Electric pulse tool motor control with power reduction phase

Abstract

A pulse tool may include a motor which may rotate a motor shaft, a drive assembly which may be operably coupled to the motor shaft to transmit rotational movement of the motor shaft to act upon a work piece, an angle sensor which may measure an angular position of the motor shaft, position control circuitry which may control the angular position of the motor shaft based on feedback from the angle sensor, and process control circuitry which may control the position control circuitry using a control value and the position control circuitry. The control value may be a torque output value indicative of the amount of torque applied to the end effector. The process control circuitry may include a control algorithm that may include a first phase in which the tool may operate at a first pulse intensity and a second phase in which the tool may operate at a reduced pulse intensity.

Description

[0001] ELECTRIC PULSE TOOL MOTOR CONTROL WITH POWER REDUCTION PHASE

[0002] TECHNICAL FIELD

[0003] Example embodiments generally relate to power tool technologies, and in particular, to pulse tools and associated components.

[0004] BACKGROUND

[0005] Driver tools are torque generating tools that may be used to drive work pieces such as fasteners. Many driver tools operate by powering a motor to generate torque that is transferred to a work piece via a series of gears, shafts and various other components. Many different types of driver tools are currently well known in the art, including drills, impact drivers, nutrunners and others.

[0006] Pulse tools are another type of driver tool that may be implemented in manufacturing settings for their precision, low reaction force on the user, and efficiency. Pulse tools work by operating their motor discontinuously to apply torque to the work piece in smaller increments. This type of discontinuous rotational output may make pulse tools easier to use for operators than some other types of driver tools that may apply torque continuously. In this regard, the maximum continuous torque output that operators of pistol-grip type driver tools may be able to comfortably withstand may be about 10 Nm, which in some cases may not be sufficient to drive many work pieces as desired. Accordingly, by applying the torque in pulses, a higher output torque may be achieved without sacrificing operator comfort or usability of the pulse tool.

[0007] In many cases, pulse tools may be controlled by monitoring the velocity of the motor or the current that the motor draws. Such existing methods of controlling the pulse tool may lead to some level of uncertainty and inefficiency of the pulse tool. Accordingly, innovation to address the technical problem of controlling pulse tools with greater accuracy, precision and efficiency is desired.

[0008] BRIEF SUMMARY OF SOME EXAMPLES

[0009] Some example embodiments may provide for a pulse tool. The pulse tool may include a motor which may be configured to output rotational movement via a motor shaft, a drive assembly which may be operably coupled to the motor shaft to transmit rotational movement of the motor shaft to an end effector for acting upon a work piece, an angle sensor which may be operably coupled to the motor to measure an angular position of the motor shaft, positioncontrol circuitry which may control the angular position of the motor shaft based on feedback from the angle sensor, and process control circuitry which may control the position control circuitry using a control value and the position control circuitry. The control value may be a torque output value indicative of the amount of torque applied to the end effector. The process control circuitry may include a control algorithm that may control the rotational movement of the motor. The control algorithm may include a first phase in which the tool may operate at a first pulse intensity and a second phase in which the tool may operate at a reduced pulse intensity.

[0010] Some example embodiments may provide for a control system for a pulse tool. The system may include at least one pulse tool, a network to which the at least one pulse tool may be operably coupled, and a tool controller which may be configured to communicate with the at least one pulse tool via the network. The at least one pulse tool may include a motor which may be configured to output rotational movement via a motor shaft, a drive assembly which may be operably coupled to the motor shaft to transmit rotational movement of the motor shaft to an end effector for acting upon a work piece, an angle sensor which may be operably coupled to the motor to measure an angular position of the motor shaft, position control circuitry which may control the angular position of the motor shaft based on feedback from the angle sensor, and process control circuitry which may control the position control circuitry using a control value and the position control circuitry. The control value may be a torque output value indicative of the amount of torque applied to the end effector. The process control circuitry may include a control algorithm that may control the rotational movement of the motor. The control algorithm may include a first phase in which the tool may operate at a first pulse intensity and a second phase in which the tool may operate at a reduced pulse intensity.

[0011] Some example embodiments may provide for method of controlling a pulse tool motor. The method may include the steps of driving the motor in a first direction at a constant velocity in a rundown period until a reverse transition trigger may be detected, transitioning the motor from the rundown period to a first phase reverse period responsive to detecting the reverse transition trigger, ceasing power supply to the motor in the coasting interval which may enable the motor to slow down, stop and rotate in a second direction until a rebound transition trigger may be detected, transitioning the motor from the coasting interval to the rebound interval responsive to detecting the rebound transition trigger, restoring power supply to the motor to rotate the motor in the second direction until a pulsing transition trigger may be detected, transitioning the motor from the first phase reverse period to the firstphase pulsing period responsive to detecting the pulsing transition trigger, driving the motor in the first direction until the reverse transition trigger may be detected, transitioning the motor from the first phase pulsing period to the first phase reverse period responsive to detecting the reverse transition trigger, alternating the motor between the first phase pulsing period and the first phase reverse period until a phase transition trigger may be detected, transitioning the motor from a first phase in which the tool may operate at a first pulse intensity to a second phase in which the tool may operate at a reduced pulse intensity, responsive to detecting the phase transition trigger, and alternating the motor between a second phase pulsing period and a second phase reverse period until a stop trigger is detected. The first and second phase reverse periods may include a coasting interval and a rebound interval.

[0012] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) Having thus described some example embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0013] FIG. 1 illustrates a functional block diagram of a pulse tool according to some example embodiments;

[0014] FIG. 2a illustrates a flow chart depicting a first phase of a control algorithm for operating the pulse tool according to an example embodiment;

[0015] FIG. 2b illustrates a flow chart depicting a second phase of the control algorithm for operating the pulse tool according to an example embodiment;

[0016] FIG. 3a illustrates an exploded perspective view of the drive in accordance with an example embodiment;

[0017] FIG. 3b illustrates a section view of an engagement interface between the hammer and the anvil in accordance with an example embodiment;

[0018] FIG. 4 illustrates a schematic block diagram of a control system for the pulse tool according to an example embodiment; and

[0019] FIG. 5 illustrates a flow chart of a method of controlling a pulse tool motor based on an angular position of a motor shaft in accordance with an example embodiment.

[0020] DETAILED DESCRIPTION

[0021] Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as beinglimiting as to the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Furthermore, as used herein, the term “or” is to be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operable coupling should be understood to relate to direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to each other.

[0022] Additionally, as used herein, terminology such as “about,” “approximately” and “substantially,” when used to refer to variability of parameters, should be understood to be definite approximations that account for variations in measurements that cannot be, or as one of skill in the art would appreciate, normally are not, measured precisely. Thus, for example, a parameter that is “about,” “approximately” or “substantially” a given value or a given characteristic should be understood to be sufficiently close to the given value or given characteristic such that performance of the object or product to which the parameter applies, from the perspective of one with ordinary skill in the art, is the same as though the object or product had precisely the given value or characteristic.

[0023] According to some example embodiments, a pulse tool and a method of controlling a pulse tool may be provided. In an example embodiment, the pulse tool may be controlled by a combination of position control circuitry, process control circuitry, and a control algorithm which may use the angular position of the motor shaft to control the motor. The control algorithm may include two distinct phases of operation: a first phase in which the tool may operate at a first pulse intensity and a second phase in which the tool may operate at a reduced pulse intensity.. The reduced pulse intensity of the second phase may therefore increase the accuracy of the pulse tool by reducing the rebound angle, reducing the motor acceleration, or both. In this regard, the pulse tool may be less likely to unintentionally overshoot a desired torque output late in the control algorithm. Additionally, position control may offer the advantage of shorter cycle times because the tool does not need to wait for the motor velocity to reach a certain threshold before transitioning to a next operating period. This may be more efficient than velocity control and may therefore save the user of the tool time by operating quicker. As such, previous methods for controlling the pulse tool (e.g. velocity control and current control) may be avoided for more convenient and consistent control of the pulse tool.

[0024] Having described some aspects of example embodiments generally, FIG. 1 illustrates a functional block diagram of a pulse tool 100 according to some example embodiments. The pulse tool 100 may include an external housing 110, within which various operationalcomponents may be disposed. In some cases, the external housing 110 may be of the pistolgrip shape type, which may indicate that the pulse tool 100 may be intended for single-handed use. The pulse tool 100 may be powered by a power source 120, such as, for example, a rechargeable battery. The power source 120 may be configured to provide electrical power to various operational components such as position control circuitry 130, process control circuitry 140 and various sensors within the pulse tool 100, in addition to a motor 150. The position control circuitry 130 may receive an input signal from a control switch 135 (e.g., trigger) and may respond by permitting controlled electrical power to be provided to the motor 150 to rotate a motor shaft 152 of the motor 150. In other words, the position control circuitry 130 may be configured to control an angular position of the motor shaft 152 based on feedback from the angle sensor 200. On the other hand, the process control circuitry 140 may control the position control circuitry 130 to control overall operation of the pulse tool 100. As such, the process control circuitry 140 may be configured to control the position control circuitry 130 using a control value and the position control circuitry 130. This relationship between the position control circuitry 130 and the process control circuitry 140 will be further described below with regard to FIG. 2.

[0025] As mentioned above, the pulse tool 100 may include a motor 150 configured to output rotational movement via the motor shaft 152. Thus, the motor 150 may be configured to rotate a drive assembly 160, which may include various gears for changing a rotational velocity of the motor shaft 152 to a desired rotational velocity for output by the drive assembly 160. The drive assembly 160 may be operably coupled to the motor shaft 152 at a first end of the drive assembly 160 to transmit rotational movement of the motor shaft 152 to an end effector 180 for acting upon a work piece 190, which may be disposed at a second end of the drive assembly 160. Among other components, the drive assembly 160 may further include a hammer 162 (e.g. an output carrier) and a gear assembly (not shown). The hammer 162 of the drive assembly 160 may operably couple to an anvil 164 (e.g. an output shaft) to transmit torque from the motor 150 to a work piece 190. The hammer 162 may be operably coupled to the motor shaft 152 via the gear assembly. As such, the gear assembly may receive torque from the motor 150 via the motor shaft 152 and may transfer the torque from the motor shaft 152 to the hammer 162, which may transfer the torque to the anvil 164 about an axis of rotation 170. In some cases, the motor 150 may be a servo motor, which may allow for more precise control of the angular position of the motor shaft 152. In an example embodiment, the gear assembly may be disposed within a carrier of the hammer 162. In this regard, the gear assembly may be a planetary gear assembly and may include a sun gear and at least one planet gear. The sun gearmay be operably coupled to the motor shaft 152 to receive torque from the motor shaft 152 and to the at least one planet gear to transmit torque to the at least one planet gear. The at least one planet gear may also be operably coupled to the carrier of the hammer 162 to rotate the hammer 162 accordingly. In some cases, the gear assembly may include additional stages of gears as well. For instance, the gear assembly may include a plurality of planet gears which may change the gear ratio of the pulse tool 100. In some cases, the gear ratio may be approximately 4: 1. In some other cases, the gear ratio may be approximately 7.5:1.

[0026] The hammer 162 may operably couple to the anvil 164 such that the hammer 162 carries the anvil 164 with it responsive to being rotated by the motor shaft 152. The drive assembly 160 will be discussed below in further detail in relation to FIG. 3. Such rotational movement may be transferred by the anvil 164 to a head end of the anvil 164 which may include a drive portion 165 shaped to operably couple to the end effector 180. The end effector 180 may be, for example, a socket, a driver bit, a drill bit, or the like. Accordingly, with the end effector 180 coupled to the drive portion 165 of the anvil 164, the pulse tool 100 may be configured to act upon the work piece 190 (e.g., a fastener such as a screw, bolt, nut, or the like), for example, which may be disposed in a work medium 195. In this regard, the pulsing rotational output evoked on the end effector 180 may operate, for example, to drive the work piece 190 to a desired torque level.

[0027] As mentioned briefly above, the pulse tool 100 may also include various sensors which may assist the position control circuitry 130 and the process control circuitry 140 in the operation of the pulse tool 100. In some cases, the pulse tool 100 may include an angle sensor 200, which may be operably coupled to the motor 150 to measure an angular position of the motor shaft 152, and a reaction torque sensor 210 which may be operably coupled to the motor shaft 152 and to the gear assembly to measure the reaction torque within the drive assembly 160 (i.e. between a ring gear of the gear assembly and the motor 150). Further, the pulse tool 100 may also include a current sensor 215. The current sensor 215 may measure the electrical current draw from the power source 120 to the motor 150. As will be described in more detail below in reference to FIG. 2, the angle sensor 200, the torque sensor 210 and the current sensor 215 may provide inputs to the position control circuitry 130 and the process control circuitry 140, respectively, to aid the process control circuitry 140 in controlling the operation of the pulse tool 100. In some example embodiments, the angle sensor 200 may be an encoder and the torque sensor 210 may be a torque transducer (e.g. a strain gauge). In some cases, the angle sensor 200 may include a magnet which may be disposed on the motor shaft 152 and a magnetic sensor disposed at the motor 150. In thisregard, the magnetic sensor may detect the position of the magnet as the motor shaft 152 rotates so that the angle sensor 200 may know the position of the motor shaft 152 at all times.

[0028] In an example embodiment, the current sensor 215 may be able to detect a potential impending stall condition of the motor 150. In this regard, responsive to detecting a sudden reduction in the angular velocity of the motor 150 along with a sudden increase in the current draw by the motor 150, the position control circuitry 130 may predict that the motor 150 may be about to enter a stall condition. In order to protect the motor 150 and the position control circuitry 130 from spikes in the electrical current, the position control circuitry 130 may stop the motor 150 when the stall condition is detected.

[0029] In an example embodiment, the position control circuitry 130 and the process control circuitry 140 may both be configured to provide electronic control inputs to one or more functional units of the pulse tool 100 and to process data received at or generated by the one or more functional units of the pulse tool 100. Thus, the position control circuitry 130 and the process control circuitry 140 may be configured to perform data processing, control function execution and / or other processing and management services according to an example embodiment. In some embodiments, the position control circuitry 130 and the process control circuitry 140 may be embodied as chips or chip sets. In other words, the position control circuitry 130 and the process control circuitry 140 may each comprise one or more physical packages (e.g., chips) including materials, components and / or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and / or limitation of electrical interaction for component circuitry included thereon. The position control circuitry 130 and the process control circuitry 140 may therefore, in some cases, be configured to implement an embodiment of the present invention on a single chip or as a single “system on a chip.” As such, in some cases, a chip or chipset may constitute means for performing one or more operations for providing the functionalities described herein.

[0030] In an example embodiment, the position control circuitry 130 and the process control circuitry 140 may each include one or more instances of a processor and memory that may be in communication with or otherwise control other components or modules that interface with the position control circuitry 130 and the process control circuitry 140. As such, the position control circuitry 130 and the process control circuitry 140 may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., with hardware, software or a combination of hardware and software) to perform operations described herein. In some embodiments, the position control circuitry 130 and the process control circuitry 140 may be embodied as aportion of an onboard computer housed in the housing 110 of the pulse tool 100 to control operation of the tool.

[0031] In an example embodiment, the process control circuitry 140 may include a control algorithm 220 that may control the rotational movement of the motor 150 based on the angular position of the motor shaft 152. In some cases, the control algorithm 220 may be stored in the memory of the process control circuitry 140. The processor of the process control circuitry 140 may be configured to access the memory in order to run the control algorithm 220 and to execute actions associated with the control algorithm 220 to control the operation of the pulse tool 100. The control algorithm 220 will be described in greater detail below in reference to FIG. 2.

[0032] FIG. 2, which may include FIGS. 2a and 2b, illustrates a flow chart depicting the control algorithm 220 for operating the pulse tool 100 according to an example embodiment. In particular, FIG. 2a illustrates a flow chart representing a first phase 222 of the control algorithm 220, and FIG. 2b illustrates a flow chart representing a second phase 224 of the control algorithm 220 in accordance with an example embodiment. In the example embodiment described herein, the control algorithm 220 may include a rundown period 230, a first phase reverse period 240, a first phase pulsing period 250, a second phase reverse period 240’ and a second phase pulsing period 250’. In an example embodiment the first phase 222 may include a plurality of first phase reverse periods 240 and first phase pulsing periods 250. As such, the first phase reverse periods 240 and first phase pulsing periods 250 may additionally be referred to as at least one reverse period 240 and at least one pulsing period 250, respectively. On the other hand, the second phase 224 may include a plurality of second phase reverse periods 240’ and second phase pulsing periods 250’. As such, the second phase reverse periods 240’ and second phase pulsing periods 250’ may additionally be referred to as subsequent reverse periods 240’ and subsequent pulsing periods 250’.

[0033] In some cases, the rundown period 230 may occur first before either of the first phase reverse period 240 or the first phase pulsing period 250. In fact, in an example embodiment, the rundown period 230 may only occur once per work piece 190 that the pulse tool 100 is used to drive. In this regard, the rundown period 230 may include the position control circuitry 130 driving the motor 150 in a first direction (e.g. clockwise) at a predetermined constant velocity until a first reverse transition trigger is detected at step 235, and the process control circuitry 140 transitions the motor to the first phase reverse period 240. In other words, the rundown period 230 typically spans from when the control switch 135 is first actuated by the operator of the pulse tool 100 (when the motor 150 begins spinning) to when a head of the work piece190 begins to seat on the work medium 195. Thus, the rundown period 230 may essentially correlate to the work piece 190 being driven into the work medium 195 for a distance approximately equal to the length of the shaft of the work piece 190.

[0034] In an example embodiment, the position control circuitry 130 may generally be in charge of controlling the operation of the motor 150. As the control algorithm 220 is described below, any time the motor 150 rotates the motor shaft 152, that may be the result of a control signal sent from the position control circuitry 130 telling the motor 150 to do so. On the other hand, the process control circuitry 140 may more broadly control the process of operating the pulse tool 100. In other words, the position control circuitry 130 may execute the control algorithm 220 and may transition the pulse tool 100 between the rundown period 230, the first phase reverse period 240, the first phase pulsing period 250, the second phase reverse period 240’ and the second phase pulsing period 250’. Accordingly, in some cases, the process control circuitry 140 may provide input signals to the position control circuitry 130 to control the rotational output of the motor 150. In some cases, like the one depicted in FIG. 4, the pulse tool 100 may be used within a group of other pulse tools 100, and the group may be controlled by a controller 300. This will be described in greater detail in reference to FIG. 4 below.

[0035] Depending on the work piece 190 and the work medium 195, the predetermined constant velocity used in the rundown period 230 may vary case by case. For instance, when the pulse tool 100 may be used on hard and medium joints, the predetermined constant velocity may be lower than when the pulse tool 100 may be used on softer joints so that the peak torque from the bottoming of the work piece 190 is not too high. During the rundown period 230, any rotational velocity less than or equal to a maximum free velocity of the motor 150 may be used as the predetermined constant velocity. In some other cases, in the rundown period 230, an acceleration rate of the motor shaft 152 may be limited to cap the maximum current drawn by the motor 150 to be less than or equal to a rundown current threshold value.

[0036] As mentioned above, the control algorithm 220 may keep the pulse tool 100 in the rundown period 230 until the reverse transition trigger is detected at step 235, at which point the control algorithm 220 may enter the first phase reverse period 240. In some cases, the reverse transition trigger may include the motor current reaching a rundown current threshold value. Thus, in this regard, the motor 150 may begin to draw more current to maintain the acceleration rate described above. When this occurs, the process control circuitry 140 may detect the current reaching the rundown current threshold value (i.e. reverse transition trigger) and may therefore transition the motor 150 to the first phase reverse period 240. In another example embodiment, the reverse transition trigger may include the torque output measured bythe torque sensor 210 reaching a rundown torque threshold value. In either case, the detection of the reverse transition trigger may correspond to the head of the work piece 190 being seated on the work medium 195, at which point the rundown period 230 may end and the motor 150 may be transitioned to the first phase reverse period 240. In some cases, the rundown period 230 may last approximately 10 revolutions of the work piece 190, depending on the size of the work piece 190.

[0037] Responsive to detecting the reverse transition trigger at step 235, the process control circuitry 140 may transition the motor from the rundown period 230 to the first phase reverse period 240. In an example embodiment, the first phase reverse period 240 may include a coasting interval 242 and a rebound interval 244, and the coasting interval 242 may occur prior to the rebound interval 244. During the coasting interval 242, power supply to the motor 150 is ceased by the position control circuitry 130, which may enable the motor shaft 152 to slow down (e.g. coast) to a stop and, after stopping, rotate backwards in a second direction (e.g. counterclockwise) until a rebound transition trigger is detected at step 243. The rotation in the second direction during the coasting interval 242 may not be driven rotation by the motor 150, but instead may be caused by tension in the gears of the drive assembly 160 which may act as potential energy to slightly rotate the motor shaft 152 in the second direction after coasting to a stop. In some cases, the rebound transition trigger may include the non-driven rotation in the second direction coming to a stop. In another case, the rebound transition trigger may include an elapsed amount of time spent in the coasting interval reaching a coasting interval duration threshold. In some cases, the rebound transition trigger may include either of the above, whichever occurs first. In other words, the control algorithm 220 may transition the motor 150 out of the coasting interval responsive to the rotation of the motor 150 in the second direction coming to a stop, or responsive to the rotation of the motor 150 in the second direction continuing for a duration of time that reaches the coasting interval duration threshold. In an example embodiment, the coasting interval duration threshold may be predetermined by the control algorithm 220.

[0038] Responsive to detecting the rebound transition trigger at step 243, the process control circuitry 140 may transition the motor 150 from the coasting interval 242 to the rebound interval 244. In the rebound interval 244 of the first phase reverse period 240, the power supply to the motor 150 may be restored by the position control circuitry 130 to rotate the motor shaft 152 further in the second direction until a pulsing transition trigger is detected at step 245. In some cases, during the rebound interval 244, the motor 150 may be powered at a given acceleration until a predetermined reverse velocity is reached. The motor 150 may then rotatein the second direction at the predetermined reverse velocity until the pulsing transition trigger is detected at step 245. Responsive to detecting the pulsing transition trigger at step 245, the process control circuitry 140 may transition the motor 150 from the rebound interval 244 to the first phase pulsing period 250. In an example embodiment, the pulsing transition trigger may include the angular position of the motor shaft 152 reaching a threshold motor shaft rebound angle. Prior to reaching the threshold motor shaft rebound angle, the position control circuitry 130 may begin to slow the motor 150 down so that it may bring the motor 150 to a controlled “stop” at the threshold motor shaft rebound angle. In this regard, the “stop” may only be a momentary “stop” in the sense that the motor velocity may very briefly be zero as the motor 150 changes from rotating in the first direction to rotating in the second direction. In other words, the motor 150 may not stop in the sense that the motor shaft 152 stays stationary, but instead the stop may correspond to the point at which the direction of rotation of the motor shaft 152 changes. Responsive to the motor reaching the threshold motor shaft rebound angle, the process control circuitry 140 may transition the motor to the pulsing period 250. In some cases, the threshold motor shaft rebound angle may be proportional to a corresponding threshold hammer rebound angle which may be calculated using the gear ratio of the gear assembly. For instance, the threshold hammer rebound angle may be equal to the threshold motor shaft rebound angle divided by the gear ratio, which in some cases may be 4 and other cases may be 7.5, as discussed above. Therefore, the threshold hammer rebound angle may be approximately 90°, which may constitute a full rebound according to some example embodiments. However, in some other cases, the threshold hammer rebound angle may be less than 90°, while in still other cases the threshold hammer rebound angle may be as large as 300°.

[0039] In the first phase pulsing period 250, the position control circuitry 130 may drive the motor shaft 152 in the first direction until a phase transition trigger is detected at step 252, or until the reverse transition trigger is detected at step 254. If no phase transition trigger is detected at step 252, then responsive to detecting the reverse transition trigger at step 254, the process control circuitry 140 may transition the motor from the first phase pulsing period 250 to the first phase reverse period 240. In this regard, the position control circuitry 130 may alternate the motor 150 between the first phase pulsing period 250 and the first phase reverse period 240 until the phase transition trigger may be detected at step 252, which may transition the motor 150 from the first phase 222 to the second phase 224. In some cases, after the first iteration of the first phase reverse period 240 of the operation of the pulse tool 100, further iterations of the first phase reverse period 240 may not include the coasting interval 242. This may be indicated by the dashed line in FIG. 2a connecting the step 254 to the rebound interval244. As such, the motor 150 may alternate between powered rotation in the first direction during the first phase pulsing period 250 and powered rotation in the second direction in the first phase reverse period 240.

[0040] In some example embodiments, the phase transition trigger may include a selected one of the torque output reaching an intermediate torque threshold value, the angular position of the motor shaft reaching an intermediate threshold rebound angle and a number of pulsing periods reaching an intermediate predetermined number of pulsing periods. Upon detecting the phase transition trigger at step 252, the power supply to the motor 150 may be reduced to be lower than the power supply to the motor 150 during the first phase 222.

[0041] As shown in FIG. 2b, the second phase 224 of the control algorithm 220 may be similar to the first phase 222, with the exception being that the second phase 224 may not include the rundown period 230. The second phase 224 may include the second phase reverse period 240’ and the second phase pulsing period 250’, which in some cases may be referred to as the subsequent reverse period and the subsequent pulsing period, respectively. In this regard, essentially, the second phase 224 of the control algorithm 220 may include continuing to alternate the motor 150 between pulsing and reverse periods, but at lower speeds and with less angular position change and torque output change than in the first phase 222. In other words, during the first phase 222 the motor 150 may make bigger changes in the torque output between consecutive first phase pulsing periods 250 so that the pulse tool 100 may make quicker progress towards the desired torque output. As the pulse tool 100 gets closer to the desired torque output, the control algorithm 220 may switch the tool 100 into the second phase 224 so that the increase in the torque output between consecutive second phase pulsing periods 250’ is reduced, which may give the control algorithm 220 a higher likelihood of detecting the stop trigger closer to the actual desired torque output.

[0042] In an example embodiment, the second phase reverse period 240’ may also include the coasting interval 242 and the rebound interval 244, and the coasting interval 242 may also occur prior to the rebound interval 244. During the coasting interval 242, power supply to the motor 150 is ceased by the position control circuitry 130, which may enable the motor shaft 152 to slow down (e.g. coast) to a stop and, after stopping, rotate backwards in a second direction (e.g. counterclockwise) until a rebound transition trigger is detected at step 243’. The rotation in the second direction during the coasting interval 242 may not be driven rotation by the motor 150, but instead may be caused by tension in the gears of the drive assembly 160 which may act as potential energy to slightly rotate the motor shaft 152 in the second direction after coasting to a stop. In some cases, the rebound transition trigger mayinclude the non-driven rotation in the second direction coming to a stop. In another case, the rebound transition trigger may include an elapsed amount of time spent in the coasting interval reaching a coasting interval duration threshold. In some cases, the rebound transition trigger may include either of the above, whichever occurs first. In other words, the control algorithm 220 may transition the motor 150 out of the coasting interval responsive to the rotation of the motor 150 in the second direction coming to a stop, or responsive to the rotation of the motor 150 in the second direction continuing for a duration of time that reaches the coasting interval duration threshold. In an example embodiment, the coasting interval duration threshold may be predetermined by the control algorithm 220.

[0043] Responsive to detecting the rebound transition trigger at step 243’, the process control circuitry 140 may transition the motor 150 from the coasting interval 242 to the rebound interval 244. In the rebound interval 244 of the second phase reverse period 240’, the power supply to the motor 150 may be restored by the position control circuitry 130 to rotate the motor shaft 152 further in the second direction until a pulsing transition trigger is detected at step 245’. In some cases, during the rebound interval 244, the motor 150 may be powered at a given acceleration until a predetermined reverse velocity is reached. In some cases, the predetermined reverse velocity in the second phase 224 may be less than the predetermined reverse velocity in the first phase 222. This may be because the pulse tool 100 may operate with a reduced pulse intensity in the second phase 224 compared to the first phase 222. In this regard, the reduced pulse intensity of the second phase 224 may therefore increase the accuracy of the pulse tool 100 by reducing the rebound angle, reducing the motor acceleration, or both. This may increase the accuracy of the pulse tool 100 and minimize the likelihood that the pulse tool 100 may unintentionally overshoot the desired torque output. The motor 150 may then rotate in the second direction at the predetermined reverse velocity until the pulsing transition trigger is detected at step 245’. Responsive to detecting the pulsing transition trigger at step 245’, the process control circuitry 140 may transition the motor 150 from the rebound interval 244 to the second phase pulsing period 250’. In an example embodiment, the pulsing transition trigger may include the angular position of the motor shaft reaching a threshold rebound angle. Upon reaching the threshold rebound angle, the position control circuitry 130 may bring the motor 150 to a controlled stop, and then the process control circuitry 140 may transition the motor to the second phase pulsing period 250’. In some cases, the threshold rebound angle in the second phase 224 may be less than 90° less than 90°. This may be because the pulse tool 100 may operate with a reduced pulse intensity in the second phase 224 compared to the first phase 222. This may increase the accuracy ofthe pulse tool 100 and minimize the likelihood that the pulse tool 100 may unintentionally overshoot the desired torque output.

[0044] In the second phase pulsing period 250’, the position control circuitry 130 may drive the motor shaft 152 in the first direction until a stop trigger is detected at step 252’, or until the reverse transition trigger is detected at step 254’ . If no stop trigger is detected at step 252’, then responsive to detecting the reverse transition trigger at step 254’, the process control circuitry 140 may transition the motor 150 from the second phase pulsing period 250’ to the second phase reverse period 240’. In this regard, the position control circuitry 130 may alternate the motor 150 between the second phase pulsing period 250’ and the second phase reverse period 240’ until the stop trigger may be detected at step 252’, which may stop the motor 150. In some cases, after the first iteration of the second phase reverse period 240’ of the operation of the pulse tool 100, further iterations of the second phase reverse period 240’ may not include the coasting interval 242. This may be indicated by the dashed line in FIG. 2b connecting the step 254’ to the rebound interval 244. As such, the motor 150 may alternate between powered rotation in the first direction during the second phase pulsing period 250’ and powered rotation in the second direction in the second phase reverse period 240’.

[0045] In some example embodiments, the stop trigger may include at least one of the torque output reaching a final torque threshold value, the angular position of the motor shaft reaching the threshold rebound angle and a number of pulsing periods reaching a predetermined number of pulsing periods. In an example embodiment, the final torque threshold value of the stop trigger may be greater than the intermediate torque threshold value of the phase transition trigger. As discussed above, a maximum angular position achieved by the motor shaft 152 during each of the subsequent pulsing periods 250’ in the second phase 224 may increase in smaller increments than during the at least one pulsing period 250 in the first phase 222. Similarly, the torque output achieved by the pulse tool 100 during each of the subsequent pulsing periods 250’ in the second phase 224 may increase in smaller increments than during the at least one pulsing period 250 in the first phase 222. Upon detecting the stop trigger at step 252, operation of the pulse tool 100 may cease at step 260, and if the pulse tool 100 is used in an assembly setting, the operator may then move on to the next task with the pulse tool 100.

[0046] In some cases, the first phase 222 may differ from the second phase 224 in a number of different aspects, as described above in reference to FIGS. 2a and 2b. Additionally, the first phase 222 and the second phase 224 may differ in that during the first phase 222, the pulse tool 100 may operate at a first pulse intensity whereas during the second phase 224, the pulse tool 100 may operate at a reduced pulse intensity, and the reduced pulse intensity may be less thanthe first pulse intensity. As such, during the second phase 224, the increments by which the torque output and the angular position of the motor shaft 152 increase may be smaller than the increments by which the torque output and the angular position of the motor shaft 152 may increase during the second phase 224. The reduced pulse intensity of the second phase 224 may therefore increase the accuracy of the pulse tool 100 by reducing the rebound angle, reducing the motor acceleration, or both. In this regard, the pulse tool 100 may be less likely to unintentionally overshoot a desired torque output late in the control algorithm 220. In some cases, the pulse intensity of the pulse tool 100 may gradually be reduced during the second phase 224. In other words, with each iteration of the second phase pulsing period and the second phase reverse period, the pulse intensity may decline. In this regard, the pulse intensity may be reduced by a single constant amount from the first phase 222 to the second phase 224 or the pulse intensity may be reduced further for each subsequent pulse during the second phase 224. In some other cases, the pulse intensity of the pulse tool 100 may remain constant throughout the second phase 224. In any case, the pulse intensity of the pulse tool 100 during the second phase 224 may be less than the pulse intensity of the pulse tool 100 during the first phase 222.

[0047] FIG. 3, which may include FIGS. 3a and 3b, illustrates an exploded perspective view of the drive assembly 160 including the hammer 162 and anvil 164 in accordance with an example embodiment (FIG. 3a) and a section view of an engagement interface 270 between the hammer 162 and the anvil 164 in accordance with an example embodiment (FIG. 3b). The hammer 162 may operably couple to the anvil 164 and to the motor shaft 152, and as such, the hammer 162 may transfer torque from the motor shaft 152 to the anvil 164. A rear end of the anvil 164 (e.g. at an opposite end of the anvil 164 from the head end and the drive portion 165) may operably couple to a first end of the hammer 162 at the engagement interface 270. In some cases, such as the one depicted in FIG. 3, the engagement interface 270 may include a receiving orifice 272 formed in the hammer 162 and a projection member 274 formed at the rear end of the anvil 164. In this regard, the projection member 274 of the anvil 164 may be inserted into the receiving orifice 272 of the hammer 162. As shown in FIG. 3, the receiving orifice 272 may include an eccentric shape that may enable the hammer 162 to rotate in the first and second directions, as indicated by arrow 275 in FIG. 3b, a predetermined amount without contacting the projection member 274 and carrying the anvil 164 with the hammer 162.

[0048] Accordingly, the eccentric shape of the receiving orifice 272 may enable the pulse tool 100 to alternate between the first phase reverse period 240 and the first phase pulsing period 250 without driving the work piece 190 in the second direction and undoing any tightening progress made during the first phase pulsing period 250. In other words, during the first phasereverse period 240 when the motor shaft 152 rotates in the second direction, the hammer 162 may rotate in the second direction with the motor shaft 152, but the anvil 164 may not rotate in the second direction with the hammer 162 due to the shape of the receiving orifice 272 enabling the hammer 162 to rotate a predetermined amount before carrying the anvil 164. Additionally, when the process control circuitry 140 transitions the motor 150 back to the first phase pulsing period 250 from the first phase reverse period 240, the motor shaft 152 and the hammer 162 can gain velocity prior to engaging / carrying the anvil 164 and thus driving the work piece 190. In some cases, the projection member 274 of the anvil 164 may only include one tang instead of the two depicted in FIGS. 3a and 3b. In this regard, with only one tang, the hammer 162 may be capable of rotating much further before engaging / carrying the anvil 164 on its one tang, and thus driving the work piece 190. This, along with the shape of the receiving orifice 272 may allow for up to approximately 300° of movement of the hammer 162 before the motor shaft 152, the hammer 162 and the anvil 164 move together.

[0049] FIG. 4 depicts a schematic block diagram of a control system 280 for the pulse tool 100 according to an example embodiment. In some cases, the system may include at least one pulse tool 100, a network 290 to which the at least one pulse tool 100 may be operably coupled (e.g. wired or wirelessly), and a tool controller 300 configured to communicate with the at least one pulse tool 100 via the network 290. In this regard, the control system 280 may be implemented in settings such as in a manufacturing facility, where the individual pulse tools 100 within the system 280 may be performing various tasks, some of which may be the same and some of which may be different. In this regard, the controller 300 may be optional, and the pulse tools 100 may also be implemented on an individual basis, or may be connected directly from tool to tool without the use of a separate controller 300. However, the controller 300 may enable system level inputs to be sent to all of the pulse tools 100 that may be connected to the network 290 simultaneously. In some cases, the network 290 may be a local network connecting all of the pulse tools 100. The local network may, in some cases, be implemented as a local plant network which may be specific to the particular location where the pulse tools 100 may be in use. In some other cases, the pulse tools 100 may be connected to a global internet network, and in such cases the pulse tools 100 may be accessed via the internet from anywhere using a virtual version of the controller 300 running on a computer. In this regard, the controller 300 or the plurality of pulse tools 100 themselves may be connected to the internet in some example embodiments. In another example embodiment, the network 290 may utilize other communication protocols, such as Bluetooth, for example. In yet another case, the network 290 may be a hard wired connection between each pulse tool 100 and the controller 300. In anycase, the controller 300 may be capable of organizing an assembly program sequence, implementing system wide changes such as changing a desired torque level, and various other administrative actions as well. In some cases, the controller 300 may communicate with the process control circuitry 140 within each pulse tool 100 to coordinate system wide operations. In the depiction of FIG. 4, it should be appreciated that the dashed lines representing the network 290 may be embodied as any lines of communication, be that wireless or wired.

[0050] FIG. 5 illustrates a flow chart of a method of controlling a pulse tool 100 motor 150 based on an angular position of a motor shaft 152 in accordance with an example embodiment. The method may include driving the motor 150 in a first direction at a constant velocity in a rundown period 230 until a reverse transition trigger is detected at operation 500, and transitioning the motor 150 from the rundown period 230 to a first phase reverse period 240 responsive to detecting the reverse transition trigger at operation 510, the first phase reverse period 240 comprising a coasting interval 242 and a rebound interval 244. The method may further include ceasing power supply to the motor 150 in the coasting interval 242 to enable the motor 150 to slow down, briefly stop as discussed above, and rotate in a second direction until a rebound transition trigger is detected at operation 520, transitioning the motor 150 from the coasting interval 242 to the rebound interval 244 responsive to detecting the rebound transition trigger at operation 530, and restoring power supply to the motor 150 to rotate the motor 150 in the second direction until a pulsing transition trigger is detected at operation 540. In response to detecting the pulsing transition trigger, the method may include transitioning the motor from the first phase reverse period 240 to the first phase pulsing period 250 at operation 550. The method may further include driving the motor 150 in the first direction until the reverse transition trigger is detected at operation 560, transitioning the motor 150 from the first phase pulsing period 250 to the first phase reverse period 240 responsive to detecting the reverse transition trigger at operation 570, and alternating the motor 150 between the first phase pulsing period 250 and the first phase reverse period 240 until a phase transition trigger is detected at operation 580. Finally, the method may include transitioning the pulse tool 100 from a first phase 222 in which the pulse tool 100 may operate at a first pulse intensity to a second phase 224 in which the pulse tool 100 may operate at a reduced pulse intensity, responsive to detecting the phase transition trigger at operation 590, and alternating the motor 150 between a second phase pulsing period 250’ and a second phase reverse period 240’ until a stop trigger is detected at operation 600.

[0051] Some example embodiments may provide for a pulse tool. The pulse tool may include a motor which may be configured to output rotational movement via a motor shaft, a driveassembly which may be operably coupled to the motor shaft to transmit rotational movement of the motor shaft to an end effector for acting upon a work piece, an angle sensor which may be operably coupled to the motor to measure an angular position of the motor shaft, position control circuitry which may control the angular position of the motor shaft based on feedback from the angle sensor, and process control circuitry which may control the position control circuitry using a control value and the position control circuitry. The control value may be a torque output value indicative of the amount of torque applied to the end effector. The process control circuitry may include a control algorithm that may control the rotational movement of the motor. The control algorithm may include a first phase in which the tool may operate at a first pulse intensity and a second phase in which the tool may operate at a reduced pulse intensity.

[0052] The pulse tool of some embodiments may include additional features, modifications, augmentations and / or the like to achieve further objectives or enhance performance of the pulse tool. The additional features, modifications, augmentations and / or the like may be added in any combination with each other. Below is a list of various additional features, modifications, and augmentations that can each be added individually or in any combination with each other. For example, the first phase may include a rundown period, at least one reverse period and at least one pulsing period. In an example embodiment, the second phase may include alternating subsequent reverse periods and subsequent pulsing periods. In some cases, in the rundown period, the position control circuitry may drive the motor in a first direction at a constant velocity until a reverse transition trigger may be detected. In an example embodiment, the reverse transition trigger may include a selected one of a motor current reaching a rundown current threshold value and the torque output reaching a rundown torque threshold value. In some cases, responsive to detecting the reverse transition trigger, the process control circuitry may transition the motor from the rundown period to the at least one reverse period. In an example embodiment, the reverse period may further include a coasting interval and a rebound interval. In some cases, in the coasting interval, power supply to the motor may be ceased to enable the motor to slow down, stop and rotate in a second direction until a rebound transition trigger may be detected. In an example embodiment, the rebound transition trigger may include one of rotation in the second direction coming to a stop and an elapsed time in the coasting interval reaching a coasting interval duration threshold, whichever may occur first. In some cases, responsive to detecting the rebound transition trigger, the process control circuitry may transition the motor from the coasting interval to the rebound interval. In an example embodiment, in the rebound interval, power supply to the motor may be restored to rotate themotor in the second direction until a pulsing transition trigger may be detected. In some cases, the pulsing transition trigger may include the angular position of the motor shaft reaching a threshold angle. In an example embodiment, responsive to detecting the pulsing transition trigger, the process control circuitry may transition the motor from the at least one reverse period to the at least one pulsing period. In some cases, in the at least one pulsing period, the position control circuitry may drive the motor in the first direction until the reverse transition trigger may be detected. In an example embodiment, responsive to detecting the reverse transition trigger, the process control circuitry may transition the motor from the at least one pulsing period to the at least one reverse period. In some cases, the position control circuitry may alternate the motor between the at least one pulsing period and the at least one reverse period until a phase transition trigger may be detected. In an example embodiment, the phase transition trigger may include a selected one of the torque output reaching an intermediate torque threshold value, the angular position of the motor shaft reaching an intermediate threshold angle and a number of pulsing periods reaching an intermediate predetermined number of pulsing periods. In some cases, responsive to detecting the phase transition trigger, the process control circuitry may transition the tool from the first phase to the second phase. In an example embodiment, in the second phase, the position control circuitry may alternate the motor between the subsequent pulsing periods and the subsequent reverse periods until a stop trigger may be detected. In some cases, the stop trigger may include a selected one of the torque output reaching a final torque threshold value, the angular position of the motor shaft reaching a threshold angle and a number of pulsing periods reaching a predetermined number of pulsing periods. In an example embodiment, the final torque threshold value may be greater than the intermediate torque threshold value. In some cases, a maximum angular position achieved by the motor shaft during each of the subsequent pulsing periods in the second phase may increase in smaller increments than during the at least one pulsing period in the first phase. In an example embodiment, the torque output achieved by the pulse tool during each of the subsequent pulsing periods in the second phase may increase in smaller increments than during the at least one pulsing period in the first phase.

[0053] Some example embodiments may provide for a control system for a pulse tool. The system may include at least one pulse tool, a network to which the at least one pulse tool may be operably coupled, and a tool controller which may be configured to communicate with the at least one pulse tool via the network. The at least one pulse tool may include a motor which may be configured to output rotational movement via a motor shaft, a drive assembly which may be operably coupled to the motor shaft to transmit rotational movement of the motorshaft to an end effector for acting upon a work piece, an angle sensor which may be operably coupled to the motor to measure an angular position of the motor shaft, position control circuitry which may control the angular position of the motor shaft based on feedback from the angle sensor, and process control circuitry which may control the position control circuitry using a control value and the position control circuitry. The control value may be a torque output value indicative of the amount of torque applied to the end effector. The process control circuitry may include a control algorithm that may control the rotational movement of the motor. The control algorithm may include a first phase in which the tool may operate at a first pulse intensity and a second phase in which the tool may operate at a reduced pulse intensity.

[0054] Some example embodiments may provide for method of controlling a pulse tool motor. The method may include the steps of driving the motor in a first direction at a constant velocity in a rundown period until a reverse transition trigger may be detected, transitioning the motor from the rundown period to a first phase reverse period responsive to detecting the reverse transition trigger, ceasing power supply to the motor in the coasting interval which may enable the motor to slow down, stop and rotate in a second direction until a rebound transition trigger may be detected, transitioning the motor from the coasting interval to the rebound interval responsive to detecting the rebound transition trigger, restoring power supply to the motor to rotate the motor in the second direction until a pulsing transition trigger may be detected, transitioning the motor from the first phase reverse period to the first phase pulsing period responsive to detecting the pulsing transition trigger, driving the motor in the first direction until the reverse transition trigger may be detected, transitioning the motor from the first phase pulsing period to the first phase reverse period responsive to detecting the reverse transition trigger, alternating the motor between the first phase pulsing period and the first phase reverse period until a phase transition trigger may be detected, transitioning the motor from a first phase in which the tool may operate at a first pulse intensity to a second phase in which the tool may operate at a reduced pulse intensity, responsive to detecting the phase transition trigger, and alternating the motor between a second phase pulsing period and a second phase reverse period until a stop trigger is detected. The first and second phase reverse periods may include a coasting interval and a rebound interval.

[0055] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it isto be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and / or functions, it should be appreciated that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and / or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits and / or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED:

1. A pulse tool comprising:a motor configured to output rotational movement via a motor shaft;a drive assembly operably coupled to the motor shaft to transmit the rotational movement of the motor shaft to an end effector for acting upon a work piece;an angle sensor operably coupled to the motor to measure an angular position of the motor shaft;position control circuitry configured to control the angular position of the motor shaft based on feedback from the angle sensor; andprocess control circuitry configured to control the position control circuitry using a control value and the position control circuitry,wherein the control value is a torque output value indicative of the amount of torque applied to the end effector,wherein the process control circuitry comprises a control algorithm that controls the position control circuitry to change the rotational movement of the motor, andwherein the control algorithm comprises a first phase in which the tool operates at a first pulse intensity and a second phase in which the tool operates at a reduced pulse intensity.

2. The pulse tool of claim 1, wherein the first phase comprises a rundown period, at least one reverse period and at least one pulsing period, andwherein the second phase comprises alternating subsequent reverse periods and subsequent pulsing periods.

3. The pulse tool of claim 2, wherein in the rundown period, the position control circuitry drives the motor in a first direction at a constant velocity until a reverse transition trigger is detected, andwherein the reverse transition trigger comprises a selected one of a motor current reaching a rundown current threshold value and the torque output reaching a rundown torque threshold value.

4. The pulse tool of claim 3, wherein responsive to detecting the reverse transition trigger, the process control circuitry transitions the motor from the rundown period to the at least one reverse period, andwherein the at least one reverse period further comprises a coasting interval and a rebound interval.

5. The pulse tool of claim 4, wherein in the coasting interval, power supply to the motor is ceased to enable the motor to slow down, stop and rotate in a second direction until a rebound transition trigger is detected.

6. The pulse tool of claim 5, wherein the rebound transition trigger comprises one of rotation in the second direction coming to a stop and an elapsed time in the coasting interval reaching a coasting interval duration threshold, whichever occurs first.

7. The pulse tool of claim 5, wherein responsive to detecting the rebound transition trigger, the process control circuitry transitions the motor from the coasting interval to the rebound interval,wherein in the rebound interval, power supply to the motor is restored to rotate the motor in the second direction until a pulsing transition trigger is detected, andwherein the pulsing transition trigger comprises the angular position of the motor shaft reaching a threshold rebound angle.

8. The pulse tool of claim 7, wherein responsive to detecting the pulsing transition trigger, the process control circuitry transitions the motor from the at least one reverse period to the at least one pulsing period, andwherein in the at least one pulsing period, the position control circuitry drives the motor in the first direction until the reverse transition trigger is detected.

9. The pulse tool of claim 8, wherein responsive to detecting the reverse transition trigger, the process control circuitry transitions the motor from the at least one pulsing period to the at least one reverse period, andwherein the position control circuitry alternates the motor between the at least one pulsing period and the at least one reverse period until a phase transition trigger is detected.

10. The pulse tool of claim 9, wherein the phase transition trigger comprises a selected one of the torque output reaching an intermediate torque threshold value, the angularposition of the motor shaft reaching an intermediate threshold rebound angle and a number of pulsing periods reaching an intermediate predetermined number of pulsing periods, wherein responsive to detecting the phase transition trigger, the process control circuitry transitions the tool from the first phase to the second phase, andwherein in the second phase the position control circuitry alternates the motor between the subsequent pulsing periods and the subsequent reverse periods until a stop trigger is detected.

11. The pulse tool of claim 10, wherein the stop trigger comprises a selected one of the torque output reaching a final torque threshold value, the angular position of the motor shaft reaching a threshold angle and the number of pulsing periods reaching a predetermined number of pulsing periods, andwherein the final torque threshold value is greater than the intermediate torque threshold value.

12. The pulse tool of claim 10, wherein a maximum angular position achieved by the motor shaft during each of the subsequent pulsing periods in the second phase increases in smaller increments than during the at least one pulsing period in the first phase, and wherein the torque output achieved by the pulse tool during each of the subsequent pulsing periods in the second phase increases in smaller increments than during the at least one pulsing period in the first phase.

13. A control system for a pulse tool, the system comprising:at least one pulse tool;a network to which the at least one pulse tool is operably coupled; anda tool controller configured to communicate with the at least one pulse tool via the network,wherein the at least one pulse tool comprises:a motor configured to output rotational movement via a motor shaft;a drive assembly operably coupled to the motor shaft to transmit the rotational movement of the motor shaft to an end effector for acting upon a work piece;an angle sensor operably coupled to the motor to measure an angular position of the motor shaft;position control circuitry configured to control the angular position of the motor shaft based on feedback from the angle sensor; andprocess control circuitry configured to control the position control circuitry using a control value and the position control circuitry,wherein the control value is a torque output value indicative of the amount of torque applied to the end effector,wherein the tool controller is configured to control the process control circuitry based on feedback from the process control circuitry,wherein the process control circuitry comprises a control algorithm that controls the position control circuitry to change the rotational movement of the motor, andwherein the control algorithm comprises a first phase in which the tool operates at a first pulse intensity and a second phase in which the tool operates at a reduced pulse intensity.

14. The system of claim 13, wherein the first phase comprises a rundown period, at least one reverse period and at least one pulsing period, andwherein the second phase comprises alternating subsequent reverse periods and subsequent pulsing periods.

15. The system of claim 14, wherein in the rundown period, the position control circuitry drives the motor in a first direction at a constant velocity until a reverse transition trigger is detected,wherein the reverse transition trigger comprises a selected one of a motor current reaching a rundown current threshold value and the torque output reaching a rundown torque threshold value,wherein responsive to detecting the reverse transition trigger, the process control circuitry transitions the motor from the rundown period to the at least one reverse period.

16. The system of claim 15, wherein the at least one reverse period further comprises a coasting interval and a rebound interval,wherein in the coasting interval, power supply to the motor is ceased to enable the motor to slow down, stop and rotate in a second direction until a rebound transition trigger is detected,wherein the rebound transition trigger comprises one of rotation in the second direction coming to a stop and an elapsed time in the coasting interval reaching a coasting interval duration threshold, whichever occurs first, andwherein responsive to detecting the rebound transition trigger, the process control circuitry transitions the motor from the coasting interval to the rebound interval.

17. The system of claim 16, wherein in the rebound interval, power supply to the motor is restored to rotate the motor in the second direction until a pulsing transition trigger is detected,wherein the pulsing transition trigger comprises the angular position of the motor shaft reaching a threshold rebound angle,wherein responsive to detecting the pulsing transition trigger, the process control circuitry transitions the motor from the at least one reverse period to the at least one pulsing period, andwherein in the at least one pulsing period, the position control circuitry drives the motor in the first direction until the reverse transition trigger is detected.

18. The system of claim 17, wherein responsive to detecting the reverse transition trigger, the process control circuitry transitions the motor from the at least one pulsing period to the at least one reverse period,wherein the position control circuitry alternates the motor between the at least one pulsing period and the at least one reverse period until a phase transition trigger is detected, wherein the phase transition trigger comprises a selected one of the torque output reaching an intermediate torque threshold value, the angular position of the motor shaft reaching an intermediate threshold angle and a number of pulsing periods reaching an intermediate predetermined number of pulsing periods,wherein responsive to detecting the phase transition trigger, the process control circuitry transitions the motor from the first phase to the second phase, andwherein in the second phase the position control circuitry alternates the motor between the subsequent pulsing periods and the subsequent reverse periods until a stop trigger is detected.

19. The system of claim 18, wherein the stop trigger comprises a selected one of the torque output reaching a final torque threshold value, the angular position of the motor shaftreaching a threshold angle and the number of pulsing periods reaching a predetermined number of pulsing periods,wherein the final torque threshold value is greater than the intermediate torque threshold value,wherein a maximum angular position achieved by the motor shaft during each of the subsequent pulsing periods in the second phase increases in smaller increments than during the at least one pulsing period in the first phase, andwherein the torque output achieved by the pulse tool during each of the subsequent pulsing periods in the second phase increases in smaller increments than during the at least one pulsing period in the first phase.

20. A method of controlling a pulse tool motor, the method comprising:driving the motor in a first direction at a constant velocity in a rundown period until a reverse transition trigger is detected;transitioning the motor from the rundown period to a first phase reverse period responsive to detecting the reverse transition trigger, the first phase reverse period comprising a coasting interval and a rebound interval;ceasing power supply to the motor in the coasting interval to enable the motor to slow down, stop and rotate in a second direction until a rebound transition trigger is detected; transitioning the motor from the coasting interval to the rebound interval responsive to detecting the rebound transition trigger;restoring power supply to the motor to rotate the motor in the second direction until a pulsing transition trigger is detected;transitioning the motor from the first phase reverse period to a first phase pulsing period responsive to detecting the pulsing transition trigger;driving the motor in the first direction until the reverse transition trigger is detected; transitioning the motor from the first phase pulsing period to the first phase reverse period responsive to detecting the reverse transition trigger;alternating the motor between the first phase pulsing period and the first phase reverse period until a phase transition trigger is detected;transitioning the motor from a first phase in which the tool operates at a first pulse intensity to a second phase in which the tool operates at a reduced pulse intensity, responsive to detecting the phase transition trigger; andalternating the motor between a second phase pulsing period and a second phase reverse period until a stop trigger is detected.

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