JP3074723B2 - Reaction correction method for bilateral manipulator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a reaction force of a master-slave type manipulator having a bilateral mechanism.

B. Summary of the Invention According to the present invention, in a master-slave type manipulator having a bilateral function, a zero point correction circuit for removing hysteresis of a torque sensor provided on a slave arm is provided, and a zero point correction for setting a bias signal in the zero point correction circuit is provided. The switch is also used as an optical switch provided on the operation grip.

For this reason, the zero point correction by the zero point correction circuit is automatically executed each time the optical switch is turned on and off, so that another worker can assist and operate the zero point correction switch,
Operability is improved as compared with the case of using a foot switch.

C. Conventional technology A master-slave type manipulator with a bilateral function transmits the reaction force of the slave arm to the master arm so that it can be operated as if the worker is actually handling an object. Yes, there is an advantage that the feeling can be easily grasped.

Here, various torque sensors are used to detect the reaction force of the slave arm. However, since the output characteristics of these sensors include offset and hysteresis, the true reaction force, that is, It did not detect the actual load acting.

That is, as shown in FIG. 3, it is ideal that the output of the torque sensor is proportional to the external force applied to the slave arm. However, actually, the output of the torque sensor becomes a hysteresis curve as shown by a broken line, and even if the external force is zero, the sensor output In some cases, the sensor output is not generated even when an external force is applied.

This is unavoidable due to the mechanism to which the torque sensor is attached or the structure of the torque sensor itself.

Therefore, conventionally, a zero point correction circuit C for correcting a zero point by adding a bias current for canceling the value AB or BC output from the torque sensor shown in FIG. 3 to the output of this sensor has been provided.

As shown in FIG. 2, the zero point correction circuit C receives an input from the torque sensor 2 when the zero point correction switch 1 is turned on.
T _in is held as a bias signal T _B , and this T _B is subtracted from the input T _in to obtain an output T _out . In particular,
As shown in Figure 4, initially a bias signal T _B left as an 0, output T when zero-point correction switch 1 is turned on
The opposite sign -T _out of _out (= T _in) as T _B, is held in a memory (not shown) or the like, after the zero point correction switch 1 is turned off, it is to the sum of T _in the T _B and T _out .

Therefore, the output T _out when the zero point correction switch 1 is turned on.
Becomes zero.

T _B = T _in T _out = T _in -T _B = 0 Here, in a state where the slave arm is in a no-load state, the zero point correction switch 1 is turned on and an input corresponding to AB or BC in FIG.
If holding the T _in the bias signal T _B, the output T _out from the torque sensor 2 will have been corrected zero.

T _out = T _in -T _B Thereafter, the output T _{out in} a state where an external force is applied to the slave arm is an ideal output proportional to the external force acting on the slave arm.

D. Problems to be Solved by the Invention However, in the conventional zero-point correction circuit C, since the zero-point correction switch 1 is provided as a dedicated switch, it is necessary for the operator to operate the zero-point correction switch 1 consciously.

In order to perform such an operation during the operation of the master arm, since both hands of the operator are occupied, the above-mentioned zero-point correction switch 1 may be used as a foot switch, or another worker may be required to use the zero-point correction switch 1. Had to be operated.

Further, when the operation of the master arm is temporarily stopped and then operated again, AB and BC shown in FIG. 3 are interchanged or their sizes change. Therefore, each time the master arm is restarted, the zero point correction switch 1 is operated. It was necessary and complicated.

The present invention has been made in view of the above-described conventional technology, and has as its object to improve the operability of a zero point correction circuit by using a zero point correction switch as a dual-purpose switch.

E. Means and Action for Solving the Problems In the present invention, the bilateral function of remotely controlling the slave arm to follow the master arm by turning on the optical switch by grasping the operation grip of the master arm is provided. In the master-slave type manipulator, a zero-point correction switch of a zero-point correction circuit for removing hysteresis of a torque sensor provided in a slave arm is also used as the optical switch.

For this reason, when the operator releases the operation grip and turns off the optical switch, it is automatically turned on each time as a zero point correction switch, and a true reaction force excluding hysteresis etc. can be output by the zero point correction circuit, so that it can be output. This eliminates the complexity of intentionally turning on the zero correction switch.

F. Examples Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 5 show an embodiment of the present invention. As shown in FIG. 5, in a master-slave type manipulator having a bilateral function, the master arm 3 generally includes an upper arm X, a forearm Y, and a wrist Z. As shown in FIG. 1, an operation grip 4 gripped by an operator is attached to the wrist Z, and an optical switch 5 is provided in a window formed in the operation grip 4.

The optical switch 5 is a switch for performing a master operation, and is provided with a light emitting unit 5a and a light receiving unit 5b adjacent to each other. Therefore, the operator grips the operation grip 4 and
When the light emitted from the light emitting unit 5a is reflected on the hand and received by the light receiving unit 5b, the optical switch 5 is turned on, and the operation with the master arm 3 becomes possible.

When the operator releases the operation grip 4 and the light is not received by the light receiving section 5b, the optical switch 5 is turned off, and the master operation cannot be performed.

Here, the master operation is to remotely operate a slave arm (not shown) by following the master arm 3.

In the present invention, the optical switch 5 is also used as the zero point correction switch 1 of the zero point correction circuit C shown in FIG.

That is, when the optical switch 5 is turned off, the zero point correction switch 1 is turned on, and the zero point correction circuit C
To hold the input T _in the torque sensor 2 at that time as a bias signal T _B.

T _B = T _in Here, when the operator releases the operation grip 4, the slave arm is generally in a no-load state.

Therefore, if the operator releases his / her hand from the operation grip 4, the zero point can be corrected. This eliminates the need for assistance from other workers, and improves operability as compared with a foot switch.

After that, when the optical switch 5 is turned on and the master operation is performed by gripping the operation grip 4, the output as shown in the following expression is performed.
T _out hysteresis is removed by a bias signal T _B,
The value is proportional to the external force acting on the slave arm.

T _out = T _in −T _{B When} the master operation is stopped and then restarted,
Since AB and BC shown in FIG. 2 change, zero point correction is required each time. However, when the zero point correction switch 1 is also used as the optical switch 5 of the operation grip 4 as in the present invention, the zero point correction is automatically performed. It is very convenient without having to do it consciously.

In the above embodiment, the optical switch for performing the master operation is also used as the zero point correction switch. However, the optical switch may be replaced with a contact switch having the same function.

G. Effects of the Invention As described above in detail based on the embodiments, the present invention provides a zero-point correction switch used for setting a bias signal in a zero-point correction circuit by using an optical type switch provided on an operation grip. Since the switch is also used as the switch, the zero point correction by the zero point correction circuit is automatically executed every time the optical switch is turned on and off, so that the operability is improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an operation grip according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a zero point correction circuit, FIG. 3 is a graph showing an output of a torque sensor, and FIG. FIG. 5 is a front view of the master arm of the bilateral manipulator. In the drawing, 1 is a zero correction switch, 2 is a torque sensor, 3 is a master arm, 4 is an operation grip, 5 is an optical switch, 5a is a light emitting section, 5b is a light receiving section, AB and BC are torque sensor outputs, C Is a zero point correction circuit, X is an upper arm, Y is a forearm, and Z is a wrist.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B25J 3/00 B25J 13/02

Claims (1)

(57) [Claims] 1. A slave arm follows the master arm by detecting a reaction force generated in the slave arm with a torque sensor and transmitting the reaction force to the master arm, and holding an operation grip of the master arm to turn on an optical switch. In a master-slave type mass manipulator having a bilateral function for performing remote control, a detection signal from the torque sensor when a zero point correction switch is turned on is held as a bias signal, and the bias signal is obtained from the detection signal from the torque sensor. And a zero-point correction circuit for outputting the zero-point correction switch to the slave arm and using the optical-point switch as the zero-point correction switch.