JP2018187715A - Robot device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot device 1 which includes an actuator 7d for changing pressurizing force applied on a workpiece by a processing part 2, and prevents trouble in adjusting the pressurizing force even when mass of the processing part 2 increases.SOLUTION: The robot device 1 includes a gravity reduction part 14 which applies force on the processing part 2 in an opposite direction to gravity. Thereby, an impact of mass of the processing part 2 on operation of the processing part 2 can be reduced by force (reduction force) the gravity reduction part 14 applies on the processing part 2. Thus, adjustment of pressurizing force is not affected even when the mass of the processing part 2 increases.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a robot apparatus that performs processing on a workpiece (hereinafter also referred to as a workpiece) by moving a machining section as an end effector three-dimensionally by a robot.

Conventionally, the robot apparatus as described above has been used in various applications (see, for example, Patent Documents 1 to 3).
For example, in the hem processing apparatus which is one aspect of the robot apparatus, the following configuration is well known. That is, in the robot apparatus, the robot has an articulated arm and holds a roller that forms a processing portion at the tip of the arm. Then, the robot apparatus controls the operation of the robot and three-dimensionally displaces the roller along a predetermined trajectory so as to perform hem processing on a continuous part to be processed in the workpiece (see, for example, Patent Document 1). ).

In recent years, demands for finished quality of workpieces after machining have increased, and in addition to controlling the position of a roller by controlling the operation of a robot, there is an increasing demand for changing the pressure applied to the workpiece.
Therefore, in the robot apparatus of Patent Document 1, an actuator such as an electric motor for changing the applied pressure is provided in the robot apparatus. In addition to the part that directly applies pressure to the workpiece (hereinafter sometimes referred to as the action part. In the hem processing device, the roller corresponds to the action part), the actuator outputs the output of the actuator. A transmission part that transmits to the action part is added.

  However, if the mass of the processing unit (end effector) increases due to the addition of a transmission unit or the like, it is difficult to operate the processing unit, and it may be difficult to adjust the pressure applied by the actuator. For this reason, even if the mass of a process part becomes large, the structure which does not have a trouble in adjustment of a pressurizing force is desired.

Japanese Patent Laying-Open No. 2015-85485 Japanese Patent Laying-Open No. 2015-136771 JP 2016-132067 A

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a robot apparatus equipped with an actuator for changing the applied pressure, even if the mass of the machining portion is increased, the applied pressure is increased. The purpose of this is to make sure that there is no hindrance to adjustment.

A robot apparatus according to a first invention of the present application includes the following processing unit and robot. First, a processing part applies a pressurizing force to a predetermined member to be processed. Further, the robot holds the processing unit as an end effector and is controlled so that the processing unit is displaced three-dimensionally.
In addition, the robot apparatus includes an actuator that generates an output for changing the pressing force, the processing unit applies an application force to the workpiece, and a transmission unit transmits the output of the actuator to the operating unit. Have Furthermore, the action part changes the pressure by changing the position relative to the robot by the output of the actuator.

The robot apparatus includes a gravity relaxation unit that exerts a force on the processing unit in a direction opposite to the gravity.
Thereby, the influence of the mass of the processed part on the operation of the processed part can be reduced by the force (hereinafter sometimes referred to as relaxation force) exerted on the processed part by the gravity relaxation part. For this reason, even if the mass of the processed part increases, it is possible to prevent troubles in adjusting the applied pressure.

According to a second invention subordinate to the first invention of the present application, the robot apparatus includes a control unit that controls a force (relaxation force) exerted on the machining unit by the gravity relaxation unit.
Thereby, since the relaxation force can be freely adjusted according to the state of the processed portion, the control accuracy of the applied pressure can be increased.

According to a third invention subordinate to the second invention of the present application, the robot apparatus includes a detection unit that detects an angle difference between the direction of the applied pressure and the direction of gravity. And a control part controls relaxation force based on the angle difference detected by a detection part.
Thereby, the relaxation force can be adjusted according to the direction of the applied pressure. That is, the relaxation force can be controlled in consideration of the influence of the mass of the processed part, that is, the gravity acting on the processed part on the applied pressure. For this reason, the applied pressure can be controlled with higher accuracy.

It is a whole block diagram of a robot apparatus (Example).

  The robot apparatus of the embodiment will be described based on the following examples.

[Configuration of Example]
The configuration of the robot apparatus 1 according to the embodiment will be described with reference to FIG.
The robot apparatus 1 includes the following processing unit 2, robot 3, and control unit 4.
First, the processing unit 2 performs processing by applying pressure to a predetermined workpiece, and the robot 3 holds the processing unit 2 and controls the control unit 4 so that the processing unit 2 is displaced three-dimensionally. Be controlled.

  Here, the robot 3 has an articulated arm 6 and holds the processing unit 2 as an end effector at the tip of the arm 6. In addition, servo motors 7a, 7b, and 7c are incorporated in the respective joints of the arm 6, and the control unit 4 controls the operation of the robot 3 by controlling the servo motors 7a, 7b, and 7c. Then, the robot 3 displaces the processing unit 2 three-dimensionally along a predetermined locus by the operation control by the control unit 4.

  The servo motors 7a, 7b, and 7c are energized and controlled by the control unit 4, and have, for example, a known brushless structure in which a stator and a rotor are each provided with a three-phase coil and a permanent magnet. Each of the servo motors 7a, 7b, 7c is equipped with encoders 8a, 8b, 8c for detecting the rotation angle of the rotor.

  The control unit 4 is a microcomputer or the like provided in a predetermined control unit, and performs arithmetic processing for energization control of the servo motors 7a, 7b, 7c and the like. Here, the control unit includes, together with the microcomputer, an inverter circuit for changing the energization amount to the servo motors 7a, 7b, 7c, a current sensor for detecting the current energized to the servo motors 7a, 7b, 7c, and the like. Is provided. The current sensor is composed of a known current detection resistor.

  And the control part 4 detects the position and attitude | position of the process part 2 based on the signal output from encoder 8a, 8b, 8c. Further, the control unit 4 controls the energization of the servo motors 7a, 7b, and 7c so that the detected value of the position and orientation of the processing unit 2 substantially matches the command value set based on a predetermined locus. Thereby, the process part 2 can be displaced three-dimensionally along a predetermined | prescribed locus | trajectory.

The robot apparatus 1 also includes a servo motor 7d as an actuator that generates an output for changing the applied pressure.
The servo motor 7d has a known brushless structure in which a stator and a rotor are each provided with a three-phase coil and a permanent magnet, and is controlled by the control unit 4 in the same manner as the servo motors 7a, 7b, and 7c. The servo motor 7d is also equipped with an encoder 8d that detects the rotation angle of the rotor.

Further, the control unit 4 performs arithmetic processing for energization control of the servo motor 7d and the control unit is energized to the inverter circuit for changing the energization amount to the servo motor 7d and the servo motor 7d. A current sensor for detecting current is provided. The current sensor is composed of a known current detection resistor.
Further, the processing unit 2 has an action part 9 that exerts a pressure force on the workpiece, and the action part 9 changes the pressure force by changing the position relative to the robot 3 by the output of the servo motor 7d. .

  Hereinafter, an example in which the robot apparatus 1 is applied to a hem processing apparatus that performs hem processing on a metal plate-like material as a workpiece will be described (hereinafter, the robot apparatus 1 will be described as the hem processing apparatus 1). The workpiece is, for example, a vehicle door panel or a hood panel.

According to the hem processing apparatus 1, the processing unit 2 includes the action unit 9, the servo motor 7d, and the transmission unit 10, and the action unit 9, the servo motor 7d, and the transmission unit 10 constitute an end effector.
First, the action part 9 is a roller that rolls while applying a pressure to the work and performs hem processing, and has a cylindrical surface that rolls while being pressed against the work (hereinafter, the action part 9 may be referred to as a roller 9). .

The transmission unit 10 transmits the output of the servo motor 7d to the roller 9, and includes the following ball screw 11, a slide unit 12, and the like.
First, the ball screw 11 is a well-known machine element that converts rotational motion into linear motion, and converts torque generated by the servo motor 7d into thrust. The slide unit 12 holds the roller 9 while rotatably supporting it, and linearly moves according to the operation of the ball screw 11.

  As described above, in the processing unit 2, torque generated by the servo motor 7 d is converted into thrust by the ball screw 11 and transmitted to the roller 9 through the slide unit 12. Further, the thrust transmitted to the roller 9 acts on the workpiece as a pressing force.

  Further, the control unit 4 controls the position and posture of the processing unit 2 by controlling the operation of the robot 3, thereby moving the roller 9 three-dimensionally along a predetermined trajectory, so that the workpiece is continuous in the workpiece. Heme processing is applied to

  Further, the control unit 4 controls the applied pressure as well as the position and orientation of the processing unit 2. For example, the control unit 4 calculates a command value for the current flowing through the servomotor 7d based on the state of the part to be processed, the target value of the applied pressure, and the like. And the control part 4 carries out energization control of the servomotor 7d so that the detection value obtained from the signal of a current sensor may substantially correspond to a command value. Thereby, the processing unit 2 freely changes the applied pressure based on the state of the part to be processed, the target value of the applied pressure, and the like, thereby improving the finished quality of the workpiece after processing.

[Features of Examples]
Features of the hem processing apparatus 1 of the embodiment will be described with reference to the drawings.
The hem processing apparatus 1 includes a gravity relaxation unit 14 that exerts a force on the processing unit 2 in a direction opposite to the gravity. And the control part 4 controls the force (relaxation force) which the gravity relaxation part 14 exerts on the process part 2. FIG. Further, the hem processing apparatus 1 includes a detection unit 15 that detects an angle difference between the direction of the applied pressure and the direction of gravity. Then, the control unit 4 controls the relaxation force based on the angle difference detected by the detection unit 15.

  First, the gravity relaxation part 14 exerts a force on the processing part 2 in a direction opposite to the gravity with respect to the processing part 2 (end effector), and has the following configuration, for example. That is, the gravity relaxation part 14 is an air cylinder which drives the piston 17 by air pressure. That is, the piston 17 and the processing part 2 are mechanically linked so that the air pressure acts in the direction opposite to the gravity, thereby causing the air cylinder to function as the gravity relaxation part 14.

  In addition to the piston 17, the air cylinder includes a spring 18 that biases the piston 17 in a direction opposite to the air pressure, and a drive unit 20 that causes the pressure air to flow into and out of the pressure chamber 19. In response to the command, the inflow and outflow of the pressure air into the pressure chamber 19 is operated. Of the air cylinders, a body 21 that forms a cylinder and incorporates the piston 17 is fixed to the robot 3, for example. The drive unit 20 has a known configuration including an electromagnetic valve or the like that opens and closes the flow paths on the inflow side and the outflow side to the pressure chamber 19.

  Next, the detection unit 15 detects an angle difference between the direction of the applied pressure and the direction of gravity, and is, for example, a digital angle meter with a built-in gyro sensor. It is integrated. Then, the control unit 4 controls the relaxation force based on the angle difference detected by the detection unit 15. Specifically, for example, the smaller the angle difference, the larger the component force acting in the direction of the applied pressure in the gravity, so the control unit 4 reduces the gravity so as to increase the relaxation force as the angle difference is smaller. The unit 14 is controlled. That is, the air pressure in the pressure chamber 19 is increased.

[Effects of Examples]
The hem processing apparatus 1 according to the embodiment includes a gravity relaxation unit 14 that exerts a force on the processing unit 2 in a direction opposite to gravity.
Thereby, the influence of the mass of the processing part 2 on the operation of the processing part 2 can be reduced by the force (relaxation force) exerted on the processing part 2 by the gravity relaxation part 14. For this reason, even if the mass of the process part 2 becomes large, it can be made not to interfere with adjustment of a pressurizing force.

Further, the control unit 4 controls the force (relaxation force) exerted on the processing unit 2 by the gravity relaxation unit 14.
Thereby, since the relaxation force can be freely adjusted according to the state of the processing part 2, the control accuracy of the applied pressure can be increased.

Furthermore, the hem processing apparatus 1 includes a detection unit 15 that detects an angle difference between the direction of the applied pressure and the direction of gravity. Then, the control unit 4 controls the relaxation force based on the angle difference detected by the detection unit 15.
Thereby, the relaxation force can be adjusted according to the direction of the applied pressure. That is, the relaxation force can be controlled by taking into account the influence of the mass of the processed part 2, that is, the gravity acting on the processed part 2 on the applied pressure. For this reason, the applied pressure can be controlled with higher accuracy.

[Modification]
The embodiment discloses a specific example, and it goes without saying that the present invention is not limited to the embodiment.
For example, although the robot apparatus 1 of the embodiment was applied to hem processing, the robot apparatus 1 can be variously processed such as deburring processing for deburring a workpiece with a grindstone and drilling processing for drilling with a cutter. You may apply to.

  In addition, an air cylinder is used as the gravity relaxation unit 14 and air pressure is used as a relaxation force. For example, a solenoid may be used as the gravity relaxation unit 14 and a magnetic attraction force may be used as the relaxation force. Alternatively, a hydraulic cylinder may be employed and the oil pressure may be used as a relaxation force, or a motor may be employed and the motor torque may be converted into a thrust and utilized as a relaxation force.

DESCRIPTION OF SYMBOLS 1 Robot apparatus, hem processing apparatus 2 Processing part 3 Robot 4 Control part 7d Servo motor (actuator) 9 Action part, roller 10 Transmission part 14 Gravity relaxation part 15 Detection part

Claims (3)

A processing section (2) for applying a pressing force to a predetermined workpiece and processing it;
In a robot apparatus (1) comprising: a robot (3) that holds the processing unit as an end effector and is controlled so that the processing unit is displaced three-dimensionally.
An actuator (7d) for generating an output for changing the applied pressure;
The working part includes an action part (9) that exerts the applied pressure on the workpiece, and a transmission part (10) that transmits the output of the actuator to the action part,
The action part changes the pressure by changing the position relative to the robot by the output of the actuator,
The robot apparatus includes a gravity relaxation section (14) that exerts a force on the processing section in a direction opposite to gravity. The robot apparatus according to claim 1,
A robot apparatus comprising a control unit (4) for controlling a force exerted by the gravity relaxation unit on the processing unit. The robot apparatus according to claim 2, wherein
A detector (15) for detecting an angle difference between the direction of the applied pressure and the direction of gravity;
The robot apparatus according to claim 1, wherein the control unit controls a force exerted by the gravity relaxation unit on the processing unit based on an angle difference detected by the detection unit.