUT in response to the motor 10 and the test unit 20 based on the change in the driving current of the motor 10.

[0016] In one embodiment, the motor 10 controls the test unit 20 to press the test object (DUT) with different measuring forces. The judgment result of the feedback force determined by the force measuring device 2 is shown in Figure 4. Ideally, the measuring force and the feedback force should be equal. In reality, the maximum error between the measuring force and the feedback force determined by the force measuring device 2 is within 6 grams. However, as shown in Figure 4, the measuring force and the feedback force determined by the force measuring device 2 have the same trend. In another embodiment, the test object (DUT) is a keyboard key. The motor 10 controls the test unit 20 to press the keyboard key along the first direction with different strokes. The judgment result of the feedback force determined by the force measuring device 2 is shown in Figure 5. As shown in Figure 5, the peak value of the three measurement results (S_1, S_2, S_3) appears near stroke 36 and the trough value appears near stroke 51. Furthermore, when comparing the three measurement results, regardless of the peak or trough value, the maximum error of the feedback force is within 7 grams. However, as shown in Figure 5, the feedback force determined by the force measuring device 2 has the same trend in multiple measurements.

[0017] Furthermore, in order to reduce the error of the feedback force determined by the force measuring device 2, step S306 may include at least one of the following steps:

[0018] Step S402: Perform a noise filter on the first measurement current to generate a second measurement current, and determine the feedback force of the device under test (DUT) based on the second measurement current.

[0019] Step S404: Perform a zero-value calculation on the second measurement current to generate a third measurement current, and determine the feedback force of the object under test (DUT) based on the third measurement current.

[0020] Step S406: Perform a current force conversion on the first measured current, the second measured current or the third measured current to generate a feedback force.

[0021] The noise filtering, zero-value calculation and current power conversion performed by the processor 40 are well known in the art and will not be described in detail here.

[0022] It should be noted that the force measurement device 2 is an embodiment of the present invention. Those skilled in the art can combine, modify, or change the above-described embodiments in accordance with the spirit of the present invention, and are not limited thereto. All the above descriptions, steps, and / or processes (including suggested steps) can be implemented by means of hardware, software, firmware (i.e., a combination of hardware devices and computer instructions, where the data in the hardware device is read-only software data), electronic systems, or combinations of the above devices. Hardware may include analog, digital, and mixed circuits (i.e., microcircuits, microchips, or silicon wafers). Electronic systems may include system on chip (SoC), system in package (SiP), computer on module (CoM), and force measurement device 2. The process steps and embodiments of the present invention can exist in the form of program code or instructions and be stored in memory. The memory can be a computer-readable recording medium, and may include, but is not limited to, read-only memory (ROM), flash memory, random-access memory (RAM), a Subscriber Identity Module (SIM), or CD-ROM / DVD-ROM / BD-ROM. The above processes and embodiments can be compiled into program code or instructions and stored in the memory. The processor 40 can be used to read and execute the program code or instructions stored in the memory to implement all the aforementioned steps and functions.

[0023] In summary, compared to conventional force measurement devices that measure the feedback force of the object under test through a load cell, the force measurement device and method of the present invention can measure the change in the drive current of the motor and determine the feedback force of the object under test accordingly. In this way, the present invention reduces the cost and installation time of the load cell and related fixtures. The above description is only a preferred embodiment of the present invention, and all equivalent variations and modifications made within the scope of the claims of the present invention should be considered within the scope of the present invention. [Simplified Explanation of the Diagram]

[0006] Figure 1 is a schematic diagram of a conventional force measurement device. Figure 2 is a schematic diagram of a force measurement device according to an embodiment of the present invention. Figure 3 is a flowchart of a force measurement method according to an embodiment of the present invention. Figure 4 is a schematic diagram of force measurement and feedback force according to an embodiment of the present invention. Figure 5 is a schematic diagram of feedback force measured multiple times according to an embodiment of the present invention.

Claims

1. A force measurement device for an object to be tested, comprising: a test unit; a motor coupled to the test unit; a processor coupled to the motor; and a memory coupled to the processor for storing program code that instructs the processor to execute a force measurement method, the force measurement method comprising: controlling the test unit to press the object to be tested with a plurality of measured forces by the motor; receiving a plurality of first measured currents from the motor in response to pressing the object to be tested; and determining a plurality of feedback forces of the object to be tested based on the plurality of first measured currents; wherein the plurality of first measured currents are changes in the drive current of the motor.

2. The force measurement device as claimed in claim 1, wherein the step of determining the plurality of feedback forces of the object under test based on the plurality of first measuring currents comprises: performing a noise filter on the plurality of first measuring currents to generate a plurality of second measuring currents; and determining the plurality of feedback forces of the object under test based on the plurality of second measuring currents.

3. The force measuring device as claimed in claim 2, wherein the step of determining the plurality of feedback forces of the object under test based on the plurality of first measuring currents comprises: performing a zero-value calculation on the plurality of second measuring currents to generate a plurality of third measuring currents; and determining the plurality of feedback forces of the object under test based on the plurality of third measuring currents.

4. The force measuring device as claimed in claim 3, wherein the step of determining the plurality of feedback forces of the object under test based on the plurality of first measuring currents comprises: performing a current force conversion on the plurality of first measuring currents, the plurality of second measuring currents, or the plurality of third measuring currents to generate the plurality of feedback forces.

5. A force measurement method for an object to be tested, comprising: controlling a test unit by a motor to press the object to be tested with a plurality of measuring forces; receiving a plurality of first measuring currents in response to pressing the object to be tested; and determining a plurality of feedback forces of the object to be tested based on the plurality of first measuring currents; wherein the plurality of first measuring currents are changes in the drive current of the motor.

6. The force measurement method as described in claim 5, wherein the step of determining the plurality of feedback forces of the object under test based on the plurality of first measuring currents comprises: performing a noise filter on the plurality of first measuring currents to generate a plurality of second measuring currents; and determining the plurality of feedback forces of the object under test based on the plurality of second measuring currents.

7. The force measurement method as described in claim 6, wherein the step of determining the plurality of feedback forces of the object under test based on the plurality of first measuring currents comprises: performing a zero-value calculation on the plurality of second measuring currents to generate a plurality of third measuring currents; and determining the plurality of feedback forces of the object under test based on the plurality of third measuring currents.

8. The force measurement method as described in claim 7, wherein the step of determining the plurality of feedback forces of the test object based on the plurality of first measuring currents comprises: performing a current force conversion on the plurality of first measuring currents, the plurality of second measuring currents, or the plurality of third measuring currents to generate the plurality of feedback forces.

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