Atherectomy motor control system

Patent metadata

Field	Value
Publication number	US-11737779-B2
Application number	US-202016737567-A
Country	US
Kind code	B2
Filing date	Jan 8, 2020
Priority date	Jan 9, 2019
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

An atherectomy system includes a drive mechanism that is adapted to rotatably actuate an atherectomy burr and a controller that is adapted to regulate operation of the drive mechanism. In some cases, the drive mechanism includes a drive cable that is coupled with the atherectomy burr and an electric drive motor that is adapted to rotate the drive cable. The controller is adapted to regulate operation of the electric drive motor such that the drive mechanism emulates one or more performance parameters of an air turbine.

First claim

What is claimed is:

1. An atherectomy system, comprising:
an electric drive mechanism adapted to rotatably actuate an atherectomy burr, the electric drive mechanism including:
a drive cable coupled with the atherectomy burr; and
an electric drive motor adapted to rotate the drive cable; and

a controller adapted to regulate operation of the electric drive mechanism such that the electric drive mechanism emulates one or more performance characteristics of an air turbine including the torque versus speed performance characteristic of an air turbine.

2. The atherectomy system of claim 1 , wherein the controller comprises:
a reference block that is adapted to receive a speed signal and output a reference signal;
a control block that is adapted to receive the reference signal from the reference block and generate a resulting control effort signal; and
a drive circuit that is adapted to receive the control effort signal from the control block and regulate operation of the drive mechanism accordingly.

3. The atherectomy system of claim 2 , wherein the control block of the controller utilizes a Proportional (P) gain, an Integral (I) gain and a Derivative (D) gain, modified to include a variable K offset value summed with a sum of the P gain, the I gain and the D gain.

4. The atherectomy system of claim 3 , wherein the control block of the controller is configured to set an initial value for the variable K offset value equal to zero.

5. The atherectomy system of claim 3 , wherein the control block of the controller is configured to calculate a new value for the variable K offset value when the electric drive motor reaches a speed reference value.

6. The atherectomy system of claim 5 , wherein the control block of the controller is further configured, when the electric drive motor reaches the speed reference value, to calculate a new value for the P gain.

7. The atherectomy system of claim 6 , wherein the control block of the controller is further configured, when the electric drive motor reaches the speed reference value, to calculate a new value for P gain in accordance with equation (1):

P

n
⁢
e
⁢
w

=

T
stall

⁡

(

P
old

+

I
old

)

ω
ref

,

(
1
)

where
P new is a new P gain value;
P old is a previous P gain value;
I old is a previous I gain value;
T stall is a desired stall torque value; and
ω ref is the speed reference value.

8. The atherectomy system of claim 7 , wherein the control block of the controller is further configured, when the electric drive motor reaches the speed reference value, to calculate a new value for the variable K term in accordance with equation (2):
K=P old +I old   (2).

9. The atherectomy system of claim 6 , wherein the control block of the controller is further configured to calculate new values for the variable K term and the P term in accordance with equations (3) and (4):
K=P*e+I*∫e   (3)

P

n
⁢
e
⁢
w

=

i

s
⁢
t
⁢
a
⁢
l
⁢
l

-
K

ω

r
⁢
e
⁢
f

,

(
4
)

where
i stall is the motor current that corresponds to a desired stall torque; and
e is the error or difference between reference speed and the speed.

10. An atherectomy system, comprising:
a drive mechanism adapted to rotatably actuate an atherectomy burr, the electric drive mechanism including:
a drive cable coupled with the atherectomy burr; and
an electric drive motor adapted to rotate the drive cable; and

a control system adapted to regulate operation of the drive mechanism, the control system including:
a reference block for providing a speed reference value; and
a controller operably coupled to the reference block for receiving the speed reference value, the controller adapted to utilize the speed reference value, a Proportional (P) gain value, an Integral (I) gain value, a Derivative (D) gain value and a K offset value in determining an output signal for the drive mechanism;
wherein the controller is further adapted to initiate actuation of the drive mechanism using an initial value for the I gain value and a value of zero for the K offset value;
wherein the controller is further adapted to reduce the I gain value and calculate a non-zero value for the K offset value once a speed of the drive mechanism reaches the speed reference value; and
wherein the controller is further adapted to regulate operation of the electric drive mechanism such that the electric drive mechanism emulates the torque versus speed performance characteristic of an air turbine.

11. The atherectomy system of claim 10 , wherein the controller is further adapted to also calculate a new P gain value once the speed of the drive mechanism reaches the speed reference value

Assignees

• Boston Scient Scimed Inc

Inventors

• Carlson Corydon
• Spangler David Gordon
• Massimini Daniel Frank
• Farago Laszlo Trent

Classifications

• A61B17/320758 Primary

  with a rotating cutting instrument, e.g. motor driven (A61B17/320725, A61B17/32075 and A61B17/320783 take precedence; for removing intra-ocular material A61F9/00763; endoscopic rotatable cutting instruments A61B17/32002) · CPC title

• A61B17/32037

  for removing obstructions from inner organs or blood vessels, e.g. for atherectomy · CPC title

• A61B2017/00017

  Electrical control of surgical instruments · CPC title

• A61B2017/00075

  Motion · CPC title

• A61B2090/066

  for measuring torque · CPC title