JPS63229279A - Master arm controller for master-slave-bilateral servo-manipulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a master-slave bilateral servo manipulator that is operated by remote control by a human.
In particular, the present invention relates to a master arm control device that improves master operability.

[Conventional technology]

2. Description of the Related Art Conventionally, there has been a master-slave type pi-two-chill servo mechanism as a control mechanism for a manipulator for remote control by a human. As shown in Fig. 2, in a manipulator consisting of a master 1 and a slave 2, each of which is constructed of articulated arms, an operator operates an effector (hand) 11 attached to the tip of the master arm 1. By doing this, slave arm 2 is made to perform the same movement.
It is used to operate the vehicle. These controls are performed by the control device 3. However, when humans actually operated the master, there was a problem that it was extremely difficult to use. Conventionally, as a measure to improve the operability of the master, each joint 1a of the master 1
Friction compensation for compensating for the friction occurring at 1d (patent application 1983-
14816) and self-weight compensation that does not feed back the slave's own weight to the master (%Kasho 5l-119481
), but no consideration was given to the fact that the proximal joints are difficult to move, which will be discussed next.

[Problem that the invention seeks to solve]

When the operator operates the master, joint 1 on the effect device 11 side
In addition, the proximal joints, such as the base joint 1a, shoulder joint 1b, and elbow joint IC, are difficult to move. Therefore, when performing coarse positioning by moving the slave to the target position, the operator applies a large operating force with one hand to the master effector.
In some cases, it was necessary to operate the master with both hands. The main reason for this is thought to be that the gear ratio of the base motor is large. In order to improve the above problem, if a Tanabata on the base side is used with a large torque, the motor itself becomes a load on the base side motor, and a higher output motor is required, and the arm weight is large. There is a drawback that it becomes

The master 1 shown in FIG. 2 has a structure similar to that of a human arm, but as shown in FIG. 3, there is a master that is composed of pitch joints 48 to 4C and roll joints 5a to 5C.

In FIG. 3, these pitch joints and roll joints are arranged alternately. In a master having such a structure, degeneracy may easily occur in each joint depending on the posture of the manipulator. For example, when the pitch joints 4a, 4b, and 4c are aligned in a straight line, this corresponds to a degenerate relationship. When there is a degenerate relationship, each joint is not independent, so the operating force from the effector is not distributed to each joint. Therefore, like Iruma's master, which has a structure similar to the arm, the joints on the effector 11 side, where the gear ratio of the motor is small, are easy to move, and the joints on the base side, where the gear ratio is large, are difficult to move.

Therefore, when operating the master manipulator in a large manner, it is necessary to apply a large operating force with one hand or to operate the master with both hands.

Therefore, an object of the present invention is to reduce the operating force to the master by making the joint on the base side of the master arm easier to move in the coarse positioning mode of the master arm in a master-slave servo manipulator. The objective is to reduce the amount of damage and improve the operability of the master arm.

[Means for solving problems]

The above purpose is to provide an operation mode designation device for specifying coarse positioning mode and fine positioning mode of the master arm, a servo characteristic parameter input device, and a servo characteristic parameter change device in the pirate servo mechanism, and to adjust the feedback gain and viscosity coefficient. This is achieved by changing servo characteristic parameters such as servo characteristic parameters according to the specification of the operation mode.

[Effect]

The operator selects coarse positioning mode or fine positioning mode as the operation mode of the master arm using the operation mode specifying device. The servo temporal parameter changing device sets the servo characteristic parameter value input in advance or at the time of operation mode selection through the servo characteristic parameter input device as the servo characteristic parameter corresponding to the operation mode.

These processes are performed for each joint. In the case of the coarse positioning mode, the values of each servo characteristic parameter are set so that the joints on the proximal side move more easily and the joints on the wrist side move less easily. Therefore, by making it easier to move a desired joint according to the specified operation mode, the operating force applied to the master can be reduced and the operability of the master can be improved.

〔Example〕

Embodiment 1 As Embodiment 1, an embodiment in which the present invention is applied to a force feedback type bilateral servo mechanism will be described.

Fig. 4 shows an outline of the force feedback pi-2 chiral servo mechanism. FIG. 4 shows a control relationship regarding a corresponding one of the joint axes of master 1 and slave 2, which are composed of a plurality of joint axes as shown in FIG. Reference numeral 10 in FIG. 4 indicates a control system on the master side. In FIG. 2, when the operator operates the master 1, each joint 1a to 1d (ld has 3 degrees of freedom) of the master 1 moves in accordance with the operating force applied to that joint. As shown in FIG. 4, the amount of movement of the joint is detected by the position encoder 13 of the master, and compared with the output of the position encoder 23 which detects the amount of movement of the corresponding joint of the slave. , is controlled by a speed servo system consisting of a position/velocity converter 26, a servo amplifier 25, a current feedback resistor 28, and a motor 24 so as to be in the same position as the master joint.

On the other hand, the external force received by the slave 2 is detected by the force sensor 22, and the control system 10 on the master side compares it with the output of the master force sensor 12 to cancel the external force. 14, torque control is performed by a servo system composed of a current feedback resistor 18. This means that when the slave grasps a work object (not shown) with its hand 21 (Fig. 2) or when the slave comes into contact with an obstacle in the work environment, the operator can This means that the reaction force can be grasped. The friction compensation circuit 17 and self-weight compensation circuit 27 in FIG.
In order to accurately grasp the reaction force, this is to correct the friction generated by the gears of each joint of the master 1 and the weight of the slave 2 itself.

FIG. 1 is a diagram showing an embodiment of the present invention in which the force feedback gain and viscosity coefficient are used as characteristic parameters in the force feedback type bilateral servo mechanism as described above. The figure shows the parts corresponding to the control system 10 on the master side, and the subscripts a%f of the reference numeral 10, such as 10a to 10f, represent the parts corresponding to the respective joints or degrees of freedom of the master. Two operation modes will be considered: a coarse positioning mode in which the position of the effector 11 is roughly moved and roughly positioned, and a precise positioning mode in which the effector 11 is moved small and precisely positioned. Table 1 shows the amount of movement of the proximal joint in each mode, desired characteristics, etc.

Table 1 Motion amount and desired characteristics of the proximal joint For the wrist joint, everything is opposite to Table 1 compared to the case of the proximal joint. In the case of coarse positioning, it is necessary to operate the master largely, so the base side joints that make a large contribution to the amount of movement are made easier to operate, and the wrist side joints that make a small contribution to the amount of movement are operated on the base side joints. In order to transmit force, it is required to have rigidity, that is, to be difficult to move. Considering this physically, the proximal joint needs to have low viscosity and be able to move easily even with a small operating force. A viscosity compensation circuit 53 is provided to control viscosity.

The viscous torque V is expressed by the formula (1), where ω is the movement speed of the joint.
It can be expressed as

v=r←)ω ・・・・・・・・・(1) Here, f←
): Viscosity function The form of the viscosity function f←) depends on how damping effects and the like are to be imparted. For example, f←)=Kv (constant) (2). The speed detection circuit 52 is a circuit that calculates the motion speed ω of the joint, and uses the output Ni1i of the master position encoder 13 to calculate it using equation (3).

Here, τ is the sampling period subscript at the encoder sampling time, and -1 indicates one sample before.

In order to control the ease of movement of each joint of the master, the feedback gain Kf is set by the feedback gain setting device 5.
Change it with 1. In coarse positioning mode, the viscosity coefficient
Table 2 shows how to change 4 to the feedback gain.

Table 2 Parameter value in coarse positioning mode Increasing the feedback gain Kf means that the output torque of the motor 14 increases because a positive loop is formed from the master force sensor 12 to the motor 14. The purpose is to increase the operating speed and make it easier to move. The smaller the viscosity coefficient K·b, the lower the viscosity, so in the rough positioning mode, the smaller the base side joint, the easier it is to move. However, if the feedback gain Kf is too large, the system tends to become unstable, so the viscosity compensation must serve as a damper, so the viscosity coefficient cannot be made smaller by 11. Considering this, the viscosity coefficient is, as shown in Figure 5,
It is better to set the value to be large when the speed is high and small when the speed is low.

In FIG. 1, the operator specifies the operation mode using the operation mode designation device 56. Then, the specific parameter converter 54
The feedback gain setter 51 and the viscosity compensation circuit 53 are supplied with the values of each parameter Kf and , which are preset as shown in Table 2 in the coarse positioning mode, and vice versa in the precise positioning mode. is set.

Here, the values of each parameter Kf given by the characteristic parameter converter 54 are inputted by the characteristic parameter input device 55. After that, when the operator operates the master, characteristic parameters are defined for each joint according to the operation mode, and the desired motion can be achieved even with a small operating force.

In the above description, the operation mode has been explained separately for the base side joint and the wrist side joint, but the same applies to the operation mode specified for each joint.

Embodiment 2 Next, an embodiment in which the present invention is applied to a symmetrical bilateral servo mechanism will be described with reference to FIG.

This section provides an overview of the symmetrical pirate servo mechanism.

In the symmetrical bilateral servo mechanism, corresponding joints of master 1 and slave 2 are controlled according to a difference 6 between the positions of corresponding joints of master 1 and slave 2 (outputs of encoders 13 and 23). In the present invention, a position feedback gain compensator 58 is provided and the feedback gain Kg is controlled to vary according to 1, thereby controlling the characteristics of each joint of the sea master. The overall gain KZ of the loop regarding the master is given by equation (4), where 57 is a multiplier.

Kz== K, (4) In a symmetrical bilateral servo mechanism, there is positive feedback for the master loop, so when g>0, the larger K is, the more The master will be able to move easily. Example 1 of operation mode
Similarly, it is divided into coarse positioning mode and fine positioning mode. If a value of 6 is set for the feedback gain in the coarse positioning mode as shown in Table 3, the base joint will be easy to move and the wrist joint will be difficult to move in the coarse positioning mode. On the other hand, in the case of precise positioning, setting K1 in the opposite direction allows the wrist side joint to move more easily.

Table 3 Operation mode designation device 56, characteristic parameter input device 55
, the function of the characteristic parameter converter 54 is similar to that of the first embodiment.

Both the first and second embodiments described above are so-called similar master arm type manipulators that control the joint rotation angles of the slave to correspond to the joint rotation angles of the master, so that the movements of the former follow the movements of the latter. As explained above, even in the so-called different-structured master-slave maniverator where the master and slave structures are different, control is performed by decomposing the force applied to the tip such as the wrist and the force and position of each joint determined from the position and orientation of the tip. It can be controlled in the same way as Kotoyoshi.

〔Effect of the invention〕

As explained above, according to the present invention, by changing the servo characteristic parameters such as the feedback gain and viscosity coefficient of the pi-2-chiral servo mechanism for each joint of the master depending on the operation mode of coarse positioning or fine positioning, The operating force can be reduced and a master with good operability can be provided.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment in which the present invention is applied to a force feedback type pi-2 chiral servo mechanism, Fig. 2 is a schematic diagram of a master-slave type manipulator, and Fig. 3 is a diagram showing an example in which pitch joints and roll joints are arranged alternately. Figure 4 is a diagram showing a conventional force feedback type bilateral servo mechanism, Figure 5 is a characteristic diagram of a preferred viscosity coefficient, and Figure 6 is a diagram showing the application of the present invention to a symmetrical type bilateral servo mechanism. FIG. Description of symbols 1...Master 2...Slave 3...Control device 51...Cafe feedback gain setter 53...Viscosity compensation circuit 54...Characteristic parameter converter 55...Characteristic parameter input Device 56...Operating mode designation device 58...Position feedback gain compensator.

Claims (1)

[Claims] 1. An operation mode specifying device that specifies the operation mode of the master arm as either a coarse positioning mode or a fine positioning mode, and a control mode for each joint of the master arm according to the operation mode specified by the operation mode specifying device. and a control parameter input device that inputs servo characteristic parameters for each joint of the master arm corresponding to the operation mode into the parameter change device. A master arm control device for a master/slave/pillateral servo/manipulator, characterized in that when specified, servo characteristic parameters for each joint of the master arm are set so that the proximal joint of the master moves more easily. 2. A master arm control device for a master/slave pilateral servo manipulator according to claim 1, wherein the master/slave pirate servo/manipulator is a force feedback type bilateral servo mechanism. 3. A master arm control device for a master-slave bilateral servo manipulator according to claim 2, wherein the servo characteristic parameter to be changed is a force feedback gain of the master. 4. The master arm control device for a master/slave pilateral servo manipulator according to claim 2, wherein the servo characteristic parameter to be changed is a viscosity coefficient of a viscosity compensation means that provides viscosity to each joint of the master. 5. A master arm control device for a master/slave pilateral servo manipulator according to claim 1, wherein the master/slave pirate servo manipulator is a symmetrical pirate servo mechanism. 6. The master arm control device for a master-slave bilateral servo manipulator according to claim 5, wherein the servo characteristic parameter to be changed is a master position servo feedback gain.