JP2007098507A - Work assisting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work assisting device, moving an object with small operating force, and stably returning the object to a preset allowable range even if the object deviates from the allowable range. <P>SOLUTION: This work assisting device 10 includes an articulated arm 11 to which the object 30 is fitted. The torque generated by a motor 36 pulls up a link 12a in the vertical direction through a wire 32, whereby the articulated arm 11 is restrained from rocking in the vertical direction by the gravity. Each joint 14 includes a resistance force applying mechanism 16 for adjustably applying resistance force when the link 12 rocks. A controller 22 reduces the resistance force applied to each joint by the resistance force applying mechanism 16 when the object is within the allowable range 50. The resistance force is increased when the object is outside of the allowable range 50. The resistance force adjusts the difficulty of moving the articulated arm 11, so that even if the resistance force applied to each joint is increased, the object can be prevented from moving in the opposite direction to the direction of operating force. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus that includes a multi-joint arm for attaching an object and assists an operator in moving the object using the multi-joint arm.

An articulated arm for attaching an object such as a work or a work implement is provided, and an apparatus for assisting an operator to move the object using the articulated arm is known.
One type of work assisting device includes a gravity compensation mechanism that compensates for gravity acting on the object and the articulated arm and suppresses the articulated arm from swinging in the vertical direction due to gravity. When an articulated arm equipped with a gravity compensation mechanism is used, the operator does not need a force to support gravity acting on the object. Even if the object is actually a heavy object, the operator can move the object with a light operating force.
Another type of work assistance device utilizes an articulated arm that can only swing in a horizontal plane. When an articulated arm that can swing only in a horizontal plane is used, the gravity acting on the object and the articulated arm is supported by a mechanism that maintains the articulated arm in the horizontal plane. The worker does not need the force to support the gravity acting on the object. Even if the object is actually a heavy object, the operator can move the object in a horizontal plane with a light operating force.
There has also been proposed a work assistance device that arranges an actuator such as a motor at the joint of a multi-joint arm to reduce the operating force, and is disclosed in Patent Document 1, for example. In the technique of Patent Document 1, a model that describes the equation of motion of a virtual object having a mass lighter than the mass of the object is built in the control device of the work assistance device. Then, an operation force applied to the operator is detected by the operator, and the motion generated when the detected operation force is applied to the virtual object by substituting the detected operation force into the motion equation is calculated. The actuator arranged at each joint of the multi-joint arm is controlled so that the calculated motion is realized at the position of the object. In the technique of Patent Document 1, so-called impedance control is performed in which the multi-joint arm is controlled so that the object realizes the movement when the operator's operating force is applied to the virtual object.

JP 2005-14133 A

In the case of a work assistance device using a multi-joint arm, there are cases where it is desired to constrain the range where the object exists. For example, when using a work auxiliary device to move a relatively heavy adhesive applicator, it is required to move the applicator along the adhesive application line formed on the workpiece. In some cases, it is desired to restrain the applicator from moving to a position far away from the line. Alternatively, when there is another object adjacent to the work space, there is a case where it is desired to constrain the target object to remain in the work space so that the target object does not interfere with the other object.
In the technique of Patent Document 1, an allowable range in which an object is allowed to exist and a non-allowable range in which the object is not allowed to be present outside the object are provided. While the object is within the allowable range, the values of the parameters (such as the mass of the virtual object, the viscosity coefficient, and the spring coefficient) of the equation of motion of the virtual object are set to be small so that the virtual object moves with a small operating force. The actuator of the articulated arm is controlled to move the object greatly by a small operation force applied by the operator. When the object is out of the allowable range, the parameter value in the equation of motion of the virtual object is set to a large value. Specifically, a spring constant that moves the object to the allowable range in proportion to the distance from the position of the object to the allowable range is set as a parameter in the equation of motion of the virtual object. When the position of the virtual object is calculated using this equation of motion, the position of the virtual object is closer to the allowable range than the previous position. The articulated arm controls the actuator of the articulated arm so that the position of the virtual object is realized by the object. When the operator applies an operating force in a direction that is outside the allowable range, the object moves in a direction opposite to the direction of the operating force. As a result, the position of the object is prevented from greatly deviating from the allowable range.

According to the technique of Patent Document 1, when the object is out of the allowable range, the object moves in the direction opposite to the direction in which the operator applies the operation force. Although it is necessary to prevent the object from greatly deviating from the allowable range, the movement of the object in the direction opposite to the direction in which the operator applied the operation force is unnatural. I feel a strong sense of incongruity.
In the technique of Patent Document 1, when the object is out of the allowable range, an elastic term corresponding to the distance between the moving range and the object is set in the motion equation of the virtual object. Due to the action of the elastic term in the equation of motion, the actuator operates the articulated arm so as to move the object outside the allowable range in the direction of the allowable range.
In impedance control (compliance control), if the viscosity coefficient, friction coefficient, and elasticity coefficient in the equation of motion of the virtual object are not set appropriately, the force generated by the actuator at the part of the multi-joint arm where the operator applies operating force There is a possibility that a so-called vibration phenomenon that the part vibrates due to a subtle difference between the operation force and the operation force. In this case as well, as in the technique of Patent Document 1, the object moves in the direction opposite to the direction in which the operator applies the operating force. Such movement of the object is unnatural and the worker feels a strong sense of incongruity.
This invention implement | achieves the technique which restrains so that an operator may not feel a strong sense of incongruity in preventing that a target object remove | deviates greatly from an allowable range.

In the present invention, a gravity compensation mechanism that suppresses the swing of the articulated arm in the vertical direction due to gravity is employed, or the movable range of the articulated arm is constrained within a horizontal plane, thereby A mechanism in which the articulated arm does not swing depending on the gravity acting on the arm is used. That is, a mechanism is used in which the swing around the joint of the multi-joint arm is not affected by gravity, and the swing around the joint is caused by the operation force applied by the operator.
In the present invention, a resistance force applying mechanism that applies a physical resistance force to the swing around the joint caused by the operation force applied by the operator is used. In the present invention, when the object is out of the allowable range, the resistance applying mechanism is operated to make it difficult for the articulated arm to physically swing compared to when the object is located within the allowable range.

  In the present invention, in order to suppress the object from greatly deviating from the allowable range, the articulated arm is physically moved rather than the actuator operating the articulated arm to actively control the position of the object. Taking advantage of the fact that making it harder to swing is more natural. If it is a system that makes it difficult to physically swing, the movement of the object in the direction opposite to the direction in which the operator applied the operation force does not occur, and the worker does not feel a strong sense of incongruity. If the object is out of the tolerance range and the articulated arm is more difficult to physically swing than when the object is located within the tolerance range, the operator moves the object further away from the tolerance range. It becomes difficult to let you. While the worker can move the object freely as if it is released from gravity within the allowable range, if the object is out of the allowable range, the worker can move the object within the allowable range. However, by making it difficult for the articulated arm to physically swing, the object can be moved freely within the allowable range, and the object can be prevented from greatly deviating from the allowable range.

  One work auxiliary device of the present invention has a multi-joint arm having two or more joints and capable of attaching an object to the tip, and compensates for the gravity acting on the object and the multi-joint arm, and multi-joint by gravity. A gravity compensation mechanism that suppresses swinging of the arm in the vertical direction, a resistance applying mechanism that can apply resistance to the swinging around the joint caused by the operating force, and that can increase or decrease the applied resistance, and a target A position detection device for detecting the position of the object, an allowable range storage device for storing a range in which the object is allowed to be located, and a position of the object detected by the position detection device are stored in the allowable range storage device. A first controller that controls the resistance applying mechanism so as to increase the resistance applied by the resistance applying mechanism when the allowable range is exceeded.

The gravity compensation mechanism may be a mechanism that balances with a counterweight having the same mass as the mass of the object and the articulated arm. Alternatively, a mechanism that balances the torque caused by the gravity acting on the object and the articulated arm by air pressure or motor power may be used. The gravity compensation mechanism may act on a part of the articulated arm. For example, the articulated arm has a first link that can swing in the vertical direction, and a second link that is connected to the tip of the first link so as to swing in a horizontal plane. When an object is attached to the tip of the link, the gravity compensation mechanism only needs to act on the first link. If the gravity compensation mechanism acts on the first link, the articulated arm can be prevented from swinging in the vertical direction due to gravity.
The resistance applying mechanism is not particularly limited as long as it provides resistance to rocking around the joint. For example, viscosity or frictional force may be used.

When using this work assistance device, the object is attached to the articulated arm. The operator applies operating force to a part of the articulated arm. The operation force may be applied to a part of the articulated arm by applying the operation force to the object attached to the articulated arm.
Since this work assisting device includes a gravity compensation mechanism, the worker is not required to support the gravity acting on the object and the articulated arm. Unless an operating force is applied, the articulated arm does not swing in the vertical direction, and the position of the object is maintained. The operator can move the object by applying a small operating force.
When the object moves outside the allowable range, a strong resistance force acts on the joint of the multi-joint arm by the resistance force applying mechanism and the first control device. The operator is less likely to move the object than when the object is within the allowable range. The object becomes difficult to move with the operation force that the operator has applied so far. It is possible to make it difficult to move the object in the direction in which the object is out of the allowable range. Further, the worker who has received a large resistance recognizes that the object is operating outside the allowable range, and performs an operation that naturally reduces the operating force. Together, it is possible to prevent the object from greatly deviating from the allowable range.
In the above apparatus, a resistance applying mechanism that applies a resistance that can adjust the ease of swinging or the difficulty of swinging of the multi-joint arm is used. The resistance force imparting mechanism does not generate force actively like an actuator, but a mechanism that dissipates the kinetic energy of an object with respect to the movement of the object, such as physical viscous resistance force or frictional resistance force. Use. Accordingly, the resistance applying mechanism corresponds to, for example, a viscous damper that can adjust the physical viscous resistance of the joint. Adjusting the physical resistance of the joint (that is, adjusting the degree to which the kinetic energy is dissipated when the multi-joint arm swings) can make the multi-joint arm easy to swing or difficult to swing. it can. The resistance force imparting mechanism dissipates the kinetic energy when the articulated arm swings, so the direction in which the operator applies operating force even if the resistance force is increased when the object is out of the allowable range. An unnatural movement in which the object moves in the opposite direction does not occur. The worker does not feel a strong sense of incongruity.

  When the object only needs to be moved in the horizontal direction, the following work assisting device can be used. This work assisting device has two or more joints that swing in a horizontal plane and can provide resistance to swinging around the joint caused by the operation force, and a multi-joint arm that can attach an object to the tip. A resistance force applying mechanism capable of increasing / decreasing the resistance force to be applied, a position detecting device for detecting the position of the object, an allowable range storage device for storing a range in which the object is allowed to be positioned, and position detection A first control that controls the resistance applying mechanism to increase the resistance applied by the resistance applying mechanism when the position of the object detected by the apparatus deviates from the allowable range stored in the allowable range storage device. Equipment.

If a multi-joint arm that swings only in a horizontal plane is used, the multi-joint arm itself incorporates a gravity compensation mechanism that suppresses the swing of the multi-joint arm in the vertical direction due to gravity. It is not necessary to prepare a gravity compensation mechanism separately from the articulated arm. The operator is not required to support the gravity acting on the object and the articulated arm. The operator can move the object freely in a horizontal plane by applying a small operating force.
Even in this work auxiliary device, when the object moves out of the allowable range, a strong resistance force acts on the joint when the multi-joint arm swings by the resistance force applying mechanism and the first control device. The operator is less likely to move the object than when the object is within the allowable range. The object becomes difficult to move with the operating force that the operator has applied so far. It is possible to make it difficult to move the object in the direction in which the object is out of the allowable range. Also, the worker who has received a large resistance recognizes that the object is operating outside the allowable range, and naturally performs an operation that weakens the operating force. Together, it is possible to prevent the object from greatly deviating from the allowable range.
In the above configuration, a resistance force applying mechanism that physically imparts the ease of swinging or the difficulty of swinging of the articulated arm is used. The resistance force imparting mechanism dissipates the kinetic energy when the articulated arm swings, so the direction in which the operator applies operating force even if the resistance force is increased when the object is out of the allowable range. An unnatural movement in which the object moves in the opposite direction does not occur. The worker does not feel a strong sense of incongruity.

  The first control device preferably increases the resistance force applied by the resistance force applying mechanism as the distance from the position of the object to the allowable range becomes longer. In this case, the longer the distance from the position of the object to the allowable range, the more difficult it is to move the object, so that the object can be prevented from greatly deviating from the allowable range.

Moreover, it is preferable that a 1st control apparatus increases the resistance force which a resistance-force provision mechanism provides, so that the speed which the position of a target object leaves | separates from an allowable range is large.
The greater the speed at which the position of the object moves away from the allowable range, the more difficult the object moves, so that the object can be prevented from greatly deviating from the allowable range.

The work assist device includes a movement direction detection device that detects the movement direction of the object, and a resistance applying mechanism when the movement direction of the object detected by the movement direction detection device approaches a permissible range. It is preferable to further include a second control device that reduces the resistance force to be applied from the resistance force adjusted by the first control device.
According to the above configuration, when the moving direction of the object is close to the allowable range, even if the position of the object is outside the allowable range, the resistance applied by the resistance applying mechanism to the joint of the multi-joint arm Controlled to reduce force. Therefore, even if the object is out of the allowable range, the object can be moved with a small operating force in the direction to return to the allowable range. An object outside the allowable range can be returned to the allowable range with a small operating force.

  The resistance force applying mechanism may be any one of a variable viscosity damper, an ER fluid damper, an MR fluid damper, and a magnetic fluid damper. Further, any one of a friction brake, a powder brake, a hysteresis brake, an ER fluid brake, an MR fluid brake, and a magnetic fluid brake with adjustable frictional resistance may be used. These dampers and brakes do not generate an active force. In either case, the difficulty of rocking the joint is adjusted by dissipating kinetic energy when the multi-joint arm rocks. Since the actuator does not apply an active torque to the joint, an unnatural movement in which the object moves in the direction opposite to the direction in which the operator applies the operating force does not occur. In addition, the damper and the brake do not apply active torque to the joint, and therefore have high safety during malfunction.

According to the present invention, the operator does not need an operation for supporting the gravity acting on the object. As long as the object is within the allowable range, the heavy object can be easily moved with a light operating force. When the operator performs an operation of moving the object in a direction outside the allowable range, a strong resistance acts on the operation of swinging the articulated arm. When the object is out of the allowable range, it is difficult for the operator to move the object. Furthermore, the operator can recognize that the object has fallen out of the allowable range by receiving a strong resistance, and can naturally stop the operation. Together, it is possible to prevent the object from greatly deviating from the allowable range.
According to the work assistance device of the present invention, an operator can freely move an object as if it is released from gravity within an allowable range, but if the position of the object is out of the allowable range, the worker can move the object. Receives strong resistance. It is possible to prevent the object from greatly deviating from the allowable range and move the object freely within the allowable range.
According to the work assistance device of the present invention, when the object is out of the allowable range, the object does not move in the direction opposite to the direction of the operation force applied by the operator. There is no unnatural movement in which the object moves in the direction opposite to the direction in which the operator applies the operating force. The worker does not feel a strong sense of incongruity.

The main features of the examples are listed.
(First Form) The work assist device has an operation force direction detection device that detects the direction of the operation force applied by the worker, and the control device of the resistance force applying mechanism has a direction in which the direction of the operation force approaches the allowable range. In this case, control is performed so as to weaken the resistance force applied to the joint of the multi-joint arm even if the position of the object is outside the allowable range.
(2nd form) The operating force direction detection apparatus is implement | achieved by the force sensor attached to the operation element which is provided in the multi-joint arm and the operator operates.
(Third Embodiment) The operating force direction detection device is realized by a joystick type operator that is provided on the articulated arm and is operated by an operator.

FIG. 1 is a schematic view of a work assistance device 10 according to an embodiment of the present invention. The work assisting device 10 is a device that assists the work of applying the adhesive along the coating line L set around the windshield W using the coating tool 30. The windshield W is supported by the work support device 24. The application line L on which the adhesive set around the windshield W is to be applied is hereinafter referred to as a target trajectory L of the application tool 30.
The work assisting device 10 includes a multi-joint arm 11 that supports an applicator 30 that is a target, and a controller 22 that controls the multi-joint arm 11.

The base 13 of the articulated arm 11 is fixed to the floor. The base 13 includes a vertical pole 13b fixed in the vertical direction. The multi-joint arm 11 includes links 12a, 12b, and 12c. A link 12a is connected to the vertical pole 13b by a joint 14a. The joint 14a supports the link 12a so that the link 12a swings in a horizontal plane. The link 12b is connected to the link 12a by a joint 14b. The joint 14b supports the link 12b so that the link 12b swings in a horizontal plane. The link 12c is connected to the link 12b by a joint 14c. The joint 14c supports the link 12c so that the link 12c swings in a horizontal plane.
The joint 14a can also swing in the vertical direction along the vertical pole 13b. That is, the joint 14a is a joint having two degrees of freedom of rotation in a horizontal plane and linear movement in the vertical direction. Accordingly, the heights of the horizontal surfaces of the links 12a, 12b, and 12c are variable.
The links 12b and 12c can swing only in a horizontal plane. The link 12a can swing in the rotational direction within a horizontal plane. Therefore, unless the link 12a swings in the vertical direction along the vertical pole 13, the links 12b, 12c do not swing in the vertical direction due to gravity acting on the links 12a, 12b, 12c and the object 30.

A motor 36 is fixed to the base 13 of the articulated arm 11. A winding wheel 34 is fixed to the rotation shaft C of the motor 36. The vicinity of one end of the wire 32 is wound around the winding wheel 34. A pulley 26 is disposed at the upper end of the vertical pole 13b. The vicinity of the other end of the wire 32 is hooked on the pulley 26 and then fixed to the link 12a. The wire 32 pulls the link 12a upward. The motor 36 is added to the link 12a via the wire 32 by adding the gravity applied to the mass from the link 12a to the tip of the articulated arm 11 and the gravity applied to the mass of the applicator 30 attached to the link 12c. It is controlled so as to generate torque that applies equal force. That is, the force by which the link 12a of the articulated arm 11 is lowered by gravity is equal to the force by which the wire 32 pulls the link 12a upward. The links 12 a, 12 b, 12 c and the applicator 30 are subjected to a force that is lowered by gravity and a force that is to be pulled up by the motor 36. Both are balanced, and unless the operator applies operating force, the links 12a, 12b, 12c and the applicator 30 are neither lowered nor raised. That is, the motor 36, the wire 32, and the like constitute a gravity compensation mechanism that compensates for the gravity acting on the links 12a, 12b, 12c and the applicator device 30, and the multi-joint arm 11 is caused by gravity by the gravity compensation mechanism. Oscillating in the vertical direction is suppressed. Since the links 12b and 12c can swing only in a horizontal plane, the gravity compensation mechanism does not need to act directly on the links 12b and 12c.
Here, when a vertical downward operating force is applied to the applicator 30, the torque generated by the motor 36 is transmitted from the link 12 a including the applicator 30 through the wire 32 to the mass (“from the link 12 a including the applicator 30). The force that pulls the “prior mass” in the following is referred to as the mass of the applicator 30 or the like) is relatively smaller than the resultant force of gravity and operating force (the force that the motor 36 pulls the wire 32 and the applicator 30). The balance between the gravity applied to the mass and the resultant force of the operation force is lost). When the force with which the motor 36 pulls the wire 32 is relatively smaller than the resultant force, the motor 36 is rotated in the direction opposite to the direction of the generated torque. The wire wound around the winding wheel 34 by the amount that the motor 36 is rotated in the direction opposite to the direction of torque is released from the winding wheel 34. As a result, the applicator 30 moves in the direction of the operating force, that is, vertically downward. Conversely, when a vertical upward operating force is applied to the applicator 30, the torque generated by the motor 36 pulls the mass of the applicator 30 etc. vertically upward via the wire 32, relative to the resultant force of gravity and operating force. (The balance between the force by which the motor 36 pulls the wire 32 and the resultant force of the gravity applied to the applicator 30 and the operation force is lost). When the force with which the motor 36 pulls the wire 32 is relatively larger than the resultant force, the motor 36 rotates the winding wheel 34 in the torque direction by the generated torque. The wire 32 is wound around the winding wheel 34. As a result, the applicator 30 moves in the direction of the operating force, that is, vertically upward.
The operation force when moving the applicator 30 in the vertical direction does not include a force that supports gravity acting on the applicator 30 or the like. The applicator 30 can be moved in the vertical direction with a small operating force.

The joint 14b is a joint that rotates the link 12b in the horizontal direction. Similarly, the joint 14c is a joint that rotates the link 12c in the horizontal direction. When the operator applies a horizontal operation force to the applicator 30, the applicator 30 moves in the horizontal direction. The vertical position of the applicator 30 does not change.
The multi-joint arm 11 can move the applicator 30 both in the vertical direction and in the horizontal direction according to the operating force applied by the operator. At this time, the motor 36 compensates the gravity applied to the mass of the applicator 30 and the like. The operator is not required to have a force that supports the weight of the applicator 30. An operator can move the applicator 30 both vertically and horizontally with a light operating force.

  Position sensors 15a, 15b, and 15c are provided in the joints 14a, 14b, and 14c of the multi-joint arm 11, respectively. The position sensor group 15 is an encoder or the like. The position sensor 15a attached to the joint 14a having two degrees of freedom of rotation and linear motion detects the rotation angle of the link 12a with respect to the vertical pole 13b and the position of the link 12a with respect to the vertical pole 13b in the vertical direction. From the value output from the position sensor group 15 and the dimension data of the link group 12 of the articulated arm 11, the coordinates of the position P of the applicator 30 in the absolute coordinate system can be obtained by geometric calculation. Hereinafter, when collectively referring to a position sensor group, a joint group, and the like, description will be made by omitting the suffixes a, b and c.

  Each of the joints 14a, 14b, and 14c is provided with variable dampers 16a, 16b, and 16c that impart resistance to the rocking of the joints. By adjusting the resistance force that the variable damper group 16 applies to each of the joint groups 14, it is easy or difficult for the operator to move the applicator 30 supported on the tip of the link. Can be adjusted. In the work assistance device 10 of the present embodiment, the gravity applied to the mass of the applicator 30 or the like is compensated by the multi-joint arm 11, so that the operator can operate with a small operating force without requiring a force to support the weight of the applicator 30. The applicator 30 can be moved. On the other hand, by adjusting the resistance force applied to each joint 14 by the variable damper group 16, the ease of movement or the difficulty of movement when the operator moves the applicator 30 is adjusted. Can do.

Next, the outline | summary is demonstrated about operation | movement of the work assistance apparatus 10 of a present Example.
The controller 22 is set with data indicating an allowable range 50 in which the applicator 30 is allowed to be located. The allowable range 50 is set to a range that includes the target trajectory L. On both sides of the allowable range 50, movement restriction ranges 52L and 52R are set. The movement restriction ranges 52L and 52R are ranges where it is desired to prevent the applicator 30 from entering the range as much as possible. In FIG. 1, the movement restriction ranges 52L and 52R are drawn as surfaces along the surface of the windshield W, but are actually set like walls extending in the vertical direction.
The operator can freely move the applicator 30 along the target trajectory L within the allowable range 50. When the position of the applicator 30 is within the allowable range 50, the controller 22 sets the value of the resistance force that the variable damper group 16 applies to the joint group 14 to be small. Thereby, the operator can move the applicator 30 with a small force.
On the other hand, when the applicator 30 is out of the allowable range 50 (that is, when the position of the applicator 30 is in the movement restriction range 52L or 52R), the controller 22 gives the variable damper group 16 to the joint group 14. Set a large resistance value. This makes it difficult for the operator to move the applicator 30 when the applicator 30 is out of the allowable range 50. Accordingly, it is possible to prevent the applicator 30 from greatly deviating from the allowable range.

Next, the work assistance apparatus 10 will be described with reference to the block diagram of FIG.
An applicator 30 is attached to the tip of the articulated arm 11. The articulated arm 11 has a position sensor group 15 and a variable damper group 16. In FIG. 2, the link group 12 of the articulated arm 11 is not shown.
The controller 22 includes a position / speed calculation unit 40 to which an output value of the position sensor group 15 is input, a damper control unit 42, and an allowable range data storage unit 44.
The allowable range data storage unit 44 stores data on the positional relationship between the allowable range 50 shown in FIG. 1 and the movement limit ranges 52L and 52R.
In the position / velocity calculation unit 40, first, based on the rotation angle of each joint 14 (and the vertical position of the link 12a with respect to the vertical pole 13b) sent from the position sensor group 15 and the geometric structure of the link of the multi-joint arm 11. The position of the applicator 30 is calculated. Next, the speed of the applicator 30 is calculated from the change over time of the position of the applicator 30.
The calculated position and speed of the applicator 30 are sent to the damper controller 42. The damper control unit 42 determines whether the current position of the applicator 30 is within the allowable range 50 with reference to the data stored in the allowable range data storage unit 44. When the position of the applicator 30 is within the allowable range 50, a command value is output to the variable damper group 16 so that the resistance force applied to each joint 14 is reduced. On the other hand, when the position of the applicator 30 is outside the allowable range 50, a command value is output to the variable damper group 16 so that the resistance force applied to each joint 14 is increased. At this time, the damper control unit 42 outputs a command value to the variable damper group 16 such that the resistance force applied to each joint 14 increases as the distance between the applicator 30 and the allowable range 50 increases. Note that when the direction of the moving speed of the applicator 30 is in the allowable range 50, the variable damper control unit 42 has the resistance of each joint 14 even if the applicator 30 is outside the allowable range 50. A command value is output to the variable damper group 16 so as to decrease.

Next, the above processing in the controller 22 will be described with reference to the flowchart of FIG.
First, in step S300, the position and speed of the applicator 30 are acquired. Next, in step S302, it is determined whether or not the position of the applicator 30 is outside the allowable range 50.
When it is determined that the position of the applicator 30 is out of the allowable range 50 (step S302: YES), the moving direction of the applicator 30 (that is, the speed direction of the applicator 30) is changed from the allowable range 50 in step S304. It is determined whether the direction is away. When the moving direction of the applicator 30 is a direction away from the allowable range 50 (step S304: YES), a resistance force FA to the applicator 30 is set in step S306. The resistance force FA will be described later with reference to FIG.
Next, in step S308, the resistance force FA set in step S306 is converted into a resistance force that each variable damper 16 should generate. Then, the resistance force converted in step S310 is output to each variable damper 16 as a command value.
On the other hand, when it is determined in step S302 that the position of the applicator 30 is within the allowable range 50 (step S302: NO), or in step S304, it is determined that the moving direction of the applicator 30 is not a direction away from the allowable range 50. In the case (step S304: NO), the process proceeds to step S312 to set the resistance force FB for the applicator 30. The set resistance force FB is converted into a resistance force to be generated by each variable damper 16 in step S308. The resistance force converted in step S310 is output as a command value to each variable damper 16. The above processing is repeated every control cycle.
In addition, the resistance force FA with respect to the applicator 30 set in step S306 is set to a value larger than the resistance force FB set in step S312.
3 is performed by the position sensor group 15 (see FIG. 1) and the position / velocity calculation unit (see FIG. 2) in the controller 22. Processing other than step S300 in FIG. 3 is executed by the damper control unit 42 shown in FIG.

Next, the resistance force to the applicator 30 when the applicator 30 is outside the allowable range 50 will be described with reference to FIG. In FIG. 4, the moving direction of the applicator is limited to two dimensions on the paper surface in order to simplify the explanation. In addition, the x-axis and y-axis directions were set as shown in FIG. 4 as an absolute coordinate system. In FIG. 4, the allowable range 50 of the position of the applicator 30 is set along the target trajectory L including the target trajectory L, and movement restriction ranges 52 </ b> L and 52 </ b> R are set on both sides of the allowable range 50. The direction of the target trajectory L is parallel to the x-axis in FIG. The boundaries between the movement restriction ranges 52L and 52R and the allowable range 50 are also parallel to the x axis.
In FIG. 4, the position of the applicator 30 is represented by a point P. In the state of FIG. 4, the position P of the applicator 30 is at a position deviated from the allowable range 50 by the distance dPy.
In addition, the operation force applied to the applicator 30 by the operator is indicated by FI. In FIG. 4, the position of the applicator 30 to which the operating force FI is applied is indicated by a point S. When the operating force FI is applied to the applicator 30, the joint group 14 of the multi-joint arm 11 swings according to the operating force FI. As a result, the applicator 30 moves in the direction of VP, which is the same direction as the operating force FI. The arrow VP also represents the moving speed of the applicator 30. VPy represents a speed component in the y-axis direction of the speed VP of the applicator 30. Therefore, the state of FIG. 4 shows a state where the applicator 30 moves away from the allowable range 50 by the velocity component VPy.

The operation of the work auxiliary device 10 in the state of FIG. 4 will be described in comparison with the flowchart of FIG. In FIG. 4, the position P of the applicator 30 is at a position deviated by dPy from the allowable range. Therefore, the determination in step S302 in FIG. The applicator 30 moves in a direction away from the allowable range 50 by the velocity component VPy. Accordingly, the determination in step S304 in FIG. 3 is also YES. Therefore, next, the resistance FA with respect to the applicator 30 is set in step S306 of FIG. The resistance force FA is set by the following first formula.
FA = − (a1 × dPy + a2 × VPy + Fc) (1)
Here, a1 and a2 are coefficients having a predetermined positive value. Fc is a constant having a predetermined positive value. The entire right side is enclosed in parentheses and is given a minus sign. When the moving direction of the position P of the applicator 30 is positive, the resistance FA is the moving direction of the position P of the applicator 30. This is because it acts in the opposite direction.
The first term on the right side of the first equation represents a resistance component having a magnitude proportional to the distance dPy from the position P of the applicator 30 to the allowable range 50. The second term represents a resistance component having a magnitude proportional to the velocity component VPy in the direction in which the applicator 30 moves away from the allowable range 50. Therefore, as the distance between the applicator 30 and the allowable range 50 increases, the resistance force FA with respect to the operating force FI applied to the applicator 30 becomes a larger value. Similarly, the resistance force FA with respect to the operating force FI applied to the applicator 30 increases as the speed component in the direction in which the applicator 30 moves away from the allowable range 50 increases.
In the present embodiment, the variable damper group 16 is controlled so that the set resistance force FA is generated at the position S where the operator operates the applicator 30. Thereby, the operator can make it difficult to move the applicator 30 when the applicator 30 is out of the allowable range 50.
When the magnitude of the resistance force FA and the position to be generated are determined, each variable damper 16 is applied to each joint 14 in order to realize the resistance force FA at the position S where the operator operates the applicator 30 in step S308 of FIG. It is converted into the magnitude of resistance to be applied. This conversion is performed by converting a force generated at a predetermined position (position S in FIG. 4) of the well-known articulated arm 11 and a force generated by each joint (corresponding to a resistance force in this embodiment). It can be calculated by an equation. In step S310, a command value to each variable damper 16 is output using the converted resistance force as a command value. As a result, as shown in FIG. 4, a resistance force FA is realized that is directed in a direction opposite to the operation force FI at the position S where the operator operates the applicator 30.
The resistance force FA is realized by applying a physical viscous resistance force or frictional resistance force to each joint 14 by the variable damper group 16 more strongly than when the applicator 30 is located within the allowable range 50. The physical viscous resistance and frictional resistance applied to each joint 14 dissipate the kinetic energy of the multi-joint arm 11, and thus do not become a force that actively moves the applicator 30 as a reaction force in impedance control. . For the same reason, the resistance force FA does not exceed the operation force FI. Therefore, the operator can stably operate the applicator 30 without causing a vibration phenomenon due to the difference between the reaction force and the operation force that may occur during impedance control. Further, the phenomenon that the applicator 30 moves in the direction opposite to the operating force does not occur. Further, since the variable damper group 16 applies physical viscous resistance force and frictional resistance force to each joint 14, the multi-joint arm 11 generates an unexpected force even if a malfunction occurs in the variable damper 16 or the controller 22. There is nothing to do. The work assistance device 10 with higher safety can be realized.

Next, the resistance force generated by the work assisting device 10 with respect to the applicator 30 in another state will be described with reference to FIG. 5, the same reference numerals as those in FIG. 4 denote the same components. In the state of FIG. 5, the position P of the applicator 30 is the same as that in FIG. 4, but the direction of the operating force FI applied to the applicator 30 is different from that in FIG. 4. In FIG. 5, the operating force FI <b> 2 faces the allowable range 50. Therefore, the speed VP2 at the position P of the applicator 30 has a speed component VPy2 in a direction approaching the allowable range 50 by the operating force FI2. In this case, even if the position P of the applicator 30 is outside the allowable range 50, the determination in step S304 in FIG. Therefore, next, the resistance FB with respect to the applicator 30 is set in step S312 of FIG. The resistance force FB is set by the following second equation.
FB = −Fc (2)
Here, Fc is the same constant as Fc used in the first equation. That is, the resistance force FB set in step S312 of FIG. 3 is always set smaller than the resistance force FA set in step S306. Note that the minus sign is attached to the right side in the same way as in the first formula, when the moving direction of the position P of the applicator 30 is positive, the resistance force FA is equal to the position P of the applicator 30. This is because it acts in the direction opposite to the moving direction of.
The resistance force FB set in step S312 is the magnitude of the resistance force that each variable damper 16 should apply to each joint 14 in order to realize the resistance force FB in step S308 of FIG. Is converted to In step S310, a command value to each variable damper 16 is output using the converted resistance force as a command value. As a result, as shown in FIG. 5, a resistance force FB that faces the direction opposite to the operation force FI <b> 2 at the position S of the operation element 18 is realized. Since the resistance force FB is smaller than the resistance force FA, the operator can move the applicator 30 in the direction of the allowable range 50 with a smaller operation force against the FA.

  When the position P of the applicator 30 is within the allowable range, the determination in step S302 shown in FIG. 3 is NO and step S312 is executed. Therefore, even when the position P of the applicator 30 is within the allowable range, the resistance force FB with respect to the applicator 30 has the same value as the second formula. The resistance force FB (= Fc) is set to a small value in advance, and the operator can move the applicator 30 with a small operation force.

As described above, when the operator moves the applicator 30 along the target trajectory L, when the position P of the applicator 30 deviates from the allowable range 50, the operator places the position P of the applicator 30 within the allowable range 50. Will receive greater resistance. Therefore, the work assisting device 10 can prevent the worker from greatly removing the applicator 30 from the allowable range 50.
At this time, since the resistance force FA is generated by physical characteristics such as viscosity and frictional resistance applied to each joint 14, the applicator 30 is actively moved like a reaction force in impedance control. It doesn't help. Accordingly, the operator can stably operate the applicator 30 without causing a vibration phenomenon due to the difference between the reaction force that may occur during impedance control and the operation force. Further, the phenomenon that the applicator 30 moves in the direction opposite to the operating force does not occur. Even when the position of the applicator 30 is out of the allowable range 50, the operator can stably move the object within the allowable range 50 without causing the vibration phenomenon due to the impedance control described above.
Further, the process of the flowchart shown in FIG. 3 is executed for each control cycle. Therefore, when the operator recognizes that the position P of the applicator 30 is out of the allowable range as shown in FIG. 4, the operating force FI2 is directed toward the allowable range 50 as shown in FIG. The resistance force to FI2 can be set to a resistance force FB smaller than the resistance force FA in the state shown in FIG. Accordingly, the object can be moved within the allowable range 50 with a small operating force that resists the small resistance force FB.

4 and 5 are limited to two dimensions, the same applies even if the direction in which the applicator 30 moves is expanded to three dimensions. The applicator 30 is attached to the articulated arm 11 by being balanced with respect to gravity by the motor 36 shown in FIG. Therefore, the same operation as that described with reference to FIGS. 4 and 5 can be obtained for the movement in the vertical direction.
More specifically, an ER fluid damper or an MR fluid damper can be used as the variable damper group 16 of the above embodiment. Alternatively, a friction brake may be used. One type of friction brake is a powder brake.

In the embodiment described above, the motor 36, the winding wheel 34, the wire 32, the pulley 26, the joint group 14, and the link group 12 shown in FIG. . Therefore, the motor 36, the winding wheel 34, the wire 32, the pulley 26, the joint group 14, and the link group 12 shown in FIG. 1 correspond to one aspect of the “gravity compensation mechanism” in the claims. That is, the “gravity compensation mechanism” of the present embodiment is configured to share a part of the articulated arm 11. Further, the damper control unit 42 (see FIG. 2) when executing step S306 in the flowchart of FIG. 3 corresponds to one aspect of the “first control device” in the claims. Further, the determination in step S304 in the flowchart of FIG. 3 is NO, and the damper control unit 42 when executing step S312 corresponds to one aspect of the “second control device” in the claims. Further, the position sensor group 15 shown in FIG. 2 and the position / velocity calculation unit 40 for calculating the position of the applicator 30 correspond to one aspect of the “position detection device” in the claims. The permissible range data storage unit 44 shown in FIG. 2 corresponds to an aspect of the “permissible range storage device” in the claims. Further, the variable damper group 16 shown in FIG. 2 corresponds to one aspect of the “resistance force applying mechanism” in the claims. The position sensor group 15 shown in FIG. 2 and the position / velocity calculating unit 40 for calculating the moving speed of the applicator 30 (that is, the moving direction of the applicator 30) are one of the “moving direction detection devices” in the claims. Corresponds to the embodiment.
Note that the position / velocity calculation unit 40 and the damper control unit 42 in the controller 22 shown in FIG. 2 may be realized as independent devices or as programs processed by a computer.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

For example, when the applicator 30 only needs to be moved in a horizontal plane, the joint 14a of the multi-joint arm 11 in FIG. 1 is not directly oscillated in the direction along the vertical pole 13b, but only rotationally oscillated in the horizontal direction. Is changed to a rotary joint with one degree of freedom. Thereby, the applicator 30 does not move in the vertical direction. In this case, the applicator 30 can be moved only in the horizontal direction by the rotary joints 14a, 14b, 14c and the links 12a, 12b, 12c. In this case, the articulated arm itself has a built-in gravity compensation mechanism that suppresses the applicator device 30 from swinging in the vertical direction due to gravity. An independent gravity compensation mechanism is not required.
In addition, when the direction of the applicator (target object) 30 is determined with respect to the target trajectory L, a storage unit that stores an angle range in which the applicator 30 may rotate may be provided. And when the rotation angle of the applicator 30 deviates from the above-mentioned angle range, it may be controlled to increase the resistance force applied to each joint in the direction in which the applicator 30 is rotated.
In this embodiment, the joint group 14, the link group 12, and the applicator 30 are arranged at the end opposite to the end fixed to the link 12 a of the wire 32 instead of the motor 36 and the winding wheel 34 as a gravity compensation mechanism. A counterweight having the same mass as the mass may be fixed. Even with such a configuration, it is possible to configure a gravity compensation mechanism that suppresses the swing of the articulated arm to which the object is attached due to gravity in the vertical direction. Moreover, you may comprise the gravity compensation mechanism which suppresses rocking | fluctuation of the articulated arm to which the target object was attached by gravity by using air pressure instead of the motor 36.

In the embodiment, the resistance forces FA and FB to be generated at the position of the applicator 30 are given by the first formula and the second formula, but the formulas giving the resistance forces FA and FB are not limited to these formulas. What is necessary is just to be set so that the resistance force FA when the object is outside the allowable range is smaller than the resistance force FB when the object is within the allowable range.
For example, the resistance force FA is decomposed into a component in a direction along the target trajectory L and a component orthogonal to the target trajectory L. For example, taking FIG. 4 as an example, the resistance force FA of FIG. 4 is shown in the direction along the target trajectory L, that is, the component FAx in the x-axis direction shown in FIG. It is decomposed into a component FAy in the y-axis direction. It is also preferable that FAx = 0 and FAy = − (a1 × dPy + a2 × VPy + Fc). Alternatively, FAx = 0 may be set to FAx = −Fc. Here, the symbols a1, dPy, a2, VPy, and Fc have the same meaning as described in the first formula. When the resistance force FA is set as in the above formula, the applicator 30 can be easily moved in the direction along the target trajectory L, while the applicator 30 is difficult to move in the direction orthogonal to the target trajectory L. it can. That is, the applicator device 30 can be easily moved in the direction along the target trajectory while making it difficult for the applicator 30 to deviate from the target trajectory.

The work auxiliary device further includes an operation direction detection device that detects the direction of the operation force applied by the operator, and the second control device is configured to detect the object when the direction of the operation force approaches a permissible range. It is also preferable that the resistance applying mechanism is controlled so as to weaken the resistance applied to each oscillating portion even if the position is outside the allowable range.
The operation direction detection device can be realized, for example, by attaching a force sensor to an operator that is operated when an operator operates an articulated arm. The direction of the operating force applied by the operator to the operator can be detected by the force sensor. Alternatively, it can be realized by a structure in which the operation element can swing in each direction like a joystick. The direction in which the operator swings corresponds to the direction of the operating force applied by the operator. Therefore, the direction of the operating force applied by the operator can be detected by detecting the direction in which the operator swings.
According to the above configuration, even when the object is located outside the allowable range and the resistance is increased, the resistance applying mechanism can be swung only by applying a small operating force that does not move the object in the direction of the allowable range. The resistance applied to the part can be weakened. If the resistance force applied by the resistance force application mechanism becomes weak, the operator can easily return the object to the allowable range.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

It is the schematic of the work assistance apparatus 10 of the Example of this invention. 1 is a block diagram of a work assistance device 10. FIG. FIG. 4 is a flowchart showing processing of the work assistance device 10. It is the figure which showed typically a mode when an applicator is outside an allowable range (1). It is the figure which showed typically a mode when an applicator is outside an allowable range (2).

Explanation of symbols

10: Work auxiliary device 11: Articulated arms 12a, 12b, 12c: Link 13: Articulated arm base 13b: Vertical poles 14a, 14b, 14c: Joints 15a, 15b, 15c: Position sensors 16a, 16b, 16c: Variable damper 22: Controller 24: Work support device 30: Application tool (object)
50: Allowable ranges 52R, 52L: Movement limit range 40: Position / velocity calculation unit 42: Damper control unit 48: Allowable range data storage unit W: Windshield L: Application line (target trajectory)

Claims (7)

It is a device that moves an object attached to a multi-joint arm by applying an operating force to a part of the multi-joint arm.
An articulated arm having two or more joints and capable of attaching an object to the tip;
A gravity compensation mechanism that compensates for gravity acting on the object and the articulated arm and suppresses the swing of the articulated arm in the vertical direction due to gravity;
A resistance force applying mechanism that applies resistance to swinging around the joint caused by the operation force, and that can increase or decrease the resistance to be applied;
A position detection device for detecting the position of the object;
An allowable range storage device for storing a range in which the object is allowed to be located;
When the position of the object detected by the position detection device is outside the allowable range stored in the allowable range storage device, the resistance applying mechanism is controlled to increase the resistance applied by the resistance applying mechanism. A first control device,
A work auxiliary device comprising: It is a device that moves an object attached to a multi-joint arm by applying an operating force to a part of the multi-joint arm.
A multi-joint arm having two or more joints that swing in a horizontal plane and capable of attaching an object to the tip;
A resistance force applying mechanism that applies resistance to swinging around the joint caused by the operation force, and that can increase or decrease the resistance to be applied;
A position detection device for detecting the position of the object;
An allowable range storage device for storing a range in which the object is allowed to be located;
When the position of the object detected by the position detection device is outside the allowable range stored in the allowable range storage device, the resistance applying mechanism is controlled to increase the resistance applied by the resistance applying mechanism. A first control device,
A work auxiliary device comprising:   The work assisting device according to claim 1, wherein the first control device increases the resistance force applied by the resistance force applying mechanism as the distance from the position of the object to the allowable range becomes longer.   The work according to any one of claims 1 to 3, wherein the first control device increases the resistance force applied by the resistance force applying mechanism as the speed at which the position of the object moves away from the allowable range is higher. Auxiliary device. A moving direction detection device for detecting the moving direction of the object;
When the moving direction of the object detected by the moving direction detection device is a direction approaching the allowable range, the resistance force applied by the resistance force applying mechanism is reduced from the resistance force adjusted by the first control device. A second control device;
The work assisting device according to claim 1, further comprising:   The work assisting device according to any one of claims 1 to 5, wherein the resistance force applying mechanism is any one of a variable viscosity damper, an ER fluid damper, an MR fluid damper, and a magnetic fluid damper.   6. The resistance applying mechanism according to claim 1, wherein the resistance applying mechanism is any one of a friction brake, a powder brake, a hysteresis brake, an ER fluid brake, an MR fluid brake, and a magnetic fluid brake capable of adjusting a friction resistance force. The work auxiliary device according to any one of the above.

Images