Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1997-12-16
2001-04-10
Grant, William (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S087000, C700S259000, C700S260000, C700S263000, C901S003000, C901S009000
Reexamination Certificate
active
06216056
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a force assisting device capable of moving an appliance having a heavy weight through assistance of an actuator by only application of small force by an operator. More particularly, the present invention relates to a method of controlling a force assisting device which is suitable to support a microscope for surgical operation movable by small force and a control apparatus using this device.
2. Related art
A force assisting device is a device for supporting a heavy object so as to be easily movable by an old person or even a common person in a manner of amplifying small force by the operator. For example, in a medical field, a doctor uses a microscope in order to observe an affected part extensively during surgical operation. The microscope, if it is large scaled, is supported by a force assisting device so that it can be moved by small force.
Examples of this force assisting device are to support the microscope by a balancer such as a weight or spring so that it can be moved by small force, and to'support the microscope by a balancer and also shift or rotate the microscope in a prescribed direction by operating a joystic or switch using an electric or hydraulic motor as a power source (e.g. Japanese Patent Publn. 5-3304).
However, the above force assisting device which moves the microscope by the balancer is poor in operability because the weight balance varies according to changes in the position and orientation of the microscope or replacement of the microscope and hence the operation force that an operator needs also varies.
Since balance adjustment is complicated, the maintenance is troublesome. The above force assisting device using the balancer cannot perform a “point lock operation” of moving an environment so as to change the observation perspective of a focal point with the focal point of the microscope being fixed (making the environment movable or rotatable along a prescribed track).
The force assisting device which shifts or rotates the microscope in a prescribed direction by operating a joystic or switch is also poor since the microscope can be shifted or moved only in a prescribed direction. When the microscope is moved by the on/off operation of the joystick or switch, it performs a clumsy operation such as abrupt start or stop so that a sense of a smooth operation cannot be obtained.
SUMMARY OF THE INVENTION
Under the circumstance described above, the present invention intends to provide a method of controlling a force assisting device which is constant in operability regardless of the position and orientation of an object to be supported such as a heavy object, can move or rotate on a prescribed track such as a “point lock” and can move or rotate smoothly using a motor as a power source. The present invention also intends to provide a control apparatus using this method.
According to the present invention, there is provided a control apparatus for controlling a force assisting device comprising:
a plurality of arms coupled so as to be sequentially drivable through joints on a stand;
a plurality of motors for driving said plurality of motors through said joints, respectively;
an appliance to be supported attached to said tip of said plurality of arms coupled with each other;
an operation handle arranged in the vicinity of the appliance and operated by an operator in order to move said appliance;
a force/torque sensor for producing force/torque information in directions of plural-axes from operation force applied to said operation handle;
an impedance control unit and track control unit for computing an operation command for each said joint in said plurality of arms on the basis of said force/torque information detected by said force/torque sensor; and
a motor control unit for controlling said motors so as to drive said plurality of arms through each said joint on the basis of the operation command of each said joint.
As apparent from the explanation hitherto made, the method of controlling the force assisting device according to the present invention detects, by the force/torque sensor, operation force applied to an operation handle arranged in the vicinity of an appliance to be supported, impedance-controls and track-controls the detected force/torque information in directions of plural axes to compute the operation command for each joint of a plurality of arms, and moves the arms in the direction of the operation force on the basis of the operation command. Further, the control apparatus for the force assisting device according to the present invention comprises a plurality of arms rotatably coupled with one another; motors each for driving each of the plurality arms; an appliance to be supported attached to the tip of the plurality of arms; an operation handle arranged in the neighborhood of the appliance; a force/torque sensor for detecting operation force; an impedance control unit and track control unit for computing the operation command for each joint based on the force/torque information; and motor control unit for performing the motor control on the basis of the operation command for each joint. For this reason, where the force/torque information of the operation force is impedance-controlled to compute the operation command for each joint, thereby providing the movement or rotation of the plurality of arms, a natural operation sense inclusive of a sense of inertial force and viscosity can be obtained. Thus, the movement and rotation of the microscope
2
can be effected smoothly.
By subjecting the force/torque information of the operation force to the track control to compute the operation command for each joint, the appliance to be supported can perform the movement or rotation on a prescribed track such as a point lock which is a predetermined operation mode and hence its operability can be improved.
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patent: 5767648 (1998-06-01), Morel et al.
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patent: 5828637 (1998-10-01), Kim
patent: 0 159 131 (1985-10-01), None
patent: 5-3304 (1993-01-01), None
Wang et al, “A Robotized Surgeon Assistant”, vol. 2, Sep. 1994, pp. 862-869 European Search Report.
Hiraguri Masao
Ito Akihiro
Kitahara Yasuyuki
Tsuneta Haruhiro
Grant William
Kabushiki Kaisha Sanyo Seiki Seisakusho
Robinson Victoria
Sughrue Mion Zinn Macpeak & Seas, PLLC
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