JP2010125265A - Motion assisting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device assisting the motion of an agent such as a human being in a suitable operation mode from the viewpoint of harmonizing with the periodic motion mode of the agent. <P>SOLUTION: In this motion assisting device 10, "a second setting processing" is exceptionally performed in such a situation that harmony between the motion mode of the agent P and the motion mode of the motion assisting device is high probably lost, to be concrete, in such a situation that an absolute value of deviation between a first phase difference and a target phase difference is a threshold or more. Since a second inherent angular velocity ω<SB>2</SB>is set based on the motion period T of the agent P by performing the second setting processing (see Fig.4), from the viewpoint of harmonizing the motion mode of the agent P with the motion assisting device, a second vibrator ξ<SB>2</SB>vibrating at a suitable angular velocity can be generated as an operation control basis of the motion assisting device 10. Further, the second setting processing may need a shorter operation time for setting the second inherent angular velocity ω<SB>2</SB>than a first setting processing according to a virtual model. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for assisting a periodic motion of an agent by applying a force to the agent.

There has been proposed a device that assists a periodic movement such as a walking movement of a human by giving a periodically changing force to an animal such as a human whose function of a body part such as a lower limb is lowered (patent) Reference 1 and 2).
Japanese Patent No. 4008464 Japanese Patent No. 4008465

  However, if the agent's motion mode changes suddenly, the phase difference between the agent's periodic motion and the motion assisting device's periodic motion is inconsistent from the viewpoint of harmony between the agent's motion mode and the device's motion mode. May be appropriate.

  Accordingly, an object of the present invention is to provide a device capable of assisting the movement of the agent by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of an agent such as a human being.

  According to a first aspect of the present invention, there is provided an exercise assisting device comprising: an appliance attached to an agent; an actuator coupled to the appliance; and a control device that controls an amplitude and a phase of an output of the actuator; A device that assists the periodic motion of the agent by transmitting an actuator output to the agent, wherein the control device is defined by a phase that periodically changes according to the periodic motion of the agent. A motion state measurement element that measures each of the motion oscillator and the second motion oscillator, and a first that generates an output vibration signal that changes at an angular velocity determined based on the first intrinsic angular velocity by drawing the input vibration signal into each other. The model inputs the first motion oscillator measured by the motion state measuring element as the input vibration signal. The first oscillator generating element that generates a first oscillator as the output vibration signal, the first motion oscillator measured by the motion state measuring element, and the first oscillator generating element generated by the first oscillator generating element A virtual model in which a first virtual oscillator and a second virtual oscillator, which change periodically with a second phase difference while interacting, are expressed based on a first phase difference that is a phase difference with the first oscillator. Based on the natural angular velocity setting element for executing the first setting processing for setting the angular velocity of the second virtual vibrator as the second natural angular velocity so that the second phase difference approaches the target phase difference, and the input vibration signal The second motion measured by the motion state measurement element is converted into a second model that generates an output vibration signal that changes at an angular speed determined based on the second natural angular speed set by the natural angular speed setting element. A second oscillator generating element that generates a second oscillator serving as a basis for controlling the force applied to the agent as the output vibration signal by inputting a vibrator as the input vibration signal, and measuring the motion state The element measures the movement period of the agent, and the intrinsic angular velocity setting element requires that the absolute value of the deviation between the first phase difference and the target phase difference is greater than or equal to a threshold value by the movement state measurement element. Based on the measured movement period of the agent, a second setting process for setting the second natural angular velocity is executed instead of the first setting process.

  According to the exercise assisting apparatus of the first aspect of the invention, the second natural angular velocity is set by executing the “first setting process” in principle, but the “second setting process” is exceptionally performed depending on the situation. By executing this, the second natural angular velocity is set. That is, in a situation where there is a high possibility that the movement mode of the agent and the movement mode of the exercise assisting device will be unbalanced, specifically, in a situation where the absolute deviation values of the first phase difference and the target phase difference are greater than or equal to the threshold value. A two-setting process is executed. Since the second intrinsic angular velocity is set based on the agent's movement cycle by executing the second setting process, an angular velocity suitable as a motion control basis for the exercise assisting device from the viewpoint of harmony between the agent's motion mode and the exercise assisting device. A second vibrator that vibrates at can be generated. In addition, the second setting process requires a shorter calculation processing time for setting the second natural angular velocity than the first setting process according to the virtual model. Therefore, when the situation where the possibility that the movement mode of the agent and the movement mode of the exercise assisting device are unbalanced as described above is increased, an appropriate second natural angular velocity is quickly set from the viewpoint of achieving the harmony. sell. Therefore, the movement of the agent can be assisted by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of the agent.

  According to a second aspect of the present invention, there is provided the exercise assisting apparatus according to the first aspect, wherein the intrinsic angular velocity setting element is in accordance with a continuous or intermittent decreasing function whose variable is a movement period of the agent. The intrinsic angular velocity is set fluidly.

  According to the exercise assisting device of the second aspect of the present invention, when the situation in which the possibility that the movement mode of the agent and the operation mode of the exercise assisting device become unbalanced as described above has occurred is increased, it depends on the length of the agent's exercise cycle. Thus, the operation cycle of the apparatus can be adjusted appropriately from the viewpoint of harmony between the movement mode of the agent and the operation mode of the apparatus. That is, in a state where the agent's motion cycle is short (a state where the agent periodically moves at a relatively fast rhythm), the agent's periodic motion is assisted by an output that changes at a relatively high angular velocity. In addition, in a state where the agent's motion cycle is long (the agent is moving at a relatively slow rhythm), the agent's periodic motion is assisted by an output that changes at a relatively low angular velocity. Therefore, the movement of the agent can be assisted by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of the agent.

  The exercise assisting device according to a third aspect of the present invention is the exercise assisting device according to the first or second aspect, wherein the two actuators are respectively connected via the two orthoses that are respectively attached to two different body parts of the agent. Each output is configured to be transmitted to each of the two body parts, and the second transducer generating element is determined based on each of the two second intrinsic angular velocities as a control basis for the two actuators. Two second vibrators that change in accordance with an angular velocity are generated, and the second inherent angular velocity of the other is synchronized with a change in one of the second intrinsic angular velocities when the intrinsic angular velocity setting element executes the second setting process. Then, the two second intrinsic angular velocities are fluidly set so as to change following or following.

  According to the exercise assisting device of the third aspect of the invention, two second vibrators that vibrate at an angular velocity determined by each of the two second intrinsic angular velocities according to the second model are generated. At this time, when one of the second natural angular velocities is changed by being set as described above, the other second natural angular velocity is set in synchronization with or following the change. That is, when one of the second natural angular velocities is changed, the other second natural angular speed is changed at the same time or after a specified time determined according to the following characteristic. Then, the amplitude and phase of the output of each of the two actuators are controlled based on the two second vibrators, and the output is transmitted to each of two different body parts of the agent, whereby the agent's periodic motion is Assisted. As a result, an excessive divergence in the operation cycle or angular velocity of the device for assisting each movement of the two body parts of the agent can be suppressed. For this reason, while the agent moves to maintain a constant correlation (phase relationship, etc.) between the movements of the two different body parts, the device operates to break this correlation. A situation in which the operation mode of the apparatus is unbalanced can be avoided. Therefore, the movement of the agent can be assisted by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of the agent.

  The exercise assistance device according to a fourth aspect of the present invention is the exercise assistance device according to the third aspect, wherein the outputs of the two actuators are transmitted to the symmetrical body parts as the two body parts of the agent. It is comprised by these.

  According to the exercise assisting device of the fourth aspect of the present invention, it is possible to suppress the deviation of the operation cycle or the angular velocity of the device for assisting each movement of the symmetrical body part of the agent. Therefore, the movement of the agent and the operation of the device are in a short time, for example, the agent moves so as to maintain the left and right motion symmetry while the device operates to break this symmetry. Can be avoided. Therefore, the movement of the agent can be assisted by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of the agent while reducing the processing load.

  The exercise assisting device according to a fifth aspect of the present invention is the exercise assisting device according to any one of the first to fourth inventions, wherein the exercise state measurement element is determined based on one or both of the agent's exercise scale and exercise rhythm. The index value is measured, and the second oscillator generation element is included in the simultaneous differential equation that defines the second model so that the motion index value measured by the motion state measurement element approaches its target value. The coefficient or term value is set fluidly.

  According to the exercise assisting device of the fourth aspect of the invention, from the viewpoint of bringing the exercise index value determined based on at least one of the exercise scale and exercise rhythm of the agent closer to the target value, one or both of the operation scale and operation rhythm of the device Can be controlled appropriately. Therefore, in addition to reducing the processing load and harmonizing with the periodic movement mode of the agent, it is appropriate to maintain the correlation between the agent's action scale and action rhythm in the target correlation. The movement of the agent can be assisted by the mode.

  An embodiment of an exercise assistance device of the present invention will be described with reference to the drawings. Hereinafter, the symbols “L” and “R” are used to distinguish the left and right of the leg and the like, but the symbols are omitted when it is not necessary to distinguish the left and right or when the vector having the left and right components is expressed. In addition, symbols “+” and “−” are used to distinguish between a bending motion (forward motion) and an extension motion (backward motion) of the leg (specifically, the thigh).

  The exercise assisting device 10 shown in FIG. 1 is a device for assisting the walking motion of the agent (human) P, and the waist (first body part) and thigh (second body part) of the agent P are illustrated. A first brace 1100 and a second brace 1200 attached to each are provided. The exercise assisting device 10 includes a hip joint angle sensor 11, an actuator 15, a control device 100, and a battery 1000.

  The first appliance 1100 includes a first link member 1110 and a first wearing instrument 1120. The outer side of the first link member 1110 is made of a rigid material such as hard resin, and the inner side is made of a flexible material such as fiber. The first link member 1110 is applied to the back side of the waist of the agent P. The actuator 15 is attached to a rigid member constituting the first link member 1110 so that the first link member 1110 is disposed near the waist side of the agent P with the first link member 1110 applied to the back side of the waist. The first wearing device 1120 has a mechanism for tightening the first link member 1110 on the back side of the waist of the agent P by being wound around the waist like a belt, and a mechanism for adjusting the strength of the tightening force. is doing. The second appliance 1200 includes a second link member 1210 and a second wearing instrument 1220. The second link member 1210 is made of a rigid material and is directly or indirectly connected to the output shaft of the actuator 15 via a speed reduction mechanism or the like. The second wearing device 1220 is connected to the second link member 1210, and a mechanism for fastening the second wearing device 1220 to the thigh by being wound around the thigh like a belt, and the tightening force. And a mechanism for adjusting. Note that the material and shape of the first brace 1100 and the second brace 1200, the position of the actuator 15, and the like can be arbitrarily changed within a range in which the relative motion of the waist and thigh of the agent P can be assisted.

  The hip joint angle sensor 11 is composed of a rotary encoder arranged beside the waist of the agent P, and outputs a signal corresponding to the hip joint angle. The actuator 15 is constituted by an electric motor and appropriately includes one or both of a speed reducer and a compliance mechanism. The battery 1000 is housed in an appropriate location of the first appliance 1100, and supplies power to the actuator 15, the control device 100, and the like. Each of the control device 100 and the battery 1000 may be attached to or stored in the second appliance 1200, or may be installed separately from the exercise assisting device 10.

  The control device 100 includes a computer (comprising a CPU, ROM, RAM, I / O circuit, A / D conversion circuit, etc.) housed in the first device 1100 and a memory or storage device (HDD, etc.) of this computer. ) Stored in the software. The control device 100 controls the operation of the actuator 15 or the output torque τ by adjusting the power supplied from the battery 1000 to the actuator 15. The control device 100 shown in FIG. 2 includes a motion state measurement element 110, a first vibrator generation element 120, a natural angular velocity setting element 130, a second vibrator generation element 140, and an auxiliary vibrator generation element 150. And. Each element may be configured by physically separate hardware (such as a CPU), or part or all may be configured by physically common hardware.

The motion state measuring element 110 measures the first motion oscillator φ ₁ and the second motion oscillator φ ₂ defined by the phase that periodically changes according to the periodic motion of the agent P. Measuring the vibrator means measuring the amplitude, phase and angular velocity of the vibrator. The movement state measurement element 110 measures a movement index value ζ determined based on one or both of the movement scale and movement rhythm of the agent P based on the output signal of an appropriate sensor. The first vibrator generation element 120 inputs the first motion oscillator φ ₁ measured by the motion state measurement element 110 as an input vibration signal to the first model, and thereby uses the first vibrator ξ ₁ as an output vibration signal. Generate. Generating an oscillator means defining a time variation mode of the amplitude and phase of the oscillator. The natural angular velocity setting element 130 sets the second natural angular velocity ω ₂ by selectively executing one of a first setting process and a second setting process described later according to the situation. The second oscillator generating element 140 generates the second oscillator ξ ₂ as an output vibration signal by inputting the second motion oscillator φ ₂ measured by the motion state measuring element 110 as an input vibration signal to the second model. To do. The auxiliary vibrator generating element 150 generates an auxiliary vibrator η that defines a change pattern of the output torque τ of the actuator 15 of the exercise assisting device 10 based on the second vibrator ξ ₂ generated by the second vibrator generating element 140. To do.

  A method for assisting the walking motion of the agent P by the motion assisting device 10 having the above-described configuration will be described.

Based on the output of the hip joint angle sensor 11, the motion state measuring element 110 measures the angular velocity of the left and right hip joints of the agent P as a first motion oscillator φ ₁ = (φ _1L , φ _1R ) (FIG. 3 / STEP002). Further, the motion state measurement element 110 measures the angle of each of the left and right hip joints of the agent P as the second motion oscillator φ ₂ = (φ _2L , φ _2R ) based on the output of the hip joint angle sensor 11 (FIG. 3 / STEP 004). .

As each of the first motion oscillator φ ₁ and the second motion oscillator φ ₂ , any variable that periodically changes according to the periodic motion of the agent P may be measured using an appropriate sensor. For example, the angle and angular velocity of an arbitrary joint such as a hip joint, a knee joint, an ankle joint, a shoulder joint, and an elbow joint as a motion oscillator, a position of a thigh, a foot part, an upper arm part, a hand part, and a waist part (agent P For example, a position in the front-rear direction or a position in the up-down direction with respect to the center of gravity may be measured. Furthermore, the change patterns of various parameters that vary with the rhythm associated with the walking movement rhythm, such as sounds generated when the left and right legs are landing, breathing sounds, intentional pronunciation, etc. are represented by the first movement oscillator φ ₁ and the first movement oscillator φ ₁ . It may be measured as one or both of the two motion oscillators φ ₂ . In addition, variables representing the periodic motion state of the same body part, such as the angle and angular velocity of the same joint, are measured as the first motion oscillator φ ₁ and the second motion oscillator φ ₂ , respectively. Variables representing the periodic motion states of different body parts, such as the respective angular velocities, may be measured as the first motion oscillator φ ₁ and the second motion oscillator φ ₂ .

  Further, the movement state measuring element 110 measures the movement index value ζ of the agent P (FIG. 3 / STEP005). Specifically, the walking ratio of the agent P is measured as the motion index value ζ. The walking ratio is the ratio of the stride representing the movement scale of the agent P to the walking rate (the number of steps per unit time) representing the movement rhythm of the agent P, and is determined based on both the movement scale and the movement rhythm. Instead of the walking ratio, the stride or walking rate may be measured as the motion index value ζ. The walking ratio, step length, or walking rate can be measured according to the method disclosed in Japanese Patent Application Laid-Open No. 2007-275282 or Japanese Patent Application Laid-Open No. 2007-275283.

Further, the movement state measuring element 110 measures the movement period T of the agent P (FIG. 3 / STEP006). Specifically, the walking period of the agent P represented by the change period of the output signals of the left and right hip joint angle sensors 11 or the average value of the change periods of the output signals of both the left and right hip joint angle sensors 11 is the exercise period. Measured as T. Incidentally, such a change period of the output signals of the hip joint angle sensor 11 is measured as the motion period T _L and T _R of the thigh of the left and right, different body parts, in particular, the motion oscillator φ amplitude, phase and angular velocity Each motion cycle of the different body parts that are directly reflected in may be measured separately. Further, according to the technique disclosed in Japanese Patent Application Laid-Open No. 2007-275282 or Japanese Patent Application Laid-Open No. 2007-275283 concerning the related application invention by the present applicant, The landing period may be measured as the movement period T.

Further, the first vibrator generating element 120 inputs the first motion oscillator φ ₁ measured by the motion state measuring element 110 to the first model as an input vibration signal, so that the first vibrator ξ is output as the output vibration signal. ₁ is generated (FIG. 3 / STEP008). The first model is a model that expresses the correlation between a plurality of first elements such as left and right legs, and the first natural angular velocity ω ₁ = (ω _1L , This is a model that generates an output vibration signal that changes at an angular velocity determined based on (ω _1R ). The first model is defined by, for example, the van der Pol equation expressed by the relational expression (10). The first vibrator generating element 120 sequentially updates the first model by adopting the latest second intrinsic angular velocity ω ₂ set by the intrinsic angular velocity setting element 130 as the latest first intrinsic angular velocity ω ₁ . The subsequent first oscillator ξ ₁ may be generated as an output vibration signal by inputting the subsequent first motion oscillator φ ₁ as an input vibration signal to the latest first model.

(Equation 1)
(d ² φ _1L / dt ² )
= A (1-ξ _1L ² ) (dξ _1L / dt) −ω _1L ² ξ _1L + g (ξ _1L −ξ _1R ) K ₁ φ _1L ,
(d ² φ _1R / dt ² )
= A (1-ξ _1R ² ) (dξ _1R / dt) −ω _1R ² ξ _1R + g (ξ _1R −ξ _1L ) K ₁ φ _1R (10)

“A” is a positive coefficient set so that the first oscillator ξ ₁ and its first-order time differential value (dξ ₁ / dt) draw a stable limit cycle on the ξ ₁ − (dξ ₁ / dt) plane. . “G” reflects the correlation between different body parts such as the left and right legs of the agent P in the correlation between the left and right components of the first oscillator ξ ₁ (correlation between output vibration signals of a plurality of first elements). Is a first correlation coefficient. “K ₁ ” is a feedback coefficient corresponding to the first motion oscillator φ ₁ .

The first oscillator ξ ₁ = (ξ _1L , ξ _1R ) is generated according to the Runge-Kutta method. The respective angular velocities of the components ξ _1L and ξ _1R of the first oscillator ξ ₁ represent a hypothetical rhythm that assists the movement of the left and right legs. In addition, the first oscillator x has a rhythm of the first motion oscillator φ ₁ that changes at substantially the same angular velocity or rhythm as the actual walking motion rhythm due to “mutual entrainment” that is one property of the Van der Pol equation. While being harmonized, there is a property of periodically changing or vibrating with an autonomous angular velocity or rhythm determined based on the first intrinsic angular velocity ω ₁ .

Note that the first model may be expressed by a Van der Pol equation that is different from the Van der Pol equation expressed by the relational expression (10). The first model may be expressed by any equation that generates an output vibration signal that periodically changes at an angular velocity determined based on one intrinsic angular velocity ω ₁ . In addition, the number of first motion oscillators φ ₁ to be measured may be increased. As the first motion oscillator φ ₁ input to the first model increases, the correlation term in the nonlinear differential equation corresponding to the generation of the first oscillator ξ ₁ such as the van der Pol equation that defines the first model. However, the adjustment of the correlation coefficient realizes more precise movement assistance in consideration of the movement of various parts of the body of the agent P.

The phase difference between the periodic motion of the agent P and the periodic motion of the motion assisting device 10 determines the motion mode of the agent P with respect to the motion of the motion assisting device 10. For example, if this phase difference is positive, the agent P can move in such a way as to lead the exercise assisting device 10. On the other hand, when the phase difference is negative, the agent P can move in a form led by the exercise assisting device 10. For this reason, if the phase difference (first phase difference) δθ _{1 of} the first oscillator ξ ₁ with respect to the first motion oscillator φ ₁ deviates from the target phase difference δθ ₀ , the motion mode of the agent P becomes unstable. Prone. As a result, there is a possibility that the motion rhythm of the agent P for which the relative motion of the lumbar region and the thigh region is assisted by the torque T that periodically changes with the angular velocity corresponding to the auxiliary oscillator η deviates from the target motion rhythm. Is expensive.

Therefore, from the viewpoint of matching the motion rhythm of the agent P with the target motion rhythm while maintaining the mutual harmony between the first motion oscillator φ ₁ and the first oscillator ξ ₁ , the second is set by the natural angular velocity setting element 130. An appropriate second natural angular velocity ω ₂ that determines the angular velocity of the vibrator ξ ₂ is set. That is, in order to match the movement rhythm of the agent P with the movement rhythm of the agent P while matching the movement rhythm of the movement assistance apparatus 10 with the movement rhythm of the agent P, From the viewpoint of realizing an appropriate phase difference, an appropriate second natural angular velocity ω ₂ is set.

Specifically, _first , the phase difference between the first motion oscillator φ ₁ and the first oscillator ξ ₁ is set as the first phase difference δθ ₁ (FIG. 3 / STEP010). For example, the first phase difference δθ ₁ is calculated based on the time difference between the time when φ ₁ = 0 and (dφ ₁ / dt)> 0 and the time when ξ ₁ = 0 and (dξ ₁ / dt)> 0. Or set.

Subsequently, it is determined whether or not the deviation absolute value | δθ ₁ −δθ ₀ | of the first phase difference δθ ₁ and the target phase difference δθ ₀ is less than the threshold value δθ _th (FIG. 3 / STEP 012).

When it is determined that the deviation absolute value | δθ ₁ −δθ ₀ | of the first phase difference δθ ₁ and the target phase difference δθ ₀ is less than the threshold value δθ _th (FIG. 3 / STEP012, YES), 1 setting process ”is executed. That is, first, the second phase difference δθ ₂ is set (FIG. 3 / STEP014). Specifically, the first virtual oscillator ψ ₁ = (ψ _1L , ψ _1R ) and the second virtual oscillator ψ ₂ = () defined in the virtual model expressed by the relational expressions (21) and (22). The phase difference from ψ _2L , ψ _2R ) is set as the second phase difference δθ ₂ according to the relational expression (23). The first virtual oscillator ψ ₁ simulates the first motion oscillator φ ₁ in the virtual model. The second virtual oscillator ψ ₂ represents the auxiliary oscillator η in a pseudo manner in the virtual model.

(Equation 2)
dψ _1L / dt = ω _1L + ε _L sin (ψ _2L −ψ _1L ), dψ _1R / dt = ω _1R + ε _R sin (ψ _2R −ψ _1R ) (21)
dψ _2L / dt = ω _2L + ε _L sin (ψ _1L −ψ _2L ), dψ _2R / dt = ω _2R + ε _R sin (ψ _1R −ψ _2R ) (22)
δθ _2L = arcsin {(ω _{1 + L} −ω _{2 + L} ) / 2ε _L }, δθ _2R = arcsin {(ω _{1 + R} −ω _{2 + R} ) / 2ε _R } (23)

Each component of ε = (ε _L , ε _R ) is a correlation coefficient representing the correlation between each component of the first virtual oscillator ψ ₁ and each component of the second virtual oscillator ψ ₂ . ω ₁₊ = (ω _{1 + L} , ω _{1 + R} ) is an angular velocity of each component of the first virtual oscillator ψ ₁ . ω ₂₊ = (ω _{2 + L} , ω _{2 + R} ) is an angular velocity of each component of the second virtual oscillator ψ ₂ .

Subsequently, the correlation coefficient ε is set so that the deviation between the first phase difference δθ ₁ and the second phase difference δθ ₂ is minimized (FIG. 3 / STEP016). Specifically, according to the relational expression (24), the correlation coefficient ε (t _i ) at each time t _{k when} the first motion oscillator φ ₁ becomes 0 is sequentially set for each of the left and right components.

(Equation 3)
ε _L (t _{k + 1} ) = ε _L (t _k ) −B _L {V _1L (t _{k + 1} ) −V _1L (t _k )} {ε _L (t _k ) −ε _L (t _k−1 )},
ε _R (t _{k + 1} ) = ε _R (t _k ) −B _R {V _1R (t _{k + 1} ) −V _1R (t _k )} {ε _R (t _k ) −ε _R (t _k−1 )},
V _1L (t _{k + 1} ) ≡ (1/2) {δθ _1L (t _{k + 1} ) −δθ _2L (t _k )} ² ,
V _1R (t _{k + 1} ) ≡ (1/2) {δθ _1R (t _{k + 1} ) −δθ _2R (t _k )} ² (24)

Each component of B = (B _L , B _R ) has a stable potential V ₁ = (V _1L , V _1R ) that brings each component of the first phase difference δθ ₁ close to the left and right components of the second phase difference δθ _2. It is a coefficient representing sex.

Next, based on the correlation coefficient ε, the deviation between the first phase difference δθ ₁ and the second phase difference δθ ₂ is minimized for each component under the condition that the angular velocity ω _{2+ of} the second virtual oscillator ψ ₂ is constant. The angular velocity of the first virtual oscillator ψ ₁ is set according to the relational expression (25) as the first angular velocity ω ₁₊ (FIG. 3 / STEP018).

(Equation 4)
ω _{1 + L} (t _k ) = − α _L ∫dtq _1L (t), ω _{1 + R} (t _k ) = − α _R ∫dtq _1R (t),
q _1L (t) = (4ε _L ² (t) − (ω _{1 + L} (t) −ω _{2 + L} (t _k ))) ^1/2
× sin (arcsin {(ω _{1 + L} (t) −ω _{2 + L} (t _k-1 )) / 2ε _L (t _k )} − δθ _2L (t _k )),
q _1R (t) = (4ε _R ² (t) − (ω _{1 + R} (t) −ω _{2 + R} (t _k ))) ^1/2
× sin (arcsin {(ω _{1 + R} (t) −ω _{2 + R} (t _k-1 )) / 2ε _R (t _k )} − δθ _2R (t _k )) (25)

Each component of α = (α _L , α _R ) is a coefficient representing the stability of the system.

By setting the correlation coefficient ε and the first angular velocity ω ₁₊ , the mutual harmony of the first motion oscillator φ ₁ and the first oscillator ξ ₁ is changed to the first virtual oscillator ψ ₁ and the second virtual vibration. A virtual model is constructed so as to have the child ψ ₂ . That is, the first virtual oscillator ψ ₁ representing the periodic motion of the agent P and the second virtual vibrator ψ ₂ representing the periodic motion of the motion assisting device 10 are harmonized with each other with the second phase difference δθ _2. A virtual model is constructed so as to change periodically.

Subsequently, based on the first angular velocity ω ₁₊ for each of the left and right components, the angular velocity of the second virtual vibrator ψ ₂ is set as the second angular velocity ω ₂₊ (FIG. 3 / STEP 020). The second angular velocity ω ₂₊ = (ω _{2 + L} , ω _{2 + R} ) is set according to the relational expression (26) so that the second phase difference δθ ₂ approaches the target phase difference δθ ₀ for the left and right components. Then, the second angular velocity ω ₂₊ is set as the second intrinsic angular velocity ω ₂ (FIG. 3 / STEP 024). A series of processing of STEP014 to STEP022 corresponds to “first setting processing”.

(Equation 5)
ω _{2 + L} (t _k ) = β _L ∫dtq _2L (t), ω _{2 + R} (t _k ) = β _R ∫dtq _2R (t),
q _2L (t) = (4ε _L ² (t _k ) − (ω _{1 + L} (t) −ω _{2 + L} (t _k ))) ^1/2
× sin (arcsin {(ω _{1 + L} (t _k ) −ω _{2 + L} (t)) / 2ε _L (t _k )} − δθ ₀ ),
q _2R (t) = (4ε _R ² (t _k ) − (ω _{1 + R} (t) −ω _{2 + R} (t _k ))) ^1/2
× sin (arcsin {(ω _{1 + R} (t _k ) −ω _{2 + R} (t)) / 2ε _R (t _k )} − δθ ₀ ) (26)

Each component of β = (β _L , β _R ) is a coefficient representing the stability of the system.

Thereby, the first motion oscillator φ ₁ is divided into the periodic motion of the agent P expressed by the first virtual oscillator ψ ₁ and the periodic motion of the exercise assisting device 10 expressed by the second virtual oscillator ψ _2. In addition, the second angular velocity ω _{2 /} is appropriately set from the viewpoint of bringing the phase difference between the first oscillator ξ ₁ and the target phase difference δθ ₀ close to each other while maintaining the mutual harmony of the first oscillator ξ ₁ .

On the other hand, when it is determined that the deviation absolute value | δθ ₁ −δθ ₀ | of the first phase difference δθ ₁ and the target phase difference δθ ₀ is equal to or greater than the threshold value δθ _th (FIG. 3 / STEP012... NO), the first setting process Instead, the “second setting process” described below is executed. That is, based on the movement period T of the agent P measured by the movement state measuring element 110, the second intrinsic angular velocity ω ₂ is set according to a decreasing function with the movement period T as a variable (FIG. 3 / STEP024). The decreasing function is stored in the storage device in the form of an arithmetic algorithm or a table, and is read out from the storage device as appropriate. The domain of the decreasing function may be discrete or continuous. For example, based on the motion period T at a certain time or period, a step-like or intermittent decreasing function ω _{2 (0)} (T) as shown by a solid line in FIG. Continuous decreasing function ω _{2 (1)} (T) in which the second derivative is negative, or continuous decreasing function ω ₂ in which the second derivative is positive as shown by the two-dot chain line ₍₂₎ The second natural angular velocity ω ₂ is sequentially set according to (T). Furthermore, the second intrinsic angular velocity ω ₂ is set according to various functions such as a function that is a decreasing function in a part of the domain defined by the motion period T and a function that is an increasing function in another part of the domain. Also good.

In addition, when the exercise cycle T is measured for each of different body parts, the second intrinsic angular velocity ω ₂ may be set independently for each exercise cycle T. For example, when the exercise periods T _L and T _R of each thigh with respect to the waist are measured, the left intrinsic angular velocity ω _L is set based on the exercise period T _L of the left thigh, and the right second intrinsic angular velocity ω. _2R may be set based on the motion period T _R of the right thigh. In addition, when one of the second natural angular velocities changes, it is set fluidly so that the other second natural angular velocity changes in synchronism with or following the change, regardless of the motion period T of the corresponding body part. May be.

Further, the second vibrator generating element 140 inputs the second motion oscillator φ ₂ measured by the motion state measuring element 110 to the second model as an input vibration signal, so that the second vibrator ξ is output as the output vibration signal. _{2 = (ξ 2L +, ξ} 2L-, ξ 2R +, ξ 2R-) to produce a (FIG. 3 / STEP026). The second model is a model that expresses the correlation between a plurality of second elements such as nerve elements that control the movement of each leg in the bending direction (forward) and the movement in the extension direction (backward). This is a model for generating an output vibration signal that changes at an angular velocity determined based on the second natural angular velocity ω ₂ set by the natural angular velocity setting element 130 based on the input vibration signal.

  The second model is defined by a simultaneous differential equation (30), for example.

(Equation 6)
-τ _{1L +} (du _{L +} / dt) =
c _{L +} ζ _{0L +} −u _{L +} + w _{L + / L−} ξ _2L− + w _{L + / R +} ξ _{2R +} −λ _L v _{L +} + f ₁ (ω _2L ) + f ₂ (ω _2L ) Kφ _2L ,
_{-τ 1L-} (du _L− / dt) =
c _L- ζ _0L- -u _L- + w _{L- / L +} ξ _{2L +} + w _{L- / R-} ξ _2R- -λ _L v _L- + f ₁ (ω _2L ) + f ₂ (ω _2L ) Kφ _2L ,
-τ _{1R +} (du _{R +} / dt) =
c _{R +} ζ _{0R +} −u _{R +} + w _{R + / L +} ξ _{2L +} + w _{R + / R−} ξ _{2R +} −λ _R v _{R +} + f ₁ (ω _2R ) + f ₂ (ω _2R ) Kφ _2R ,
-τ _1R- (du _R- / dt) =
c _R- ζ _0R- -u _R- + w _{R- / L-} ξ _2L- + w _{R- / R +} ξ _{2R +} -λ _R v _R- + f ₁ (ω _2R ) + f ₂ (ω _2R ) Kφ _R ,
τ _2i (dv _i / dt) = − v _2i + ξ _2i (i = L +, L−, R +, R−),
ξ _2i = H (u _i −u _th ) = 0 (u _i <u _th ) or u _i (u _i ≧ u _th ), or ξ _2i = fs (u _i ) = u _i / (1 + exp (−u _i / D)) (30)

In this simultaneous differential equation (30), a state variable u _i expressing a behavior state (specified by amplitude and phase) of each thigh in the bending direction (front) and the extending direction (back), A self-suppression factor v _i for expressing the adaptability of each behavior state is included. The simultaneous differential equation (30) includes a coefficient c _i related to the target value ζ ₀ of the motion index value ζ. First time constant tau _1i as described later, the second time constant tau _2i, coefficients c _i and the value of the correlation coefficient w _{i /} among _j such part or all according to the target value zeta _0i of the motion variable zeta _i fluidity Can be set automatically. As described above, the number of motion oscillators φ to be measured may be increased. As the motion oscillator φ input to the second model increases, the correlation term in the simultaneous differential equation increases, but the agent is considered in view of the correlation between the motion states of various parts of the body of the agent P by adjusting the correlation coefficient. The periodic motion of P can be appropriately assisted.

The first time constant “τ _1i ” is a time constant that defines the change characteristic of the state variable u _i , and uses a coefficient t (ω) having ω dependency and constants γ = (γ _L , γ _R ). Although expressed by the relational expression (31), it varies depending on the natural angular velocity ω.

(Equation 7)
τ _{1L +} = τ _1L− = (t (ω _L ) / ω _L ) −γ _L , τ _{1R +} = τ _1R− = (t (ω _R ) / ω _R ) −γ _R (31)

The second time constant “τ _2i ” is a time constant that defines the change characteristic of the self-inhibiting factor v _i . “W _{i / j} ” represents the correlation between the state variables u _i and u _j representing the movement of the left and right legs of the agent P in the bending direction and the extension direction, and the correlation between the components of the second oscillator ξ This is a negative second correlation coefficient to be expressed as (correlation between output vibration signals of the second element). “Λ _L ” and “λ _R ” are habituation coefficients. “K” is a feedback coefficient corresponding to the motion oscillator φ.

The first function “f ₁ ” is a linear function of the natural angular velocity ω defined by the relational expression (32) using the positive coefficient c. The second function “f ₂ ” is a quadratic function of the natural angular velocity ω defined by the relational expression (33) using the coefficients c ₀ , c ₁ and c ₂ .

(Equation 8)
f ₁ (ω) ≡cω (32)
f ₂ (ω) ≡c ₀ ω + c ₁ ω + c ₂ ω ² (33)

Second oscillator xi] _2i, if when the value of the state variable u _i is smaller than the threshold u _th 0 is the value of the state variable u _i is the threshold value u _th or more takes the value of the u _i. Alternatively, the second oscillator ξ _2i is defined by the sigmoid function fs (see relational expression (30)). Accordingly, when the state variable u _{L +} representing the behavior of the left thigh _forward is increased, the amplitude of the left / bending component ξ _{2L +} of the second vibrator ξ ₂ becomes larger than the left extension side component ξ _2L− . Further, when the state variable u _{R +} representing the behavior toward the front side of the right thigh increases, the amplitude of the right / bending component ξ _{2R +} of the second vibrator ξ ₂ becomes larger than the amplitude of the right extension side component ξ _2R− . Further, when the state variable u _L− representing the behavior toward the rear side of the left thigh increases, the amplitude of the left extension side component ξ _2L− of the second vibrator ξ ₂ becomes larger than the left / flexion component ξ _{2L +} . Further, when the state variable u _R− representing the rearward behavior of the right thigh increases, the amplitude of the right extension side component ξ _2R− of the second vibrator ξ ₂ is larger than the amplitude of the right / flexion component ξ _{2R +.} Become. The forward or backward movement of the leg (thigh) is identified by, for example, the polarity of the hip joint angular velocity. The forward or backward movement of the leg (thigh) is identified by, for example, the polarity of the hip joint angular velocity.

In the generation of the second oscillator ξ ₂ , the simultaneous differential equation (30) is set so that the motion index value ζ of the agent P measured by the motion state measuring element 110 of the basic vibrator generating element 140 approaches its target value ζ _0. The value of the included coefficient or term is set fluidly (FIG. 3 / STEP007). The setting target first time constant tau _1i (see equation (31)), the second time constant tau ₂ = tau _2i, coefficients c _i of the target value zeta _0i of the motion variable zeta _i, correlation coefficients w _{i / j} , one of the positive coefficients c defining the first function f ₁ (see relational expression (32)) and the coefficients c _{0 to} c ₂ defining the second function f ₂ (see relational expression (33)). Parts or all values are set fluidly.

After the generation of the second oscillator ξ ₂ , the auxiliary oscillator generation element 150 sets the auxiliary oscillator η = (η _L , η _R ) based on the second oscillator ξ ₂ according to, for example, the relational expression (40). (FIG. 3 / STEP014). That is, the left component η _L of the auxiliary oscillator η is the sum of the product of the left / bending component ξ _{L +} and the coefficient χ _{L +} of the second oscillator ξ and the product of the left extension component ξ _L- and the coefficient −χ _L-. Calculated as The right component η _R of the auxiliary oscillator η is calculated as the sum of the product of the right / bending component ξ _{R +} and the coefficient χ _{R +} of the second oscillator ξ and the product of the right extension component ξ _R- and the coefficient −χ _R- Is done. The auxiliary oscillator η is one or both of an elastic force by a virtual elastic element as disclosed in Patent Documents 1 and 2 or a damping force by a virtual damping element in addition to the elastic force. May be generated to represent.

(Equation 9)
η _L = χ _{L +} ξ _{L +} −χ _L- ξ _L- , η _R = χ _{R +} ξ _{R +} −χ _R- ξ _R- (40)

Then, the control device 100 adjusts the current I = (I _L , I _R ) supplied from the battery 1000 to the left and right actuators 15 based on the auxiliary vibrator η. The current I is expressed as, for example, I (t) = G ₁ · η (t) (G ₁ : proportional coefficient) based on the auxiliary oscillator η. Accordingly, the force applied to the agent P from the exercise assistance device 10 via the first brace 1100 and the second brace 1200 to move each thigh (second body part) relative to the waist (first body part) or The torque τ = (τ _L , τ _R ) around the hip joint is adjusted (FIG. 3 / STEP016). The torque τ is based on the current I and is expressed, for example, as τ (t) = G ₂ · I (t) (G ₂ : proportional coefficient). Thereafter, the above-described series of processing is repeatedly executed. Thereby, the second brace 1200 is moved with respect to the first brace 1100, and the periodic movement of the thigh (second body part) with respect to the waist (first body part) is assisted. It should be noted that the operation of the exercise assisting device 10 is performed so that the thigh is appropriately moved with respect to the waist during the period from the start of the walking motion of the agent P to the completion of the walking motion for two to three steps. It may be controlled independently of the control method. The walking movement of the agent P may be performed on a treadmill.

According to the exercise assisting apparatus 10 that exhibits the above function, in principle, the “first setting process” is executed (see FIG. 3 / STEP014 to STEP022). As a result, the first motion is divided into the periodic motion of the agent P expressed by the first virtual oscillator ψ ₁ and the periodic motion of the exercise assisting device 10 expressed by the second virtual oscillator ψ _{2 as} described above. The second intrinsic angular velocity ω ₂ is appropriately set from the viewpoint of bringing the phase difference between the vibrator φ ₁ and the first vibrator ξ ₁ close to the target phase difference δθ ₀ while providing the mutual harmony of the vibrator φ ₁ and the first vibrator ξ ₁ . Therefore, the second oscillator xi] ₂ to the output torque τ, which is controlled on the basis of which periodically changes at the angular velocity determined based on the second intrinsic angular velocity omega _2, the period at an angular velocity determined based on the second intrinsic angular velocity omega ₂ (Refer to FIG. 3 / STEP026 to STEP030). Therefore, torque τ oscillating at an appropriate angular velocity is transmitted to the agent P from the viewpoint of harmonizing the movement mode of the agent P and the movement mode of the exercise assisting device 10, and as a result, the periodic walking movement of the agent P is performed. It can be supported appropriately.

On the other hand, the situation where the possibility that the movement mode of the agent P and the movement mode of the exercise assisting device 10 are unbalanced is high, specifically, the deviation absolute values of the first phase difference and the target phase difference are equal to or greater than the threshold value. As an exception, the “second setting process” is executed (see FIG. 3 / STEP024). Since the second intrinsic angular velocity ω ₂ is set based on the motion period T of the agent P by executing the second setting process (see FIG. 4), from the viewpoint of achieving harmony between the motion mode of the agent P and the motion assisting device 10. The second vibrator ξ ₂ that oscillates at an appropriate angular velocity can be generated as the operation control basis of the exercise assisting device 10. In addition, the second setting process requires a shorter calculation processing time for setting the second natural angular velocity ω ₂ than the first setting process according to the virtual model. Therefore, when the situation where the possibility that the movement mode of the agent P and the movement mode of the exercise assisting device 10 are unbalanced as described above is increased, an appropriate second natural angular velocity ω ₂ is obtained from the viewpoint of achieving the harmonization. It can be set quickly. Therefore, the movement of the agent P can be assisted by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of the agent P.

Further, in a situation where there is a high possibility that the movement mode of the agent P and the movement mode of the exercise assisting device 10 will be unbalanced, the second intrinsic angular velocity ω ₂ and eventually the agent P will be changed according to the length of the movement period T of the agent P. The operation cycle of the apparatus 10 can be appropriately adjusted from the viewpoint of harmony between the movement mode and the operation mode of the apparatus 10. That is, in a state where the motion period T of the agent P is short (a state where the agent P is periodically moving at a relatively fast rhythm), the periodic motion of the agent P is assisted by an output that changes at a relatively high angular velocity. Further, in a state where the motion period T of the agent P is long (a state where the agent P is moving at a relatively slow rhythm), the agent's periodic motion is assisted by an output that changes at a relatively low angular velocity. For this reason, it is possible to control the operation mode of the apparatus 10 so as to appropriately follow the change in the movement mode of the agent P in spite of the simplification of the arithmetic processing contents. Therefore, the movement of the agent P can be assisted by an appropriate operation mode from the viewpoint of harmony with the periodic motion mode of the agent P while reducing the processing load.

Further, when each of the two second natural angular velocities ω _2L and ω _2R is set independently based on a separate motion cycle, one of the second natural angular velocities is changed by being set fluidly as described above. In this case, the other second intrinsic angular velocity can be set in synchronization with or following the change. That is, when one of the second natural angular velocities is changed, the other natural angular speed is changed at the same time or after a specified time determined in accordance with the following characteristic. For example, when one second intrinsic angular velocity changes from one value to another value, the other second intrinsic angular velocity changes so as to coincide with or approach the other value simultaneously or substantially simultaneously. Based on the two second oscillators ξ _2L and ξ _2R , the amplitude, phase and angular velocity of each of the two actuators 15 are controlled, and this torque τ is transmitted to each of the different body parts of the agent P. Thus, the periodic motion of the agent P is assisted (see FIG. 5). As a result, an excessive divergence of the operation cycle or angular velocity of the device 10 for assisting each movement of the two body parts of the agent P can be suppressed. For this reason, while the agent P moves so as to maintain its left and right movement symmetry, the movement of the agent P and the movement of the apparatus P are harmonized for a short time, for example, the apparatus 10 operates so as to break this symmetry. Even so, it is possible to avoid a situation where it collapses excessively.

Further, from the viewpoint of bringing the motion index value ζ determined based on the motion scale and motion rhythm of the agent P closer to the target value ζ ₀ , the motion scale (or motion amplitude) and motion rhythm (motion angular velocity or motion angular velocity) of the apparatus 10. And phase) can be appropriately controlled (see relational expressions (30) to (33), FIG. 3 / STEP005 and STEP007). The process of measuring the motion index value ζ and setting values such as coefficients may be omitted.

  In the above embodiment, the human movement as the agent P is assisted. However, as another embodiment, the walking movement of a non-human animal such as a monkey, a dog, a horse, or a cow as the agent is assisted. Good.

  In the embodiment, the exercise assisting device 10 is configured so that the walking motion is assisted by assisting the movement of two symmetrical body parts, that is, the left and right thighs (see FIG. 1). ), As another embodiment, the exercise assisting device 10 is such that each movement of a plurality of non-symmetrical body parts of the agent P such as the upper right arm and the left forearm, the right thigh and the upper right arm is assisted. May be configured. Further, the exercise assisting device 10 may be configured such that only the movement of one body part of the agent P, such as one of the left and right thighs and one of the left and right upper arms, is assisted. The shape, material, number, etc. of the brace can be changed so that it can be worn on various body parts of the agent P.

Structure explanatory drawing of the exercise assistance apparatus as one Embodiment of this invention Configuration explanatory diagram of the control device of the exercise assist device Explanatory drawing about the control method of the exercise assistance device Explanatory diagram on how to set the natural angular velocity

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Movement assistance apparatus, 11 ... Hip joint angle sensor, 15 ... Actuator, 100 ... Control apparatus, 110 ... Movement state measurement element, 120 ... 1st vibrator production | generation element, 130 ... Natural angle setting element, 140 ... 2nd vibrator Generating element, 150 ... auxiliary vibrator generating element, 1000 ... battery, 1100 ... first device, 1200 ... second device

Claims (5)

An appliance mounted on the agent; an actuator coupled to the appliance; and a control device that controls the amplitude and phase of the output of the actuator, and the output of the actuator is transmitted to the agent via the appliance. A device for assisting the periodic movement of the agent by:
The control device is
A motion state measuring element that measures each of the first motion oscillator and the second motion oscillator defined by a phase that periodically changes according to the periodic motion of the agent;
The first motion oscillator measured by the motion state measuring element is used as a first model that generates an output vibration signal that changes at an angular velocity determined based on a first natural angular velocity by mutually attracting the input vibration signal. A first vibrator generating element for generating a first vibrator as the output vibration signal by inputting as an input vibration signal;
Based on a first phase difference that is a phase difference between the first motion oscillator measured by the motion state measurement element and the first oscillator generated by the first oscillator generation element, the first In accordance with a virtual model in which a first virtual oscillator and a second virtual oscillator that periodically change with two phase differences are expressed, the second virtual oscillator approaches the target phase difference. A natural angular velocity setting element for executing a first setting process for setting the angular velocity of the second angular velocity as a second natural angular velocity;
Based on the input vibration signal, a second model that generates an output vibration signal that changes at an angular velocity determined based on the second natural angular velocity set by the natural angular velocity setting element is used as the second model measured by the motion state measurement element. A second oscillator generating element that generates a second oscillator serving as a basis for controlling the force applied to the agent as the output vibration signal by inputting a two-motion oscillator as the input vibration signal;
The movement state measuring element measures the movement period of the agent;
Based on the movement period of the agent measured by the movement state measurement element, the natural angular velocity setting element is required that the absolute value of the deviation between the first phase difference and the target phase difference is greater than or equal to a threshold value, An exercise assisting apparatus, wherein a second setting process for setting the second natural angular velocity is executed instead of the first setting process. The exercise assisting device according to claim 1,
The exercise assisting apparatus, wherein the intrinsic angular velocity setting element fluidly sets the intrinsic angular velocity in the second model according to a continuous or intermittent decreasing function having the movement period of the agent as a variable. The exercise assisting device according to claim 1 or 2,
Each of the two actuators attached to each of the two different body parts of the agent is configured to transmit the output of each of the two actuators to each of the two body parts;
The second vibrator generating element generates two second vibrators that change at angular velocities determined based on the two second intrinsic angular velocities as a control basis of the two actuators,
The second angular velocity setting element changes the second second angular velocity in synchronism with or following the change in the second intrinsic angular velocity when the second setting process is executed. An exercise assist device characterized by fluidly setting an intrinsic angular velocity. The exercise assisting device according to claim 3, wherein
The exercise assisting device is configured so that outputs of the two actuators are transmitted to each of symmetrical body parts as the two body parts of the agent. In the exercise assistance device according to any one of claims 1 to 4,
The movement state measurement element measures a movement index value determined based on one or both of the movement scale and movement rhythm of the agent;
The second oscillator generating element calculates a coefficient or term value included in the simultaneous differential equation that defines the second model so that the motion index value measured by the motion state measuring element approaches its target value. An exercise assistance device characterized by being set fluidly.

Images