JPH0366543A - Speed control method corresponding to weight of work - Google Patents

Abstract

PURPOSE:To select an optimum transport speed corresponding to a load by axially moving a work loaded pallet together with a machine table at a constant speed, and replacing an increase portion against current value at no load on the table with the parameter of a transport speed. CONSTITUTION:A no load current value (a) at which a table 1 is driven in no load condition with an instituted constant speed, in detected current values sent from a X-shaft driving part 17, is stored in a current memory and comparison part 19. A loaded current value (b) at which it is driven in work 3 loaded condition with the same speed, is compared with the value (a), and an increase portion (c) is obtained. The increase portion value (c) is replaced with the parameter of transport speed of a pallet 2, and the transport speed is decided in an optimum speed deciding part 20. The pallet number and the optimum speed are stored in an optimum speed memory part 21, a corresponding speed is drawn out by APC drive command, and the pallet 2 is transported at the optimum speed with a servo motor 4, corresponding to the load.

Description

[Detailed description of the invention] Industrial application field The present invention relates to an automatic pallet moving device (hereinafter referred to as APC).
1IIIll of the pallet movement speed of ? This relates to the ff1 method.

BACKGROUND OF THE INVENTION The exchange speed of conventional APCs is set at a constant speed based on the maximum allowable load weight to protect the machine.

Problems to be Solved by the Invention The APC speed, which is set based on the maximum allowable load weight as described in the prior art, has the problem of inefficiency because it takes longer than necessary for light workpieces. .

The present invention was made in view of the above-mentioned problems of the conventional technology, and its purpose is to improve the safety range of the mechanical structure according to the weight of the workpieces on the pallet, fixtures, etc. The object of the present invention is to provide a speed control method that can control the maximum speed of the motor.

Means for Solving the Problems In order to achieve the above object, the workpiece weight responsive speed control method of the present invention moves the barre 7) loaded with the workpiece at a constant speed together with the machine table, and The increment relative to the current value when the pallet is empty is replaced with the pallet conveyance speed parameter, and the corresponding optimum pallet conveyance speed is selected.

In addition, the total weight of the workpiece and its fixtures can be input directly, and the input weight can be converted into the current value when both the pallet and the machine table are moved at a constant speed. The corresponding optimum pallet transport speed is selected by replacing the increment with respect to the current value with the parameter of barre +-S transport speed.

The increment is calculated by comparing the load current when a pallet loaded with workpieces is placed on the machine table and the axis is moved at a constant speed, and the no-load current when the machine table is empty. Or, if the total weight of the workpiece and its attachments is known, enter the weight directly, convert it to a load current value, compare it to the no-load current value to find the increment, and use this increment to determine the optimum value. Determine pallet transport speed. Then, the pallet transport speed of the APC is controlled using the determined speed as a command value.

Embodiment An embodiment will be explained with reference to FIGS. 1 and 2. In a known machining center with APC, a table 1 is movably placed on a sliding guide surface in the X-axis direction cut on a bed, a pallet 22 is exchangeably placed on the table 1, and Workpiece 3 is attached to. The table 1 is moved and positioned by a servo motor 4 fixed to the bed via a ball screw 5.

A plurality of pallets 2 are placed on the APC 6 installed on the floor in front of the bed so that they can be indexed to the exchange position.
The pallet on APC6 or the pallet on table 1 is
Pallets are exchanged by moving along guides in two axes (front and back) provided on the APC frame. Palette 2
The movement is carried out by a hook 9 moved by a servo motor 7 fixed to the frame via a ball screw 8 and removably engaged with the pallet 2.

Next, the feed axis servo system will be explained with reference to the block diagram section in FIG. 1. The 0 manual input section 11 is a section provided on the NC operation panel where information is manually input using input keys, switches, switches, etc. The program input section 12 is a section for inputting information using a tape or the like. The position control unit 13 compares the input position command value with the current position from the position configurator 14 and outputs a signal, and the speed control unit 15 performs acceleration/deceleration control n at the time of starting and stopping. The current control section 16 is a section that converts the commanded speed into a current value and controls the current, the X-axis drive section 17 is a section that drives the X-axis servo motor 4, and the Apcu movement section 18 is a section that maintains the specified speed. A
This is the part that drives the PC servo motor 7, and the above is no different from a general NC servo system. Table 1 at a constant speed
Store the no-load current value a when the is driven in an empty state, and compare it with the current value a when the workpiece 3 to be measured is mounted and the load current value is driven under the same conditions. (b-
a) A part that calculates the increment C, an optimal speed determining unit 20, a part that determines an optimal pallet transport speed including acceleration and deceleration by replacing the value of the increment C with a pre-stored pallet transport speed parameter, an optimal speed storage unit 21 is a part in which the determined optimum speed is recorded together with the pallet number. The workpiece weight-to-radio wave converter 22 is a part that converts the directly written workpiece weight into a load special current value b' of the X-axis servo motor 4 when the workpiece weight is a predetermined value.

Next, regarding the operation of this embodiment, the flowchart shown in Fig. 2 will be explained.
・Explain according to the diagram. First, in the measurement program when the workpiece weight is unknown, the first workpiece 3 is loaded on the pallet 2 in step S2, manual mode is selected by the manual input section 11 in step S2, and in step S3, the first workpiece 3 is loaded on the pallet 2. The pallet 2 of the machine is carried onto the chiffle 1 of the machine at the minimum speed. In step S4, the parameter mode is selected by the manual input unit 11, in step S5, the workpiece electricity measurement function key is selected, and in step S6, the pallet 2 loaded with the first workpiece according to the guidance display on the CRT screen
is moved in the X-axis direction at a predetermined table feed rate. In step S7, the load current value of the X-axis servo motor 4 at this time is detected, and in step S8, the current comparator 19 compares this current value t with the previously stored no-load current value a. are compared to determine the increment C.

In step S9, the optimum speed determination unit 20 increments C.
The pallet transport speed is determined by replacing the value of with the pallet transport speed parameter. In step 310, the optimum speed is stored together with the current number in the optimum speed storage unit 21. In step 311, confirmation is made on the parameter screen displayed on the CTR. In step 312, it is confirmed whether there is any next measurement work, and if NO If so, the process returns to step S1, and if YES, the measurement program ends this winter.

Next is work! ! In the data setting program when the amount is known, in step 313, the total amount of the workpiece 3 and its fixtures on the pallet is directly written in by the manual input section 11, and in step S14, the load is written in the workpiece weight-to-current conversion section 22. The process proceeds to step S8, where it is compared with the no-load current value a to obtain an increment C. Steps S9 to S12 have already been explained and will therefore be omitted.

Next, enter the execution program, set the operation mode in step 315, select the NC program (or manual) in step 316, and select A in step S17.
A drive command for the PC 6 is output, and a pallet number is designated at the same time in step 31B. In step S19, the optimum speed corresponding to the current number is extracted by the optimum speed storage section 21 and outputted to the speed control section 15, and in step S20, the optimum speed corresponding to the valent number is extracted and outputted to the speed control section 15. Current wI Oshibe 1
6 The APC servo motor 7 is rotated via the APC decoder 18 to move the pallet 2.

Effects of the Invention Since the present invention is configured as described above, it produces the following effects.

A pallet loaded with workpieces is placed on the table of this machine, the axis is moved at a constant speed, and the load current value at this time is compared with the no-load current value when the table top is empty. AP with the optimum speed determined by the increment as the command value.
The conveyance speed of the C-barret is controlled, so that heavy workpieces are exchanged at a slow speed that does not exceed the machine protection limit, and lightweight workpieces are exchanged at an efficient fast speed. Therefore, the APC speed, which is the non-machining time, can be shortened to the limit and it is effective in protecting the machine.

Additionally, if the total weight of the workpiece and its attachments is known, the workpiece weight can be directly entered as data, converted to a load current value, and the increment determined to determine the optimal pallet transport speed. This machine shortens the measurement time on the table, further improving efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the feed axis servo system including a part of the machine table drive section and APC drive section, and FIG. 2 is a flow chart diagram for explaining the operation of this embodiment. 1. Machine table 2. Pallet 3. Workpiece
6.APC

Claims (2)

[Claims] (1) In the pallet exchange speed control method of the automatic pallet exchange device (6), the pallet loaded with the workpiece (3) (
2) is moved along with the machine table (1) at a constant speed, and the increment (c) relative to the current value (a) when the machine table is empty is replaced with the pallet transport speed parameter, and the corresponding optimal pallet is calculated. A speed control method corresponding to the weight of a workpiece, which is characterized by selecting a transport speed. (2) In the pallet exchange speed control method of the automatic pallet exchange device (6), the total weight of the workpiece (3) and its fixtures is directly input as data, and the input weight is transferred to the pallet (2) and the machine table (1). Convert the current value (b') when moving at a constant speed to the current value (a) when the machine table is empty, and replace the increment (c') with the pallet transport speed parameter. A speed control method corresponding to the weight of a workpiece, which is characterized by selecting an optimal pallet transport speed.