JP2007143704A - Ultrasonic probe moving holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic probe moving holding device capable of suppressing the occurrence of the oscillation and vibration of a robot arm caused by an abrupt input signal inputting into a force detector when bringing an ultrasonic prove into contact with a body surface from outside of the body surface or when the ultrasonic prove collides with a hard object. <P>SOLUTION: The ultrasonic probe moving holding device according to the present invention has the ultrasonic prove transmitting and receiving ultrasonic wave while coming into contact with the body surface, the robot arm equipped with a force detector detecting the force from outside, and a controller controlling the force for bringing the ultrasonic prove into contact with the body surface with constant force, includes an operation grip section arranged in the force detector, an elastic mechanism connecting the operation grip section and the ultrasonic probe, and a displacement detector detecting the displacement of the elastic mechanism, and changes the parameter of the force control of the controller by the displacement detector, and can suppress the occurrence of the oscillation and vibration of the robot arm by this constitution. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a moving and holding apparatus for an ultrasonic probe that receives an echo signal by irradiating an ultrasonic wave into a living body.

  Ultrasound diagnostic equipment is used in the diagnosis of tumors and vascular conditions that form on the body surface and breast. At that time, the ultrasound probe is held in contact with the body surface of the subject with a certain force at a notable site, and diagnosis is performed while viewing the image displayed on the ultrasound diagnostic apparatus. .

  Patent Document 1 is for diagnosing the state of the blood vessels of the arm, and detects the contact pressure on the body surface from the pressure of the water bag of the ultrasonic probe, and controls the isobaric pressure along the body surface. A robot arm that mechanically scans (moves) an ultrasound probe is disclosed.

In Patent Document 2, the ultrasonic probe is held by a passive arm, the contact pressure on the body surface is detected by a pressure detector attached to the ultrasonic probe, and the contact pressure is detected by a linear actuator. An ultrasonic probe holding device to be controlled is disclosed.
JP 2002-238899 A Japanese Patent Laid-Open No. 2003-384821

  However, in the conventional ultrasonic probe moving and holding device, when the ultrasonic probe is brought into contact with the body surface from outside the body surface or when the ultrasonic probe hits a hard object such as a bone. In some cases, a steep input signal is input to the force detector, and the controller may react excessively, causing the robot arm to oscillate or vibrate.

  The present invention has been made to solve the conventional problems. After detecting the contact of the ultrasonic probe with the body surface by the displacement detector, the target of the ultrasonic probe on the body surface is detected. Switching the control parameter to a constant force reduces the sudden force input to the force detector when contacting the body surface from outside the body surface, or hits an ultrasonic probe on a hard object, etc. It is an object of the present invention to provide an ultrasonic probe moving and holding device that can reduce the input of a rapid force to a force detector by an elastic mechanism and suppress the oscillation and vibration of a robot arm.

  The ultrasonic probe moving and holding according to the present invention includes an ultrasonic probe that contacts a body surface and transmits and receives ultrasonic waves, a robot arm that includes a force detector that detects external force, and the ultrasonic wave An ultrasonic probe moving and holding device comprising a controller for controlling the force of bringing the probe into contact with the body surface with a constant force, and an operation grip unit installed in the force detector; A feature is provided that includes an elastic mechanism that connects the operation grip portion and the ultrasonic probe, and a displacement detector that detects a displacement of the elastic mechanism, and switches a force control parameter of the controller by the displacement detector. have.

  With this configuration, after detecting the contact of the ultrasonic probe with the body surface by the displacement detector, the control parameter is switched to the target constant force on the body surface of the ultrasonic probe, thereby enabling the detection of the extraneous surface. Reduces the input of a sudden force to the force detector when contacting the body surface from the body, or when the ultrasonic probe hits a hard object etc., the sudden force to the force detector by an elastic mechanism Input, and the generation of vibration and vibration of the robot arm can be suppressed.

  In the ultrasonic probe moving and holding according to the present invention, the controller includes an impedance control unit and a position / posture control unit.

  With this configuration, the controller can perform hybrid control capable of simultaneously performing force control by the impedance control unit and position / posture control.

  The ultrasonic probe moving and holding according to the present invention is characterized in that the controller retains orbit data and performs an operation following the orbit data.

  With this configuration, the copying operation can be performed according to the trajectory data while maintaining a constant force.

  In addition, the ultrasonic probe moving and holding according to the present invention is characterized in that the elastic mechanism includes a replaceable holder portion for holding the ultrasonic probe.

  With this configuration, it is possible to easily attach ultrasonic probes having various shapes by exchanging the holder portion.

  The ultrasonic probe moving and holding according to the present invention is characterized in that the elastic mechanism is an elastic body including a damping material.

  With this configuration, when the ultrasonic probe hits a hard object or the like, a rapid force input to the force detector can be reduced by the damping material.

  In the ultrasonic probe moving and holding according to the present invention, the displacement detector includes a light emitting member indicating a displacement range.

  With this configuration, the contact force can be detected visually.

  Further, the ultrasonic probe moving and holding according to the present invention is characterized in that the robot arm has a parallel link mechanism.

  With this configuration, it is possible to configure a moving and holding device that is lightweight and highly rigid.

  The ultrasonic probe moving and holding according to the present invention includes an ultrasonic probe that contacts a body surface and transmits and receives ultrasonic waves, a robot arm that includes a force detector that detects external force, and the ultrasonic wave An ultrasonic probe moving and holding device comprising a controller for controlling the force of bringing the probe into contact with the body surface with a constant force, and an operation grip unit installed in the force detector; A feature is provided that includes an elastic mechanism that connects the operation grip portion and the ultrasonic probe, and a displacement detector that detects a displacement of the elastic mechanism, and switches a force control parameter of the controller by the displacement detector. have.

  With this configuration, after detecting the contact of the ultrasonic probe with the body surface by the displacement detector, the control parameter is switched to the target constant force on the body surface of the ultrasonic probe, thereby enabling the detection of the extraneous surface. Reduces the input of a sudden force to the force detector when contacting the body surface from the body, or when the ultrasonic probe hits a hard object etc., the sudden force to the force detector by an elastic mechanism Input, and the generation of vibration and vibration of the robot arm can be suppressed.

  Hereinafter, ultrasonic probe movement holding according to an embodiment of the present invention will be described with reference to the drawings.

  The ultrasonic probe moving and holding according to the embodiment of the present invention is shown in FIGS.

  1 and 2, the robot arm 1 has a force detector 2 that detects an external force at the tip, and the detector 2 has an operation grip 3. The force detector 2 is, for example, a strain gauge type or electrostatic force type force sensor, and desirably has 6 degrees of freedom (3 degrees of freedom for translation and 3 degrees of freedom for rotation). Inside the operation grip portion 3 is a holder portion 5 to which an ultrasonic probe 7 is attached, and is connected to the operation grip portion 3 by an elastic mechanism 4.

  In FIG. 2, the holder part 5 slides in the direction of the arrow. In addition, the holder part 5 can be replaced, and the ultrasonic probe 7 can be easily replaced by making a holder part corresponding to the ultrasonic probe 7 of various shapes. The displacement detector 6 is installed in the operation grip unit 3 and detects the displacement of the elastic mechanism 4, that is, the ultrasonic probe 7 with respect to the operation grip unit 3.

  The elastic mechanism 4 is a spring whose spring constant is known, for example, and can calculate the generated force from the displacement from the displacement detector 6 and the spring constant. The elastic mechanism 4 may be an elastic body such as a coil spring, a leaf spring, or rubber, and may be plural as shown in the figure. The elastic mechanism 4 may be an elastic body including a damping material such as a urethane material or a gel material.

  In addition, the displacement detector 6 may be a direct acting type or a rotary type, and the detection method may be a magnetic type or an optical type. The installation location of the displacement detector 6 may not be the location shown in the figure. The light-emitting member 6a is, for example, a light-emitting diode, and is a single light-emitting diode. The light-emitting member 6a may be a single light-emitting pattern or a change in color.

  The operation of the robot arm 1 is controlled by giving a position angle and a speed of a motor installed at each joint by the controller 8. The robot arm 1 is an articulated robot arm, and the degree of freedom of joint may be six axes, or may have redundancy of six axes or more. The robot arm 1 may be a parallel link mechanism as well as a serial link mechanism as shown in FIG.

  By using a parallel link mechanism, a lightweight and highly rigid robot arm can be configured, but the movable range is narrower than that of a serial link mechanism. The coordinate position of each joint of the robot arm 1 is calculated by the control unit 8. The signal from the ultrasonic probe 7 is processed and displayed in the ultrasonic diagnostic apparatus 9.

4A is a model diagram of contact with the body surface 100. FIG. The contact part to the body surface can be expressed by an impedance control model of the following formula. However, M, B, and K represent the virtual mass, viscosity coefficient, and spring coefficient, respectively, in the impedance control model, X represents displacement, V represents velocity, A represents acceleration, and F represents force. In this case, the elastic mechanism 4 is also added,
M ₀ A ₀ + B ₀ V ₀ + K ₀ X ₀ = F ₀ (Formula 1)
M ₁ A ₁ + K ₁ V ₁ = F ₁ -F ₀ (Formula 2)
It becomes. Here, as shown in FIG. 4B, from the force detector 2 to the body surface together,
MA + BV + KX = F (Formula 3)
It can be expressed as F corresponds to the output value from the force detector 2.

  FIG. 5 is a block diagram of the controller 8. The contact force calculation unit 205 calculates the contact force based on the signal from the displacement detector 6, and the main control unit 202 determines whether or not the contact is made. Based on the signal from the force detector 2, the impedance control unit 203 obtains the displacement and sends it to the displacement / speed control unit 204 of the entire robot arm.

  As the output, the angle and speed of each joint of the robot arm 1 are generated and given to each joint, and the position of the ultrasonic probe 7 installed at the tip of the robot arm 1 is determined. Further, the displacement / speed control unit 204 can perform hybrid control in which the displacement from the force control in the impedance control unit 203 and the displacement from the position / posture control unit 206 are added, and by changing each control parameter, It is also possible to switch between control and position / posture control.

  In addition, the trajectory data can be obtained from the trajectory data unit 207, and can perform a copying operation based on the trajectory data while contacting with a constant value by hybrid control. The operation unit 201 can input an operation command to the main control unit 202.

  The operation of the ultrasonic probe moving and holding configured as described above will be described with reference to FIGS.

  In FIG. 1, the ultrasonic probe 7 can be brought into contact with the body surface 100 by moving the joint of the robot arm 1 according to a command from the controller 8. The robot arm 1 is an articulated robot arm, and the ultrasonic probe 1 can be brought into contact with the body surface of various shapes if the degree of freedom is 6 degrees or more.

Until the ultrasonic probe 7 comes into contact with the body surface 100, the operator holds the operation grip 3 with his hand and moves the tip of the robot arm 1 to a predetermined location. In (Equation 3), force control is applied. Here, skip inertia term, the feedback gain of the speed and displacement and force, respectively, B, K, and the K _f, in the six-axis directions (three translational directions and three rotational directions), the target force F _a Then,
_{B V + KX = -K f (} F - F a) ( Equation 4)
Force control is applied using (Equation 4). At this time, by setting the target force _Fa to zero, the robot arm 1 moves so as to cancel the force when the holder unit 3 is pushed by the operator. That is, the robot arm 1 can be moved with a light force following the operation of the operator. Here, the parameters of the force control refers B, K, K _f, that of F _a.

  Next, a target force in a direction perpendicular to the contact surface of the ultrasonic probe 7 is defined as Fb. The target force Fb is, for example, about 200 gf to 500 gf. The operator holds the operation grip portion 3 and brings the ultrasonic probe 7 into contact with a predetermined body surface 100 as shown in FIGS. 3 (a) to 3 (b).

  At this time, the holder portion 5 slides in the direction of the arrow in FIG. 3B, and the displacement is detected from the displacement detector 6 as shown in FIG. In FIG. 3C, it is determined that the body surface 100 is touched when the displacement y0 corresponding to the force f0 is reached.

  The force f0 is preferably set within 30% of the target force. After determining that the contact has occurred, in Expression (4), the target force in the direction perpendicular to the contact surface of the ultrasonic probe 7 (that is, the direction in which the holder unit 5 slides) is switched to Fb.

As a result, the robot arm 1 moves so as to achieve the target force Fb, and the force is controlled with the target force Fb. Thereby, after the contact with the body surface 100 is detected by the displacement detector 6, force control with the target force Fb to the body surface 100 can be performed using the output signal of the force detector 2. In other words, from the moment of contact with the body surface 100 until the displacement y0, the force control of the reaction force zero of the formula (4) is performed, so that it does not react to a sudden force generated by contact or the like. (No repulsion). When force control is performed with the target force Fb, the output signal of the displacement detector 6 is the displacement y1 corresponding to the target force f1. Here, although the target force switching the value of Fb, may be switching speed and displacement and force feedback gain B, K, the value of K _f.

Next, when the ultrasonic probe 7 is pulled away from the body surface 100, the operator holds the operation grip portion 3 and performs an operation of pulling the ultrasonic probe 7 away in a direction perpendicular to the contact surface. At that time, the robot arm 1 operates so that the force is controlled to the operation grip portion 3 with the target force Fb, that is, moves away from the body surface 100, while the output signal from the displacement detector 6 is the displacement y1. become displaced y0 from, when turned to the displacement y0, it is determined that remote from the body 100, in the formula (4), switch the F _a zero. Thus, the reaction force is zero and the robot arm follows the operation of the operator.

  When changing the location of the ultrasound probe 7 in contact with the body surface 100, if the operator holds the operation grip portion 3 by hand and moves it in a direction not perpendicular to the body surface, the robot arm Can follow the ultrasonic probe 7 while keeping it in contact with the body surface 100. At that time, when a hard object such as a bone hits the ultrasonic probe 7 against the body surface and a sudden force is generated, the force is suppressed by the elastic mechanism 4 to suppress the oscillation and vibration of the robot arm. be able to.

  If the contact resistance is large when the ultrasonic probe 7 is moved, the ultrasonic probe 7 is moved so that the output signal of the displacement detector 6 is between the displacement y1 and the displacement y0. If it is lifted, the ultrasonic probe 7 can be moved by making contact with a force smaller than the force f1 that becomes the contact force. This is less affected by the change in the hardness of the body surface 100 because the contact resistance is reduced.

In addition, body 100 is moved rapidly increases, even if the output signal of the displacement detector 6 exceeds a displacement y2, switch the F _a to zero in equation (4), to force control of the reaction force zero. As a result, the force from the ultrasonic probe 7 to the body surface 100 becomes zero, and the force is separated from the body surface 100.

  Further, in the hybrid control in which the displacement from the force control in the impedance control unit 203 and the displacement from the position / posture control unit 206 are added, each control parameter is changed to switch between the force control and the position / posture control. It is also possible to change the ratio of addition of force control and position / posture control.

  In addition, predetermined trajectory data is acquired from the trajectory data unit 207, and by hybrid control, a copying operation can be performed based on the trajectory data while contacting the body surface 100 with a constant force.

  In addition, even if a sudden force is input to the contact portion with the body surface 100 for some reason, the sudden force is suppressed by the elastic mechanism 4. At this time, when the elastic mechanism 4 includes a damping material, the effect of suppressing a rapid force is increased.

  In addition, the light emitting member 6a installed in the displacement detector 6 does not emit light, for example, less than the displacement y0, emits light in the range from the displacement y0 to the displacement y2, and blinks and emits light above y2, thereby visually observing ultrasonic waves. The contact state of the probe 7 with the body surface 100 can be detected, and safety can be improved.

  According to such an embodiment of the present invention, with this configuration, after detecting the contact of the ultrasonic probe with the body surface by the displacement detector, the target on the body surface of the ultrasonic probe is detected. Switching the control parameter to a constant force reduces the sudden force input to the force detector when contacting the body surface from outside the body surface, or hits an ultrasonic probe on a hard object, etc. In some cases, the elastic mechanism can reduce the rapid input of force to the force detector and suppress the oscillation and vibration of the robot arm.

  As described above, the ultrasonic probe moving and holding according to the present invention is a robot arm provided with an ultrasonic probe that makes contact with the body surface and transmits and receives ultrasonic waves, and a force detector that detects external force. And an ultrasonic probe moving and holding device comprising a controller that controls the force of bringing the ultrasonic probe into contact with the body surface with a constant force, and is installed in the force detector An operation grip unit, an elastic mechanism that connects the operation grip unit and the ultrasonic probe, and a displacement detector that detects a displacement of the elastic mechanism, and force control of the controller by the displacement detector It has a feature of switching the parameters.

  With this configuration, after detecting the contact of the ultrasonic probe with the body surface by the displacement detector, the control parameter is switched to the target constant force on the body surface of the ultrasonic probe, thereby enabling the detection of the extraneous surface. Reduces the input of a sudden force to the force detector when contacting the body surface from the body, or when the ultrasonic probe hits a hard object etc., the sudden force to the force detector by an elastic mechanism This is useful for moving and holding an ultrasound probe that receives an echo signal by irradiating a living body with ultrasonic waves. is there.

Overview of ultrasonic probe movement holding in the embodiment of the present invention FIG. 3 is an external view around the tip of the ultrasonic probe moving and holding according to the embodiment of the present invention. The figure for demonstrating the operation | movement of ultrasonic probe movement holding | maintenance in embodiment of this invention The figure for demonstrating the operation | movement of ultrasonic probe movement holding | maintenance in embodiment of this invention Control block diagram of ultrasonic probe movement holding in the embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot arm 2 Force detector 3 Operation grip part 4 Elastic mechanism 5 Holder part 6 Displacement detector 6a Light emission member 7 Ultrasonic probe 8 Controller 9 Ultrasonic diagnostic apparatus 100 Body surface 201 Operation part 202 Main control part 203 Impedance Control unit 204 Position / velocity control unit 205 of the entire robot arm 205 Contact force calculation unit 206 Position / attitude control unit 207 Trajectory data unit

Claims (7)

An ultrasonic probe that makes contact with the body surface and transmits / receives ultrasonic waves, a robot arm equipped with a force detector that detects external force, and the ultrasonic probe to the body surface with a constant force An ultrasonic probe moving and holding device comprising a controller for controlling a force to be brought into contact with an operation grip portion installed in the force detector, the operation grip portion, and the ultrasonic probe, An ultrasonic probe moving and holding apparatus, wherein a force control parameter of the controller is switched by the displacement detector. . The ultrasonic probe movement holding apparatus according to claim 1, wherein the controller includes an impedance control unit and a position / posture control unit. The ultrasonic probe movement holding apparatus according to claim 2, wherein the control unit retains trajectory data and performs a copying operation based on the trajectory data. The ultrasonic probe moving and holding device according to claim 1, wherein the elastic mechanism includes a replaceable holder portion that holds the ultrasonic probe. The ultrasonic probe moving and holding device according to claim 1, wherein the elastic mechanism is an elastic body including a damping material. The ultrasonic probe movement holding device according to claim 1, wherein the displacement detector includes a light emitting member indicating a displacement range. The ultrasonic probe movement holding apparatus according to claim 1, wherein the robot arm has a parallel link mechanism.

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