JPH0160381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automated batch assembly technique using a manipulator controlled by a computer program. More specifically, the present invention provides job settings,
It relates to automated robotic batch assembly or processing of small jobs without downtime that requires reliance on operators for activities related to changes or error conditions.

[Background technique]

Applications of conventional robots in the industrial field are numerous and well known. Many robots are dedicated to a single specific type of highly repetitive task, such as spot welding, spray application, loading and unloading. Other applications for robots are light processing tasks such as deburring, drilling or tapping. Each of these robotics applications can be operated according to computer programmed patterns. During assembly or processing, robots are used as dedicated parts of rigid systems that operate on large numbers of identical or family subassemblies. It is generally uneconomical to use one robot for more than one application. This is because there is a lot of human and machine downtime associated with switching or configuring applications.

It has been found that more than two-thirds of all human effort expended in manufacturing is spent processing batches of work consisting of fewer than 50 parts. Robotics experts generally do not expect robots to operate at much higher throughput rates than 150% of human throughput rates for the same assembly task. In the case of assembly or processing of small volumes or small lots, the time, effort and cost expended in setting up and changing tools, parts, etc. when switching from one assembly task to another can be eliminated when automating this task. easily surpasses the high throughput and other advantages of Furthermore, set-up/change times controlled by human operators reduce productivity and result in loss of capital. Similarly, if settings/changes are made within the robot's work envelope, there may be a risk to the operator.

[Disclosure of the present invention]

The present invention relates to apparatus relating to the efficient operation of robots programmed for small lot assembly or processing operations. The apparatus of the present invention combines a mobile work station or wheelbarrow with a self-contained task to provide a highly sophisticated system consisting of a manipulator that can move in multiple degrees of freedom and a device that provides feedback regarding its position and condition. Including robots. Each task wheelbarrow contains the necessary tools and/or parts to enable the robot to perform this task. The manipulator is suitably programmed to grasp the tool and perform the desired sequence of operations on the parts that may be applied to the desired wheelbarrow. Once one task is completed, either satisfactorily or unsatisfactorily, the manipulator advances to the wheelbarrow of other tasks. The wheelbarrow is suitable for offline use and is brought within the working envelope of the robot, thus significantly reducing downtime.

In some applications, there is a need to distribute a supply of tools and parts on one or more wheelbarrows. Conversely, several unrelated tasks can be worked on one wheelbarrow. Great flexibility is gained using the present invention.

[BEST MODE FOR CARRYING OUT THE INVENTION]

The robot and computing devices described have been chosen for illustrative purposes, and it will be clear that other types of robots and related devices may be used without departing from the scope of the invention.

Please refer to FIG. 1 to understand an exemplary system for operating a robot, generally designated 8. An automated manipulator 10 is mounted at the end of the arm 14. Arm 14 is movable along and at right angles to arm 16 by means of a motorized trolley 18. Arm 16 is connected at one end to idler support trolley 24. The other end of the arm 16 is connected to a trolley 26 having a motor. Trolleys 24 and 26 are movable along parallel tracks 28 and 30, respectively. Hoses and lines for supplying fluid power and electrical power to the trolley are not shown. Track 28 is pillar 36
and 38 to the base 34 . Track 30 is connected to base 34 by posts 42 and 44. Columns 42 and 44 are column 3
6 and 38, the arm 14 and thus the manipulator 10 are oriented at an angle from the vertical. For the structure shown, an offset of about 30 degrees has been found to be advantageous. The upper frame, consisting of tracks 28 and 30 and rails 46 and 48, is offset approximately 30 DEG from horizontal to support manipulator 10 in the desired position. The work envelope of the robot 8 includes the space enclosed by the tracks 28 and 30 and the rails 46 and 48 and the dashed line 51.

The robot's work envelope is divided into three independent work areas. Broken line areas 52, 54 and 5
6 represents the position of a wheelbarrow or mobile work station with its own tasks that can be brought into the work envelope when work is to be performed by the robot 8. Three corresponding ports 53, 55 and 5
7 is present inside the base 34. Each port 5
3, 55, and 57 include alignment posts 58 that engage alignment apertures present on any wheelbarrow. A rotatable air clamp type latch 59 is provided at each port to lock the mobile work station in place. The latches 59 at ports 53, 55, 57 are shown in different relative positions to indicate that they are rotatable. Manipulator 1
0 is positioned under computer control by a fluid-powered movable arm 14. A suitable manipulator is disclosed in US Pat. No. 4,132,318.
An exemplary control system is also shown in FIG. 1 and includes a keyboard display input/output device 6 for input.
2, a processor/storage device 64, a printer 66 for hard copy output, and a fluid power source 68.

The details of the system components described above are not directly relevant to the present invention. IBM Robot System/1 General
Information Manual and Users' Guide GA34−
0180-1 and related updated editions of the Technical Newsletter.

FIG. 2 is a perspective view of the robot 8 from the front of FIG. 1 with two task carts 104 and 106 positioned at locations 56 and 54, respectively, of FIG. Wheelbarrow 104 carries gears 108 and 10 from gravity feedable trays 110 and 111.
9 has been set up for assembly tasks including positioning. Tool 112 is specifically designed to position gears 108 and 109 on gear plate 114. To accomplish this task, the tool 112 uses a gravity-fed source 115.
Pick up the plate 114 and place it on the fixture 116. Completed subassembly 11 consisting of plates and gears
8 is then dropped into chute 120. Chute 120 communicates with a container (not shown) that can be emptied at will by a human operator.
A determination post 117 is present adjacent to the fixture 116 . This decision column 117 is used by the robot to accurately relate the position of the task cart 104 to the position of the manipulator 10.

Wheelbarrow 106 is set up for other tasks that may be completely unrelated to the tasks on wheelbarrow 104. Wheelbarrow 106 is provided with a tool 122 for picking up parts from area 124 and placing them on a subassembly in area 126, and dropping the subassembly into chute 128 upon completion. The judgment pillar 129 is similar to the judgment pillar 117 described above.
used in the same way as the wheelbarrow, in this case 10
6 positions are precisely related to the manipulator 10.

Each wheelbarrow generally has the following common characteristics: (1) Having a source of parts to be assembled into a given subassembly. (2) Has a work area for performing assembly. (3) There is a judgment column used to measure the relative position of the manipulator within the working envelope of the handcart and robot. (4) Having a receiving area for the completed subassembly and one or more tools to accomplish the task. Each tool has 10 manipulators
It is uniform in that it can be grasped by. That is, each tool is aligned with a gripping portion of the manipulator 10 so that it can move together with the manipulator 10.
Each barrow also has an alignment and locking device (FIG. 3) to allow the barrow to be used in any of the barrow positions 52, 54 and 56 (FIG. 1). The primary working surface of each wheelbarrow extends upwardly from the upper surface 50 on the base 34 upon which all robots 8 are mounted, as illustrated by the side portions 127 of the wheelbarrow 106 (FIG. 2).
It's tilted 30 degrees. The construction of this movable wheelbarrow and its location with the manipulator provides other advantages. That is, no complicated mechanical parts feeding device is required, and feeding by gravity is sufficient.

Other advantages result from an arrangement such as that shown in FIG. By dividing the work envelope of the robot 8 into sections, the manipulator automatically progresses from one task to another until all work is completed for all task barrows. Furthermore, smaller sections improve cycle times and reduce wear and tear on the manipulator mechanism.

FIG. 3 shows a movable self-contained task cart 130 suitable for conveying screws from a supply tube 132 to brackets being removed from a stack 140. Tools 144 for these tasks are contained in a special holder 146. A decision column 148 is provided for determining the position of the manipulator.

In this particular case, tool 144 is suitable for performing one or more tasks. That is, it picks up a bracket from stack 140 and places it in work area 150. When the work on the bracket is completed, the bracket is placed in bin 154.
Bin 1 is placed in chute 152 guided by
54 and removed by the operator.

It should be noted that the structure of equipment on wheelbarrow 130 is exemplary. The optimum location of the fixture will vary from application to application and is to some extent a matter of choice. It is often desirable to provide multiple sources for a single input component in order to increase the interval between refeeding the wheelbarrow and increase the possibility of error recovery due to misfeeding.

Alignment apertures 160 are provided in the front rail 158 to properly position the wheelbarrow 130 within the robot's work envelope, and the robot's base 34
It is adapted to receive the alignment pillar 58 therein. A latch 59 (FIG. 1) in the robot's base 34 cooperates with the front rail 158 of the wheelbarrow. The rotatable latch 59 moves the rail 158 rearward to pull the barrow into its final position and lock it.

The surface 50 of the robot base 34 is level and raised sufficiently above the floor to coincide with the front edge of the wheelbarrow. As shown in FIG. 3, it is embodied as a front rail 158. This height is chosen to provide comfort for the seated operator. Such a structure is desirable for maximizing the use of the wheelbarrow. The wheelbarrow is not limited to use with robots, but can also be used as a traditional non-automated mobile work station for small jobs or quick jobs.

Individual task barrows, also referred to as adaptive subassembly barrows, are designed and equipped to support specific assembly applications. One advantage of this technique is that it facilitates the development of new applications. Given a basic wheelbarrow design,
Through many trials, engineers are able to manufacture, test, and modify actual wheelbarrows before relying on large human/mechanical resources. Certain applications require two or more identically designed and equipped wheelbarrows so that a large number of individual subassemblies can be manufactured.

The adaptive assembly system of the present invention can accommodate such changes. After all, once a task wheelbarrow assembly application has been developed and debugged, this program can be stored and recalled as needed for the robot to perform a given task.

Reference is now made to FIG. 4, which is a flow diagram of the entire process of adaptive batch assembly using the present invention. Considerable attention and time is spent during the wheelbarrow and software design stages in determining the optimal use of expensive equipment and human resources. Therefore,
The process begins at entry point 200 and decision block 204 determines whether there is more work to be done in setting up a particular manufacturing run. If the answer is YES, the wheelbarrow is designed and equipped. The time spent at this stage will of course vary depending on the complexity of the task and is an iterative process.

Block 208 represents hardware design and testing, and block 212 represents program design and testing. This program is the software necessary to command the manipulator to perform the tasks set out on the wheelbarrow. This program is also an iterative process. This is because not only direct assembly activities but also appropriate error routines must be developed. Details of this design stage do not form part of the invention. A particular language associated with a particular manipulator is program support provided for the IBM Robotic System I A Machine.
Language (AML).

At decision block 216, a determination is made whether the robot is ready to begin work, in other words whether all barrows and programming have been attempted or the robot is ready for a production run. If not, the process continues at decision block 204. However, when the wheelbarrow is ready, they are positioned in their respective positions (see FIG. 1), as indicated by block 220.

The control system software allows task 1
As part of the process, priorities are assigned at block 224. One major advantage of the adaptive batch assembly technique of the present invention is that it can optimize the use of robots and reduce the need for human operator intervention.
One way to achieve this advantage is to prioritize the robot's work relative to the wheelbarrows directed to a given task. Briefly, the robot's control includes the ability to perform tasks on the wheelbarrows at locations 52, 54, and 56 in any order. Alternatively, these positions may be assigned a particular priority and the wheelbarrow may be positioned accordingly.

The task is performed as shown at 230, leaving the operator free to attend to other duties.
When all tasks are completed, the end of the process is reached, as indicated by terminal 240.

Processing block 230 of FIG. 4 is illustrated in FIG. 5 as a set of decisions and actions. Each task, ie, each set of actions and decisions associated with the wheelbarrow, includes: This processing block is entered at terminal 231. The robot performs the previously programmed steps of the task as shown in block 232. As each step or series of steps is completed, a determination is made at decision block 233 whether it was completed successfully. If YES, the program determines at block 234 whether it has completed performing the series of steps. If not, control returns to the task execution stage block 232. The essence of determining whether the performance of a given task is complete is a check on the status of parts supply. If parts are missing, a decision is made that no more work can be done on this task.

A determination is then made at decision block 235 whether this is the last task or last wheelbarrow. If it is the last task, the process returns to the basic process of FIG. 4 as indicated by.

When the last task is not completed, the system of the present invention immediately and automatically switches to the next task on the next priority wheelbarrow located within the robot's work envelope. This next task follows much the same general flow as described above.

Returning to decision block 233, if a particular manipulator movement is not performed satisfactorily or an error condition occurs, an error routine shown at block 237 is entered. Regardless of the actual state of any error routine, determine whether a minimally successful recovery is possible and attempt recovery. If decision block 238 determines that recovery from the erroneous condition has been achieved, the robot continues through its preprogrammed steps. dashed line 239
The steps forming the loop enclosed by are repeated. This is because various error conditions may occur when performing particular task steps in block 232. Some examples include misdelivery of parts, part-to-part variations, and deviations from part specifications. Such conditions are often detected by a sensor in the gripper or manipulator 10 or by a particular tool held in the gripper in the manipulator 10. However, if the error condition is such that it cannot be successfully recovered after multiple attempts, the task is automatically switched to the next lower priority task barrow. Such switching is, of course, accompanied by the provision of an audible or visual signal to the operator as a warning, as is well known to those skilled in the art.
However, please note that robots are not playing around.

Although the invention has been described with particular hardware and software, its basic concepts are applicable to other situations. For example, the robot can be human-shaped or a different, less complex robot, such as a pedestal-shaped robot mounted on the floor, ceiling or wall. Furthermore, IBM Robot System I
A robot can be used whose work envelope is described in polar rather than rectangular coordinates.
Robots with various degrees of freedom may be used, and the manipulator may or may not be tilted with arbitrary displacements.

The wheelbarrow can be designed to suit the particular contours of the selected robot's work envelope. For example, a pedestal-shaped human robot can be centrally positioned such that a wheelbarrow can be latched in a suitable radial position around the pedestal-shaped base. Obviously the working surface can be flat or sloped.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating an exemplary hardware configuration for implementing the present invention. FIG. 2 is a perspective view of the work envelope of the robot of FIG. 1 with two task barrows in operating position; FIG. 3 shows a wheelbarrow set up for the third task. FIG. 4 is a flow diagram of the operation of the system of the present invention. FIG. 5 is a more detailed flowchart of one of the process blocks of FIG. 8...Robot, 10...Manipulator, 1
4, 16... Arm, 24, 26... Trolley, 34
... Base, 52, 54, 56 ... Mobile work station, 53, 55, 57 ... Port, 62 ...
... Display input/output device, 64 ... Processor/storage device, 66 ... Printing machine, 68 ... Fluid power source, 10
4,106,130...Task wheelbarrow.

Claims (1)

[Claims] 1. A frame to which a plurality of work stations can be mounted at once; a programmable manipulator supported by the frame and capable of gripping various tools; and a plurality of manipulators movable so as to be attached to and detached from the frame respectively. Each work station is equipped with tools and parts that can be gripped by the manipulator so that each work station can perform the work with the manipulator, and A flexible manipulator device comprising programming means for giving commands to the manipulator. 2. The above program means is capable of executing operations at other work stations when work cannot be continued at one work station.
The flexible manipulator device according to claim 1, characterized in that it includes a program for switching to perform operations at the station.