BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a work device and a dual-arm work device for use in equipment that requires high-speed and high-accuracy work such as medical equipment and industrial equipment, equipment that requires fine work such as assembly, a robot coexisting with a person, etc.

Description of Related Art

An articulated robot type work device with six degrees of freedom is suggested in Patent Documents 1 and 2 listed below. The work device of Patent Document 1 has a single-arm configuration, and the work device of Patent Document 2 has a dual-arm configuration. These work devices are each configured with six degrees of freedom as a whole by combining six mechanisms each having one rotational degree of freedom.

RELATED DOCUMENT

Patent Document

[Patent Document 1] JP Laid-open Patent Publication No. 2005-329521[Patent Document 2] JP Patent No. 4528312

The work device of Patent Document 1 is configured by a combination of the mechanisms all of which have one rotational degree of freedom, and thus, has the following problems1to6.

(Problem 1) In the case of slightly changing the posture of an end effector mounted on a distal end or in the case of linearly moving the end effector, it is necessary to drive a plurality of motors in a cooperative manner, and thus, it is impossible to perform fine work at a high speed.

(Problem 2) Even in the case of slightly changing the posture of the end effector, not only a movement amount of a wrist joint (a joint near the end effector) but also a movement amount of an arm (a part away from the end effector) is increased. Therefore, a part of the work device is likely to come into contact with an object around the work device. In order to completely avoid such contact, it is necessary to provide a large enclosure, and thus, the occupation area is rendered to be wide.

(Problem 3) There are a plurality of solutions for one posture of the end effector in some cases, and thus, it is hard to imagine in which direction the distal end moves even when each shaft is moved in performing teaching. Therefore, knowledge and experience are required to perform manipulations.

(Problem 4) Since the range of movement is wide, it is necessary to assume contact with an object and to enhance a contact prevention function. Therefore, the entire device is rendered to be expensive.

(Problem 5) In order to avoid contact with an object, it is necessary to perform work at a reduced operation speed, or to perform work, at lower capability than a potential one, even in an operation range. Therefore, the ability cannot be fully realized.

(Problem 6) Even in the case where the contact prevention function is enhanced, an operator minds coming into contact with the work device, and thus it is difficult for a person and the work device to coexist.

The work device of Patent Document 2 is also configured by a combination of the mechanisms, all of which have one rotational degree of freedom, and thus, has the same problems as those of the work device of Patent Document 1. In addition, the work device of Patent Document 2, which is of a dual-arm type, has the following problems7and8.

(Problem 7) Since the range of movement of each arm is wide, a region where the arms interfere with each other is also wide. Therefore, knowledge and experience are required to perform operation such that the arms do not come into contact with each other.

(Problem 8) Since two arms having a wide range of movement are used, the occupation area is rendered to be even wider when an enclosure is provided.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a work device that can reduce an operation amount of a work device body when performing fine work, can prevent an object from coming into contact with the work device body, and can automatically perform work that is close to manual work performed by a person.

Another object of the present invention is to provide a dual-arm work device that can reduce an operation amount of a work device body when performing fine work, can prevent an object from coming into contact with the work device body, and can perform work that is similar to a work performed by a person with both hands.

A work device of the present invention has six degrees of freedom and is configured to perform work using an end effector, the work device including: a work device body; and a contact preventer configured to prevent an object from needlessly coming into contact with the work device body. The work device body includes: a linear motion unit having three degrees of freedom and obtained by combining three linear motion actuators; and a rotary unit having three degrees of freedom and obtained by combining a plurality of rotating mechanisms each having one or more rotational degrees of freedom. The linear motion unit has a base portion fixed to a mount, the rotary unit has a base portion thereof fixed to an output portion of the linear motion unit, and the end effector is mounted on an output portion of the rotary unit. The contact preventer separates a working region, which is a space in which the work device body is installed, from a non-working region that is a space outside the working region. The contact preventer has an entry allowing portion allowing an object to enter the working region therethrough from the non-working region, and an entry allowing portion entry detection sensor configured to detect entry of an object into the working region through the entry allowing portion.

In the work device body having this configuration, in performing work by the end effector, a position of the end effector is determined mainly by the linear motion unit having three degrees of freedom, and a posture of the end effector is determined by the rotary unit having three degrees of freedom. Each linear motion actuator of the linear motion unit and each rotating mechanism of the rotary unit correspond to the position of the end effector represented in a rectangular coordinate system, and the posture of the end effector represented in a polar coordinate system, respectively. Thus, operations of each linear motion actuator and each rotating mechanism with respect to the position and the posture of the end effector are easily imagined, and as a result, operation patterns for posture teaching work and the like can be easily set. In addition, an operating position of each linear motion actuator and an operating angle of each rotating mechanism are uniquely determined relative to the position and the posture of the end effector. That is, there is no singular point. Due to this, the work device can be manipulated even without proficient knowledge and experience.

Additionally, the following operation and advantageous effects (Effects 1 to 4) are achieved.

(Effect 1) In the case of performing fine work such as assembling work, the work can be performed mainly by moving only the rotary unit. Accordingly, an operation amount of the linear motion unit can be reduced, and thus, an operation amount of the entire work device body can be reduced. In addition, an area where it is necessary to install the contact preventer such as an enclosure can be narrow.

(Effect 2) Since the linear motion actuators are used in a portion that greatly influences the range of movement, the operation range can be easily limited by using a mechanical stopper or a limit sensor in accordance with work contents or the ambient environment.

(Effect 3) Since the linear motion unit and the rotary unit are separately provided, it is possible to change only either unit in the case of changing the specifications of the work device body. Accordingly, components can be shared by work device bodies having different specifications.

(Effect 4) Since the position of the end effector is determined by the linear motion actuators, a linear motion of the end effector can be accurately made at a high speed.

Moreover, the contact preventer acts as described below (Effects 5 and 6).

(Effect 5) The entry allowing portion is provided in the contact preventer, and an object cannot enter the working region through a portion other than the entry allowing portion. Thus, a range, where an object and the work device body can come into contact with each other, is limited.

(Effect 6) Since the entry detection sensor is provided, entry of an object into the working region can be assuredly detected. When the entry detection sensor has detected entry, operation of the work device body can be stopped or decelerated. Accordingly, in a state where detection of entry by the entry detection sensor is not present and an object is not close to the work device body, the work device body can be operated at a high speed, and thus, productivity is improved.

In the work device of the present invention, the contact preventer may include a plurality of face members, the plurality of face members may form a cover surrounding the work device body, and each of the plurality of face members may be parallel to two movable directions of three movable directions of the three linear motion actuators. When the contact preventer is composed of the cover having the above shape, the volume of the internal space of the cover and the volume of a region where movable portions of the work device body move, can be substantially equal to each other. Therefore, even when the contact preventer is provided, the configuration of the work device can be compact. An object does not come into contact with the work device body through a portion other than the entry allowing portion, and thus an operator can perform work at ease even in the vicinity of the work device.

In the work device of the present invention, lengths of the entry allowing portion in the movable directions of the two linear motion actuators parallel to a plane on which the entry allowing portion is present may be smaller than ranges of movement of the two linear motion actuators, respectively. With this configuration, an object cannot enter between the cover and the work device body, and thus, contact between the work device body and an object can be assuredly prevented.

In the work device of the present invention, at least one of the plurality of rotating mechanisms of the rotary unit may be a link actuating device having two degrees of freedom. The link actuating device includes: a proximal end side link hub; and a distal end side link hub coupled to the proximal end side link hub via three or more link mechanisms such that a posture of the distal end side link hub can be changed relative to the proximal end side link hub. Each of the link mechanisms has a proximal side end link member having one end rotatably coupled to the proximal end side link hub, a distal side end link member having one end rotatably coupled to the distal end side link hub, and an intermediate link member having opposite ends rotatably coupled to other ends of the proximal side and distal side end link members, respectively. A posture control actuator configured to arbitrarily change the posture of the distal end side link hub relative to the proximal end side link hub may be provided to each of two or more link mechanisms of the three or more link mechanisms.

In the link actuating device, the proximal end side link hub, the distal end side link hub, and the three or more link mechanisms cooperate together to form a two-degrees-of-freedom mechanism in which the distal end side link hub is rotatable about two mutually orthogonal axes relative to the proximal end side link hub. This two-degrees-of-freedom mechanism is compact in size, but can achieve a wide range of movement for the distal end side link hub. For example, the maximum value of the bending angle between an axis or center line of the proximal end side link hub and an axis or center line of the distal end side link hub is about ±90°, and the turning angle of the distal end side link hub relative to the proximal end side link hub can be set in the range of 0° to 360°. In addition, in the operation range of a bending angle of 90° and a turning angle of 360°, smooth operation can be performed without any singular point.

As described above, by using the link actuating device, which can smoothly operate in a wide range of movement, as the rotary unit, fine work can be performed at a high speed. In addition, the link actuating device has a compact configuration but has a wide range of movement, and thus, the entire configuration of the work device is rendered to be compact.

In the case where the rotary unit includes the link actuating device, the posture control actuator may have a torque detector, and a contact detector may be provided to detect contact of an object with the rotary unit on the basis of a detection signal from the torque detector. The link actuating device is configured to be smoothly movable in all directions within the range of movement thereof without any singular point. Thus, even when foreign matter comes into contact with the distal end side link hub from various directions, torque is assuredly transmitted to each posture control actuator. Accordingly, the torque detector can detect torque in various directions, and thus, the contact detector can accurately detect contact of an object. As described above, by using the torque detector, which is provided in each posture control actuator, for detecting contact, the necessity to provide another sensor for contact detection is eliminated. As a result, the work device body is made compact and reduced in cost.

In the case where the rotary unit includes the link actuating device, an entry prevention cover may be provided to prevent an object from entering an internal space between the proximal end side link hub and the distal end side link hub. By using the entry prevention cover, an object can be prevented from entering the internal space by mistake.

In the work device of the present invention, a cushioning material may be provided to the rotary unit, which cushioning material alleviates shock when coming into contact with an object. According to this configuration, an object can enter the working region only through the entry allowing portion of the contact preventer. Therefore, a portion of the work device body, which may come into contact with an object, is substantially limited to the rotary unit. Thus, when the cushioning material is provided only to the rotary unit, an object can be protected. Accordingly, installation of a facility for contact prevention can be minimized, and the entire device is rendered to be inexpensive.

In the present invention, each of the linear motion actuators of the linear motion unit may have a stage including an advancing/retracting portion, which stage is disposed so as to be directed toward an outer side with respect to a working space in which work is performed by the end effector. By disposing the stage of each linear motion actuator such that the stage is directed toward the outer side relative to the working space, the working space can be wide, and also, the possibility of coming into contact with an object when the object has entered the working space can be reduced.

In the present invention, a control device may be provided to perform control so as to decrease an operation speed of the work device body or stop operation of the work device body when the entry detection sensor detects entry of an object into the working region. According to this configuration, operation of the work device body is controlled by the control device, according to a detection result of the entry detection sensor. Thus, the operator can perform work of carrying a workpiece into/out of the working region or assisting work for the work device body at ease.

In the present invention, the contact preventer may include: at least one workpiece carrying-in/out portion configure to carry in/out a workpiece between the working region and the non-working region; and a workpiece carrying-in/out portion entry detection sensor configured to detect entry of an object into the working region through the workpiece carrying-in/out portion.

When the contact preventer includes the workpiece carrying-in/out portion, the work device body can be installed on a device for carrying a workpiece into/out of the working region, for example, on a line of a conveyor device. A hand is put into the working region through the entry allowing portion when performing assisting work for the work device body. Thus, normally, an object does not enter the working region through the workpiece carrying-in/out portion. Therefore, by providing the entry detection sensor, it is possible to detect an abnormal situation in which an object has entered the working region through the workpiece carrying-in/out portion. Accordingly, it is possible to take prompt action.

A dual-arm work device of the present invention includes: two work device bodies each having six degrees of freedom and configured to perform work by using an end effector, the two work device bodies being aligned so as to be geometrically symmetrical with each other; and a contact preventer configured to prevent an object from needlessly coming into contact with any of the two work device bodies. Each of the work device bodies includes: a linear motion unit having three degrees of freedom and obtained by combining three linear motion actuators; and a rotary unit having three degrees of freedom and obtained by combining a plurality of rotating mechanisms each having one or more rotational degrees of freedom. The linear motion unit has a base portion fixed to a mount, the rotary unit has a base portion thereof fixed to an output portion of the linear motion unit, and the end effector is mounted on an output portion of the rotary unit. The contact preventer separates a working region, which is a space in which the two work device bodies are installed, from a non-working region that is a space outside the working region. The contact preventer has an entry allowing portion allowing an object to enter the working region therethrough from the non-working region, and an entry allowing portion entry detection sensor configured to detect entry of an object into the working region through the entry allowing portion.

The two work device bodies of the dual-arm work device having this configuration, also, achieve the same advantageous effects as the above-described work device body of the work device of the present invention. Since the two work device bodies are aligned in the dual-arm work device, the dual-arm work device can perform work that is performed with both hands by a person. Accordingly, work that is performed as a substitute for a person, in particular, work such as assembly of components, can be performed.

Any combination of at least two constructions, disclosed in the appended claims and/or the specification and/or the accompanying drawings should be construed as included within the scope of the present invention. In particular, any combination of two or more of the appended claims should be equally construed as included within the scope of the present invention.

