Rotary medical device

Abstract

The present invention relates to medical systems and methods for making and using such systems. An exemplary medical system may include an atherectomy system configured to engage an inner wall of a vessel in a vasculature to remove plaque. The atherectomy system may include a drive shaft, a rotating member coupled to an end of the drive shaft, a motor coupled to the drive shaft to rotate a rotating tip, and a control unit configured to control a motor state of the motor. The motor may be an electric motor. The control unit may adjust the motor state to slow the motor in response to detecting a stall or stall condition. A stall or stall condition may be detected when the motor speed or other motor state reaches or exceeds a threshold defined by a reference schedule.

Description

Technical Field

[0001] The present invention relates to medical devices and methods for manufacturing and using medical devices. More particularly, the present invention relates to rotary medical devices, methods, and systems, including those having an electric motor.

Background Art

[0002] A wide variety of medical devices have been developed for medical use, for example, for accessing body cavities and interacting with fluids and structures within the body cavity. Some of these devices may include guidewires, catheters, pumps, motors, controllers, filters, grinders, needles, valves, and delivery devices and / or systems used to deliver such devices. These devices are manufactured by any one of a variety of different manufacturing methods and can be used according to any one of a variety of methods. Among known medical devices and methods, each has specific advantages and disadvantages.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The present invention provides designs, materials, manufacturing methods, and alternatives for medical devices and systems.

Means for Solving the Problems

[0004] In a first aspect, a medical device includes a drive shaft, a rotating member coupled to a first end of the drive shaft, a motor coupled to a second end of the drive shaft to rotate a rotating tip, and a control unit that controls a motor state of the motor. The control unit is further configured to adjust the motor state to decelerate the motor in response to a detected stall state.

[0005] In an additional or alternative second aspect, the motor state is the torque of the motor, and the stall state is detected when the speed of the motor reaches or exceeds a threshold level. In an additional or alternative third aspect, adjusting the torque of the motor can include reversing the direction of the torque of the motor.

[0006] In an additional or alternative fourth aspect, the control unit is configured to adjust the motor state of the motor by reversing the direction of the current supplied to the motor in order to decelerate the motor in response to the detected stall state.

[0007] In an additional or alternative fifth aspect, the control unit is configured to adjust the motor state of the motor by reducing the amount of voltage supplied to the motor in order to decelerate the motor in response to the detected stall state.

[0008] In an additional or alternative sixth aspect, the control unit is configured to adjust the motor state of the motor based on a predetermined motor speed reference schedule and motor parameters received by the control unit during operation of the motor.

[0009] In an additional or alternative seventh aspect, the motor parameters can include a measurement of the current supplied to the motor and a measurement of the rotational position of the motor. In an additional or alternative eighth aspect, the medical device further comprises a first sensor for detecting the current supplied to the motor and a second sensor for detecting the position of the motor, wherein the first sensor can provide a signal indicative of the detected current to the control unit and the second sensor can provide a signal indicative of the detected position to the control unit.

[0010] In an additional or alternative ninth aspect, the control unit can be configured to determine the speed of the motor based on a signal indicating the detected position of the motor, and the control unit determines the motor state of the motor based on a signal indicating the detected current and a signal indicating the detected position. When determining the motor, the determined motor state is a motor state other than the determined speed of the motor.

[0011] In an additional or alternative tenth aspect, the control unit is configured to determine a reference motor state based on the speed of the motor, compare the determined reference motor state with the determined motor state, and issue a command signal to the motor based on the comparison between the reference motor state and the determined motor state.

[0012] In an additional or alternative eleventh aspect, the control unit includes a controller, a motor state estimator that communicates with the controller, and a reference schedule element that communicates with the controller and the motor state estimator. The reference schedule element provides an output to the controller based on an input from the motor state estimator. The controller is configured to output a control signal for decelerating the motor based on the output received from the reference schedule element when the input from the motor state estimator to the reference schedule element reaches or exceeds a threshold level.

[0013] In an additional or alternative twelfth aspect, the input from the motor state estimator to the reference schedule element can be the motor speed, and the reference schedule element is configured to provide a reference motor state based on the motor speed.

[0014] In an additional or alternative thirteenth aspect, the motor state estimator is configured to receive a signal indicating the detected motor parameter and provide an output to the controller based on the received signal indicating the detected motor parameter. The output control signal is based on the output from the motor state estimator to the controller.

[0015] In an additional or alternative fourteenth aspect, the output from the reference schedule element to the controller can be a reference motor state, the output from the motor state estimator to the controller can be a real-time motor state, and the controller determines a control signal based on the difference between the reference motor state and the real-time motor state.

[0016] In an additional or alternative fifteenth aspect, the reference motor state can be a reference torque of the motor, and the real-time motor state can be a real-time torque of the motor.

[0017] In an additional or alternative sixteenth aspect, the control unit further includes a processor, a memory communicating with the processor, and an input / output port communicating with the processor, and the processor and the memory execute operations of the controller and the reference schedule element to output a control signal via the input / output port.

[0018] In an additional or alternative seventeenth aspect, a method for controlling a medical device includes receiving a signal indicating a detected position of a motor, determining a motor speed based on the signal indicating the detected position of the motor, identifying a reference motor state based on the determined motor speed and a predetermined reference schedule, and outputting a control signal to the motor to decelerate the motor, wherein the output control signal is based on the reference motor state.

[0019] In an additional or alternative eighteenth aspect, the method further includes receiving a signal indicating a current provided to and detected by the motor, and determining a real-time motor state based on the received signal indicating the detected motor parameter and the received signal indicating the detected current, and the output control signal can be based on the real-time motor state.

[0020] In an additional or alternative nineteenth aspect, the reference motor state can be a reference motor torque, and the real-time motor state can be a real-time motor torque. In an additional or alternative twentieth aspect, when the determined motor speed reaches or exceeds a threshold level, a control signal for decelerating the motor can be output to the motor.

[0021] Although the present disclosure is susceptible to various modifications and alternative forms, specific details thereof are shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0022] The present disclosure can be more fully understood in consideration of the following description of various exemplary embodiments of the present disclosure in connection with the accompanying drawings.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0024] While various modifications and alternative forms are possible for the present disclosure, the details thereof are shown in the drawings for illustrative purposes and will be described in detail. However, it should be understood that the aspects of the present disclosure are not intended to be limited to the specific exemplary embodiments described herein. Rather, it is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0025] For the following defined terms, these definitions apply unless a different definition is provided in the claims or elsewhere in the specification. All numerical values in this specification are to be considered as being modified by the term "about", whether explicitly indicated or not. The term "about" generally refers to a range of numerical values that a person skilled in the art would consider equivalent to the recited value (e.g., having the same function or result). In many cases, the term "about" includes the value rounded to the nearest significant digit.

[0026] The recitation of a numerical range by endpoints includes all numerical values within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5). As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in the sense including "and / or" unless the context clearly dictates otherwise.

[0027] Note that references to "one embodiment", "some embodiments", "other embodiments", etc. in this specification indicate that the described embodiments may include one or more specific features, structures, and / or characteristics. However, such enumerations do not necessarily mean that all embodiments include the specific features, structures, and / or characteristics. Further, when a specific feature, structure, and / or characteristic is described in relation to one embodiment, it should be understood that such feature, structure, and / or characteristic may be used in relation to other embodiments, whether or not explicitly described, unless explicitly stated otherwise.

[0028] The following detailed description is read with reference to the drawings in which the same reference numerals are used for the same elements in different drawings. The drawings are not necessarily to scale and are exemplary embodiments and are not intended to limit the scope of the invention.

[0029] Cardiovascular disease and peripheral artery disease result from the accumulation of atherosclerotic substances on the inner walls of the blood vessel lumen, which causes a condition known as atherosclerosis. Atherosclerotic and other vascular deposits can restrict blood flow and cause ischemia in the patient's heart, the vascular systems of the patient's extremities (e.g., legs, arms, head, etc.), the patient's carotid arteries, and / or other vascular systems. Such ischemia can cause pain, swelling, non-healing wounds, amputations, strokes, myocardial infarctions, and / or other conditions.

[0030] Atheromatous deposits can have various properties, some deposits being relatively soft, others being fibrous and / or calcified. In the latter case, the deposits may be called plaques. Atherosclerosis occurs naturally as a result of aging, but can also be exacerbated by factors such as diet, high blood pressure, genetics, and vascular injury. Atherosclerosis can be treated in various ways, including drugs, bypass surgery, and various catheter-based approaches, which rely on intravascular dilation or the removal of atherosclerotic vessels or other substances occluding the vessels. Atherectomy is a catheter-based therapeutic intervention that can be used in the treatment of atherosclerosis.

[0031] Atherectomy is a therapeutic intervention technique performed to restore blood flow through a portion of a patient's vasculature that is blocked by plaque or other substances. In an atherectomy procedure, a device at the end of a drive shaft is used to capture or remove (e.g., ablation, abrasion, cutting, shaving, etc.) plaque and other substances from the patient's blood vessels (such as arteries and veins). In some cases, the device at the end of the drive shaft can perform abrasion and / or, in other ways, when the device rotates and engages the plaque or other obstacles, it is configured to remove the plaque from the vessel wall or other obstacles within the vessel.

[0032] Figure 1 shows an atherectomy system 10. The atherectomy system 10 can include a drive assembly 12 and a control unit 14 (e.g., a controller). The drive assembly 12 can include, among other elements, an advancement assembly 16, a drive shaft 18 (e.g., a flexible drive shaft or other drive shaft), a rotating device 20 (e.g., a rotating member such as a rotating chip or other rotating member), and an elongate member 22 having a first end (e.g., a distal end), a second end (e.g., a proximal end), and extending from the first end to the second end and having a lumen for receiving the drive shaft 18. Optionally, the elongate member 22 can be an elongate tubular member. The rotating device 20 can have a rough, abrasive, or sharp surface for ablating, polishing, cutting, or shaving plaque on the blood vessel wall or other obstructions within the blood vessel when rotated.

[0033] The advancement assembly 16 can include an advancement knob 23 and can house a motor (e.g., an electric motor, an air motor, or other motor) that communicates with the advancement knob 23, the drive shaft 18, and the control unit 14. The advancement knob 23 can be configured to advance along a longitudinal path to longitudinally advance the motor and the rotating device 20. The motor can be coupled to the drive shaft 18 in a suitable manner including, but not limited to, welding, clamp connection, adhesion, screwing, and / or other suitable connections configured to withstand high rotational speeds and rotational forces. Since the drive shaft 18 can rotate over a wide range of speeds (e.g., speeds between zero (0) RPM and 250,000 RPM or more), the connection between the motor and the drive shaft 18 can be configured to withstand such rotational speeds and associated forces.

[0034] The drive shaft 18 can be formed from one or more various materials. For example, the drive shaft 18 can be formed from one or more various materials including steel, stainless steel, and / or other suitable materials.

[0035] The drive shaft 18 can have an appropriate diameter and / or length for passing through a patient's vasculature. In some cases, the drive shaft 18 can have a diameter in the range of about 0.05 centimeters (cm) to about 0.130 cm, and a working length in the range of about 10 (cm) to about 200 (cm). In one example, the drive shaft 18 can have a diameter of about 0.05715 cm and a length of about 50 cm. Alternatively, the drive shaft 18 can have different appropriate diameters and / or different appropriate lengths.

[0036] The rotating device 20 can have an outer circumference equal to or larger than the distal diameter of the drive shaft 18 and / or the elongate member 22. Alternatively or additionally, the rotating device 20 can have an outer circumference smaller than the diameter of the drive shaft 18 and / or the elongate member 22. The rotating device 20 can have a symmetric design that penetrates equally well in both rotational directions, but this is not essential, and the rotating device 20 can be configured to penetrate in only one direction. The diameter of the drive shaft 18 can depend on the dimensions of the lumen of the elongate member 22 and / or one or more other factors.

[0037] The rotating device 20 is coupled to the drive shaft 18. If the drive shaft 18 has a first end (e.g., a distal end portion) and a second end (e.g., a proximal end portion), the rotating device 20 can be coupled to the drive shaft 18 at the first end or in its vicinity. In some cases, the rotating device 20 can be disposed at or adjacent to the terminus of the first end of the drive shaft 18.

[0038] The rotating device 20 can be coupled to the drive shaft 18 in any manner. For example, the rotating device 20 can be coupled to the drive shaft 18 by adhesion, screwing, welding, clamp connection, and / or other suitable connections configured to withstand high rotational speeds and forces. Similar to what was described above regarding the connection between the drive shaft 18 and the motor, since the drive shaft 18 and / or the rotating device 20 can rotate at speeds from zero (0) RPM to 250,000 RPM or more, the drive shaft 18 and the rotating device 20 can be configured to withstand such rotational speeds and the associated forces.

[0039] The drive assembly 12 and the control unit 14 can communicate, may be disposed in the same housing, and / or may be disposed in separate housings (e.g., the forward assembly housing 26 and the control unit housing 28 or other housings). Whether within the same housing or separate housings, the drive assembly 12 and the control unit 14 can communicate via a wired connection (e.g., via one or more wires of the electrical connector 24) and / or a wireless connection. The wireless connection is made via one or more suitable communication protocols including, but not limited to, cellular communication, ZigBee (trademark), Bluetooth (registered trademark), WiFi (registered trademark), IrDA (trademark), dedicated short range communication (DSRC), EnOcean (trademark), and / or other suitable general or proprietary wireless protocols.

[0040] Although not necessarily shown in FIG. 1, the drive assembly 12 can include and / or house one or more operating structures. For example, among others, the drive assembly 12 can include operating structures such as a motor, a start / stop button, a control knob configured to advance the rotating device 20, rubber feet, a mode selection button, a mode start / stop button, control electronic circuits, drive circuits, and the like.

[0041] The control unit 14 may include several features that can be separated from the drive assembly 12 (e.g., as shown in FIG. 1) or can be included in the drive assembly 12. For example, as shown in FIG. 1, the control unit 14 may include a display 30 and a control knob 32 (e.g., a motor speed (e.g., RPM or other speed) adjustment knob or other control knob). Additionally or alternatively, the control unit 14 may include one or more other structures for controlling the motor and / or other structures of the drive assembly 12 (e.g., one or more motor states of the motor), which may include a processor, memory, input / output devices, speakers, volume control buttons, on / off power switch, motor start switch, timer, clock, and / or other functions.

[0042] In some cases, the control unit 14 may include one or more safety mechanisms for controlling the operation of the atherectomy system 10. In one example of a safety mechanism that may be included in the control unit 14, the control unit 14 may be configured to adjust the motor state to decelerate the motor in response to the detection of a stall or stall condition. Exemplary motor states that the control unit 14 may be configured to control include, but are not limited to, motor torque, drive current to the motor, drive voltage to the motor, motor speed, etc. Additionally or alternatively, the control unit 14 may include other safety mechanisms for controlling the operation of the atherectomy system 10 and reducing the risk to the patient. The detection of a stall or stall condition is described herein as being performed by a controller such as the control unit 14, but one or more additional or alternative components may detect and / or facilitate the detection of a stall or stall condition.

[0043] Figure 2 shows a block diagram of the atherectomy system 10. Although the drive assembly 12 and the control unit 14 are depicted in Figure 2 as separate components, all or part of the control unit 14 can be incorporated into, or with, all or part of the drive assembly 12 and / or the drive unit, or the drive assembly 12 may be incorporated within or with the control unit 14. As described above, the drive assembly 12 and the control unit 14 may be within the same housing or separate housings.

[0044] The atherectomy system 10 may include a drive circuit 36 (optionally included), a motor 37 (e.g., an electric motor or other suitable drive mechanism) that communicates with the drive circuit 36, and sensors (e.g., a first sensor 44, a second sensor 46, and / or other suitable sensors) for detecting motor parameters (e.g., drive current, drive voltage, motor position, etc.), and a rotary device 20 that communicates with the motor 37 via a drive shaft 18. The drive assembly 12 communicates with the control unit 14 via an electrical connection (e.g., an electrical connector 24 or other connection configured to transmit signals). Since torque may accumulate on the drive shaft 18, the drive shaft 18 is shown as a spring in Figures 2 and 3.

[0045] When the drive circuit 36 is included in the atherectomy system 10, the drive circuit 36 can be mounted on a substrate or other component within the forward assembly housing 26 of the drive assembly 12 and can communicate electrically with the control unit 14. The drive circuit 36 can include, but does not necessarily include, a microprocessor and / or a microcontroller, an application-specific integrated circuit ("ASIC"), and / or an application-specific standard product ("ASSP"). In some cases, the drive circuit 36 may be (at least partially) incorporated into the control unit 14, but this is not essential.

[0046] As described above, the control unit 14 may include one or more functions configured to facilitate the control of the drive assembly 12. As shown in FIG. 2, the atherectomy system 10 may include, among other things, a processor 38 (e.g., a microprocessor, a microcontroller, etc.), a memory 40, a display 30, and an input / output port 42 (e.g., in the control unit 14 or elsewhere). The processor 38 may be operably coupled to the memory 40. The memory 40 may be used to store any desired information such as control algorithms, setpoints, schedules, reference schedules, times, diagnostic limits, such as diagnostic limits including, for example, speed limits, RPM limits, torque limits, current limits, voltage limits, etc. The memory 40 may include any one or more suitable types of storage devices including, but not limited to, RAM, ROM, EPROM, flash memory, hard drives, and the like. In some cases, the control unit 14 may be able to store information in the memory 40 and then retrieve the stored information from the memory 40 to perform and / or analyze the operation of the atherectomy device. Further, the processor 38 and / or the memory 40 may include or communicate with a timer (not shown).

[0047] FIG. 3 shows a schematic block diagram of the control software and circuitry of the atherectomy system 10 connected to the motor 37, which is operably attached to the drive shaft 18 and the rotating device 20. The control software and circuitry can include, among other things, a drive circuit 36 (if included), a reference schedule element 48, a motor state estimator 50 (e.g., a motor state observer or other motor state estimator), and a controller 52 (e.g., a feedback controller, a closed-loop controller, or a feedback regulator such as a proportional-integral-derivative (PID) controller or other controller). The reference schedule element 48, the motor state estimator 50, and the controller 52 are shown as separate elements in FIG. 3, but one or more of the reference schedule element 48, the motor state estimator 50, and the controller 52 may be implemented as a single controller or processor. Alternatively, in a plurality of controllers or processors, they may be configured to perform the functions of the above reference schedule element 48, motor state estimator 50, and controller 52. Although not necessarily required, one or more of the Reference schedule components 48, motor state estimator 50, controller 52, drive circuit 36, and / or other electronic processing components of the atherectomy system 10 can be implemented in the processor 38, memory 40, and / or input / output port 42. (For example, the processor 38, memory 40, and / or input / output port 42 can be configured to effect the operation of one or more of the reference schedule element 48, motor state estimator 50, controller 52, drive circuit 36, and / or other electronic processing components of the atherectomy system 10.) The reference schedule element 48 may include a reference schedule that associates the motor state with a motor input or a setpoint (e.g., reference value) of the motor state. That is, for every possible value of the motor state, the reference schedule may have an associated reference value (e.g., motor input or setpoint of the motor state). Exemplary motor states may include, but are not limited to, motor speed, motor position, motor torque, motor drive current, motor drive voltage, motor drive power, and / or other motor states. Exemplary reference schedules can associate speed with torque, speed with current, speed with voltage, and / or can associate one or more other motor states with a reference motor state. For example, associating speed with torque Reference A control system that utilizes the schedule receives a speed input (e.g., from a motor state estimator or other component of the atremectomy system 10) and provides a reference torque (e.g., for use by the controller 52 or other element of the atremectomy system 10), and the control signal is based thereon.

[0048] In some cases, the reference schedule of the reference schedule element 48 is stored in the memory 40 and / or other memory and is accessed or otherwise utilized by the processor 38 to determine a reference value based on an input (e.g., input motor state, speed, etc.). The reference schedule element 48 may be the memory 40 or may include the memory 40, but this is not essential.

[0049] The reference schedule is determined in advance (e.g., during calibration or preset by the manufacturer) before the operation of the atremectomy device and may be stored in the memory 40 or other memory. In some cases, the user may be able to adjust or change the reference schedule and store it in the memory 40 or other memory to establish a predetermined or offline reference schedule. The reference schedule can be considered predetermined or offline if it is not changed in real time during the operation of the drive assembly 12.

[0050] The motor state estimator 50 can be configured to estimate one or more states of the motor 37 based on an input received from a sensor that detects motor parameters (e.g., the detected motor parameters can be the measured motor states). Examples of motor parameters include drive current, drive voltage, input power, motor position, etc. In some cases, the first sensor 44 can detect the input current to the motor 37 and provide a signal indicating the value of the motor drive current or other electrical input to the motor state estimator 50. Additionally, or alternatively, the second sensor 46 can detect the position of the motor 37 and provide a signal indicating the position value of the motor 37 to the motor state estimator 50. In some cases, the sensor configured to detect the position of the motor may be a Hall effect sensor, although other position sensors may be additionally or alternatively utilized. Sensors 44, 46 are disclosed as detecting current and motor position, but these sensors can be configured to detect additional or alternative other parameters and / or other sensors detecting similar or different motor parameters can be included in the arthroscopic system 10.

[0051] Based on the detected values of the motor parameters provided to the motor state estimator 50, the motor state estimator 50 can calculate (e.g., estimate) one or more motor states. In one example, based on the received value indicating the motor position, the timing of the position value, and a known relationship between the motor position and time, the motor state estimator 50 can calculate or determine (e.g., estimate) the speed of the motor 37 (e.g., RPM or other speed parameter). In another example, based on the received value indicating the motor position, the received value indicating the drive current or other electrical input, and a known relationship between the motor position and the electrical input to the motor, the motor state estimator 50 can calculate or determine (e.g., estimate) the torque of the motor 37. Other motor states may be determined by the motor state estimator 50.

[0052] The controller 52 or another controller may be configured to provide control signals to the drive circuit 36 (if included) and / or the motor 37. In some cases, the controller 52 or another controller can receive a reference value based on motor parameters from the reference schedule element 48 and the calculated or determined current values of the motor state from the motor state estimator 50. Based on comparing the reference value with the calculated or determined value, the controller 52 or another controller determines a control signal for maintaining or adjusting the operation of the motor 37 is made. In addition to or instead of the controller 52, a controller configured to determine a motor control signal based on a reference value of a parameter that is compared with the real-time value of the measured, determined, or calculated parameter can be utilized.

[0053] In addition to feedback from the first sensor 44, the second sensor 46, and / or other sensors, the reference schedule element 48, the motor state estimator 50, and the controller 52 or other systems having a functionally similar configuration facilitate closed-loop control of the motor 37 and the rotary device 20, which control is based on feedback from sensors (e.g., the first sensor 44 and the second sensor 46) and Reference the schedule component 48 of Reference the schedule. This closed-loop control of the motor 37 and the rotary device 20 enables active deceleration of the motor 37 upon detection or identification of a stall condition, thereby facilitating use of the atherectomy system 10 in a safe manner while maintaining maximum torque at the rotary device 20 for an effective treatment over a suitable length of time. Further, the closed-loop control configuration enables reduction of the force acting on the patient when a stall or stall condition occurs by continuous monitoring for a stall or stall condition, early identification of a stall or stall condition, and implementation of proactive steps (such as an active brake of the motor 37).

[0054] FIG. 4 shows three graphs on the same time scale (seconds) representing how three different atherectomy systems respond to stalling or stalling in their respective rotating devices (e.g., when the rotating device 20 stops moving due to a malfunction). As shown in FIG. 4, graph 54 shows the motor torque over time, graph 56 shows the motor speed over time, and graph 58 shows the torque in the rotating device (e.g., load) over time.

[0055] In the graphs of FIG. 4, lines 60, 62, 64 represent different atherectomy systems. Line 60 shows the operation of the atherectomy system 10 that uses the Reference schedule configuration described herein and disclosed to automatically identify and address stalling or stalling conditions. Line 62 (e.g., dashed line) represents an atherectomy system that monitors for stalling or stalling conditions in the system, addresses the detected stalling or stalling condition by removing power from the motor, and freely rotates the power until the accumulated system torque dissipates. Line 64 (e.g., bold line) represents a conventional atherectomy system that does not include automatic monitoring of stalling or stalling conditions and addressing the identified stalling or stalling conditions, but instead relies on the user to stop the motor of the atherectomy system when stalling or stalling occurs.

[0056] In the 9 - second operation history of three different atherectomy systems shown in the graph of FIG. 4, each motor starts from a complete stop for a time equal to zero (0) and then is turned on. After reaching full speed for approximately 6 seconds, at line 66, it can be seen that each rotating device has stalled and stopped almost instantaneously. Such an instantaneous or almost instantaneous stop of the rotating device causes each drive shaft to function like a large spring fixed at one end (e.g., the end where the rotating device has stalled), and the motor acts on a combination of a mass and a damper on the opposite side. After the stall occurs, the atherectomy system represented by line 64 continues to drive the motor, as a result, forces from both motor torque and kinetic energy are supplied to the drive cable, the torque of the motor increases (graph 54), and the torque of the rotating device (graph 58) increases. After the stall occurs, the atherectomy system represented by line 62 stops the rotation of the motor and stops introducing torque into the system, but all the kinetic energy already present in the system is still transmitted to the stalled rotating device, resulting in torque generation, which results in a torque spike in the rotating device as shown in graph 58. After a stall or stall condition is identified, the atherectomy system 10 disclosed herein and represented by line 60 applies a brake to the motor (e.g., motor 37) and effectively dissipates a portion of the kinetic energy of the system. In the atherectomy system 10, when a stall occurs or is identified, there is less force transmitted to the patient through the rotating device when the stall is detected than in conventional atherectomy systems that do not monitor for stall or have an automatic response to stall, and also because the motor is automatically disengaged during rotation, the atherectomy system 10 provides an improvement over existing techniques for dealing with stall and / or stall conditions in atherectomy systems.

[0057] FIG. 5 shows a flowchart of a method 100 for controlling an atherectomy system (e.g., atherectomy system 10 or other atherectomy system), detecting a stall condition or stalling in a rotating device (e.g., rotating device 20 or other rotating device), and in response, decelerating a motor (e.g., motor 37 or other motor) in an automated manner to facilitate reducing the force applied to a patient if a stall or stalling occurs. In method 100, one or more motor states of the motor can be monitored based on values from sensors that detect motor parameters including, but not limited to, drive current, drive voltage, motor position, etc.

[0058] Refer to method 100. As shown in FIG. 5, a signal indicative of a parameter value of the motor can be received 102. The parameter value of the motor can be detected by one or more sensors (e.g., first sensor 44, second sensor 46, and / or other sensors), and a signal indicative of the detected parameter value can be transmitted from the sensor to a controller (e.g., control unit 14 having a motor state estimator 50 or other controller). Examples of detected parameter values include, but are not limited to, drive current of the motor, drive voltage to the motor, position of the motor, etc. The controller uses the signal indicative of the detected parameter value and a known relationship (e.g., an equation) between the detected parameter value and the motor state to determine one or more motor states of the monitored motor (104). Examples of motor states include, but are not limited to, real-time motor speed, real-time motor torque, real-time drive current, real-time drive voltage, real-time drive power, etc. Values and / or motor states obtained or determined in real time may be considered to be obtained or determined during operation of the atherectomy system.

[0059] Next, the controller can identify a reference motor state or a reference motor input based on the determined motor state (106). In one example, the controller can identify a reference motor state based on the determined motor speed (106). Next, based on the reference motor state (e.g., directly based on the reference motor state and / or based on a comparison between the reference motor state and the determined motor state), the controller outputs a control signal based on the reference motor state or the reference motor input (108). In some cases, the control signal output from a control unit (e.g., control unit 14 or another control unit) can be a control signal that decelerates the motor and stops the motor after a stall or stall state is detected. The control signal can reverse the direction of the torque to the motor, reverse the direction of the current provided to the motor, reduce the amount of voltage provided to the motor, reverse the direction of the current provided to the motor, and / or result in applying one or more other effects to the motor state of the motor to decelerate the motor in response to the detection of a stall or stall state. In one example, a stall or stall state can be detected when the determined motor state (e.g., speed or other motor state) reaches or exceeds a threshold, as described in more detail with reference to FIGS. 6-8.

[0060] Further, in some cases, the control of the aterectomy system can include identifying a first motor state and a second motor state, where the first motor state (e.g., speed) is used to determine a reference motor state and the determined second motor state (e.g., torque) is compared to the reference motor state. In such cases, the controller can output a control signal to maintain or change the operation of the motor based on the reference motor state and the determined current motor state.

[0061] A controller or other monitoring element can continuously monitor for a stall or stall condition during operation of the atherectomy system using the method 100 disclosed herein and / or other techniques. In one example, the controller continuously repeats the steps of method 100 and / or repeats the steps of method 100 at predetermined intervals during operation of the motor of the atherectomy system to monitor for a stall or stall condition occurring in the rotational device of the atherectomy system.

[0062] Figures 6 - 8 illustrate an exemplary schedule component 48 that the atherectomy system 10 can follow to identify a stall or stall condition and address the stall or stall condition. Reference Exemplary Reference schedule. Figure 6 shows line 68 of reference schedule 69 that compares motor torque to motor speed, where torque is measured as a percentage of target motor torque and speed is measured as a percentage of target motor speed. Figure 7 shows line 70 of reference schedule 71 that compares drive current of the motor to motor speed, where the drive current supplied to the motor is measured as a percentage of the target current of the motor and speed is measured as a percentage of motor speed. Figure 8 shows lines 72, 74 of reference schedule 75 that compares drive voltage to the motor to motor speed, where the drive voltage of the motor is measured as a percentage of the target drive voltage of the motor and speed is measured as a percentage of motor speed.

[0063] Figures 6 - 8 show the reference schedule in graphical form, but the reference schedule may be in other forms. Examples of forms of the reference schedule include, but are not limited to, graphs, equations, look-up tables, etc. Note that using a look-up table or graph for the reference schedule can reduce the processing power required during operation of the atherectomy system 10 compared to following a reference schedule represented by an equation.

[0064] When the determined speed or other determined motor state reaches or exceeds a threshold value (e.g., the speed value T in FIGS. 6-8), the control system automatically changes the operation of the atremectomy system 10 and indicates that a stall or stall condition has been detected and addressed via a visual alarm, audible alarm, or one or more other mechanisms on the display or in other ways. In some cases, no indication of a stall or stall condition is provided other than automatically decelerating the motor of the atremectomy system 10.

[0065] As shown in FIGS. 6-8, the speed threshold is set at 75% of the target speed. However, Reference the schedule threshold can be a different percentage of the target speed, can be different speed values, and / or can be a threshold for a motor state or motor parameter different from speed. Further, the threshold can vary based on the settings or other conditions of the atremectomy system 10. For example, the atremectomy system 10 can include multiple speed settings (e.g., a first setting with a first maximum speed and a second setting with a second maximum speed), and each setting can have different thresholds associated with two or more settings. Using a threshold has the advantage, among other advantages, of making it easier to detect a stall or stall condition before it actually occurs, but this is not essential.

[0066] When displaying the reference schedules of FIGS. 6-8, there are several points to note, some of which are described below. First, when the target RPM of a motor is the target RPM, the torque value, current value, and the difference between the target voltage and the back electromotive force (EMF) (e.g., the scheduled root mean square (RMS) voltage value) are zero or near zero, as shown in FIGS. 6-8, respectively. Second, when the motor speed reaches or exceeds a threshold value, the torque value, current value, and the difference between the back electromotive force voltage and the target voltage can shift rapidly from positive to negative, as shown in FIGS. 6-8, respectively. Third, although the figures generally show flat lines 68, 70, 72 (e.g., in some cases, based on a linear function), the reference schedules may actually be based on quadratic functions and / or other non-linear functions in order to obtain suitable performance when controlling the atherectomy system 10 in the manner described herein.

[0067] In one exemplary method of controlling the atherectomy system 10, in FIG. 6 ReferenceIn accordance with schedule 69, the following steps can be repeatedly performed over time until a stall or stalling state is identified. First, the real-time or instantaneous torque of the motor 37 can be identified. The real-time or instantaneous torque to the motor 37 can be based on the measured motor state and the measured motor drive state. For example, the real-time or instantaneous torque of the motor can be calculated or determined using the measured or sensed drive power (e.g., drive current) and / or manufacturing parameters of the motor 37. Next, the real-time or instantaneous motor speed is determined based on the measured or sensed motor position, and the determined real-time or instantaneous motor speed and the reference motor torque from line 68 of the reference schedule 69 in FIG. 6 are identified. Next, based on the reference motor torque and the real-time or instantaneous torque, a control signal for the motor 37 is generated by the controller. In one example, if the real-time speed or instantaneous speed has not reached or exceeded the threshold speed value T (e.g., to the right of the threshold T in FIG. 6), the reference torque may be similar to the real-time or instantaneous torque, and the controller maintains the operation of the motor or issues a control signal to make a slight change (e.g., attenuation, correction, other changes) based on the difference between the reference torque and the real-time or instantaneous torque. However, if the real-time or instantaneous speed reaches or exceeds the threshold T (e.g., at or to the left of the threshold speed value T in FIG. 6), the reference torque may be significantly different from the determined real-time or instantaneous torque, and the controller applies a brake to the motor and outputs a control signal to reduce the force applied to the patient when the speed of the motor decreases. In the example of FIG. 6, the control signal can reverse the motor torque to decelerate the motor until the motor speed is substantially zero (0).

[0068] In a further exemplary method of controlling the atherectomy system 10, in FIG. 7 ReferenceIn accordance with schedule 71, the following steps can be repeated over a certain period of time until a stalled or stalled state is identified. First, the real-time or instantaneous drive current to motor 37 can be identified. The real-time or instantaneous drive current to motor 37 can be based on the measured motor state and the measured motor drive state (e.g., measured motor parameters). Next, the real-time or instantaneous motor speed is determined based on the measured or detected motor position, and the reference drive current of the motor can be identified from line 70 of the reference schedule 71 in FIG. 7 and the determined real-time or instantaneous motor speed. Next, based on the reference drive current and the real-time or instantaneous current, a control signal for motor 37 is generated by the controller. In one example, if the real-time or instantaneous speed reaches or does not exceed the threshold T (e.g., to the right of the threshold speed value T in FIG. 7), the reference drive current may be similar to the real-time or instantaneous drive current, and the controller may maintain the operation of the motor or make slight changes (e.g., attenuation, correction, and / or other changes) based on the difference between the reference drive current and the real-time or instantaneous drive current. However, if the real-time speed or instantaneous speed reaches or exceeds the threshold speed value T (e.g., at or to the left of the threshold T in FIG. 7), the reference drive current is significantly different from the determined real-time or instantaneous drive current, and the controller outputs a control signal based on the difference between the reference drive current and the real-time or instantaneous drive current, applies a brake to the motor, and reduces the force applied to the patient when the speed of the motor decreases. In the example of FIG. 7, the control signal can reverse the direction of the drive current to decelerate the motor until the motor speed reaches zero or nearly zero (0).

[0069] In a further exemplary method of controlling the atherectomy system 10, in FIG. 8 ReferenceAccording to schedule 75, the following steps can be repeated over a certain period of time until a stalled or stalled state is identified. First, identify the real-time or instantaneous back electromotive force. The real-time or instantaneous back electromotive force of the motor 37 can be based on the measured motor state and the measured motor drive state. For example, the real-time or instantaneous back electromotive force can be calculated using known voltages, motor positions, and / or motor manufacturing parameters. Next, the real-time or instantaneous RMS voltage can be determined or estimated based on the measured motor drive state (e.g., measured motor parameters). For example, the real-time or instantaneous RMS voltage can be determined or estimated by combining the known voltage from the power supply to the motor with a known pulse width modulation (PWM) duty cycle. Next, determine the real-time or instantaneous motor speed based on the measured or detected motor position, and identify the reference voltage of the motor from the determined real-time or instantaneous motor speed, back electromotive force, and line 72 of the reference schedule 75 in FIG. 8 of the reference schedule. Next, the control signal for the motor 37 can be generated by the controller based on the reference voltage and the real-time or instantaneous RMS voltage. In one example, if the real-time speed or instantaneous speed has not reached or exceeded the threshold T (e.g., to the right of the threshold speed value T in FIG. 8), the reference voltage may be similar to the real-time or instantaneous RMS voltage, and the controller may maintain the operation of the motor or make minor changes (e.g., attenuation, correction, other changes) based on the difference between the reference voltage and the real-time or instantaneous RMS voltage. However, if the real-time speed or instantaneous speed reaches or exceeds the threshold speed value T (e.g., threshold T in FIG. 8 or to its left), the reference voltage is significantly different from the determined real-time or instantaneous RMS voltage, and the controller outputs a control signal based on the difference between the reference voltage and the real-time or instantaneous RMS voltage, applies a brake to the motor, and relaxes the force applied to the patient when the motor speed decreases. In the example of FIG. 8, the control signal can lower the motor voltage to decelerate the motor until the motor speed reaches zero or nearly zero (0).

[0070] Although various features have been described, the related embodiments are not limited to these, and the present disclosure contemplates that those features can be included in any embodiment. Further, although the embodiments described herein may omit some combinations of the various features described, this disclosure contemplates embodiments that include any combination of each of the features described. Accordingly, modifications of the embodiments and details can be made without departing from the scope and spirit of the present disclosure as set forth in the appended claims.

Claims

1. A drive shaft, a rotational device for atherectomy coupled to a first end of the drive shaft, a motor coupled to a second end of the drive shaft for rotating the rotational device, a sensor for detecting motor parameters of the motor, and a control unit configured to estimate one or more motor states of the motor based on an input received from the sensor and to control the motor state of the motor wherein the control unit includes: a reference schedule associating the motor state with a motor input as a reference value or a setpoint of the motor state, the reference schedule associating a motor speed detected by the sensor with a reference motor state serving as a reference for control, using the reference schedule to identify a reference voltage derived from the motor speed detected by the sensor, determining a real-time RMS voltage of a voltage provided to the motor during operation of the motor, and adjusting the voltage provided to the motor such that the real-time RMS voltage approaches the reference voltage based on a difference between the reference voltage and the real-time RMS voltage so as to actively decelerate the motor until the motor speed becomes zero or substantially zero in response to a detected stall state, thereby adjusting the motor state of the motor A medical device configured as such.

2. The medical device according to claim 1, wherein the detected stall state is detected when the speed of the motor reaches or exceeds a certain threshold level.

3. further comprising a first sensor for detecting a current supplied to the motor and a second sensor for detecting a position of the motor, wherein the first sensor provides a signal indicating the detected current to the control unit, and the second sensor provides a signal indicating the detected position to the control unit.

4. In a control unit of a medical device comprising a motor, a sensor for detecting motor parameters of the motor, and a rotational device for atherectomy driven by the motor, a controller, and a motor state estimator communicating with the controller and configured to estimate one or more motor states of the motor based on an input of motor parameters received from the sensor. ​ A reference schedule element that communicates with the controller and the motor state estimator, the reference schedule including associating a first motor state with a motor input or a setpoint of a second motor state, a value of the second motor state being provided to the motor, the first motor state of the motor being adjusted by adjusting the value of the second motor state, and a reference schedule element configured to provide an output to the controller based on an input from the motor state estimator. The reference schedule associates a motor speed detected by the sensor with a reference value of the second motor state that serves as a control reference. The controller uses the reference schedule to identify a reference value of the second motor state based on the motor speed detected by the sensor. determines a real-time value of the second motor state during operation of the motor. When the motor speed reaches a certain threshold level or exceeds the threshold level, by outputting a control signal for actively decelerating the motor until the motor speed becomes 0 or almost 0 based on the difference between the reference value and the real-time value, based on the difference between the reference value and the real-time value, the value of the second motor state provided to the motor is adjusted so that the real-time value approaches the reference value, thereby adjusting the first motor state of the motor. A control unit configured as follows. The control unit according to claim 4, wherein the output control signal is based on an output from the motor state estimator to the controller. The control unit according to claim 5, wherein the output from the motor state estimator to the controller is a real-time motor state. The control unit according to claim 6, wherein the real-time motor state is the real-time torque of the motor.

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