WO2005038640A1 - A computer hand-writing input platform and information-getting method - Google Patents

Abstract

The invention discloses a computer hand-writing input platform and hand-writing information-getting method, the said computer hand-writing input platform is composed of a elbow flat , a signing plat ,a five-dimention force/moment sensitivity structure(including center axis, sensitivity unit and contact flange), prepositive sign process circuit, universal bus network interface and a base, witch is used to real-time detect, record the force/moment information between a pen and signing plat when writing. The said hand-wring information-getting method , by inputting the force/moment information of plat-detecting , gets the information of the strokes, orders of strokes, hand-writing speed and so on during the input process . The hand-wring platform is not only as a computer's peripheral equipment directly, at the same time it can be used for hand-writing in the plat with any pen , without consuming ink; and it can be embeded into a computer system to replace the keyboard. The invention can also be used in the occasion of e­commerce, e- government affair and so forth, in which signing of encrypt and forgery prevention is in need.

Description

 Computer handwriting input platform and information acquisition method

Technical field

 The present invention relates to the field of computer information and the field of automated electronics, and in particular, to a novel computer handwriting input platform and method for obtaining handwritten information. Input peripherals.

Background technique

 In e-commerce, e-government, office automation and digital electronic handwriting input urgently need a convenient, fast, natural and secure way. At present, there are many mature methods and technologies for digital signature and handwriting input in this field, but digital signature and handwriting input are separated from each other and are not implemented in the same system. In addition to requiring natural, convenient, and fast input methods for digital signatures, it is more important to require uniqueness, security, and confidentiality with biological characteristics.

 Digital electronic handwriting input technology collects handwritten input information through a computer, and processes and recognizes the computer to generate a computer document to achieve the same effect as writing on paper, thereby realizing a paperless office. Paperless office is the most basic component of e-commerce solutions. With the further development of computer technology and network technology, and the widespread development of e-commerce and e-government, it is urgent to resolve legal liabilities such as contract signing and document signing. In terms of online authentication, such online authentication is mainly implemented by using a third-party authentication mode based on biometrics. The current handwriting input method cannot solve the problems of uniqueness, security, and confidentiality of biometrics.

The traditional paper-based commerce and computer-based commerce are different in their physical foundations, specific practices, and legal meanings. The key factor is the inherent security attributes of signed paper documents. None of these attributes include ink that can be permanently embedded in paper fibers, biometrics (signature, shape, stroke order, direction, etc.) and time stamp when signing. Any modification and deletion can be easily made. Identify. Computer-based information and records do not have these inherent security attributes. Computer-based information is simply a binary character that represents information in an encoded form. In the signing of a contract or document involving legal responsibility, the originality and uniqueness of the document are the basic requirements in business and government affairs. It is clear that the traditional digital data of electronic signatures do not have this attribute. At present, the main handwriting electronic pen products with electronic signature functions in China include: Daheng pen, Hanwang pen, Meng Tian pen, Tsinghua Ziguang pen, and WACOM input pen.

 Daheng pen mainly uses Japanese WACOM technology. It is a pressure-sensitive pen. In addition to high handwriting recognition rate, it can also be used for computer painting.

 Backed by the Institute of Automation of the Chinese Academy of Sciences, Hanwang Pen has been engaged in research and development of character recognition for many years. At present, it has evolved from a simple Chinese character input product to an all-round input tool for reading, writing, listening, and drawing.

 Meng Tian Pen PenPower is the "king of stylus recognition" in Chinese handwriting input. There are many types. At present, it mainly uses technologies such as voice combination and wireless input to enhance the recognition rate of stroke-free writing based on the original three recognition cores.

 Tsinghua Unispen's Unispen products mainly use pressure-sensitive electromagnetic technology and a large handwriting area tablet. Wireless and pressure-sensitive input are the key to its technology. Not only is it more suitable for Chinese people ’s handwriting input habits, but it also greatly reduces the accuracy error to 0.42. Bandit, making handwriting recognition rate as high as 99.96%

 WACOM's stylus pioneered the electromagnetic induction method without wires and batteries in 1983. It has obtained patent rights in many countries (including China). WACOM stylus has developed various specifications and series of high-quality input boards. From ultra-large to A6 ultra-thin and ultra-small, from direct pen input LCD panels to remote communication electronic blackboards. After 20 years of continuous improvement, the input interface has reached a level close to the use of paper and pen. The pressure pen of WACOM company input pen is convenient, light, and easy to change pressure, and has long been famous in the professional field. The pressure sensitivity level of WACOM's input pen reaches the world's highest level of 1024 (Intuos series). WACOM's stylus computer input hardware products have long been known as well-known international brands and are the world's top products in the industry.

 Judging from the development of these electronic pens, we use the latest technology such as USB interface and wireless transmission methods to solve the input problems of electronic pens for various new application software platforms and expand new application fields. These hand-written electronic pens focus on input recognition issues and use their signature functions, but they cannot resolve legal security issues, especially the originality and uniqueness of signed documents.

 It is for this reason that electronic digital signatures have more used digital signature recognition based on biometric technology to establish personal verification, such as: fingerprint recognition, voice recognition, writing recognition, face recognition, retinal scanning and hand shape. Identification, etc., to store and transfer the measured biometric code in a secure format (encryption and decryption protection). Obviously, this digital signature and authentication method is no longer a traditional handwritten signature. It has changed both in form and process. How to find a security attribute that retains the traditional handwriting input method and has the requirements of modern e-commerce has always been Electronic pen handwriting input urgently needs to be solved.

Everyone has unique behavior characteristics when writing, especially the weight, shape, Features such as stroke direction are unique, and any modification or deletion can be easily identified. And it cannot be unintentionally generated or fulfilled by others. Therefore, it will not be forgotten or passed on to others like ID and password. At the same time, it will not be emotionally exclusive or violate personal privacy.

 In short, there are many mature products for electronic pen handwriting input technology in the domestic and foreign markets. These methods are mainly used to solve the problems of electronic pen handwriting input and font recognition. The lack of information on handwriting characteristics is not available in government and enterprises. Signing important documents in paper-based offices and signing contracts in e-commerce involves legal liability occasions, and there is an increasing need for an input method that is both natural and retains personal handwriting characteristics.

Summary of the invention

 The technical problem to be solved by the present invention is to develop a natural and safe handwriting input platform and propose a method for acquiring handwritten information based on five-dimensional force / torque information, which can provide real-time information between the pen tip and the signature pad. Dimension contact force / torque information, and obtain handwriting characteristics such as the amount of force when writing, the shape of the pen when writing, stroke order, strokes, and writing speed based on these information. In addition to the traditional writing function, it also has the ability to obtain writing The force information function of the wrist and the signature time information can be used instead of the keyboard and the mouse, and can be directly used as the external device of the personal computer, which is used for the occasion where the computer needs handwriting input.

 The technical solution of the present invention is: A computer handwriting input platform including a signature tablet (2), an upper sensitive unit (4), a lower sensitive unit (7), a pre-signal processing circuit (8), and a universal bus network interface (9 ), Wherein the upper sensitive unit (4), the lower sensitive unit (7) and the central axis (3) form a five-dimensional force / torque sensitive structure, and the pre-signal processing circuit (8) includes a five-way low-pass filter (13), The instrumentation amplifier (14), the reference voltage source (15), and the feedback amplification resistor (16). The universal bus network interface (9) includes five 12-bit A / D microprocessors, a USB interface circuit, and an RS232 interface. :

 The overall structure of the computer handwriting input platform is composed of a handrail tablet (1), a signature tablet (2), a central axis (3), an upper sensitive unit (4), an upper connecting flange (5), a lower connecting flange (6), and a lower The sensitive unit (7), the pre-signal processing circuit (8), the universal bus network interface (9), and the base (10) are collectively composed, and the armrest plate (1) and the base (10) may be an integrated structure. Depending on the installation position and size of the signal processing circuit (8);

The upper connecting flange (5) and the lower connecting flange (6) must ensure the coincidence of the central shaft (3), which is achieved through the matching of the shaft hole. That is, the center of the signature plate (2) has a concave cylindrical cavity with an inner diameter. The outer diameter is the same as that of the upper connecting flange (5), and the clearance fits with each other. At the same time, the upper connecting flange (5) and the upper sensitive unit (4) 釆 use the engraved line alignment and positioning pins to ensure the transmission of the central shaft (3) ; ' The upper sensitive unit (4), the lower sensitive unit (7) and the central axis (3) are five-dimensional force / torque sensitive units, and are used to detect the five-dimensional force between the pen and the signature tablet (2) when writing. Moment information, the upper sensitive unit (4), the lower sensitive unit (7) and the central shaft (3) can be designed as a unitary structure, which is connected by adhesive, and the upper sensitive unit (4), the upper connecting flange (5), and the center The shaft (3), the lower sensitive unit (7), and the lower connecting flange (6) can also be designed as an integrated structure and directly processed into a whole;

 The circuit board of the front signal processing circuit (8) is fixed in the cavity formed by the lower sensitive unit (7), the lower connection flange (6) and the base 10 to ensure that the original output signal can be amplified and filtered and output to the interface. In the circuit part, the universal bus network interface (9) is arranged on the base (10), which mainly completes the digital processing of the amplified and filtered analog signals and connects to the personal computer through the USB interface circuit.

 The computer handwriting input platform can be directly used as the input peripheral of the computer. You can use any pen to write directly on the tablet without consuming ink. Or you can embed the writing platform base with the computer case and embed it directly into the personal computer system. Instead of the keyboard for handwriting input.

 A method for acquiring computer handwritten information, characterized in that the method for acquiring handwritten information includes a method for acquiring five-dimensional force / torque information during handwriting input, and a method for acquiring handwriting characteristic information such as pen shape, stroke order, stroke, and writing speed of a signature. ;

A. Method for obtaining five-dimensional force / torque information during handwriting input, where: Three sets of foil strain resistors are affixed to the round diaphragm of the lower sensitive unit (7), and two sets are affixed to the round diaphragm of the upper sensitive unit (4) Foil's force-sensitive strain resistance, or three sets of Foil's force-sensitive strain resistance can be pasted on the round diaphragm of the upper sensitive unit (4), that is, the sensitive resistances R _FZ1 , R _FZ2 , and R _ra used to measure Fz force R and R ™ can be pasted on the round diaphragm of the lower sensitive unit (7), or on the round diaphragm of the upper sensitive unit (4), and use a specific bridge to achieve a five-dimensional force / torque during writing. The information is obtained, and the inter-dimensional coupling relationship is obtained through calibration. After filtering, amplification, A / D conversion, and data processing, the five-dimensional force / torque information of the pen tip and the flat plate is obtained. The lower sensitive unit (7) is sensitive on the circular diaphragm. The resistors RP _X i, RFX, RF, and R ™ are used to realize the measurement of the force information Fx; the lower sensitive unit (7) the sensitive resistors R _PY ι, RPY, RFY _s , and R ™ on the circular diaphragm are used to achieve the force Information Fy measurement; lower sensitive unit (7) round diaphragm Sensitive resistors _{R PZ, RFZ, RFZ;,} R ™ to achieve measurement of the force Fz information; sensitive unit (4) on the circular diaphragm sensitive resistor _{R FX i, RF, Rr ,,} R ™ used to achieve the force Measurement of information Mx; Upper sensitive unit (4) Sensitive resistors R _PY i, RFY, RFY ₃ on the circular diaphragm, for measuring force information My;

The lower sensitive unit (7) is attached with R _M , R _FX2 , R _RO , R ™, R _FY1 , R _FY2 , R _FY3 , R, R,

There are 12 strain resistors in R _ra , R _ra , and R ™. Among them, R ™ and R _ra and R ™ are symmetrically arranged on a straight line in the X direction, and R, 1 ^ ₂ and 1 ^ ₃ , and R _{m are} symmetrically arranged in the Y direction. R _m , R _FZ2 and R _ra , R ™ are arranged symmetrically with Y two straight lines that intersect each other at 45 degrees, three straight lines pass through the center of the circular diaphragm, and R _FX1 , R ™, R _M , R ™, RPZI> R ™ are arranged near the outer circle of the circular diaphragm _{, Χ2, RPX3> R tO,} R ™, R, 1 ^ 3 disposed at a position close to the center circle of the hard film; hard center where the diameter of the center axis (3) outer diameter cylindrical portion is smaller than the resistance of the strain down link Inner flange.

The upper sensitive unit (4) is equipped with R _M , R _FX2 , R _FX3 , R ™, R _M , R _FY2 , R _TO , 8 sensitive resistors, among which R ™, R _FX2 and R ™, R ™ are symmetrically arranged on a straight line in the X direction, R _FY1 , 1 ^ ₂ and 1 ^ ₃ , and R _{m are} symmetrically arranged on a straight line in the Y direction, and both straight lines pass through the center of the circular diaphragm; and R _FX1 , R ™ , R _M ,! ^ Arranged near the outer circle of the circular diaphragm, R ™, R _RA , R _TO , R _TO are arranged near the hard center of the circular diaphragm; where the diameter of the hard center is the outer diameter of the central axis (3), the strain resistance The outer circle is smaller than the inner circle of the upper and lower connecting flanges. But it is also possible to paste three sets of foil-type strain-sensitive strain resistors on the round diaphragm of the upper sensitive unit (4), that is, the sensitive resistors R _PZ1 , _Z2 , and R _M used to measure Fz force information can be attached to the lower sensitive unit (7). The circular diaphragm can also be affixed to the circular diaphragm of the upper sensitive unit (4).

 B. Method for obtaining information such as pen shape, stroke order, stroke, and writing speed of a handwritten signature, two-dimensional moment obtained by the pen tip three-dimensional force information (Fx, Fy, Fz) obtained by the lower sensitive unit (7) and the upper sensitive unit (4) Information (Mx, My) Calculate the position of the pen tip during the handwriting process, get the position of the pen tip and the contact point on the handwriting signature tablet (2) in the coordinate system of the handwriting platform system, and continuously calculate the contact between the pen tip and the handwriting signature tablet (2) The position is connected to obtain the pen shape, stroke order, and stroke information in the process of handwriting input, and the writing speed information can be further obtained through microprocessor calculation. The formula for the contact position of the pen tip and tablet is:

The beneficial effects of the present invention are: through the computer handwriting input platform and the handwriting information acquisition method provided by the present invention, not only can the function of recording handwritten static information such as pen shapes and fonts in the process of handwriting, but also have the ability to acquire fingers holding the pen when writing, The function of three-dimensional contact force information between the wrist and the writing object and dynamic information such as writing speed, writing order, and writing time. The computer handwriting input platform can be used not only as a computer input peripheral, but also the writing platform base and the computer shell can be embedded directly into the personal computer system, instead of the keyboard to achieve handwriting input.

The invention provides a new solution for the natural and secure electronic handwriting input in current e-commerce and e-government. The solution, especially the combination of recording handwriting features and natural writing, retains the traditional writing habit on paper, and provides a new solution to the current contradiction between natural handwriting input and electronic handwriting signatures in e-commerce and e-government. s method. It can be directly used as an input peripheral of a computer or directly embedded in a computer system, instead of the traditional keyboard, mouse and other input methods, it becomes a component of a personal computer. And through the adjustment of its structural size and the placement of sensitive units,

Changes and changes in the multidimensional force elastomer can achieve different sensitivities and different ranges to meet the needs of people with different writing abilities and writing habits.

 '' The handwriting platform and handwriting input method provided by the present invention are safe and cannot be imitated, and the handwriting input platform can be directly used as a standard input interface device for personal computers. It can be used in government e-government, corporate paperless office and e-commerce contracts. Signs and other occasions have broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

The patent of the present invention will be further described below with reference to the drawings and embodiments.

Figure 1 is a schematic diagram of the overall structure of a handwriting input platform;

Figure 2 is a schematic diagram of a five-dimensional force / torque sensitive structure of the integrated structure;

Figure 3 is a schematic diagram of a five-dimensional force / torque sensitive structure of a split structure;

Figure 4 is a schematic diagram of the position of the strain gauge of the lower sensitive unit;

Figure 5 is a schematic diagram of the position of the strain gauge of the upper sensitive unit;

Figure 6 is a schematic block diagram of the principle of a pre-signal processing circuit;

Figure 7 is a block diagram of digital signal processing and bus interface;

FIG. 8 is a schematic diagram of calculating a coordinate position during a handwriting process.

 FIG. 1 is a schematic diagram of the overall structure of the handwriting input platform of the present invention, which is composed of an armrest plate 1, a signature plate 2, a central axis 3, an upper sensitive unit 4, an upper connecting flange 5, a lower connecting flange 6, a lower sensitive unit 7, The front signal processing circuit 8, the universal bus network interface 9 and the base 10 are composed together.

 The armrest plate 1 and the base 10 may be an integrated structure, which depends on the installation position and size of the signal processing circuit. The signature plate 2, the upper sensitive unit 4, the lower sensitive unit 7, the upper connecting flange 5, and the lower connecting flange. 6 It is necessary to ensure the coincidence of the central axis, which is achieved through the matching of the shaft hole, that is, the center of the signature plate 2 has a concave cylindrical cavity with an inner diameter equal to the outer diameter of the upper connecting flange 5 and a clearance fit with each other. Lan 5 and upper sensitive unit 4 釆 use engraved line alignment and positioning pins to ensure the transmission of the axis.

The center holes of the upper sensitive unit 4 and the lower sensitive unit 7 are respectively matched with the central axis 3, and the front signal processing circuit The circuit 8 is installed in the lower connection flange cavity to ensure that the original output signal can be amplified and filtered and output to the interface circuit section. The universal bus interface circuit 9 is also installed on the base, which mainly completes the digitization of the amplified and filtered analog signal. Processed and connected to a personal computer via a USB interface.

 FIG. 2 is a schematic diagram of a five-dimensional force / torque sensitive structure with integrated structure, which is a key part of the digital handwriting input of the present invention. The upper sensitive unit 4, the lower sensitive unit 7, the central axis 3, the upper connection flange (5) and the lower connection. The flange (6) is machined to become a whole, and the accuracy of the machining is used to ensure the parallelism of the upper and lower sensitive units and the connection position between the central axis and the upper and lower sensitive units.

 FIG. 3 is a schematic diagram of a five-dimensional force / torque sensitive structure of a split structure. The upper sensitive unit 4 and the lower sensitive unit 7 are fixed to the central shaft 3 through a fixed nut 12 and a fixed pressure ring 11. Specifically, the central shaft 3 is fixed. The length of the mating shaft at both ends is increased, and pressure blocks fitted with the shaft are added to the sensitive unit, respectively, and the pressure ring 11 is fixed by a nut. The shoulders at both ends of the central shaft 3 are respectively threaded in symmetrical positions in the X and Y directions. Here, the M3 nut and screw are used to fix the upper sensitive unit 4, the lower sensitive unit 7, and the central shaft 3.

Figure 4 is a schematic diagram of the position of the strain gauge patch of the lower sensitive unit. The position of the circular diaphragm of the lower sensitive unit 4 is as shown in the figure, and R, R, R, R, R,> R, Rl¾l, R, R, ¾l. A total of 12 strain resistances, of which R ™, R _FX2 and R∞, R _{M are} symmetrically arranged on a straight line in the X direction, Rm, ₂ and 1 ^ ₃ , and R ™ are symmetrically arranged on a straight line in the Y direction, and R ™, 1 ^ ₂ and ^ _{3 are} symmetrically arranged on a straight line that intersects with two straight lines of XY at 45 degrees, and all three straight lines pass through the center of the circular diaphragm. R ™, R ™, R, F, R _m , are arranged near the outer circle of the diaphragm, χ ₂ , R, R _TO , R ™, R _FZ3 are arranged near the hard center of the diaphragm, where the hard The central diameter is the outer diameter of the central axis 3, and the outer circle of the strain resistance is smaller than the inner circle of the upper and lower connecting flanges.

 Figure 5 is a schematic diagram of the location of the strain gauge of the upper sensitive unit. The round diaphragm of the upper sensitive unit 7 is provided with R ™,

There are 8 sensitive resistors in R ₂ , R _FX3 , R ™, R _m , R ™, and RR. Among them, R _PXI , R _FX2 and R _ra , R ™ are symmetrically arranged on a straight line in the X direction. R, and R _TO , R _{m is} symmetrically arranged on a straight line in the Y direction, and both straight lines pass through the center of the circular diaphragm; and R _PX1 , R ™, R _m , R are arranged near the outer circle of the circular diaphragm, R, R _ra , R ™ _{RTO is} arranged near the hard center of the circular diaphragm; the hard center diameter here is the outer diameter of the central axis (3), and the outer circle of the strain resistance is smaller than the inner circle of the upper and lower connecting flanges. At the same time, the upper sensitive unit 4 can also use the sticking method of FIG. 4 to paste three sets of strain gauges on the diaphragm, that is, add a set of four strain gauges R _m , R, R for detecting the force in the direction of Fz.

Figure 6 is a schematic block diagram of the pre-signal processing circuit. The pre-signal processing circuit 8 is composed of a 5-channel signal amplifier circuit and a filter circuit. Here, the amplifier circuit uses a differential instrument amplifier 14 to directly amplify the original signal output from the bridge circuit. The filter circuit is mainly a low-pass filter. Here, in order to reduce the volume, an RC low-pass filter 13 is used. Can also use special filtering integrated chip. The front signal processing circuit system uses a single power supply mode. The reference terminal of the instrumentation amplifier 14 is provided by a reference power source 15. Here, a 1.2V reference is selected. Each bridge is routed to the difference in resistance value of the resistance strain gauge, and the zero position needs to be adjusted. 电阻 Use the resistor to directly compensate the bridge circuit to ensure that the output of each group of bridge circuits is about 0mV. The amplification factor is externally fed back by the instrumentation amplifier 14. Resistance 16 is determined. The specific adjustment method is as follows: After the zero position of the bridge circuit is adjusted, by adding the design full-scale load to the corresponding direction, read the output voltage value from a high-accuracy 6 and a half digital voltmeter, and divide the expected output voltage by the voltmeter. The reading is the desired magnification. The calculation of the resistance value of the amplification feedback resistor is obtained according to the calculation formula of the selected instrumentation amplifier 14. The selected instrumentation amplifier 14 is AD623. The corresponding feedback resistance calculation formula is: R _G / 100, common

Where V. Is the expected voltage output, and is the original output when fully loaded before amplification, R. The value of the feedback resistor needed for the design. Figure 7 is a block diagram of the digital signal processing and bus interface. It consists of five 12-bit A / D converters, a single-chip MCU system (microprocessor), and a USB interface circuit (including RS232 interface). The integrated A / D and It is implemented by a system on a chip with a USB interface, or it is composed of discrete components of an A / D chip, a sample holding circuit, an MCU, and a USB control chip. It is mainly used to digitize analog signals and send them after digital smoothing filtering. To an external computer and communicate with the computer. Figure 8 is a schematic diagram of the calculation of the coordinate position during the handwriting process. The calculation of the coordinate position during the handwriting process is performed by a computer. Since the contact position of the pen tip and the writing tablet and the five-dimensional force / torque information are desired, the force / torque measured by the sensor itself The information is the result obtained from the coordinate system relative to itself, and the coordinate transformation calculation needs to be performed according to the position diagram shown in Fig. 8. The calculation formula is as follows:

 -M „+ F-z

 X:

M + F-z

F 'According to the five-dimensional force / torque information output by the handwriting input platform, according to the above formula, the continuous trajectory of the pen tip in contact with the tablet can be calculated according to the above formula, so as to obtain its handwriting information such as pen shape, stroke order, stroke, and writing speed. The force and direction of the pen tip and tablet during personal writing, the shape of the pen, The stroke order, stroke, and writing speed are not the same. The present invention can not only record these characteristic information, but also can identify which person wrote the character and whether it was written by the same person. It is very suitable for e-commerce and e-government that require encrypted signatures and anti-counterfeiting. Signing occasion. detailed description

 In the present invention, the upper sensitive unit 4 and the lower sensitive unit 7 are directly processed from a copper-based material with a thickness of 0.3 ram into a round membrane with a diameter of 60 bands. At the same time, a hole with a diameter of 10 mm is processed in the center for use with The center axis 3 is aligned, and 4 holes with a diameter of 3.2 mm are processed at a position of 20 mm in diameter. The directions of the holes are perpendicular to each other, and the straight lines passing through the center of the circle are used as the score lines in the X and Y directions. A hole with a diameter of 5 mm is processed in the center of the shaft 3, and a lead wire for the upper sensitive bridge circuit is connected to the front signal processing circuit board 8. The central shaft 3 has an outer diameter of 28 mm, and both ends are machined with steps with a diameter of 10 pans and a height of 2 ram. For specific assembly, the two steps of the central shaft 3 are matched with the center holes of the upper and lower sensitive units, and the method is pasted. Make the ends fixed to the plane of the upper and lower sensitive units, and at the same time, ensure that the X and Y engraving directions on the upper and lower sensitive units are consistent.

 The strain resistance on the sensitive unit uses a 350 ohm foil strain gage, which requires its own temperature compensation. During specific bonding, an additional mask needs to be made to ensure the accuracy of the location of the strain gage. The specific size of the mask is sensitive to the top and bottom. The size of the unit is the same, and the size of the hole on it is also the same to facilitate the alignment of the X and Y coordinate directions when the resistor is pasted. In addition, a hole is engraved on the mask according to the position of the strain gauge. The hole size is 0.3 mm larger than the actual size of each side of the strain gauge. When the strain gauge is actually attached, the mask and the four diameters on the sensitive unit are first affixed. Align the holes in 3.2, and then paste the strain gages in the corresponding direction in the corresponding mask holes. After the strain gages are fully attached, remove the mask.

 In addition, the holes on the upper and lower sensitive units can also be used for fixing. This requires the M3 screw holes to be processed at the corresponding positions on the shoulders of the central axis. The screw fixing method can be used in actual applications or not. .

 The upper and lower flanges are also aligned using a pre-marked method. Specifically, after the flange processing is completed, the inner side is engraved with a straight line at a position 90 degrees perpendicular to each other. The outer diameter of the flange is equal to the diameter of the sensitive unit. , The inner diameter is larger than the outer circle of the paste resistor on the sensitive unit. After the scribe lines are aligned, the upper and lower flanges can be fixed to the sensitive unit by a paste method, so that the processing and assembly of the force information acquisition unit of the present invention is completed.

 The bridge power line of the upper sensitive unit 4 is introduced from the hole of the central axis 3, and the bridge signal is also drawn through the hole of the central shaft 3. The power line of the lower sensitive unit 7 and the bridge signal line can be connected to the front signal processing. The circuit 8 and the circuit board of the pre-signal processing circuit 8 are fixed in a cavity formed by the lower sensitive unit and the base 10.

For the entire five-dimensional force / torque part to be fixed to the base 10 and the signature plate 2 directly with screws and threads Realization of holes also requires scribe line alignment.

 In order to measure the contact force between the pen tip and the surface of the platform 2 during the handwriting process, the entire force measurement part must be calibrated. The coordinate center corresponding to the calibration is the center of the upper sensitive unit 4, and the XY plane is the upper surface of the upper sensitive unit 4. During the calibration process, a calibration auxiliary device is designed with this coordinate system, and the original six-dimensional force calibration platform is used to realize the original calibration. The calibration of the signal and the determination of the magnification, and the mathematical relationship between the force input in each direction and the voltage output of the bridge are obtained, and the force information is obtained by the MCU in the signal processing unit.

 Through the USB interface, the five-dimensional force / torque information collected by the microprocessor is sent to the personal computer, and the characteristic information such as pen shape, stroke order, stroke, and writing speed during the handwriting process are obtained according to the calculation formula provided above.

 The computer handwriting input platform provided by the present invention is based on a traditional electronic writing board that records information such as stroke order, strokes, and fonts, and simultaneously records the five-dimensional force / torque information of the pen in contact with the handwriting input platform. During the signature process, Static information such as fonts is easy to imitate, while dynamic information such as writing rate, time, stroke order, and writing pressure generated during the signature process varies from person to person and cannot be imitated. Handwritten signatures represent long-term continuous habitual behavior in the human brain. The characteristics of the brand are consistent in a certain range and will not change in the short term. The handwriting input platform and writing information acquisition method provided by the present invention can not only record static information such as handwriting type and strokes, but also obtain stroke order, writing speed, time, and five-dimensional force / torque information of the pen tip and the table surface. Using this input platform, Even though static information is imitated, the above dynamic information is difficult to imitate because they are invisible and it is very difficult to imitate more than five behavioral characteristics. Therefore, the digital signature method provided by the present invention has a good anti-counterfeiting effect, and also retains the habit of natural writing, which has a very good application prospect. .

Claims

Rights request 1. A computer handwriting input platform comprising a signature tablet (2), an upper sensitive unit (4), a lower sensitive unit (7), a pre-signal processing circuit (8), and a universal bus network interface (9), of which the upper sensitive The unit (4), the lower sensitive unit (7) and the central axis (3) form a five-dimensional force / torque sensitive structure. The pre-signal processing circuit (8) includes a five-way low-pass filter (13) and an instrumentation amplifier (14). The reference voltage source (15), the feedback resistor (16), and the universal bus network interface (9) include a microprocessor with five 12-bit A / Ds, a USB interface, and an RS232 interface, which are characterized by:  The computer handwriting input platform is composed of a handrail tablet (1), a signature tablet (2), a central axis (3), an upper sensitive unit (4), an upper connecting flange (5), a lower connecting flange (6), and a lower sensitive unit. (7), the front signal processing circuit (8), the universal bus network interface (9), and the base (10), where the armrest plate (1) and the base (10) can be an integrated structure, according to the front signal Depending on the installation position and size of the processing circuit (8);  The upper sensitive unit (4), the lower sensitive unit (7) and the central axis (3) form a five-dimensional force / torque sensitive structure, and the upper sensitive unit (4), the lower sensitive unit (7) and the central axis (3) It can adopt a split structure, that is, they are connected together by adhesive, and the upper sensitive unit (4), the upper connecting flange (5), the central shaft (3), the lower sensitive unit (7), and the lower connecting flange (6) An integrated structure can also be adopted, that is, directly processed into a whole through machining;  The signature plate (2), the upper sensitive unit (4), the lower sensitive unit (7), the upper connecting flange (5), and the lower connecting flange (6) must ensure the coincidence of the central axis (3), specifically through the shaft hole The matching mode is realized, that is, a recessed cylindrical cavity is provided in the center of the signature plate (2), and the inner diameter is equal to the outer diameter of the upper connection flange (5), and the clearance fits with each other. At the same time, the upper connection flange (5) and the upper sensitive unit ( 4) Use engraved line alignment and positioning pins to ensure the transmission of the central axis (3);  The circuit board of the front signal processing circuit (8) is fixed in the cavity formed by the lower sensitive unit (7), the lower connection flange (6) and the base 10 to ensure that the original output signal can be amplified and filtered and output to the interface. The circuit part, the USB interface (9) is placed on the base (10); The computer handwriting input platform can be directly used as the computer's input peripheral. You can use any pen to write directly on the tablet without consuming ink, or you can embed the writing platform base with the computer case and directly embed it. In a personal computer system, handwriting input is implemented instead of a keyboard. 2. A method for obtaining information during handwriting on a computer handwriting input platform according to claim 1, wherein the method for obtaining information comprises a method for obtaining five-dimensional force / torque information during handwriting and handwriting Method of obtaining signature pen shape, stroke order, stroke, and writing speed information; A. The five-dimensional force / torque information acquisition method during the writing input process, namely the three-dimensional force information and the two-dimensional torque information acquisition method, wherein-three sets of foil-type force-sensitive strain resistors are pasted on the round diaphragm of the lower sensitive unit (7), Two sets of foil-type force-sensitive strain resistors are attached to the round membrane of the sensitive unit (4), or three sets of foil-type force-sensitive strain resistors can be pasted to the round membrane of the sensitive unit (4), which is used to measure Fz force information The sensitive resistors R _FZ1 , R _FZ2 , Rp _Z3 > R ™ can be pasted on the round diaphragm of the lower sensitive unit (7), or on the round diaphragm of the upper sensitive unit (4), and adopt a specific bridge method The five-dimensional force / torque information is obtained during the writing process, and the inter-dimensional coupling relationship is obtained through calibration. After filtering, amplification, A / D conversion, and data processing, the contact force information of the pen tip and the tablet is obtained. 7) Sensitive resistors R, _X2 , R ™, and R ™ on the circular diaphragm are used to measure the force information Fx; Sensitive resistors Rm, R _TO , R ™, and R are used to measure the force information Fy; Sensitive resistors R _FZl , R _FZ2 , R _FZ3 , R ™ is used to achieve the measurement of force information Fz; Among them, R _FX1 , R _FX2, R _FX3 , and R ™ are symmetrically arranged on a straight line in the X direction, R, R _FY2 and R ™, R _{FY4 are} symmetrically arranged on a straight line in the Y direction, and Rm, and 1 ^ _{3 are} symmetrically arranged. On the straight line that intersects with two straight lines of XY at 45 degrees, the three straight lines pass through the center of the circular diaphragm, and R _F , R ™, R _m , R ™, R _FZ1 , R ™ are arranged near the circular diaphragm. The position of the outer circle, R∞, R ™, RPV2, R _TO , R _FZ2 , ₃ are arranged near the hard center of the circular diaphragm; the hard center diameter here is the outer diameter of the central axis (3), and the outer part of the strain resistance is smaller than Inner circle of upper and lower connecting flanges; Upper Sensing Unit (4) Sensitive resistors R _rai and Rpx ₂ on the round diaphragm are used to measure the force information Mx; Sensitive resistors R _m , R _FY2 , R _TO , and Rm are used to achieve the force Measurement of information My; where R _FX1 , R _FX2 and R _FX3 , R ™ are symmetrically arranged on a straight line in the X direction, R, Rp _Y2 and R ™, R _{m are} symmetrically arranged on a straight line in the Y direction, and both straight lines pass The center of the round diaphragm; and RP _X1 , R ™, Rm, R are arranged near the outer circle of the round diaphragm, and R _FX2 , R ™, R, R _TO are arranged near the hard center of the round diaphragm; here The hard center diameter is the outer diameter of the central axis (3), and the outer circle of the strain resistance is smaller than the inner circle of the upper and lower connecting flanges; B. The method for obtaining information about the shape, stroke order, stroke, and writing speed of a handwritten signature, calculating the position of the contact point of the pen tip on the handwriting signature tablet (2), and the position in the coordinate system of the handwriting platform, and Real-time detection and continuous calculation to obtain the stroke shape, stroke order, stroke, and writing speed information during the handwriting process, and the writing speed information can be further calculated by the microprocessor. The formula for the contact position of the pen tip and tablet is as follows: