EP3435905A1

EP3435905A1 - Medical manipulator and method for controlling a medical manipulator

Info

Publication number: EP3435905A1
Application number: EP17714639.6A
Authority: EP
Inventors: Henrik Keller; Tobias Reichl; Oliver Thilmann
Original assignee: KUKA Deutschland GmbH
Current assignee: KUKA Deutschland GmbH
Priority date: 2016-03-29
Filing date: 2017-03-29
Publication date: 2019-02-06
Also published as: US20190099228A1; DE102016205085B3; WO2017167444A1

Abstract

The invention relates to a medical manipulator 1 having a manipulator arm 10, an end effector 20 which is secured to the manipulator arm 10 and which has at least one tool 21, 22, 23 with a changing mass and/or mass distribution 46, and a manipulator controller 30 for controlling the medical manipulator 1. In each control step, the manipulator controller 30 uses a current load data matrix 40 comprising the changing mass and/or mass distribution 46 of the tool 21, 22, 23 in order to prevent deviations from a target position or target path of the tool 21, 22, 23. The invention further relates to a corresponding method for controlling a medical manipulator.

Description

Medical manipulator and method for controlling a

medical manipulator

1. Technical area

The present invention relates to a medical manipulator and a method for controlling a medical manipulator. The medical manipulator can be used, for example, in robotic surgery.

2. Technical background

For example, a medical manipulator is used in robotic surgery for minimally invasive surgical procedures. In these smaller procedures, compared to conventional surgical techniques, the organism is less heavily loaded and possibly remaining scars are only very small. With the help of the medical manipulator, interventions with a very high precision can be carried out in the smallest space in and on the human body. The arm of a medical manipulator can be a plurality of tools, such. a camera system, a scalpel and a gripper, be attached. These tools can be moved in or out of the human body, for example, by means of linear axes via a trocar.

Due to the movement of the tools, however, their mass distribution changes with respect to the manipulator, which can lead to an unwanted deviation from the Sollpose or desired path of the tool.

In machine-controlled systems, such a deviation over the

Minimizing the drag error of driven mechanical elements, e.g. compensated for the above linear axes. However, the deviation first occurs before the manipulator control can react to it. However, the occurrence of such deviations already affects the precision of the

Manipulator and is therefore undesirable.

For handheld manipulators, the change in the mass distribution of the

Tool is interpreted by the manipulator control as a force coming from the hand

CONFIRMATION COPY the operator goes out. Consequently, an operator must then also permanently counteract this force manually. Especially with long hand-held

This is ergonomically unfavorable and leads to fatigue of the operator.

It is therefore the object of the present invention to provide a medical manipulator and a method for controlling a medical manipulator, which overcome the above-mentioned problems. In particular, the

Deviations of the tool from the Sollpose or Sollbahn be reduced to increase the precision of the manipulator and provide ergonomic operation in a hand-held manipulator control.

3. Summary of the invention

The above object is achieved by a medical manipulator according to claim 1 and a method for controlling a medical manipulator according to claim 8.

The above-mentioned object is solved in particular by a medical manipulator comprising a manipulator arm, an end effector attached to the

Manipulator is attached and having at least one tool with a changing mass and / or mass distribution, a manipulator control for controlling the medical manipulator, the manipulator controller in each control step uses a current load data matrix with the changing mass and / or mass distribution of the tool Deviations from a Sollpose or desired path of the tool to avoid. The mass distribution of the

Tool can change in that the tool is moved relative to the manipulator. As described above, in a surgical procedure, this can be done by inserting or removing tools in and out of the human body. The mass of the tool may change when, for example, objects are picked up with a gripper, or, for example, by introducing or depositing objects or substances into the body, such as, e.g. Stents in vascular surgery or staples for closing wounds. The mass of the

Tooling can also change by pumping saltwater into a balloon to expand it. Because of the manipulator control in each Control step uses a current load data matrix, always the current values of the mass and mass distribution of the tool are taken into account in the scheme, whereby a deviation from the Sollpose or desired path of the tool is avoided. In addition, the pose of the manipulator is precise because the current load data matrix is updated in each control step.

The manipulator control preferably uses a dynamic model of the tool, in the calculation of which the changing mass and / or mass distribution of the tool is included. Changes in the mass and / or mass distribution that occur due to the movement of the mechanical elements are taken into account in the dynamics model and the manipulator control can be adjusted accordingly. With the help of the dynamics model, the load data can also be determined with a higher temporal resolution in the manipulator control. In addition, the manipulator control can also determine future values, in particular the values of the mass distribution of the tool, from the dynamics model and

consider.

Preferably, the dynamics model of the tool is in the dynamics model of

Integrated manipulator. As a result, all movements of the manipulator are described in a common model, which avoids communication errors and improves the overall control of the manipulator.

The manipulator control preferably takes into account the knowledge of a change in the mass and / or mass distribution of the tool. This allows preparatory calculations to be carried out or consistent values to be recognized. This facilitates subsequent calculations and makes data processing faster overall. In addition, a deviation already during a time step

(Controller cycle) regulated, and thus reduced, and not only afterwards.

Preferably, the end effector has a plurality of tools that can be moved independently of each other with respect to the manipulator arm. The simultaneous use of several tools, such as a camera and a gripper, the operator of the manipulator is facilitated by, for example, get better insight into the operating area. In addition, more complex tasks can be performed by, for example, a gripper Keep opening free while working with a scalpel in the opening. Due to the independent flexibility of the tools, it is optionally possible to introduce only certain tools in the respective trocar, which increases the clarity at work.

Preferably, the mass distribution is calculated via the known position of one or more mechanical elements of the tool and then fed to the manipulator control. The calculation of the mass distribution can be done in the manipulator control as well as directly in the tool (end effector). The mass distribution can be calculated in advance and indirectly, so that deviations from a Sollpose or desired path of the tool are avoided from the outset. Preferably transmits an electronic control unit, the mechanical

Controls elements, information about a current and / or upcoming change of the position of the mechanical elements of the tool to the manipulator control. As a result, the manipulator control can take account of this coming change in the position of these, preferably driven mechanical elements, before or in the next control step.

Preferably, a mechanical element is a linear axis. With a linear axis extremely precise positioning and highly dynamic movements are possible. This is especially relevant for applications in a medical manipulator where work is done in a very small space (in the human body).

The above object is also achieved by a method for controlling a medical manipulator, comprising the following steps:

a. Providing a manipulator arm having an end effector attached thereto, which has at least one tool with a changing mass and / or mass distribution;

b. Controlling the medical manipulator by means of a manipulator control; c. Using a current load data matrix of changing mass

and / mass distribution of the tool in the manipulator control in each Control step to avoid deviations from a Sollpose or desired path of the tool.

This procedure increases the precision of the movements of the manipulator and improves the ergonomics of manually-controlled manipulator work by keeping the current values of mass and mass distribution of the tool in each

Control step in the manipulator control are taken into account.

Preferably, a dynamics model is used in the manipulator control, in whose calculation the changing mass and mass distribution of the tool are included. Thus, if the manipulator control itself controls the mechanical elements, then the values for the mass distribution of the tool in each can be determined

Determine control step. Also could be values for future

Mass distributions are calculated according to the dynamics model and in the

Manipulator control are taken into account.

Preferably, the dynamics model of the tool is included in the dynamics model of the tool

Integrated manipulator. By using a global dynamics model, fewer interfaces between manipulator control and dynamic model (s) are required, which reduces communication errors and the overall control error rate.

The manipulator control preferably takes into account the knowledge about a change of mass and mass distribution. As a result, the control method can react to the error more quickly, namely already in the current or subsequent time step (control cycle), and control it accordingly. In addition, the determination of the

Load data matrix can be optimized in terms of the volume of data to be calculated, the number of calculations or the speed, resulting in shorter

Control times are possible. Preferably, the mass distribution is calculated via the known position of one or more mechanical elements of the tool and then fed to the manipulator control. Since the position of the mechanical elements is generally very precisely determinable, the values of the mass distribution can be determined very precisely. Overall, this leads to a very precise manipulator control. Information about a current and / or upcoming change of the position of the mechanical elements of the tool from an electronic device is preferred

Control unit that controls the mechanical elements to which

Manipulator control transmitted. Since the electronic control unit the

Information about the upcoming change, on the basis of which it already controls the mechanical elements in a next control step already owns, they can forward this information also to the manipulator control, which in turn can take into account this information in advance to the

Deviation from a Sollpose or desired path of the tool to avoid.

4. Brief description of the figures

A preferred embodiment of the present invention is shown in the attached figure. Showing:

Fig. 1 shows a schematic structure of a medical manipulator according to the present invention.

5. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached figure.

Fig. 1 shows an embodiment of a medical manipulator 1. On a base mounting surface B, a manipulator arm 10 is attached. In the illustrated

Embodiment, the manipulator arm 10 consists of three arm parts A and two

However, the kinematic chain of the manipulator arm 10 can also have any other number of arm parts A and joints G. Of the

Manipulator 10 can be moved freely in all directions. On the manipulator arm 10, an end effector 20 is attached, the at least one

Tool 21, 22, 23 comprises, which has a changing mass and / or mass distribution. Usually, the tools 21, 22, 23 are movable relative to the manipulator arm 10 and change in such movements their respective mass distribution with respect to the manipulator arm 10. The tools 21, 22, 23 can thereby For example, be moved by means of mechanical elements 52 regardless of the pose or movement of the manipulator arm 10. In the illustrated

Embodiment, the end effector 20 has three tools 21, 22, 23, which can be moved individually by means of the mechanical elements 52,

for example, into or out of a patient's body. For example, the mechanical elements linear axes 52, with which the tools 21, 22, 23 can be moved individually linear. However, the end effector 20 can also have any other number of tools 21, 22, 23. If the tools 21, 22, 23, in particular the medical instruments, for example, are inserted as far as possible into the body of a patient, then the mass distribution of the tool is at maximum forward. If all tools or instruments 21, 22, 23 are led out of the body of the patient at maximum, the mass distribution is maximally far behind.

The mechanical elements 52 of the tools 21, 22, 23 are replaced by a

electronic control unit 50 controlled. The electronic control unit 50 preferably transmits information about the position of the mechanical elements 52 to the manipulator control 30 via data connections 60.

The manipulator control 30 has a current load data matrix 40, which is preferably selected by the controller 30 from the current mass distributions and masses of the

Tools 21, 22, 23 is calculated. The current mass distributions and masses of the tools 21, 22, 23 can be stored in the controller 30 as data 46. Due to the use of the current load data matrix, the movement of the medical manipulator 1 is performed exactly according to the specifications of an operator or a program. The current load data matrix 40 is also using a

Dynamic model 42 of the tool or tools 21, 22, 23 are determined. The data 46 on the mass distribution and mass of the tool 21, 22, 23 can from the

medical manipulator 1 are routed via the data link 60 in each control step to the manipulator control 30 or is calculated in each control step from the dynamics model 42. In this case, the dynamics model of the tool 42 can also be integrated into the dynamics model of the manipulator 44. In particular, future changes in the mass distribution and the mass of the

Tool are taken into account in the control of the manipulator 1. In a method for controlling a medical manipulator 1, the

Load data matrix 40 updated in each control step. By taking into account the actual mass distribution and the mass 46, the manipulator control 30 can determine the forces and moments occurring on the tool 21, 22, 23 and correct the pose or track of the tool so that a deviation to a

original Sollpose or Sollbahn is avoided.

In particular, the dynamics model 42, 44 may be extrapolated into the future to determine values for the mass distribution 46 that lie in the future. However, information about planned changes of the mechanical elements 52 from the electronic control unit 50 to the manipulator control unit 30 can also be provided

be transmitted. This information can then be taken into account directly in the subsequent time step in the manipulator control. As a result, the current control commands that take into account the change in mass and mass distribution of the tool 21, 22, 23 will be in each

Control step via the data link 60 to the medical manipulator 1 transmitted. Thus, movement or pose of the tool 21, 22, 23 may be allowed without deviation from the desired or desired pose, although the mass or mass distribution of the tool 21, 22, 23 changes.

Reference Signs List

1 medical manipulator

10 manipulator arm

20 end effector

21 tool

22 tool

23 tool

24 mounting surface

30 manipulator control

40 load data matrix

42 dynamic model of the tool

44 dynamic model of the manipulator

46 mass distribution or mass of the tool 50 electronic control unit

52 mechanical elements

60 data connections

A arm part

B base mounting surface

G joint

Claims

claims

Medical manipulator (1), comprising: a. a manipulator arm (10); b. an end effector (20) secured to the manipulator arm (10) and having at least one tool (21, 22, 23) with a varying mass and / or mass distribution (46); c. a manipulator controller (30) for controlling the medical

Manipulator (1); where d. the manipulator control (30) in each control step a current load data matrix (40) with the changing mass and / or

Mass distribution (46) of the tool (21, 22, 23) used to

Deviations from a Sollpose or desired path of the tool (21, 22, 23) to avoid.

The medical manipulator according to claim 1, wherein the manipulator controller (30) uses a dynamics model of the tool (42), in the calculation of which the changing mass and / or mass distribution of the tool (21, 22, 23) is included.

The medical manipulator according to claim 2, wherein the dynamics model of the tool (42) is integrated in a dynamics model of the manipulator (44). The medical manipulator according to one of the preceding claims, wherein the manipulator control (30) takes into account the knowledge about a change in the mass and / or mass distribution of the tool (46). A medical manipulator according to any one of the preceding claims, wherein the end effector (20) comprises a plurality of tools (21, 22, 23) which can be moved independently of each other with respect to the manipulator arm (10).

The medical manipulator according to claim 1, wherein the mass distribution (46) is calculated via the known position of one or more mechanical elements (52) of the tool (21, 22, 23) and then fed to the manipulator control (30).

The medical manipulator according to claim 6, wherein an electronic control unit (50) which controls the mechanical elements (52) has information about a current and / or coming change in the position of the mechanical elements (52) of the tool (21, 22, 23). to the

Manipulator control (30) transmitted.

The medical manipulator according to one of claims 6 or 7, wherein the mechanical element (52) is a linear axis.

A method of controlling a medical manipulator (1), comprising the following steps: a. Providing a manipulator arm (10) with an end effector (20) attached thereto, which has at least one tool (21, 22, 23) with a changing mass and / or mass distribution; b. Controlling the medical manipulator (1) by means of a

Manipulator control (30); c. Using a current load data matrix (40) of the changing mass and / or mass distribution of the tool (21, 22, 23) in the manipulator control (30) in each control step to unwanted Deviations from a Sollpose or desired path of the tool (21, 22, 23) to avoid.

10. The method of claim 9, further comprising using in the

Manipulator control (30) of a dynamics model (42) in the calculation of the changing mass and mass distribution of the tool (21, 22, 23) received.

The method of claim 10, wherein the dynamics model of the tool (42) is integrated into the dynamics model of the manipulator (44).

12. The method according to any one of claims 9 to 11, wherein the

Manipulator control (30) takes into account the knowledge about a change of mass and mass distribution.

13. The method according to any one of claims 9 to 12, wherein the mass distribution (46) on the known position of one or more mechanical elements (52) of the tool (21, 22, 23) calculated and then the manipulator control (30) is supplied.

14. The method according to claim 13, further comprising the step of

About an information about a current and / or upcoming change of the position of the mechanical elements (52) of the tool (21, 22, 23) from an electronic control unit (50), which controls the mechanical elements (52), to the manipulator control (30 ).

March 29, 2016

KUKA Roboter GmbH K137916 Maj / AWu / BEU