DE102008058604A1 - For Natural muscle's movement behavior simulation device for e.g. robot arm, has mechanical energy source arranged parallel to damping member, where damping member regulates force delivered by device to load - Google Patents

Abstract

The device has a mechanical energy source (2) and an elastic element e.g. mechanical tension spring (3), arranged in series. The mechanical energy source is arranged parallel to a damping member (6) e.g. magneto-rheological damper and hydro-pneumatic suspension system, that regulates force (5) delivered by the device to a load. The mechanical energy source comprises electromechanical, hydraulic or pneumatic drive, electric motor, a drive using metal hydride as a working medium, a drive using shape memory alloy as a working medium, or a drive using organic materials as a working medium.

Description

The The invention relates to a device for simulating the movement behavior a natural muscle with which this movement behavior in terms of elasticity and damping as possible Really should be reshaped, so this actuator in his Effect can be used as an artificial muscle. This is intended for both small or large travel ranges as well as for the generation of small or large ones Forces of the actuator apply.

human and animal muscle is characterized by compliance and by a load-dependent damping behavior. These features make it easier to control the movement, increase it the efficiency of the implementation and reduce the burden of the elements.

Generally is expected to be due to muscle-like drives Properties improves the performance of technical systems can be. This is especially true for robotic arms, running machines and prostheses.

Actuators with hyperbolic dependence of the force-velocity characteristics and integrated compliance are known (for example B. Hannaford, K. Jaax, G. Klute: Bio-Inspired Actuation and Sensing, Autonomous Robots, vol. 11, 2001, 267-272 However, a dynamic adaptation of the muscle properties to the requirements of the movement system is not realized therein. Among other things, this is due to the fact that the force to be generated is predetermined and only a strain signal is measured in series with the engine (simulation of the stretch reflex, not of the muscle properties themselves). However, drives with both load and strain as well as strain rate-dependent properties of isolated natural muscles have not been disclosed. In particular, the properties of the existing drive elements and their interaction limit such a reproduction of the property combination.

By using materials that change their extent depending on voltages or currents, drives can be made. Dielectric polymers are a known example (e.g. R. Pelrine, RD Kornbluh, Q. Pei, S. Stanford, OH Seajin, J. Eckerle, RJ Full, MA Rosenthal, K. Meijer: Dielectric elastomeric artificial muscle actuators: toward biomimetic motion, Conference Paper, SPIE Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, vol. 4695, 2002, pp. 126-37, USA However, these are usually very stiff and inelastic and therefore unsuitable for the construction of muscle-like drives.

Mechano-chemical drives are also known through intercalation materials ( US 6,577,039 ), which simulate the energy conversion (from chemical to mechanical) of living organisms.

The use of plastics can cause a material-dependent compliance and damping at least in a limited range ( R. Pelrine, RD Kornbluh, Q. Pei, S. Stanford, OH Seajin, J. Eckerle, RJ Full, MA Rosenthal, K. Meijer: Dielectric elastomeric artificial muscle actuators: toward biomimetic motion, Conference Paper, SPIE Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, vol. 4695, 2002, USA, 126-37 ). However, both properties are not sufficient for the known materials in their combination of the nachzubildenden properties of natural muscles; this applies in particular to their different-order damping coefficients (hyperbolic: decreases with increasing speed), which is also too low for the low frequencies dominant for motion systems ( R. Pelrine, RD Kornbluh, Q. Pei, S. Stanford, OH Seajin, J. Eckerle, RJ Full, MA Rosenthal, K. Meijer: Dielectric elastomeric artificial muscle actuators: toward biomimetic motion, Conference Paper, SPIE Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, vol. 4695, 2002, USA, 126-37 ).

Pneumatic artificial muscles (with plaited shell: "McKibben muscles"), eg. Eg Festo-Mas ( DE 100 52 663 C1 with references given there), produce a maximum shortening of 30% (ie, not more than half of the values of natural muscles) and yield elastically under load. Damping properties in contractions have also been demonstrated ( T. Kerscher, J. Albiez, JM Zöllner, R. Dillmann: Evaluation of the Dynamic Modeling of Fluidic Muscles Using Quick Release, Proceedings of the First IEEE / RAS-EMBS International Conference to Biomedical Robotics and Biomechatronics, 2006, 637-642 ; B. Tondu, P. Lopez: Modeling and Control of McKibben artificial muscle robot actuators, IEEE Control Systems Magazine, 2000, vol. 20, no. 2, 15-38 ). The force-velocity characteristic is even hyperbolic in this special contraction situation (quick-release at fixed pressure), but the hystereses in realistic load situations (strain-shortening cycles) are high even at unusually low speeds ( Lecture by Ivo Boblan, Technical University Berlin, at the Friedrich-Schiller-University Jena on 15.10.2008 ). In addition, the damping is too low, resulting in dynamic loads to strong vibrations.

In a study on the structure of an artificial muscle ( GK Klute, JM Czerniecki, B. Hannaford: Artificial muscles: actuators for biorobotic systems, The International Journal of Robotics Research, vol. 21, 2002, 295-309 ), a damper element was used in parallel with a "McKibben's muscle" (both in series with a chord), but with the damping coefficient not controlled as in the present invention. As a result, the force-velocity behavior of the actuator thus assembled was not hyperbolic as in the real muscle, but exhibits a precisely reversed curvature (ie, low damping at rest and high damping at high contraction speed).

Meanwhile, there are "McKibben muscles" that have a hybernoid force-velocity curve ( B. Tondu: Artificial Muscles for Humanoid Robots, in: Humanoid Robots, Human-like Machines, Ed. M. Hackel, I-Tech Education and Publishing, Vienna, Austria, 2007 ,). However, there remain the following principal problems inherent in "McKibben's muscle" technology: they show non-constant volumes (large broadening) on contraction, and clear hystereses even at very low speeds, have lower maximum shortening pathways than the real muscle energetically inefficient compared to other technologies (among others, although its weight is low, but the weight is increased many times by the connection end pieces) and the moving substrate has only limited autonomy, as gas volumes consuming (including additional mass) must be transported.

Are known further pneumatic ( US 6,684,754 ) and hydraulic ( US 6,168,634 ; US 5,021,064 ) Actuators. However, according to their nature, neither the elasticity nor the damping behavior are defined in these, nor is it intended that these properties should be adjustable and thus scalable according to the size (mass) of the movement system to be driven, nor do the abovementioned patents provide instructions as to how to adjust these variables - and scalable.

Electric motors can be coupled with spring elements to produce elastic behavior. The torque-speed characteristics can be considered as equivalent to the force-velocity curve. In particular, electromagnetic and / or electrostatic drives show in principle hyperbolic torque-speed characteristics ( T. Frank, C. Schilling: The development of cascadable microdrives with muscle-like operating behavior, J. Micromech. Microeng. 8, 1998, 222-229 ).

In usually the fast rotating electric motors with gears Combined, giving moments and speeds to running machines and robots are adjusted to usual values. The with the Prevent geared friction and inertia muscle-like performance though.

Direct-drive motors, Those who do without gearboxes achieve high torques at high speeds Speed, so show a reverse course of the torque / (force) speed - / (speed) characteristic compared to the force-speed relation of natural Muscles. They also have a large size.

In modern prosthetics, motors are combined with damping elements in order to achieve movements that are as natural as possible ( SK Au et al .: Powered ankle-foot prosthesis for the improvement of amputee ambulation, Engineering in Medicine and Biology Society, 29th Annual International Conference of the IEEE 22-26 Aug. 2007, 3020-3026 ). In this context, drives with muscle-like movement behavior would be very beneficial. In the professional world, however, nothing has become known about this.

Flexible, muscle-like, balloon-like drives (eg US 6,067,892 . US 6,223,648 ) allow larger contraction pathways than the aforementioned pneumatic [McKibben] muscles. With regard to the muscle properties, the properties of the resulting drive are not precisely defined; flexible adaptation to requirements is only possible to a very limited extent.

In US 7,264,289 For example, a mechanism is proposed for sequencing several muscle-like drives. Scalability is not given here. Also known are muscle-like drives for controlling valves in engines ( US 6,830,019 ).

In addition, there are a variety of other types of drives that can be used as a mechanical energy source for actuators, such as hydraulic drives (such US 7,284,374 ; US 6,868,773 ) as well as polymer drives that convert electrical energy into mechanical energy (eg US 6,940,211 ; US 6,909,220 ; US 6,194,073 ; US 5,976,648 ).

Also known drives with metal hydride as a working medium (eg. US 6,405,532 ), mechanical energy sources, represented by shape memory alloys, whose properties are close to those of a contractile element in the natural muscle (eg. US 5,092,901 ) and organic materials that can serve as a mechanical energy source (for example US 7,128,707 ; US 6,921,360 ; US 6,781,284 ; US 6,749,556 ).

In summary It must be noted that all these drives no load-dependent movement behavior exhibit how they are from the properties of natural muscle are known. Also in the professional world are no measures known to such actuators with related movement characteristics equip.

Devices are also known which can be switched between complete elasticity and elasticity coupled with damping properties (eg. US 4,673,169 ). These are used in particular for suspensions of vehicle engines.

Furthermore, devices are generally known which vary the damping properties as a function of force (for example, a hydropneumatic suspension system according to US Pat US 5,344,124 ). Nothing has become known about their use, in particular to impart natural muscle movement properties to actuators for robot arms, running machines and prostheses.

Of the Invention is based on the object, a basic structure of a To create actuator that respects elasticity and Load dependence on the movement behavior of a natural Muskels corresponds and the most aufwandgering as well as with as few elements as possible for both big ones as well as for small artificial muscles and through these manipulated paths to be manipulated can be technically implemented.

The Device for simulating the movement behavior of a natural Muskels, consists in a conventional manner of a mechanical energy source (Engine), for example, an electromechanical, hydraulic or pneumatic drive, and at least one for mechanical Energy source connected in series elastic element, z. Legs mechanical tension spring. According to the proposal is the mechanical energy source an attenuator in parallel switched, that of the force, which the entire device as an actuator (artificial muscle) to one of this too moving load is regulated.

On surprising low-cost manner, in particular with only a few elements, is an actuator principle structure allows the movement behavior a natural muscle with high robustness and movement stability shows and in the load-dependent controls for Such a movement behavior already takes place directly in the actuator. It is already at the lowest level of motion generation (in the actuator itself) in terms of damping and elasticity creates a movement that is a natural muscle corresponds or comes very close to such a movement behavior.

With the said very few elements and their sizing and coordination can also increase the elasticity and set the load-dependent response of the actuator so be, that so that the actuator on the one hand, as mentioned above, with least effort and on the other hand with minimal deviations between theoretical requirements and requirements as well as their practical Implementation for both big and for small artificial muscles realized in the technique and the connection to a substrate to be manipulated (eg prosthesis, Robot) with the desired typical loads and travel ranges can be scaled accordingly.

These technical implementation regarding elasticity, damping and scalability is possible in the proposed basic structure, in what way and by what means the individual elements (mechanical energy source, steamed elastic element as well as the force-controlled feedback damping according to the invention the mechanical energy source) are specially designed. In the subclaims examples are given without however, to limit the scope of the invention to these.

In addition, devices such as z. B. by US 5,648,709 (Control method and control apparatus for controlling the output path and dynamic characteristics of a non-linear system) are described, used for higher control tasks appropriate. The invention provides the prerequisite for control and regulation principles, as they are to be found abundantly in biology and which have developed in close evolutionary interlocking with the actuator "muscle" as well as its movement economy and dynamic stability, in the simplest possible way to technical systems can be transmitted.

The Invention will be described below with reference to an embodiment be explained in more detail.

The drawing shows the basic arrangement of an actuator for the simulation of the movement behavior of a natural muscle according to the invention 1 is symbolized at the top of the picture for better understanding additionally the natural muscle to be replicated, whose length corresponds to the outer length l _{a of} the artificial muscle (actuator).

An also illustrated in the figure inside length l _i of the artificial muscle forming the outer length l _a additional and independent mechanical degree of freedom for a motor 2 , in the technical implementation of any mechanical energy source, such as a elektromechani rule, hydraulic or pneumatic drive represented.

The motor 2 as a mechanical energy source transmits its mechanical work generally via a visco-elastic element (represented by parallel connection of a spring 3 as an elastic element and an attenuator 4 ) to the load applied to the artificial muscle (not explicitly shown in the figure for reasons of clarity). The visco-elastic element (spring 3 and attenuator 4 ) in series with the engine 2 can be realized for example by a technical tension spring. The arrangement shown by the principle shown actuator thereby acts with a force F to said adjacent external load.

This force F on the load to be moved by the artificial muscle acts in a feedback 5 (symbolized by an arrow) according to the invention to a motor 2 parallel and in size controllable attenuator 6 , where the arrow of the attenuator 6 should symbolize the variable with this feedback control variable attenuation.

When the internal length l _i is changed by a motor, mechanical energy is thus dissipated (the attenuator depending on the force F of the artificial muscle acting on the load 6 parallel to the engine 2 acts as a controllable energy sink). The engine 2 Parallel damping increases with increasing force F of the actuator as an artificial muscle.

As attenuator 6 For example, a magneto-rheological damper is used.

1

naturally muscle

2

engine

3

feather

4

attenuator

5

Feedback from the force F to the controllable attenuator 6

6

from the force F of the artificial muscle (actuator) dependent attenuator

l _a

External length of the actuator (corresponds to the length of the natural muscle to be simulated in the movement behavior 1 )

_i

inner Length of the actuator

F

Force, with which the artificial muscle (actuator) on an outer Last acts

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6577039 [0006]
• - DE 10052663 C1 [0008]
• - US 6684754 [0011]
• US 6168634 [0011]
• US 5021064 [0011]
• - US 6067892 [0016]
• US 6223648 [0016]
• US 7264289 [0017]
• US 6830019 [0017]
• US 7284374 [0018]
• US 6868773 [0018]
• US 6940211 [0018]
• - US 6909220 [0018]
• US 6194073 [0018]
• US 5976648 [0018]
• - US 6405532 [0019]
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• US 7128707 [0019]
• US 6921360 [0019]
• - US 6781284 [0019]
• US Pat. No. 6,749,556 [0019]
• US 4673169 [0021]
• US 5344124 [0022]
• US 5648709 [0028]

Cited non-patent literature

• Hannaford, K. Jaax, G. Klute: Bio-Inspired Actuation and Sensing, Autonomous Robots, vol. 11, 2001, 267-272 [0004]
• - R. Pelrine, RD Kornbluh, Q. Pei, S. Stanford, OH Seajin, J. Eckerle, RJ Full, MA Rosenthal, K. Meijer: Dielectric elastomeric artificial muscle actuators: toward biomimetic motion, Conference Paper, SPIE Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, vol. 4695, 2002, pp. 126-37, USA [0005]
• - R. Pelrine, RD Kornbluh, Q. Pei, S. Stanford, OH Seajin, J. Eckerle, RJ Full, MA Rosenthal, K. Meijer: Dielectric elastomeric artificial muscle actuators: toward biomimetic motion, Conference Paper, SPIE Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, vol. 4695, 2002, USA, 126-37 [0007]
• - R. Pelrine, RD Kornbluh, Q. Pei, S. Stanford, OH Seajin, J. Eckerle, RJ Full, MA Rosenthal, K. Meijer: Dielectric elastomeric artificial muscle actuators: toward biomimetic motion, Conference Paper, SPIE Int. Soc. Opt. Eng. Proceedings of Spie - the International Society for Optical Engineering, vol. 4695, 2002, USA, 126-37 [0007]
• - T. Kerscher, J. Albiez, JM Zöllner, R. Dillmann: Evaluation of the Dynamic Modeling of Fluidic Muscles Using Quick-Release, Proceedings of the First IEEE / RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics, 2006, 637- 642 [0008]
• B. Tondu, P. Lopez: Modeling and Control of McKibben's artificial muscle robot actuators, IEEE Control Systems Magazine, 2000, vol. 20, no. 2, 15-38 [0008]
• - Lecture by Ivo Boblan, Technical University Berlin, at the Friedrich-Schiller-University Jena on 15.10.2008 [0008]
• - GK Klute, JM Czerniecki, B. Hannaford: Artificial muscles: actuators for biorobotic systems, The International Journal of Robotics Research, vol. 21, 2002, 295-309 [0009]
• - B. Tondu: Artificial Muscles for Humanoid Robots, in: Humanoid Robots, Human-like Machines, Ed. M. Hackel, I-Tech Education and Publishing, Vienna, Austria, 2007 [0010]
• - T. Frank, C. Schilling: The development of cascadable microdrives with muscle-like operating behavior, J. Micromech. Microeng. 8, 1998, 222-229 [0012]
• - SK Au et al .: Powered ankle-foot prosthesis for the improvement of amputee ambulation, Engineering in Medicine and Biology Society, 29th Annual International Conference of the IEEE 22-26 Aug. 2007, 3020-3026 [0015]

Claims (10)

Device for simulating the movement behavior of a natural muscle, consisting of a mechanical energy source (motor), for example, an electromechanical, hydraulic or pneumatic drive, as well as from a connected in series elastic element, for. B. a mechanical tension spring, characterized in that the mechanical energy source ( 2 ) a force delivered by the device to the load ( 5 ) controlled attenuator ( 6 ) is connected in parallel. Device according to claim 1, characterized in that as mechanical energy source an electric motor 2 is used. Device according to claim 1, characterized in that as a mechanical energy source ( 2 ) a pneumatic drive is used. Device according to claim 1, characterized in that as a mechanical energy source ( 2 ) a hydraulic drive is used. Device according to claim 1, characterized in that as a mechanical energy source ( 2 ) a polymer drive is used. Device according to claim 1, characterized in that as a mechanical energy source ( 2 ) a drive with metal hydride is used as the working medium. Device according to claim 1, characterized in that as a mechanical energy source ( 2 ) A shape memory alloy drive is used as the working medium. Device according to claim 1, characterized in that as a mechanical energy source ( 2 ) a drive with organic substances is used as the working medium. Device according to claim 1, characterized in that as an attenuator ( 6 ) a magneto-rheological damper is used. Device according to claim 1, characterized in that as an attenuator ( 6 ) a hydropneumatic suspension system is used.