JPH0795244B2 - Position control drive method - Google Patents

Description

The present invention relates to a position control driving method for transmitting a driving force of a driving body to a driven body via a power transmission mechanism.

B. SUMMARY OF THE INVENTION In the present invention, in an operating device that requires position control drive, only the final output shaft or joint shaft is free of rattling such as backlash, and two prime movers and a reducer or link are used to operate the shaft. The load and speed of joints can be controlled by configuring a drive system with two series of normal backlash, which are configured with Under the above conditions, two series of drives can be appropriately jointed with a phase difference.

C. Problems to be Solved by the Invention In a drive device for controlling a position or a rotation angle position, in order to obtain accuracy, it is necessary to reduce play or backlash in the drive device system such as a speed reducer or a link to obtain high accuracy. It was impossible to drive with position control. Therefore, in order to remove the backlash, the backlash was removed by a preloading mechanism or the like, but for that purpose, a large frictional resistance was generated during the operation, and it was not possible to perform fine feed and the position accuracy could not be obtained so much.

In particular, in a manipulator that requires a good sense of force, even if the friction resistance of the power transmission mechanism, reduction mechanism, etc. is not required, if there is backlash, increasing the drive system gain will cause oscillation and oscillation will occur easily. It was

D. Means and Actions for Solving the Problems In view of the above problems, the present invention performs the deviation processing of the first position detection signal of the drive system and the position command signal corresponding to the driven body to perform the first operation. Deviation signal is obtained, and the first deviation signal
A first drive system for controlling the drive source, and a position command signal and a phase difference command signal are calculated to obtain a calculation signal, and the calculation signal and the second position detection signal are subjected to deviation processing to obtain a second deviation. A signal is obtained, and a driven system having one degree of freedom is drive-controlled by a second drive system which controls a second drive source by the second deviation signal.

Further, according to the present invention, the first position detection signal of the drive system and the position command signal corresponding to the driven body are subjected to deviation processing to obtain a first deviation signal, and the first deviation source is used to generate the first driving source. A first drive system to be controlled, a phase difference command signal is obtained from the first deviation signal, and a second deviation signal is obtained by calculating the phase difference command signal and the position command signal. The second drive system for controlling the second drive source by the deviation signal of 1 drives and controls the driven system having one degree of freedom.

E. Examples The present invention will be specifically described below with reference to Examples shown in FIGS. 1 to 5.

The present invention relates to a driving method for driving one driven part by two driving prime movers. As shown in FIG. 5, motors 10 and 20 are used as drive motors. Power is transmitted to each motor in parallel by a speed reducer, a link, etc., which are necessary. The motors 10 and 20, and the speed reducers 11 and 21 of the respective motors preferably have a small backlash, but the preload is not applied so that the frictional resistance increases, and it is more efficient that there is some backlash. 12, 22 are output gears of the reduction gear, 30 is a main gear of the final target shaft, 32, 33 are bearings, and 31 is an arm fixed to the output shaft 30a. Here, a backlash required for efficient rotation is set between the gears 12 and 30 and the gears 22 and 30. However, the relationship between the gear 30 and the arm 31 is fixed so that there is no backlash, and the bearings 32 and 33 are configured to have no backlash even when a necessary preload is applied. As a result, some friction occurs, but since it has only one axis, it has little effect on the whole. Motor 10,2
Rotation angle position sensors (encoders etc.) 13 and 23 are attached to 0 respectively. The motors 10 and 20 are fixed to the machine base side by fixing frames 14 and 20, respectively. Such a configuration may be appropriately configured in various other ways within the scope of the following basic form.

First, two prime movers and a mechanism that allows the backlash required for efficient power transmission between the output shaft and the final drive target shaft are configured. However, the final axis is
A fixed structure that completely eliminates play between the shaft and the arm that performs work or the like by rotation of the shaft, and a bearing that receives this final output shaft is also preloaded to make it free from play. A rotational angle position sensor is attached to each of the two prime movers.

In the above structure, the present invention is characterized by being controlled and driven as follows.

(1) When the reference positions of the two rotation angle position sensors 13 and 23 are N = 0 and M = 0, respectively,
21 shall have a suitable backlash. Then N
It is possible to rotate by p ₁ so that the backlash up to the gear 30 is removed when the prime movers 10 and 20 make small rotations such that == p ₁ and M = −p ₁ (reverse rotation direction). Is. Further, when each prime mover is turned to N = + p ₁ + α and M = −p ₁ −α, it can be considered as α such that the speed reducers 11 and 21 and the like elastically generate a slight twist.

In this way, by shifting the drive positions of the two prime movers, the speed reducers 11 and 21 each having a backlash are individually provided.
Can be adjusted to any sufficiently small backlash, and even a state in which some elastic preload is applied can be selected. It can be selected regardless of whether it is stopped or accelerated or decelerated.

(2) These two prime movers use the gear 30 of the final target shaft,
It is natural that a large output can be obtained by driving the outputs of the two prime movers together if they are driven in synchronism.

(3) The drive transmission systems of these two prime movers, due to their mutual positions, have a relatively large backlash and operate lightly without friction, and conversely, under the load condition where the drive system easily oscillates. By driving with the removed phase difference, it is possible to select driving without oscillation even with a large gain.

(4) Send a rotation command to each of the two prime movers and use the sensor 1
When performing position control drive with feedback back at 3,23, if accuracy is required, drive with a phase difference even if there is some friction increase, or if only final position accuracy is required, At the beginning, the backlash is driven in the same phase with efficient co-tone drive, and the phase is gradually shifted after the object is approached to eliminate the backlash, and the braking is performed accurately and without oscillation due to overshoot near the target position. It is also possible to select a drive that does.

(5) In addition, the drive mechanical system and gears naturally expand with the time of use due to wear of the parts, but even in that case, readjustment of the flash just adjusts the direction to increase the phase difference between the two drive commands. You can solve it just by doing.

(6) In order to perform positioning drive with higher accuracy,
Although not shown in the figure, it is an application range where it is easy to perform servo control using the sensor information by attaching the rotational position sensor of the gear 30. Sensors 13 and 23 depending on the deviation value
Calculated from the information in the above and using the drive system backlash
It is possible to perform drive control in accordance with various conditions in an optimum state, such as re-driving only one side, or driving it in one direction, driving in a direction in which the backlash increases and reducing friction to re-drive again and finally stopping accurately.

(7) Such a drive exerts an effect similar to that of a human arm joint, etc., that is loose and shakes gently, or that force is applied to stiffen the joint and move it without shaking. Is.

In the above explanation, adjustment was done mainly with the backlash, but especially for machines that respond at high speed and manipulators that are required to output a large amount of light due to their own weight, the drive system itself is small and lightweight. , The elastic displacement also becomes large. Even in such a case, by applying the phase difference of the two-row drive system to a large phase difference so as to apply a preload to a range that also compensates for elastic displacement, it is difficult to control oscillation. You can also select.

The present invention relates to a position control drive method, the first feature is the use of two drive systems for the operation of one degree of freedom, and the second feature is to set the phase difference between the two drive systems. It is possible.

FIG. 1 shows an embodiment of the present invention, in which 10,20 are motors and 11,21
Is a speed reducer, and 13 and 23 are position sensors, which are the same as those in FIG. 5, including other symbols. Also, 15 and 25 are the motor 10 and
The drive amplifier drives 20 and operates each motor in response to the position deviation signals S10 and S20 from the control unit 40. The control unit 40 performs a deviation processing the position detection signals S ₁ a corresponding position by entering the position instruction S11 with respect to the driven member such as the arm portion 31 sensor 13, outputs the deviation signal S10 to the drive amplifier 15 and, at the same time performs a deviation processing from the position instruction S11 to the value S21 obtained by subtracting the phase difference command φ and the output S ₂ of the position sensor 23, and outputs the S20 to the driving amplifier 25. By the above control, the motor 10 is controlled so as to be the position command S11,
The motor 20 is controlled to a position command S21, that is, a position having a phase difference of φ from S11.

Next, the operation in which the motors 10 and 20 are not controlled with the phase difference of φ will be described. FIG. 2 is a schematic representation of the backlash of a reduction gear, etc., with the main gear 30 and the motor 1
The amount of backlash between 0 and 20 was assumed to be θ.

Now, if φ = 0 in FIG. 1, the motors 10 and 20
Have no phase difference and are controlled by the same position command. At this time, a constant backlash exists between the main gear 30 and the motors 10, 20, and the position command and the position of the main gear 30 may not match. Further, in order to eliminate this positional deviation, it is necessary to consider externally, such as performing control by applying a preload with a spring or the like. However, since the motors 10 and 20 operate in unison, they operate lightly.

Next, when φ = 0, the positions of the motor 10 and the motor 20 are controlled by the phase difference corresponding to the flash, so ideally, the flash does not exist, and the position command and the main gear are not present.
The position of 30 matches. Therefore, there is no need to take any measures such as compensating for the positional deviation as in the case of φ = 0. Further, since the motor 10 and the motor 20 operate while maintaining the phase difference of φ = θ, they do not interfere with each other and accordingly operate relatively lightly.

Further, when φ> θ, the phase difference between the motor 10 and the motor 20 is controlled to be larger than the backlash, so that the main gear 30 in FIG. 2 is just slanted in the opposite directions. Since it will be operated while matching, there is no backlash, but the operation becomes heavy. Also, the position of the main gear 30 when stopped does not match the position command,
It is expected that there will be some position where the torques of 10 and 20 will be balanced. However, it is possible to perform the control for eliminating the positional deviation without any external consideration by a method such as φ = θ after the suspension of the load.

Further, in the range of 0 <φ <θ, there is a backlash, and the position command and the position of the main gear do not match is φ = 0.
However, since the motors 10 and 20 do not necessarily perform the coordinating work, the easiness of operation is about the same as when φ = θ.

The above description is tabulated below.

According to this, when the position control driving method of the present invention is realized with a phase difference of φ = θ, there is no backlash, there is no position deviation with respect to the position command, and in addition, the position control of the final target axis is performed with a relatively light motion. It can be seen that driving is possible.

FIG. 3 shows another embodiment of the present invention. In the above-mentioned embodiment, the position control driving method is shown in which the phase difference φ for the two drive systems is set to a constant value. Command
It is characterized in that the phase difference φ is changed in a predetermined pattern depending on the value of the deviation S10 between S11 and the position sensor output S ₁ . Most are the same as those in FIG. 1, except that the phase difference φ is not set from the outside and the phase difference determination unit 41
It is to decide based on the value of S10. The phase difference determination unit 41 determines φ in the pattern shown in FIG. 4, for example.
The main point of FIG. 4 is that first, when the difference S10 between the position command S11 and the position of the main gear 13 is large, φ = 0 and the motors 10 and 20 are operated in a coordinated manner, and are driven lightly. Until S10 approaches 0 and stops, φ = θ is set and there is no backlash, and position control and position-free control are performed. By performing control in this way, it is possible to drive the final target axis lightly, and therefore drive at high speed, ensuring position accuracy during stop and low speed operation. For example, manipulator joint drive. When applied to, the effect is great.

F. Effects of the Invention (a) The power transmission system from the prime mover to the final drive shaft may have a backlash in a normal state, and an optimal one can be selected from various reducers and link mechanisms. The backlash can be adjusted to any value according to the operating conditions according to the invention.

(B) Since the joint can be controlled in a relaxed state or a tightly bound state like the joint of a human arm, it is possible to perform fine work, or oscillation is unlikely to occur. If oscillation occurs, the relaxed state at that time can be set. It is possible to perform control to restore stability by changing it.

(C) In the field of manipulators, where it seems wasteful to have two drive systems, but where reliability is particularly required, the output is halved due to one failure, but operation is surplus on the other side. It is possible to improve the sex.

[Brief description of drawings]

FIG. 1 is a block connection diagram of a position control drive method according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a backlash, and FIG. 3 is a block connection diagram of a position drive control method according to another embodiment of the present invention. FIG. 4 is a diagram showing a pattern example of the phase difference determining unit, and FIG. 5 is a perspective view of a drive system showing an application example of the present invention. 10,20 …… Motor, 11,21 …… Reducer, 13,23 …… Position sensor, 12,22 …… Reducer output gear, 15,25 …… Drive amplifier, 30 …… Main gear, 31 …… Arm, 40 ... Control unit, 41 ... Phase difference determination unit.

Claims (2)

[Claims] 1. A plurality of drive systems independent of each other
In a driving device for driving a driven body having a degree of freedom, a first deviation signal is obtained by subtracting a first position detection signal and a position command signal corresponding to the driven body to obtain a first deviation signal. And a first drive system for controlling the first drive source, and a second deviation signal is obtained by subtracting the position command signal and the constant phase difference command signal from the second drive signal. It comprises a second drive system that subtracts the position detection signal to obtain a third deviation signal, and controls the second drive source by the third deviation signal, and comprises the first drive system and the second drive system. A position control driving method characterized in that the driven body having one degree of freedom is driven by a system. 2. A plurality of drive systems independent of each other
In a driving device for driving a driven body having a degree of freedom, a first deviation signal is obtained by subtracting a first position detection signal and a position command signal corresponding to the driven body to obtain a first deviation signal. And a phase difference command signal corresponding to the first deviation signal is determined from a preset pattern, and the phase difference command signal and the position command signal are subtracted. To obtain a second deviation signal, subtract the second deviation signal and the second position detection signal to obtain a third deviation signal, and control the second drive source by the third deviation signal. And a second drive system for driving the driven body having one degree of freedom.