METHOD FOR CONTROLLING AN ORTHOPEDIC DEVICE AND ORTHOPEDIC DEVICE

Abstract

The invention deals with a method for controlling an orthopedic device, the method comprising the following steps of: —Providing input signals, —Using said input signals as input variables of a musculoskeletal model, —Determining feedback signals using said musculoskeletal model, —Transmitting said feedback signals to said user of said orthopedic device.

Claims

1. A method for controlling an orthopedic device, comprising: providing input signals, using said input signals as input variables of a musculoskeletal model, determining feedback signals using said musculoskeletal model, transmitting said feedback signals to a user of said orthopedic device.

2. The method according to claim 1, wherein the step of providing input signals comprises detecting measurement data from the user of the orthopedic device and/or the orthopedic device using at least one measurement device.

3. The method according to claim 2, wherein the detected measurement data is processed to provide input signals from the measurement data of the at least one measurement device.

4. The method according to claim 2, wherein the measurement data comprise myoelectric signals picked up from skin and/or at least one muscle and/or nerves of said user.

5. The method according to claim 1 further comprising determining control signals for said orthopedic device using the musculoskeletal model or another musculoskeletal model.

6. The method according to claim 5, wherein the feedback signals and the control signals are determined using the same musculoskeletal model.

7. The method according to claim 5 wherein, at least two different control signals for said orthopedic device are determined in the determining control signals step.

8. The method according to claim 1 wherein the feedback signals are somatosensory signals, and further comprising transmitting the somatosensory signals to said user via at least one of electrotactile stimulators, vibrotactile stimulators, auditory stimulators, visual stimulators, mechanical stimulators capable of generating a force and/or a torque, cuff electrodes, temperature stimulators, subdermal electrodes, percutaneous electrodes, implanted electrodes, peripheral nerve electrodes or intramuscular electrodes.

9. The method according to claim 1 wherein the feedback signals are determined using sensor information provided by at least one sensor, wherein the sensor information comprise information about at least one of position, orientation, velocity, and acceleration of said orthopedic device and/or a part thereof, a torque, a force and/or a momentum acting on said orthopedic device and/or a part thereof, environment of the orthopedic device, and another body part of the user.

10. The method according to claim 7 further comprising updating, correcting or amending said musculoskeletal model using the sensor information.

11. The method according to claim 1 further comprising using said musculoskeletal model to model muscle forces, joint torques, joint stiffnesses and/or joint dampings said user intends to exert by said input signals.

12. The method according to claim 11, wherein the feedback signals are determined based on said muscle forces, joint torques, joint stiffnesses and/or joint dampings.

13. The method according to claim 11 wherein said muscle forces, joint torques, joint stiffnesses and/or joint dampings are encoded in the feedback signals.

14. An orthopedic device comprising an electronic controlling device which performs a method according to claim 1.

15. The method according to claim 7 wherein the at least two different control signals are determined simultaneously.

16. The method of claim 9 wherein the environment is selected from temperature, surface, and terrain.

Description

[0044] Using the attached drawings different embodiments of the present invention are described in the following.

[0045] FIGS. 1-4 show flow diagrams of different methods according to different embodiments of the present invention.

[0046] FIG. 1 shows a pretty simple embodiment of a flowchart for a method for controlling an orthopedic device 2. First input signal have to be provided. According to method illustrated in FIG. 1 measurement data 8 is detected form a user 4, which are then processed in an input sensor interface 6. In this input sensor interface 6 the measurement data 8 detected by at least one sensor are transformed and translated into input variables 10 for a musculoskeletal model 12. This model 12 is used to determine control signals 14 for the orthopedic device 2 and to determine feedback signals 16 which are then after being processed in a sensory feedback interface 18 transmitted to the user 4. The orthopedic device is provided with at least one sensor, which is not shown in FIG. 1. This at least one sensor senses sensor information 20 which is used both to update and check the validity of the model 12 and to improve feedback in the sensory feedback interface 18. In the embodiment shown in FIG. 1 the input sensor interface, the musculoskeletal model 12 and the sensory feedback interface 18 are parts of an electronic data processing unit 22, illustrated by the dashed line.

[0047] FIG. 2 is a more detailed flow chart. Again measurement data 8 are detected from the user 4 using at least one sensor. Said measurement data 8 is fed into the electronic data processing unit 22, which is again illustrated by the dashed line. The measurement data 8 is processed in the input sensor interface 6 which in this case is an EMG sensor interface, such as an 8 channel EMG sensor interface. When sensors other than an EMG sensor setup are used, also another input sensor interface 6 is to be used in order to be able to process forcemyography, ultrasound sensor or inertial sensor measurement data 8. The input variables 10 might for example be normalized EMG data based on the maximum voluntary contraction of the user 4. They are fed into the musculoskeletal model 12, which in FIG. 2 comprises several units and is thus illustrated by the dotted line. In the user-specific model unit 24 the input signals 10 are processed in order to determine an intended motion or action the user 4 intends to perform next. From this different movements, actions, tensions and/or forces of different elements of the orthopedic device are calculated in the user-specific model unit 24. These elements then are transformed in the device control transformation unit 26, which generates the control signals 14 which are then sent to the orthopedic device 2. The device 2 comprises at least one sensor the sensor information 20 of which is in the embodiment shown in FIG. 2 used only for updating the musculoskeletal model 24 in the user-specific model unit. The sensor information 20 can additionally or alternatively be used to update other units of the musculoskeletal model 12 and/or to improve the feedback signals 16 transmitted to the user 4.

[0048] In addition the elements calculated in the user-specific model 24 are also fed into a feedback normalization unit 28, which is also part of the musculoskeletal model 22. This unit 28 inter alia normalizes the joint moments that are calculated in the user-specific model unit 24 to the maximum closure joint moment that the user 4 can achieve as calculated by the user-specific model unit 24. This allows to measure the joint moments in percentages of the maximum joint moment. This of course is also done with other parameters that are calculated in the user-specific model unit 24 and that are to be used for the feedback that is to be transmitted to the user 4. The normalized parameters are then transformed into signal patterns in a feedback transformation unit 30 before they are transformed into feedback signals 16 in a feedback signal generator 32. These feedback signals 16 can be vibrotactile or other signals. The pattern generated in the feedback transformation unit 30 can be an intensity varying pattern or a temporal pattern. Of course, other patterns using other varying parameters can also be used. The feedback signal generator 32 and the feedback transformation unit 30 are two different parts of the sensory feedback interface 18 denoted by the dotted line.

[0049] FIG. 3 shows a method very similar to the one of FIG. 2. It is used to control a prosthetic device for the lower limb, such as a leg prosthesis. The main difference to the more generically usable method of FIG. 2 is a gait cycle calculation unit 34. It is provided with sensor information 20 of at least one sensor positioned at or near the prosthetic device 2. This sensor information 20 is used to update and check the validity of the user-specific model unit 24 and the musculoskeletal model 12, but also to calculate when in a gait cycle the user 4 is. The sensor information 20 can be provided by an angular position sensor, an acceleration sensor and/or a gyroscope which are possibly available in the prosthetic device. The sensory feedback interface 18 and the electronic data processing unit 22 as well as the musculoskeletal model 12 remain the same as described with respect to FIG. 2.

[0050] FIG. 4 shows a method similar to the one in FIG. 3. The main difference is a parameter adjustment unit 36. This unit 36 is part of the musculoskeletal model 12 and the electronics data processing unit 22 and receives both sensor information 20 from at least one sensor of the orthopedic device 2 and elements and parameters calculated in the user-specific model unit 24. The parameter adjustment unit 36 compares expected values for different parameters that have been calculated in unit 24 with sensor information 20 from the at least one sensor on or at the orthopedic device 2. If deviations occur, that exceed a certain predetermined threshold, parameter information 38 is sent to the user-specific model unit 24 and the corresponding parameters become adjusted.

[0051] Another difference of the method according to FIG. 4 from the method according to FIG. 3 is the use of at least one sensor 40, that determines sensor information 20 that is basically or fully unrelated to the user and to the orthopedic device. This sensor information 40 is related to the environment the user 4 is in, such as weather conditions, temperature and moisture, and/or information concerning the ground the user 4 is walking on. This can relate to the slope and/or the kind of ground covering, such as grass, stone, wood or other materials. For the application in the upper limb orthopedic device, this information can be a snapshot of an object that is supposed to be grasped by a grasping device. This information also enters the musculoskeletal model 12 and is used to further improve the controlling of the orthopedic device 2 and the feedback signals 16 that are transmitted to the user 4.

LIST OF REFERENCE NUMBERS

[0052] 2 orthopedic device [0053] 4 user [0054] 6 input sensor interface [0055] 8 measurement data [0056] 10 input variables [0057] 12 musculoskeletal model [0058] 14 control signals [0059] 16 feedback signals [0060] 18 sensory feedback interface [0061] 20 sensor information [0062] 22 electronic data processing unit [0063] 24 user-specific model unit [0064] 26 device control transformation unit [0065] 28 feedback normalization unit [0066] 30 feedback transformation unit [0067] 32 feedback signal generator [0068] 34 gait cycle calculation unit [0069] 36 parameter adjustment unit [0070] 38 parameter information [0071] 40 sensor