JPH1067500A - Assistant arm provided with power assist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey a workpiece lightly irrespective of its weight. SOLUTION: A load cell 18 detecting the dimensions of force, which is applied to a workpiece by a worker, in the three-dimensional directions and in the torsional direction of each dimension is arranged, while in a plurality of arms 10, 14, 16, motors 13, 17, 20 driving these arms 10, 14, 16 are installed individually, and on the basis of the dimensions and the directions of the force detected by means of the load cell 18 and the rotation angles of the respective motors 13, 17, 20 detected by means of encoders provided in the respective motors 13, 17, 20, torque of each of the motors 13, 17, 20 is controlled by means of a controller 25 so that torque compensating the working force of the worker can be applied to the workpiece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assist arm with power assist which can be lightly conveyed regardless of the weight of a work.

[0002]

2. Description of the Related Art Conventionally, an assisting arm as shown in FIG. 3 has been used in order to reduce a burden when a heavy object is carried. The assisting arm includes a cylinder 12 attached to the arm 10 (in some cases, a motor is used).
Thus, the weight of the work can be offset.
The arm 10 can be moved up and down, and
The work can be freely conveyed because it can be swiveled with respect to 4 and its tip can be slid forward and backward.

[0003]

However, in such a conventional assisting arm, the weight of a heavy object (work) can be offset by the action of the cylinder 12.
When a work is transported, an inertial force corresponding to the weight of the work is applied. Therefore, particularly when the work is heavy, there is a problem that a considerable labor is required for the transport.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has a power assist for providing an assisting force according to a force applied by an operator and facilitating the transfer of heavy objects. The purpose is to provide a helping arm.

[0005]

The present invention for achieving the above object is constituted as follows for each claim.

According to a first aspect of the present invention, there is provided an assisting arm provided with an arm for transferring a work to a desired position and a gravitational balance mechanism for balancing the weight of the work with gravity on the arm. Force detecting sensor for detecting a force acting on the assisting arm by a worker, driving means for driving the arm, and the action of the worker based on the magnitude and direction of the force detected by the force detecting sensor. And a control means for driving the driving means so as to supplement the force. With this configuration, the assist force is applied to the arm in accordance with the force acting on the assisting arm by the worker, so that the inertial force accompanying the conveyance can be canceled, and even if the work is a heavy object, It can be easily transported.

According to a second aspect of the present invention, there are provided a plurality of arms for transferring a work to a desired position, and a gravitational balance mechanism which acts on one of the arms to balance the weight of the work with gravity. An assisting arm, an acting force detecting sensor that detects a magnitude of a force in a three-dimensional direction and a torsion direction in each dimension that an operator acts on the work, and a driving unit provided in each of the plurality of arms. A control for controlling the operation of each of the plurality of driving means so that a torque supplementing the acting force of the worker acts on the work based on the magnitude and direction of the force detected by the acting force detection sensor. And an assisting arm with power assist. With this configuration, the assist force is applied to the work in accordance with the force applied to the work by the worker, so that the inertial force accompanying the conveyance can be canceled, and even a heavy work can be easily performed. Can be transported to

According to a third aspect of the present invention, there are provided a plurality of arms for transporting a work to a desired position, and a gravitational balance mechanism which acts on one of the arms to balance the weight of the work with gravity. An assisting arm, an acting force detecting sensor that detects a magnitude of a force in a three-dimensional direction and a torsion direction in each dimension that an operator acts on the work, and a motor provided in each of the plurality of arms, An encoder for detecting a rotation angle of each of the motors, and an action of the worker based on the magnitude and direction of the force detected by the acting force detection sensor and the rotation angle of each of the motors detected by the encoder. Control means for controlling the operation of each of the plurality of driving means so that torque for supplementing the force acts on the work. Is the power assist with helping arm to. With this configuration, an assist force is applied to the work according to the force acting on the work or the speed at which the work is moved, so that the inertial force accompanying the conveyance can be canceled, and The work can be easily conveyed.

According to a fourth aspect of the present invention, the control means of the positioning assisting arm according to any one of the first to third aspects further comprises an adjusting means for adjusting a ratio of a torque for supplementing the working force to the working force of the worker. It is. With this configuration,
Since an assisting force can be generated according to the preference of the operator, the assisting arm with power assist is easy to use.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an assisting arm with power assist according to the present invention will be described below.
FIG. 1 is an external view of an assisting arm with power assist of the present invention.

As shown in the drawing, a cylinder 12 for gravity balance is attached to the arm 10. This arm moves a main shaft 14 in a vertical direction by a motor 13. An arm 16 for moving the hand 15 is provided at the distal end of the arm 10. The arm 17 is moved forward and backward by a motor 17. A load cell 18 for detecting a force applied by an operator to a work is attached to the hand 15, and the load cell 18 allows the hand 15 to perform three-dimensional (X, Y, Z) operations.
The external force in the direction and the force in the torsional direction in each of these dimensions are detected. The arm 10 can turn with respect to the main shaft 14, and this turning is performed by a motor 20.

The controller 25 controls the operation of the assisting arm with power assist. The controller 25 includes a detection signal from the load cell 18,
A pulse signal is input from a rotation angle detection encoder (not shown) of each of the motors 13, 17, and 20, and a current and a voltage applied to each of the motors 13, 17, and 20 are output from the controller 25. Further, it has an adjusting function for freely adjusting the assist force. Note that these motors 13, 17, 20 have an 80 W
A low-power servomotor of about the same degree is used.

FIG. 2 is a schematic configuration diagram of a control system of the assisting arm with power assist according to the present invention.

The encoders 1 to 3 are provided in each of the motors 13, 17, and 20 for driving the respective arms shown in FIG. 1, and output pulse signals at fixed rotation angles. Is configured.

The pulse signals q1 to q3 output from the encoder 1 to the encoder 3 are converted into a Jacobian matrix operation unit 30, a differential operation unit 32, an h (q, q dot) operation unit 34, and an R (g) operation unit, which will be described later. 36 respectively.

The Jacobian matrix operation unit 30 outputs pulse signals q output from the encoders 1 to 3 respectively.
Jacobian matrix J for calculating the torque to be output from each of the motors 13, 17, 20 based on 1 to q3
This is the part for calculating (g).

The obtained Jacobian matrix J (g) is J
^-1 (g) calculation section 41 and J ^T (g) calculation section 43, and the J ^-1 (g) calculation section 41 outputs the Jacobian matrix J (g).
The inverse matrix J ^-1 (g) are also, J ^T (g) transposed matrix J ^T of the arithmetic unit 43 in the Jacobian matrix J (g) (g) is being respectively calculating the inverse obtained matrix J ^-1 (G) and the transposed matrix J ^T (g) are output to each axis motor torque calculator 50.

The differential operation section 32 is a section for differentiating the pulse signals q1 to q3 output from the encoder 1 to the encoder 3 and obtaining the differential values q1 to q3 dots. The obtained differential value is output to the h (q, q dot) calculation unit 34 and each axis motor torque calculation unit 50.

The h (q, q dot) calculation unit 34 calculates the differential values q1 to q3 dots obtained by the differential calculation unit 32 and the pulse signals q1 to q3 output from the encoder 1 to the encoder 3, respectively. , Coriolis force,
This is a part for calculating terms h (q, q dots) relating to centrifugal force and viscous friction force. The obtained h (q, q dots) are output to each axis motor torque calculation unit 50.

The R (g) calculation section 36 outputs pulse signals q 1 to q output from the encoder 1 to the encoder 3 respectively.
3 is a part for calculating an inertia matrix R (g) for each arm or the like based on the equation (3). The obtained inertia matrix R (g) is
It is output to each axis motor torque calculation unit 50.

The load cell 18 divides the force applied to the work by the worker into the three-dimensional direction and the torsion direction in each dimension as described above, and outputs the electric signal. The external force in the X, Y, and Z directions is provided. F and the torsional forces N in the X, Y, and Z directions are output to each axis motor torque calculation unit 50.

Each axis motor torque calculation unit 50 includes a motor 1
3, 17 and 20 have a function of calculating the torque to be generated. The calculation of the torque is performed by inverting the Jacobian matrix J (g) J ^-1 (g) and the Jacobian matrix J (g transposed matrix J ^T of) (g), the pulse signal q1 to q
The differential value of q1 dot to q3 dot Term h (q, q) relating to Coriolis force, centrifugal force, viscous friction force
(Dot) Inertia matrix R (g) The torque is calculated by performing the following calculation using the external force F in the X, Y, and Z directions and the torsional force N in the X, Y, and Z directions.

Generally, assuming that the torque of the motor corresponding to the force applied to the work is τ, the torque of each motor can be represented by the following equation.

[0024] Where J ^T (θ) is the Jacobian matrix of the arm, F
Is an external force applied to the work, N is a torsional force, and θ is an indirect angle. Therefore, the assist force may be generated by causing the motor to cancel the torque τ.

At this time, the motor torque τ is Becomes

The external force F and the torsional force N are obtained from the load cell 18, and the indirect angle θ is obtained from a pulse signal output from the encoder.

The general formula is as described above. Further, considering a specific equation of motion for the work, if the external force applied to the work by the operator is F, the desired motion of the work is given by the following formula.

F = M · d ² x / dt ² + D · dx / dt + Kx At this time, if it is desirable to reduce the load on the worker,
It is assumed that K = 0 and D = 0, and M is selected to be smaller than the actual mass of the work (the smaller the smaller, the larger the load reduction rate).

When the above equation is rewritten based on the above condition, F = M · d ² x / dt ² (1)

On the other hand, the equation of motion of the assisting arm is generally represented by the following equation.

[0031] τ = (J0 + R (g )) d 2 q / dt 2 +
h (q, q dot) + g (q) where J0 is the moment of inertia of each arm and R (g)
Is an inertia matrix, h (q, q dots) is a term relating to Coriolis force, centrifugal force, viscous friction force, g (q) is a term relating to gravity, and τ is a torque of each motor.

Therefore, the torque of the motor giving the desired motion characteristics is given by τ = h (q, q dot) + g (q)-(J0 + R
(G)) · J ^-1 (g) · J dot (g) · q dot +
｛(J0 + R (g)) · J ^-1 (g) · M ^-1 -J
^T (g)｝ · F In the case of the assisting arm, gravity is canceled by a cylinder or the like, so that τ = h (q, q dot) − (J0 + R (g)) · J
^-1 (g) · J dot (g) · q dot + ｛(J0 + R
(G)) · J ⁻¹ (g) · M ⁻¹ −J ^T (g)｝ · F

As described above, the various quantities required for this operation are calculated as follows: J ^-1 (g) operation unit 41, J ^T (g) operation unit 43, differentiation operation unit 32, h (q, q dot) operation unit 34, R
(G) Since the output is provided from the calculation unit 36 and the load cell 18, if the weight M of the work is given, the torque to be generated in each of the motors 13, 17, 20 can be calculated by the motor torque calculation unit 50 for each axis. .

Further, each axis motor torque calculating section 50 includes:
Since the adjusting means for adjusting the ratio of the torque to supplement the external force applied to the work by the worker is provided, the assist force can be adjusted according to the preference of the worker.

More specifically, the torque to be generated in each of the motors 13, 17, 20 is adjusted by multiplying the torque τ calculated as described above by a coefficient K (0 ≦ K ≦ 1) set by the adjusting means. I do.

Each axis motor torque calculating section 50 outputs a command for generating the calculated torque to the current amplifying sections 13A, 17A, 20A provided for the respective motors, and outputs the current amplifying sections 13A, 17A. , 20A, the motors 13, 17, 20 generate desired torque.

The assisting arm with power assist of the present invention is configured to generate the assisting force by performing the above-described calculation, so that even if the work is heavy, the inertial force can be canceled. Therefore, even when the workpiece is moved in any direction such as horizontal, vertical, or diagonal, the workpiece can be quickly and easily moved.

Further, the assist force is generated only when the worker applies an external force to the work, so that the work can be stably transported.

Further, since the assist force can be freely changed by the operator, it is possible to generate an assist force adapted in accordance with the preference of the operator and the work content. As described above, the assisting arm with power assist of the present invention does not require a complicated mechanism or control system unlike a robot, so that it can be produced at very low cost, and by arranging a large number at a production site, You can work more efficiently.

[0040]

The present invention configured as described above has the following effects for each claim. According to the first aspect of the present invention, the driving means is driven so as to supplement the working force of the worker based on the magnitude and direction of the force detected by the working force detection sensor. By applying the assisting force to the arm according to the force acting on the arm, the inertial force accompanying the conveyance can be canceled, and even a heavy work can be easily conveyed.

According to the second aspect of the present invention, the torque that supplements the working force of the worker is applied to the work based on the magnitude and direction of the force detected by the working force detection sensor. An assist force is applied to the work according to the force applied to the work by the worker, so that the inertial force accompanying the transfer can be canceled, and even a heavy work can be easily transferred. become.

According to the third aspect of the present invention, the operation force of the worker is determined based on the magnitude and direction of the force detected by the operation force detection sensor and the rotation angle of each motor detected by the encoder. Is applied to the work, so that an assist force is applied to the work according to the force acting on the work or the speed at which the work is moved, thereby canceling the inertial force accompanying the conveyance. Therefore, even a heavy workpiece can be easily transported.

According to the fourth aspect of the present invention, the control means of the positioning assist arm is provided with an adjusting means for adjusting a ratio of a torque for supplementing the working force to the working force of the worker, so that the worker's preference is provided. Can be generated in accordance with the assist force, and the assisting arm with power assist is easy to use.

[Brief description of the drawings]

FIG. 1 is an external view of an assisting arm with power assist of the present invention.

FIG. 2 is a schematic configuration diagram of a control system of the assisting arm with power assist of the present invention.

FIG. 3 is a diagram for explaining the operation of a conventional assisting arm.

[Explanation of symbols]

10, 16: arm, 12: cylinder, 14: spindle, 15: hand, 13, 17, 20: motor, 18: load cell, 25: controller.

Claims (4)

[Claims] 1. An assisting arm comprising an arm for transferring a work to a desired position and a gravitational balance mechanism for balancing the weight of the work with gravity in the arm, wherein an operator acts on the assisting arm. Acting force detecting sensor for detecting a force to be applied, driving means for driving the arm, magnitude of the force detected by the acting force detecting sensor,
And a control means for driving the driving means so as to supplement the working force of the worker based on a direction. 2. An assisting arm comprising a plurality of arms for transporting a work to a desired position, and a gravitational balance mechanism acting on one of the arms to balance the weight of the work with gravity. Force detecting sensor for detecting the magnitude of a force in a three-dimensional direction and a torsion direction in each dimension to be applied to the workpiece by a person, a driving unit provided on each of the plurality of arms, and the working force detecting sensor. The magnitude of the detected force,
Controlling means for controlling the operation of each of the plurality of driving means so that a torque supplementing the acting force of the worker acts on the work based on a direction. . 3. An assisting arm comprising a plurality of arms for transporting a work to a desired position and a gravitational balance mechanism acting on one of the arms to balance the weight of the work with gravity. Force acting sensors for detecting the magnitudes of forces in the three-dimensional direction and in each of the torsional directions applied to the workpiece by a person, motors provided on each of the plurality of arms, and a rotation angle of each of the motors An encoder for detecting the magnitude of the force detected by the acting force detection sensor;
Control means for controlling the operation of each of the plurality of drive means based on the direction and the rotation angles of the respective motors detected by the encoder, so that a torque supplementing the working force of the worker acts on the work; An assist arm with power assist, characterized in that: 4. The control means according to claim 1, wherein said control means is provided with an adjusting means for adjusting a ratio of a torque for supplementing said working force to a working force of an operator. 3. The positioning assisting arm according to item 1.