JP3797437B2 - Continuous passive motion device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention is a device for preventing or alleviating contracture of a joint part before and after surgery or when performing rehabilitation, and enables flexible movement of the thigh and crus and does not apply a load to the joint. Further, the present invention relates to a continuous passive motion apparatus for a knee joint that has a compact mechanism, is convenient to carry, and can repeatedly perform a treatment operation by direct teaching.
[0002]
[Prior art]
Continuous passive movement is a treatment method that promotes joint repair by moving the joint to be treated passively and continuously for a long time immediately after injury or immediately after surgery, and has the effect of significantly shortening the joint recovery period. When the joint part of the human body is damaged or operated, the conventional treatment method is fixed with a cast or the like. As a result, the symptom of contracture that caused the movement of the joint to worsen was caused, and subsequent rehabilitation was required for a long time. However, a continuous passive movement method was proposed by Prof. Salter of Canada in 1980 as a new treatment alternative to the treatment, and the effect of the device has been gradually revealed along with the invention of a device for performing the treatment (Salter). , RB: The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage., J. Bone Joint Surg., 62-A, pp.1232-1251, 1980.).
A conventional continuous passive motion apparatus is as shown in FIG. FIG. 4 is a “device for applying continuous passive motion to the lower leg of a human body” of JP-T-4-506610. This device induces an open / close motion of the knee joint by sliding the leg back and forth in a sitting or supine posture.
[0003]
[Problems to be solved by the invention]
However, the conventional device shown in FIG. 4 is compact and easy to carry because the mechanism is simple with a one-degree-of-freedom slide mechanism, but it causes congestion because the thigh and crus are always located below the knee. There was a fear. In addition, this device uses a mechanism with one degree of freedom that slides in the bending direction of the leg to open and close the knee with one degree of freedom, so that loads from the thigh and crus are always applied to the knee joint. Therefore, there was a problem that an excessive load was applied to the knee.
Therefore, the present invention is a device for preventing or reducing joint contracture before and after surgery or during rehabilitation, and allows free movement of the thigh and lower leg, and does not apply a load to the joint. It is an object of the present invention to provide a continuous passive motion apparatus capable of realizing simple control, having a compact mechanism and convenient to carry, and capable of repeatedly reproducing and executing a treatment operation by direct teaching.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a continuous passive motion apparatus used for a treatment for passively continuously moving a knee joint to be treated to promote joint repair,
A multi-degree-of-freedom motion mechanism that supports the lower leg and applies force
Base 100 and
Two first links 201 and 202 having the same length and driven by driving force at both ends of the base portion 100;
From the first links 201 and 202, two second links 203 and 204 having the same length, one having a driving force and the other connected by a free joint,
A parallel mechanism having three degrees of freedom in a vertical plane of two translational degrees of freedom and one degree of freedom of rotation composed of a third link 205 connecting the two second links 203 and 204 with a free joint,
The lower leg support portion is provided on the third link.
[0005]
[Action]
The parallel mechanism is also called a parallel mechanism, and unlike a so-called parallel link, the degree of freedom of the device can be increased, and the drive device can be arranged on the base portion, so that the device can be reduced in weight, and This is a mechanism construction method having the feature that the link rigidity can be increased. Further, in the present invention, a force sensor for measuring the force acting between the mechanism part and the leg is arranged in the mechanism part that grips the lower leg part, and force control and compliance control are performed by feeding back the force. Do it. Also, compliance control is performed on the mechanism that holds the leg, and if the force is applied, the mechanism can move freely along the direction of the force, and the leg can be moved directly to move the thigh and A treatment operation for continuous passive movement of the lower leg is directly taught, the taught data is stored, and the treatment operation can be repeatedly reproduced according to the stored teaching data.
By the above means, the entire leg can be supported so as to be positioned above the body and the knee can be opened and closed, so the entire leg is always above the torso, so there is no possibility of causing congestion in the leg. . In addition, since the device has a three-degree-of-freedom mechanism by a parallel mechanism, free movement of the legs is guaranteed and there is no possibility that an unreasonable load is applied to the knee. Furthermore, since force control and compliance control are performed by feeding back the force measured by the force sensor arranged between the mechanism part and the leg, no excessive force is applied to the leg. In addition, by using compliance control, it is possible to directly teach the therapeutic action of continuous passive movement of the thigh and crus by moving the leg directly, so the therapeutic action is repeatedly reproduced according to the teaching data. be able to.
[0006]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a view showing a continuous passive motion apparatus of the present invention.
In the figure, 100 is a base portion of the apparatus, 101 is a first drive shaft, 102 is a second drive shaft, 104 is a third drive shaft, and 103, 105, and 106 are free joints. Reference numerals 201, 202, 203, 204, and 205 denote links that connect the axes of the apparatuses. Reference numeral 206 denotes a belt drive mechanism for driving the drive shaft 104 with a base motor. Reference numeral 301 denotes a force sensor fixed to the link 205 and measures the force generated between the device and the leg. 302 fixed to the upper part of the force sensor is a splint for fixing the leg to the apparatus. The lower leg 401 is fixed to the apparatus by a sprint 302. The lower leg 401 and thigh 403 are driven around the joints 404 and 402 by the operation of the apparatus.
[0007]
FIG. 2 is a side view of the continuous passive motion apparatus of the present invention.
In the figure, reference numeral 500 denotes a base portion of the apparatus, reference numeral 501 denotes a second drive shaft motor, and reference numeral 502 denotes a third drive shaft motor. The third drive shaft motor drives the third drive shaft 506 via the belt drive mechanism 509. Reference numeral 503 denotes a second drive shaft, 504 denotes a shaft connecting the motor 502 and the belt drive mechanism 509, and 505, 507, and 508 denote free joints. Reference numerals 601, 602, 603, 604, 605, and 606 are links that connect the axes of the apparatus. A force sensor 701 is fixed to the link 605 and measures a force generated between the device and the leg. Reference numeral 702 fixed to the top of the force sensor is a splint for fixing the leg to the apparatus. The lower leg 801 is fixed to the apparatus by a sprint 702.
With the mechanism as described above, the knee can bend and extend with the lower leg always raised, and it has 3 degrees of freedom in a vertical plane with 2 degrees of translation and 1 degree of freedom of rotation. Exercise can be guaranteed. In addition, since all three motors can be placed at the base of the device, the load on the link is reduced, so the link rigidity can be lowered, and the center of gravity of the entire device can be lowered. The overall configuration can be made compact.
[0008]
FIG. 3 is a diagram showing the operation of the continuous passive motion apparatus of the present invention.
In the figure, reference numerals 111, 112, and 113 denote a first drive shaft, a second drive shaft, and a third drive shaft, respectively. The force sensor 211 measures three axial forces generated between the leg and the device in three degrees of freedom in the plane in the knee extension and contraction directions, ie, two translational directions and one rotational direction. The measured force information 212 is sent to the force sensor amplifier 311 of the controller 310, converted into a triaxial force value 312, and sent to the impedance controller 313. In the impedance controller 313, a force value vector F indicated by 312 according to the target impedance (target inertia matrix M, target viscosity matrix B, target stiffness matrix K)
F = Mα + BV + K (X−Xo) (1)
The position vector command value X is generated so as to realize the above, and this is coordinate-converted into a joint angle command vector θ which is a value in the joint coordinate system, and then sent to the servo amplifier 315. In response to this, the servo amplifier 315 calculates the torque 316 to be generated on each drive shaft and controls the joint value of each shaft. Here, Xo is the equilibrium point of the spring at the target stiffness, the target trajectory for driving the device, V is the first derivative of X, and α is the second derivative of X. As a method for realizing the expression (1), for example, there is a literature (Hirabayashi et al .: Virtual compliance control of multi-degree-of-freedom robot, Transactions of the Society of Instrument and Control Engineers, Vol.
[0009]
Next, a procedure for teaching and executing the operation of the apparatus will be described.
In order to teach the operation of the apparatus, the sprint 302 or the leg 411 for fixing the leg to the apparatus is directly held and manually taught. When a force is applied in the direction in which the leg 411 is moved in order to teach the operation of continuously performing knee extension and contraction, the force is detected by the force sensor 211 as a force generated between the device and the leg. Is done. The force information is converted into a joint angle command value θ according to the procedure described above. At this time, the apparatus moves while showing the characteristic of the target impedance set in the direction of movement. Further, since the joint angle command value θ is recorded as time series data in the controller 310 memory 317, the taught operation is recorded as the value of the joint angle of the drive shaft of the apparatus. The operation can be taught as described above. Next, when executing the operation, the time-series data as the recorded teaching data is sequentially delivered from the memory 317, and the apparatus is driven using this as the target trajectory. Further, if a force is generated between the leg and the device during the operation of the device, a position deviation according to the target impedance is generated with respect to the force by using the teaching data as the equilibrium point of the spring according to the procedure described above. While drawing a trajectory that follows the motion of the device, the device will perform the motion. The mechanism and operation of the apparatus have been described above.
[0010]
In this way, the mechanism as described above can support the entire leg to be positioned above the body, and the knee can be opened and closed, so the entire leg is always positioned above the torso. There is no risk of congestion in the legs. In addition, since the device has a three-degree-of-freedom mechanism by a parallel mechanism, free movement of the legs is guaranteed and there is no possibility that an unreasonable load is applied to the knee. Furthermore, since the parallel mechanism has an actuator at the base, there is no problem even if the link rigidity is significantly reduced compared to the method shown in FIG. The problem of becoming is solved. Furthermore, since force control and compliance control are performed by feeding back the force measured by the force sensor arranged between the mechanism part and the leg, no excessive force is applied to the leg. In addition, by using compliance control, it is possible to directly teach the therapeutic action of continuous passive movement of the thigh and crus by moving the leg directly, so the therapeutic action is repeatedly reproduced according to the teaching data. be able to.
[0011]
【The invention's effect】
As described above, according to the present invention, the multi-degree-of-freedom motion mechanism capable of freely controlling the positions and postures of the thigh and crus is provided by the three actuators arranged at the base portion of the apparatus. Driven by a shaft and link directly connected to the actuator, and a shaft and link driven by a belt drive mechanism or shaft drive mechanism directly connected to the actuator, gripping and supporting the crus and applying force, translational two degrees of freedom rotation Since it is composed of a parallel mechanism with 3 degrees of freedom in a vertical plane with 1 degree of freedom, the entire leg can be moved from the torso by supporting the entire leg so that it is positioned above the body and opening and closing the knee. Because it is always on the top, there is no risk of causing congestion in the legs. In addition, since the device has a three-degree-of-freedom mechanism by a parallel mechanism, free movement of the legs is guaranteed and there is no possibility that an unreasonable load is applied to the knee. Furthermore, since the parallel mechanism has an actuator at the base, there is no problem even if the link rigidity is significantly reduced compared to the method of FIG.
In addition, a force sensor that measures the force acting between the mechanism and the leg is placed in the mechanism that grips the lower leg, and force control and compliance control are performed by feeding back the force. There is an effect that it does not apply a strong force.
In addition, by using compliance control, it is possible to directly teach the therapeutic action of continuous passive movement of the thigh and crus by moving the leg directly, so the therapeutic action is repeatedly reproduced according to the teaching data. There is an effect that can be. In addition, the apparatus of this invention can be used also as a rehabilitation and exercise training apparatus with the structure of the same mechanism and control system.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing a side view of an embodiment of the present invention.
FIG. 3 is a diagram showing the operation of the embodiment of the present invention.
FIG. 4 is a view showing a mechanism of a conventional apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Base part 101 ... 1st drive shaft 102 ... 2nd drive shaft 104 ... 3rd drive shaft 103, 105, 106 ... Free joint 201, 202, 203, 204, 205 ... Connection of the axis | shaft of an apparatus Link 206 ... Belt drive mechanism 301 ... Force sensor 302 ... Sprint 401 ... Lower leg 403 ... Thigh

Claims (3)

  In the continuous passive motion apparatus used for the treatment that promotes joint repair by passively moving the knee joint to be treated, a multi-degree-of-freedom motion mechanism that applies force to support the lower leg, From the base part 100, two first links 201 and 202 having the same length driven by driving force at both ends of the base part 100, and one of the first links 201 and 202 having one driving force and the other. Is composed of two second links 203 and 204 having the same length and connected by a free joint, and a third link 205 connecting the two second links 203 and 204 by a free joint. A continuous passive motion apparatus comprising a parallel mechanism having three degrees of freedom in a vertical plane of one degree of freedom and one degree of rotation, and a support portion for the lower leg is provided on the third link. A force sensor that measures forces in two translational directions and one rotational direction acting between the exercise mechanism and the crus is arranged in the mechanism that grips the crus, and force control is performed by feeding back the force. The continuous passive motion apparatus according to claim 1, wherein the compliance control is always performed during the operation of the apparatus. By performing compliance control on the mechanism that grips the lower leg, and applying force, the thigh can be moved directly along the direction of the force by moving the leg directly. Directly teach the treatment action of continuous passive movement of the head and lower leg , memorize the taught data, perform force control and compliance control , repeat the treatment action according to the memorized teaching data The continuous passive motion apparatus according to claim 1 or 2.

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