Impact testing methods for power tools and power tools

Abstract

This application provides an impact detection method for power tools and the power tool itself. The impact detection method includes: determining a first time based on the mechanical parameters of the power tool; the first time being the cycle time of the impact current; determining a second time based on the first time and a preset duration; the second time being a sampling time for a set of current data; acquiring first current data sampled within the second time; and determining whether the power tool has undergone an impact operation based on the first current data. This application determines the sampling time of the current data by calculating the impact cycle time of the power tool, and then detects whether an impact has occurred based on the trend of current change within the sampling time, thereby improving the accuracy and applicability of the impact detection method.

Description

Technical Field

[0001] This application relates to the field of electromechanical technology, and in particular to an impact detection method for power tools and the power tool itself. Background Technology

[0002] With the advancement of technology, impact tools have gradually replaced traditional manual tools and are used in drilling, fastener installation and other applications. In impact tools, after tightening screws or bolts, the structural release mechanism will perform a release impact.

[0003] In some construction environments, such as thin iron or plywood, continuous impact after tightening screws can easily puncture or damage the workpiece. Therefore, it is necessary to control the stopping of tools by detecting impact.

[0004] Currently, without using sensors, impact is generally detected by detecting changes in current. However, the current conditions for impact detection vary and are complex under different working conditions, different rotational speeds, etc., making it difficult to accurately detect tool impact by detecting current. Summary of the Invention

[0005] In view of this, this application provides an impact detection method for power tools and a power tool. The method determines the sampling time of a set of current data by calculating the impact cycle time of the power tool, and then detects whether an impact has occurred based on the change of current during the sampling time, thereby improving the accuracy and applicability of the impact detection method.

[0006] In a first aspect, embodiments of this application provide an impact detection method for power tools, the impact detection method comprising:

[0007] The first time is determined based on the mechanical parameters of the power tool; the first time is the cycle time of the impact current.

[0008] The second time is determined based on the first time and a preset duration; the second time is the sampling time for a set of current data.

[0009] Acquire the first current data sampled during the second time period;

[0010] The power tool was determined to have undergone an impact operation based on the first current data.

[0011] The above technical solution can improve the accuracy of impact detection by current and avoid false detection of impact caused by sudden current changes due to working conditions or operation.

[0012] In some embodiments, determining whether the power tool has undergone an impact operation based on the first current data includes:

[0013] The trend of current change in the second time period is determined based on the analysis of the first current data.

[0014] The power tool was determined to have undergone an impact operation based on the changing trend.

[0015] In some embodiments, when the mechanical parameters include: number of motor pole pairs, mechanical reduction ratio, and impact block type, the first time is calculated according to the following formula:

[0016]

[0017] T2 = T1 × n;

[0018]

[0019] In the formula, T1 is the cycle time of one revolution of the motor, t is the cycle time of two phase commutations of the motor of the power tool, p is the number of pole pairs of the motor, T2 is the cycle time of one revolution of the output shaft of the power tool, n is the mechanical reduction ratio, T3 is the cycle time of a single impact of the power tool, and c is the number of impacts of one revolution of the striking block.

[0020] The above technical solution can accurately calculate the cycle time of a single impact of various types of impact power tools.

[0021] In some embodiments, determining whether the power tool has undergone an impact operation based on the first current data includes:

[0022] The trend of current change in the second time period is determined based on the analysis of the first current data.

[0023] The power tool was determined to have undergone an impact operation based on the changing trend.

[0024] The above technical solution can quickly and accurately determine the overall trend of current change in the second time period.

[0025] In some embodiments, determining the trend of current change over the second time period based on the analysis of the first current data includes:

[0026] The first current data is divided into multiple groups of second current data according to the time sequence of current sampling.

[0027] The changing trend of each group of second current data is calculated according to the preset algorithm;

[0028] The trend of current change in the second time period is determined based on the trend of change in each set of current data.

[0029] In some embodiments, calculating the changing trend of each group of second current data according to a preset algorithm includes:

[0030] If the first data point of the second current data in the same group is greater than the last data point, then the second current data in that group is determined to be in a downward trend.

[0031] If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is determined to be on an upward trend.

[0032] If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group.

[0033] If the first data point is greater than the median data point, then the trend of the second current data point in this group is determined to be first decreasing and then increasing.

[0034] If the first data point is less than the median data point, then the trend of the second current data point in this group is determined to be an initial increase followed by a decrease.

[0035] In some embodiments, determining the current change trend within the second time period based on the change trend of each set of current data includes:

[0036] The multiple sets of second current data are sorted according to the current sampling time.

[0037] The changing trends of the multiple sets of second current data are marked;

[0038] The trend of current change within the second time period is determined based on the annotation;

[0039] The labels include: rising, falling, rising then falling, and falling then rising.

[0040] In some embodiments, determining the current change trend over the second time period based on the first current data analysis further includes:

[0041] The first current data is divided into four groups of second current data according to the time sequence of current sampling.

[0042] Calculate the trend of change of the second current data for each group. If the first data of the second current data in the same group is greater than the last data, then mark the second current data of that group as having a downward trend.

[0043] If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is marked as having an upward trend.

[0044] If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group.

[0045] If the first data point is greater than the median data point, then the trend of the second current data point in this group is marked as first decreasing and then increasing.

[0046] If the first data point is less than the median data point, then the trend of the second current data point in this group is marked as first rising and then falling.

[0047] The trend of current change during the second time period is determined based on the aforementioned markings.

[0048] In some embodiments, determining whether the power tool has undergone an impact operation based on the trend of change includes:

[0049] If the current change trend in the second time period conforms to the preset change trend, then it is determined that the power tool has performed an impact operation.

[0050] The preset change trends include: rise-fall, fall-rise, rise-fall-rise, fall-rise-fall-fall.

[0051] In some embodiments, the impact detection method for power tools further includes:

[0052] If an impact operation is detected by the power tool, a preset working mode is executed;

[0053] The preset operating modes include: immediate shutdown, shutdown after a preset time, or shutdown after a preset number of impacts.

[0054] The above technical solution can automatically stop the power tool after an impact is detected, based on the actual working conditions and needs. This helps to accurately control the fastening status and avoid damage to the workpiece caused by poor fastening.

[0055] Secondly, embodiments of this application provide a power tool, the power tool comprising:

[0056] Electric motor;

[0057] An output shaft, configured to hold a pointed tool for applying a tightening or loosening force to a fastening member, is driven by the motor.

[0058] The controller is configured to:

[0059] The first time is determined based on the mechanical parameters of the power tool; the first time is the cycle time of the impact current.

[0060] The second time is determined based on the first time and a preset duration; the second time is the sampling time for a set of current data.

[0061] Acquire the first current data sampled during the second time period;

[0062] The trend of current change in the second time period is determined based on the analysis of the first current data.

[0063] The power tool was determined to have undergone an impact operation based on the changing trend.

[0064] This application provides an impact detection method for power tools and the power tool itself. The impact detection method includes: determining a first time based on the mechanical parameters of the power tool; the first time being the cycle time of the impact current; determining a second time based on the first time and a preset duration; the second time being a sampling time for a set of current data; acquiring first current data sampled within the second time; and determining whether the power tool has undergone an impact operation based on the first current data. This application determines the sampling time of the current data by calculating the impact cycle time of the power tool, and then detects whether an impact has occurred based on the trend of current change within the sampling time, thereby improving the accuracy and applicability of the impact detection method.

[0065] It should be understood that the description in the Summary Section is not intended to limit the key or essential features of the embodiments of this application, nor is it intended to restrict the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0066] Figures 1-3 This is a flowchart illustrating an impact detection method for power tools according to an embodiment of this application;

[0067] Figures 4-26 This is a schematic diagram illustrating the changing trend of the first current data in an embodiment of this application;

[0068] Figure 27 This is a schematic diagram of the structure of a power tool according to an embodiment of this application;

[0069] Figure 28 This is a schematic diagram of the control logic of an electric tool according to an embodiment of this application. Detailed Implementation

[0070] To make the technical solution and beneficial effects of this application more apparent and understandable, a detailed description is provided below by listing specific embodiments. The accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.

[0071] The embodiments in this application are not exhaustive, but merely illustrative of some embodiments, and are not intended to limit the scope of protection of this disclosure. Unless otherwise specified, each step in a particular embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a particular embodiment can also be implemented as an independent embodiment, and the order of the steps in a particular embodiment can be arbitrarily interchanged. Furthermore, the optional implementation methods in a particular embodiment can be arbitrarily combined; moreover, the embodiments can be arbitrarily combined, for example, some or all steps of different embodiments can be arbitrarily combined, and a particular embodiment can be arbitrarily combined with the optional implementation methods of other embodiments.

[0072] In each embodiment of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of the embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0073] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure.

[0074] In the embodiments of this application, unless otherwise stated, elements expressed in the singular form, such as "a," "an," "the," "the," "the," "the," "the," "the," "this," etc., can mean "one and only one," or "one or more," "at least one," etc. For example, when using articles such as "a," "an," "the," etc. in translation, the noun after the article can be understood as either a singular expression or a plural expression.

[0075] In the embodiments of this application, "multiple" refers to two or more.

[0076] The prefixes "first," "second," etc., used in the embodiments of this application are merely for distinguishing different descriptive objects and do not impose restrictions on the position, order, priority, value, or content of the descriptive objects. The description of the descriptive objects should be found in the claims or the context of the embodiments, and the use of prefixes should not constitute unnecessary restrictions. For example, if the descriptive object is a "field," the ordinal numbers preceding "field" in "first field" and "second field" do not restrict the position or order of the "fields." "First" and "second" do not restrict whether the "fields" they modify are in the same message, nor do they restrict the order of "first field" and "second field." Similarly, if the descriptive object is a "level," the ordinal numbers preceding "level" in "first level" and "second level" do not restrict the priority between "levels." Furthermore, the value of the descriptive object is not limited by ordinal numbers and can be one or more. For example, in "first device," the value of "device" can be one or more. Furthermore, the objects modified by different prefixes can be the same or different. For example, if the object being described is "device", then "first device" and "second device" can be the same device or different devices, and their types can be the same or different. Similarly, if the object being described is "information", then "first information" and "second information" can be the same information or different information, and their content can be the same or different.

[0077] Furthermore, each element, each row, or each column in the embodiments of this application can be implemented as an independent embodiment, and any combination of any element, any row, or any column can also be implemented as an independent embodiment.

[0078] Figure 1 An impact detection method for power tools, as described in this application embodiment, is as follows: Figure 1 As shown, the impact testing method includes:

[0079] S101. Determine the first time based on the mechanical parameters of the power tool.

[0080] The mechanical parameters include: the number of motor pole pairs, the mechanical reduction ratio, and the type of impact block; the first time is the cycle time of the impact current.

[0081] In one possible implementation, determining the first time based on the mechanical parameters of the power tool includes:

[0082] The first time is calculated according to the following formula:

[0083]

[0084] T2 = T1 × n;

[0085]

[0086] In the formula, T1 is the cycle time of one revolution of the motor, t is the cycle time of two phase commutations of the motor of the power tool, p is the number of pole pairs of the motor, T2 is the cycle time of one revolution of the output shaft of the power tool, n is the mechanical reduction ratio, T3 is the cycle time of a single impact of the power tool, and c is the number of impacts of one revolution of the striking block.

[0087] In one specific embodiment, the cycle time of two phase commutations of the motor of the power tool is t = 3.51 ms, the number of pole pairs of the motor is p = 2, the mechanical reduction ratio is n = 8, the striking block type is T-type, and the striking block strikes twice in one rotation, i.e., c = 2.

[0088] The cycle time T3 of a single impact by the power tool can be calculated using the above formula as 14.04 ms.

[0089] It should be noted that when calculating T3, the lag in current sampling may cause an error between the calculated T3 and the impact period in the actual sampled current waveform. This error can be avoided by adjusting the mechanical parameters, for example, by adjusting the mechanical reduction ratio of the power tool.

[0090] S102. Determine the second time based on the first time and the preset duration.

[0091] The second time is the sampling time of a set of current data.

[0092] In one possible implementation, the second time is equal to the first time plus a preset duration.

[0093] It should be noted that the preset duration can be determined according to the application scenario of the power tool, and the preset duration can also be a negative number.

[0094] For example, if the application scenario of the power tool is to work on a thinner material, such as thin iron or plywood, the preset time is one-eighth of the first time.

[0095] For example, if the application scenario of the power tool is to work on a thicker and less easily damaged material, such as thick iron, the preset duration is zero to the first time.

[0096] For example, when setting the preset duration, the operating conditions of the power tools can be disregarded, and the preset duration can be uniformly set to the time from zero to the first moment.

[0097] For example, when the preset duration is negative, the range of the preset duration is from negative one-quarter of the first time to zero.

[0098] S103. Obtain the first current data sampled within the second time period.

[0099] In one possible implementation, a small precision resistor is connected in series in the circuit. When current flows through this resistor, a voltage drop proportional to the current is generated across it. The analog-to-digital converter in the power tool's control chip can read this voltage drop and thus calculate the magnitude of the current.

[0100] In one possible implementation, current sampling can be achieved using a Hall sensor. First, the analog voltage signal output by the Hall sensor is acquired, amplified by an operational amplifier circuit, and then the amplified analog voltage signal is input to a microcontroller or other control chip's digital converter module for analog-to-digital conversion. Finally, the acquired digital signal is analyzed and processed according to a pre-set algorithm or model to obtain the final current value.

[0101] In one specific embodiment, after determining the second time, the first current data within the second time length can be collected in real time to perform impact detection.

[0102] In another specific embodiment, the first current data can be collected in real time and stored in the storage unit of the power tool controller, and then the first current data within a second time length can be read from the memory to perform impact detection; wherein, the start node for reading the first current data can be preset in advance according to the second time length.

[0103] It should be noted that if the preset duration is uniformly set to zero to the first time in step S102, then multiple sets of first current data will be obtained in step S103.

[0104] S104. Determine whether the power tool has undergone an impact operation based on the first current data.

[0105] In one possible implementation, such as Figure 2 As shown, determining whether the power tool has undergone an impact operation based on the first current data includes:

[0106] S1041. Analyze and determine the trend of current change in the second time period based on the first current data.

[0107] In one possible implementation, such as Figure 3 As shown, determining the current change trend within the second time period based on the analysis of the first current data includes:

[0108] S10411. Divide the first current data into multiple groups of second current data according to the time sequence of current sampling.

[0109] In one possible implementation, the first current data can be divided into four groups of second current data.

[0110] In a specific embodiment, if the first current data is {buf1, buf2, buf3… buf} x}, where x is the number of the first current data;

[0111] Based on the time sequence of current sampling, the first current data is divided into four equal parts to obtain the following four groups of second current data:

[0112] I [0] ={buf1,buf2,buf3…buf N};

[0113] I [1] ={buf N+1 ,buf N+2 ,buf N+3 …buf 2N};

[0114] I [2] ={buf 2N+1 ,buf 2N+2 ,buf 2N+3 …buf 3N};

[0115] I [3] ={buf 3N+1 ,buf 3N+2 ,buf 3N+3 …buf 4N};

[0116] in,

[0117] In another specific embodiment, if the current data is {buf1, buf2, buf3… buf} x}, where x is the number of the first current data;

[0118] Based on the time sequence of current sampling, the first current data is divided into four equal parts to obtain the following eight groups of second current data:

[0119] I [0] ={buf1,buf2,buf3…buf N};

[0120] I [1] ={buf N+1 ,buf N+2 ,buf N+3 …buf 2N};

[0121] I [2] ={buf 2N+1 ,buf 2N+2,buf 2N+3 …buf 3N};

[0122] I [3] ={buf 3N+1 ,buf 3N+2 ,buf 3N+3 …buf 4N};

[0123] I [4] ={buf 4N+1 ,buf 4N+2 ,buf 4N+3 …buf 5N};

[0124] I [5] ={buf 5N+1 ,buf 5N+2 ,buf 5N+3 …buf 6N};

[0125] I [6] ={buf 6B+1 ,buf 6N+2 ,buf 6N+3 …buf 7N};

[0126] I [7] ={buf 7N+1 ,buf 7N+2 ,buf 7N+3 …buf 8N};

[0127] in,

[0128] It should be noted that the number of groups can be set according to factors such as actual impact detection requirements and the number of first current data samples. The number of groups can be greater than two. When grouping, equal division or non-equal division can be used.

[0129] S10412. Calculate the trend of change of the second current data for each group according to the preset algorithm.

[0130] In one possible implementation, the step of calculating the changing trend of each group of second current data according to a preset algorithm includes:

[0131] If the first data point of the second current data in the same group is greater than the last data point, then the second current data in that group is determined to be in a downward trend.

[0132] If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is determined to be on an upward trend.

[0133] If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group.

[0134] If the first data point is greater than the median data point, then the trend of the second current data point in this group is determined to be first decreasing and then increasing.

[0135] If the first data point is less than the median data point, then the trend of the second current data point in this group is determined to be an initial increase followed by a decrease.

[0136] It should be noted that, Figures 4-11 This is a schematic diagram illustrating the trend of the second current data when the second time is equal to the first time.

[0137] For example, such as Figure 4 As shown, according to the method in step S10412, the trend of change of the first group of second current data is decreasing, the trend of change of the second group of second current data is increasing, the trend of change of the third group of second current data is increasing, and the trend of change of the fourth group of second current data is decreasing.

[0138] For example, such as Figure 5 As shown, according to the method in step S10412, the trend of change of the first group of second current data is increasing, the trend of change of the second group of second current data is decreasing, the trend of change of the third group of second current data is decreasing, and the trend of change of the fourth group of second current data is increasing.

[0139] For example, such as Figure 6 As shown, according to the method in step S10412, the trend of change of the first group of second current data is increasing, the trend of change of the second group of second current data is increasing, the trend of change of the third group of second current data is decreasing, and the trend of change of the fourth group of second current data is decreasing.

[0140] For example, such as Figure 7 As shown, according to the method in step S10412, the changing trend of the first group of second current data is decreasing, the changing trend of the second group of second current data is decreasing, the changing trend of the third group of second current data is increasing, and the changing trend of the fourth group of second current data is increasing.

[0141] For example, such as Figure 8 As shown, according to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is first upward and then downward, the trend of change of the third group of second current data is downward, and the trend of change of the fourth group of second current data is first downward and then upward.

[0142] For example, such as Figure 9 As shown, according to the method in step S10412, the changing trend of the first group of second current data is first rising and then falling, the changing trend of the second group of second current data is falling, the changing trend of the third group of second current data is first falling and then rising, and the changing trend of the fourth group of second current data is rising.

[0143] For example, such as Figure 10 As shown, according to the method in step S10412, the trend of change of the first group of second current data is decreasing, the trend of change of the second group of second current data is decreasing first and then increasing, the trend of change of the third group of second current data is increasing, and the trend of change of the fourth group of second current data is increasing first and then decreasing.

[0144] For example, such as Figure 11 As shown, according to the method in step S10412, the changing trend of the first group of second current data is first decreasing and then increasing, the changing trend of the second group of second current data is increasing, the changing trend of the third group of second current data is first increasing and then decreasing, and the changing trend of the fourth group of second current data is decreasing.

[0145] It should be noted that, Figures 12-23 This is a schematic diagram illustrating the trend of the second current data when the second time interval is longer than the first time interval.

[0146] For example, such as Figure 12 As shown, according to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is upward, the trend of change of the third group of second current data is downward, and the trend of change of the fourth group of second current data is upward.

[0147] For example, such as Figure 13 As shown, according to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is downward, the trend of change of the third group of second current data is upward, and the trend of change of the fourth group of second current data is upward.

[0148] For example, such as Figure 14 As shown, according to the method in step S10412, the changing trend of the first group of second current data is decreasing, the changing trend of the second group of second current data is decreasing, the changing trend of the third group of second current data is increasing, and the changing trend of the fourth group of second current data is decreasing.

[0149] For example, such as Figure 15As shown, according to the method in step S10412, the trend of change of the first group of second current data is decreasing, the trend of change of the second group of second current data is increasing, the trend of change of the third group of second current data is decreasing, and the trend of change of the fourth group of second current data is decreasing.

[0150] For example, such as Figure 16 As shown, according to the method in step S10412, the changing trend of the first group of second current data is first rising and then falling, the changing trend of the second group of second current data is falling, the changing trend of the third group of second current data is rising, and the changing trend of the fourth group of second current data is rising.

[0151] For example, such as Figure 17 As shown, according to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is first upward and then downward, the trend of change of the third group of second current data is downward, and the trend of change of the fourth group of second current data is upward.

[0152] For example, such as Figure 18 As shown, according to the method in step S10412, the changing trend of the first group of second current data is first decreasing and then increasing, the changing trend of the second group of second current data is increasing, the changing trend of the third group of second current data is decreasing, and the changing trend of the fourth group of second current data is decreasing.

[0153] For example, such as Figure 19 As shown, according to the method in step S10412, the trend of change of the first group of second current data is decreasing, the trend of change of the second group of second current data is decreasing first and then increasing, the trend of change of the third group of second current data is increasing, and the trend of change of the fourth group of second current data is decreasing.

[0154] For example, such as Figure 20 As shown, according to the method in step S10412, the changing trend of the first group of second current data is decreasing, the changing trend of the second group of second current data is decreasing, the changing trend of the third group of second current data is increasing, and the changing trend of the fourth group of second current data is first increasing and then decreasing.

[0155] For example, such as Figure 21 As shown, according to the method in step S10412, the trend of change of the first group of second current data is decreasing, the trend of change of the second group of second current data is increasing, the trend of change of the third group of second current data is first increasing and then decreasing, and the trend of change of the fourth group of second current data is decreasing.

[0156] For example, such as Figure 22As shown, according to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is downward, the trend of change of the third group of second current data is first downward and then upward, and the trend of change of the fourth group of second current data is upward.

[0157] For example, such as Figure 23 As shown, according to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is upward, the trend of change of the third group of second current data is downward, and the trend of change of the fourth group of second current data is first downward and then upward.

[0158] For example, when the second time is equal to the first time and the first current data is equally divided into eight groups of second current data, the trend of the second current data is as follows: Figure 24 As shown:

[0159] According to the method in step S10412, the trend of change of the second current data in the first group is decreasing, the trend of change of the second current data in the second group is decreasing, the trend of change of the second current data in the third group is increasing, the trend of change of the second current data in the fourth group is decreasing and then increasing, the trend of change of the second current data in the fifth group is increasing, the trend of change of the second current data in the sixth group is increasing, the trend of change of the second current data in the seventh group is decreasing, and the trend of change of the second current data in the eighth group is decreasing.

[0160] It should be noted that when the second time equals the first time and the first current data is equally divided into eight groups of second current data, other trends in the second current can be judged by referring to... Figures 5-11 (exist Figures 5-11 (The second current data is further grouped above, which will not be elaborated here.)

[0161] For example, when the second time is longer than the first time and the first current data is equally divided into eight groups of second current data, the trend of the second current data is as follows: Figure 25 As shown:

[0162] According to the method in step S10412, the trend of change of the second current data in the first group is upward, the trend of change of the second current data in the second group is upward, the trend of change of the second current data in the third group is upward, the trend of change of the second current data in the fourth group is first downward, the trend of change of the second current data in the fifth group is downward, the trend of change of the second current data in the sixth group is downward, the trend of change of the second current data in the seventh group is upward, and the trend of change of the second current data in the eighth group is upward.

[0163] It should be noted that when the second time is longer than the first time and the first current data is equally divided into eight groups of second current data, other trends in the second current can be judged by referring to... Figures 13-23 (exist Figures 13-23 (The second current data is further grouped above, which will not be elaborated here.)

[0164] For example, when the second time is equal to the first time and the first current data is unequally divided into four groups of second current data, the trend of the second current data is as follows: Figure 26 As shown:

[0165] According to the method in step S10412, the trend of change of the first group of second current data is upward, the trend of change of the second group of second current data is downward, the trend of change of the third group of second current data is downward, and the trend of change of the fourth group of second current data is upward.

[0166] It should be noted that when the second time is longer than the first time and the first current data is unequally divided into multiple groups of second current data, the trend of the second current data can be judged by referring to... Figure 26 This will not be elaborated upon here.

[0167] It should be noted that when the second time is less than the first time, the trend of the second current data can be referenced from the trend chart when the second time is greater than the first time; at this time, the preset duration ranges from negative one-quarter of the time to zero.

[0168] S10413. Determine the trend of current change in the second time period based on the trend of change in each group of current data.

[0169] In one possible implementation, determining the current change trend within the second time period based on the change trend of each set of current data includes:

[0170] The multiple sets of second current data are sorted according to the current sampling time.

[0171] The changing trends of the multiple sets of second current data are marked;

[0172] The trend of current change within the second time period is determined based on the annotation;

[0173] The labels include: rising, falling, rising then falling, and falling then rising.

[0174] It should be noted that annotations are not limited to text; numbers or letters can also be used.

[0175] For example, such as Figure 4As shown, the second current data is labeled as: decreasing-increasing-increasing-decreasing. By merging adjacent and identical trends, the final current trend in the second time interval is: decreasing-increasing-decreasing.

[0176] For example, such as Figure 5 As shown, the second current data is labeled as: rising-falling-falling-rising. By merging adjacent and identical trends, the final current trend in the second time period is: rising-falling-rising.

[0177] For example, such as Figure 6 As shown, the second current data is labeled as: rising-rising-falling-falling. By merging adjacent and identical trends, the final current trend in the second time interval is: rising-falling.

[0178] For example, such as Figure 7 As shown, the second current data is labeled as: decreasing-decreasing-increasing-increasing. By merging adjacent and identical trends, the final current trend in the second time interval is: decreasing-increasing.

[0179] For example, such as Figure 8 As shown, the second current data is labeled as: rising - rising then falling - falling - falling then rising. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: rising - falling - rising.

[0180] For example, such as Figure 9 As shown, the second current data is labeled as: first rise then fall - fall - first fall then rise - rise. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: rise - fall - rise.

[0181] For example, such as Figure 10 As shown, the second current data is labeled as: decreasing - decreasing then increasing - increasing - increasing then decreasing. By merging adjacent and identical trends, the final trend of the current in the second time period is: decreasing - increasing - decreasing.

[0182] For example, such as Figure 11 As shown, the second current data is labeled as: first decrease then increase - increase - first increase then decrease - decrease. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: decrease - increase - decrease.

[0183] For example, such as Figure 16 As shown, the second current data is labeled as: first rise then fall - fall - rise - rise. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: rise - fall - rise.

[0184] For example, such as Figure 17 As shown, the second current data is labeled as: rising - rising then falling - falling - rising. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: rising - falling - rising.

[0185] For example, such as Figure 18 As shown, the second current data is labeled as: first decrease then increase - increase - decrease - decrease. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: decrease - increase - decrease.

[0186] For example, such as Figure 19 As shown, the second current data is labeled as: decreasing - decreasing then increasing - increasing - decreasing. By merging adjacent and identical trends, the current trend in the second time period is finally obtained as: decreasing - increasing - decreasing.

[0187] For example, such as Figure 20 As shown, the second current data is labeled as: decreasing-decreasing-increasing-increasing-decreasing. By merging adjacent and identical trends, the final current trend in the second time interval is: decreasing-increasing-decreasing.

[0188] For example, such as Figure 21 As shown, the second current data is labeled as: decreasing-increasing-increasing-decreasing. By merging adjacent and identical trends, the final current trend in the second time interval is: decreasing-increasing-decreasing.

[0189] For example, such as Figure 22 As shown, the second current data is labeled as: rising-falling-falling then rising-rising. Adjacent and identical trends are merged, and the final trend of current change in the second time period is: rising-falling-rising.

[0190] For example, such as Figure 23 As shown, the second current data is labeled as: rising-rising-falling-falling then rising. By merging adjacent and identical trends, the current trend in the second time interval is finally obtained as: rising-falling-rising.

[0191] S1042. Determine whether the power tool has undergone an impact operation based on the changing trend.

[0192] In one possible implementation, determining whether the power tool has undergone an impact operation based on the changing trend includes:

[0193] If the current change trend in the second time period conforms to the preset change trend, then it is determined that the power tool has performed an impact operation.

[0194] The preset change trends include: rise-fall, fall-rise, rise-fall-rise, fall-rise-fall-fall.

[0195] It should be noted that if multiple sets of first current data are collected in step S103, the trend of change of each set of first current data is judged according to the method in step S104. If the trend of change of any set of first current data in multiple sets of first current data conforms to the preset trend, it is determined that the power tool has performed an impact operation.

[0196] In another specific implementation, determining whether the power tool has undergone an impact operation based on the first current data further includes:

[0197] The first current data is plotted as a current change curve. The current change curve is identified using image recognition technology. If the current change curve at the time of impact is identified, it is determined that the power tool has performed an impact operation. The current change curve is identified using a pre-trained image recognition model.

[0198] In another specific implementation, determining whether the power tool has undergone an impact operation based on the first current data further includes:

[0199] Impact is detected by the rate of change or the magnitude of the first current data. If the rate of change of the first current data is greater than the rate of change threshold or the value of the first current data is greater than the current threshold, it is determined that the power tool has performed an impact operation.

[0200] In one possible implementation, the impact detection method for the power tool further includes:

[0201] If an impact operation is detected by the power tool, a preset working mode is executed;

[0202] The preset operating modes include: immediate shutdown, shutdown after a preset time, or shutdown after a preset number of impacts.

[0203] In one specific embodiment, when an impact is detected in the power tool, the power tool immediately performs a stop operation according to a preset working mode.

[0204] In one specific embodiment, when an impact is detected from the power tool, the power tool will stop after 2 seconds according to a preset working mode.

[0205] In another specific embodiment, when an impact is detected by the power tool, the power tool continues to detect impacts and accumulate the number of impacts according to a preset working mode. When the number of impacts reaches 3, a shutdown operation is performed.

[0206] It should be noted that the preset working modes may also include: alarming via the power tool's light, and manually or automatically stopping the machine upon receiving the alarm signal; and alarming via sound, and manually or automatically stopping the machine upon receiving the alarm signal.

[0207] This application provides an impact detection method for power tools. By calculating the impact cycle time of the power tool, the sampling time of the current data is determined. Then, the impact is detected based on the current change trend within the sampling time, which improves the accuracy and applicability of the impact detection method. Furthermore, after an impact is detected, a corresponding preset working mode is matched, which can automatically stop the power tool according to the actual working conditions and needs. This is beneficial for precise control of the fastening state and avoids damage to the workpiece caused by poor fastening.

[0208] The above combination Figures 1 to 26 The impact detection method for power tools provided in the embodiments of this application is described in detail below. Figure 27 The power tools provided in the embodiments of this application are described in detail.

[0209] Figure 27 An example of an electric tool according to an embodiment of this application, such as Figure 27 As shown, the power tool includes:

[0210] Motor 10;

[0211] The output shaft 20 is configured to hold a tip tool for applying a fastening or loosening force to a fastening member, and the output shaft is driven by the motor 10.

[0212] The controller is configured to:

[0213] The first time is determined based on the mechanical parameters of the power tool; the first time is the cycle time of the impact current.

[0214] The second time is determined based on the first time and a preset duration; the second time is the sampling time for a set of current data.

[0215] Acquire the first current data sampled during the second time period;

[0216] The power tool was determined to have undergone an impact operation based on the first current data.

[0217] In one possible implementation, the controller is further configured to calculate the first time according to the following formula when the mechanical parameters include: number of motor pole pairs, mechanical reduction ratio, and impact block type:

[0218]

[0219] T2 = T1 × n;

[0220]

[0221] In the formula, T1 is the cycle time of one revolution of the motor, t is the cycle time of two phase commutations of the motor of the power tool, p is the number of pole pairs of the motor, T2 is the cycle time of one revolution of the output shaft of the power tool, n is the mechanical reduction ratio, T3 is the cycle time of a single impact of the power tool, and c is the number of impacts of one revolution of the striking block.

[0222] In one possible implementation, the controller is further configured to: analyze and determine the trend of current change over the second time period based on the first current data;

[0223] The power tool was determined to have undergone an impact operation based on the changing trend.

[0224] In one possible implementation, the controller is further configured to: divide the first current data into multiple groups of second current data according to the time sequence of current sampling;

[0225] The changing trend of each group of second current data is calculated according to the preset algorithm;

[0226] The trend of current change in the second time period is determined based on the trend of change in each set of current data.

[0227] In one possible implementation, the controller is further configured to: determine that the second current data in the same group is in a downward trend if the first data is greater than the last data in the same group;

[0228] If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is determined to be on an upward trend.

[0229] If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group.

[0230] If the first data point is greater than the median data point, then the trend of the second current data point in this group is determined to be first decreasing and then increasing.

[0231] If the first data point is less than the median data point, then the trend of the second current data point in this group is determined to be an initial increase followed by a decrease.

[0232] In one possible implementation, the controller is also configured to: sort the plurality of sets of second current data in chronological order of current sampling time based on the current sampling time;

[0233] The changing trends of the multiple sets of second current data are marked;

[0234] The trend of current change within the second time period is determined based on the annotation;

[0235] The labels include: rising, falling, rising then falling, and falling then rising.

[0236] In one possible implementation, the controller is further configured to: divide the first current data into four groups of second current data according to the time sequence of current sampling;

[0237] Calculate the trend of change of the second current data for each group. If the first data of the second current data in the same group is greater than the last data, then mark the second current data of that group as having a downward trend.

[0238] If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is marked as having an upward trend.

[0239] If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group.

[0240] If the first data point is greater than the median data point, then the trend of the second current data point in this group is marked as first decreasing and then increasing.

[0241] If the first data point is less than the median data point, then the trend of the second current data point in this group is marked as first rising and then falling.

[0242] The trend of current change during the second time period is determined based on the aforementioned markings.

[0243] In one possible implementation, the controller is further configured to: determine that the power tool has performed an impact operation if the current change trend in the second time period conforms to a preset change trend;

[0244] The preset change trends include: rise-fall, fall-rise, rise-fall-rise, fall-rise-fall-fall.

[0245] In one possible implementation, the controller is also configured to execute a preset operating mode if an impact operation is detected by the power tool.

[0246] The preset operating modes include: immediate shutdown, shutdown after a preset time, or shutdown after a preset number of impacts.

[0247] For example, Figure 28 This is a schematic diagram of the control logic of a power tool according to an embodiment of this application, such as... Figure 28 As shown:

[0248] The controller is used to control the data acquisition module to acquire data and to provide control strategies and drive signals (PWM) to control the operation of the motor through the motor control module.

[0249] The data acquisition module includes: a three-phase voltage sampling unit, used to sample the operating waveform of the motor for commutation strategy and motor speed calculation; and a current sampling unit, used to sample the operating current of the motor.

[0250] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0251] In the description of this specification, references to "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0252] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An impact detection method of a power tool, characterized by, The impact detection method for the screwdriver includes: The first time is determined based on the mechanical parameters of the power tool; the first time is the cycle time of the impact current. The second time is determined based on the first time and a preset duration; the second time is the sampling time for a set of current data. Acquire the first current data sampled during the second time period; The power tool was determined to have undergone an impact operation based on the first current data.

2. The impact detection method of the power tool according to claim 1, characterized by, Determining the first time based on the mechanical parameters of the power tool includes: When the mechanical parameters include: number of motor pole pairs, mechanical reduction ratio, and impact block type, the first time is calculated according to the following formula: T2 = T1 × n; In the formula, T1 is the cycle time of one revolution of the motor, t is the cycle time of two phase commutations of the motor of the power tool, p is the number of pole pairs of the motor, T2 is the cycle time of one revolution of the output shaft of the power tool, n is the mechanical reduction ratio, T3 is the cycle time of a single impact of the power tool, and c is the number of impacts of one revolution of the striking block.

3. The impact detection method of the power tool according to claim 1, characterized by, The step of determining whether the power tool has undergone an impact operation based on the first current data includes: The trend of current change in the second time period is determined based on the analysis of the first current data. The power tool was determined to have undergone an impact operation based on the changing trend.

4. The impact detection method of the power tool according to claim 3, characterized by, The step of determining the current change trend within the second time period based on the analysis of the first current data includes: The first current data is divided into multiple groups of second current data according to the time sequence of current sampling. The changing trend of each group of second current data is calculated according to the preset algorithm; The trend of current change in the second time period is determined based on the trend of change in each set of current data.

5. The impact detection method of the power tool according to claim 4, characterized by, The step of calculating the changing trend of each group of second current data according to a preset algorithm includes: If the first data point of the second current data in the same group is greater than the last data point, then the second current data in that group is determined to be in a downward trend. If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is determined to be on an upward trend. If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group. If the first data point is greater than the median data point, then the trend of the second current data point in this group is determined to be first decreasing and then increasing. If the first data point is less than the median data point, then the trend of the second current data point in this group is determined to be an initial increase followed by a decrease.

6. The impact detection method of the power tool according to claim 4, characterized by, Determining the current change trend within the second time period based on the change trend of each set of current data includes: The multiple sets of second current data are sorted according to the current sampling time. The changing trends of the multiple sets of second current data are marked; The trend of current change within the second time period is determined based on the annotation; The labels include: rising, falling, rising then falling, and falling then rising.

7. The impact detection method of the power tool according to claim 4, characterized by, The step of determining the current change trend within the second time period based on the analysis of the first current data further includes: The first current data is divided into four groups of second current data according to the time sequence of current sampling. Calculate the trend of change of the second current data for each group. If the first data of the second current data in the same group is greater than the last data, then mark the second current data of that group as having a downward trend. If the first data point of the second current data in the same group is less than the last data point, then the second current data in that group is marked as having an upward trend. If the first data of the second current data in the same group is equal to the last data, then determine the magnitude of the median data and the first data of the second current data in that group. If the first data point is greater than the median data point, then the trend of the second current data point in this group is marked as first decreasing and then increasing. If the first data point is less than the median data point, then the trend of the second current data point in this group is marked as first rising and then falling. The trend of current change during the second time period is determined based on the aforementioned markings.

8. The impact detection method of the power tool according to claim 3, characterized by, Determining whether the power tool has undergone an impact operation based on the changing trend includes: If the current change trend in the second time period conforms to the preset change trend, then it is determined that the power tool has performed an impact operation. The preset change trends include: rise-fall, fall-rise, rise-fall-rise, fall-rise-fall-fall.

9. The impact detection method of the power tool according to any one of claims 1 to 8, characterized by, Also includes If an impact operation is detected by the power tool, a preset working mode is executed; The preset operating modes include: immediate shutdown, shutdown after a preset time, or shutdown after a preset number of impacts.

10. A power tool, characterized in that, The power tool includes: Electric motor; An output shaft, configured to hold a pointed tool for applying a tightening or loosening force to a fastening member, is driven by the motor. The controller is configured to: The first time is determined based on the mechanical parameters of the power tool; the first time is the cycle time of the impact current. The second time is determined based on the first time and a preset duration; the second time is the sampling time for a set of current data. Acquire the first current data sampled during the second time period; The power tool was determined to have undergone an impact operation based on the first current data.

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