1、 ABSTRACT A workstation and method for processing a plurality of workpieces includes at least one material handling robot movable along a processing path for supporting a workpiece to be moved along the processing path. At least one station can be defined by at least one processing position adjacent
2、 the processing path for receiving workpieces to be processed when delivered and positioned by the at least one material handling robot. Interchangeable end effecters can be con-nected to the material handling robot for holding and sup-porting different configurations of workpieces. The material han
3、dling robot can disengage from the end effecter at the processing position, to allow engagement with a processing tool for performing additional processing operations on the workpiece. A flexible body workstation for assembling workpieces can use multiple robots and/or multiple fixtures for processi
4、ng different workpiece configurations in any sequential order along two processing paths. RELATED APPLICATIONS The present application claims the benefit of pro-visional application Ser. No. 60/548,129 filed on Feb. 26, 2004 and Ser. No. 60/618,422 filed on Oct. 13, 2004. FIELD OF THE INVENTION The
5、present invention relates to a flexible body workstation for assembling workpieces using multiple robots and multiple fixtures, and more specifically, the present invention provides welding workstations for auto-motive assembly lines having multiple independently work-ing welding robots and multiple
6、 fixtures for holding work-pieces. BACKGROUND OF THE INVENTION The efficiency of a welding workstation can be defined by the amount of time, normally a percentage, that a welding robot spends welding compared to the total time required for a particular repetitive cycle. The efficiency of the worksta
7、tion relates to the amount of time that a welding robot takes to perform various welding operations compared to the total amount of time that the welding robot requires for a particular repetitive cycle. Idle time for a welding robot can occur when a new workpiece is loaded and prepared in a fixture
8、. If the workstation has one welding robot and one fixture, the welding robot will stand idle as a completed part is unloaded from the fixture and a new workpiece is loaded onto the fixture. In the prior art, this problem was addressed by adding a second fixture at the workstation within reach of a
9、single welding robot. In a workstation with two fixtures, the welding robot can complete welding operations at one fixture while workpieces are being loaded and unloaded at the second fixture. When the welding process is complete at the first fixture, the welding robot can move to the second fixture
10、 and immediately commence welding. The amount of time that a workpiece is positioned in a fixture while work is being performed compared to the total amount of time that a workpiece is positioned in a fixture corresponds to workpiece efficiency. The amount of time that a workpiece sits idle in a fix
11、ture reduces the overall operating capacity of the workstation by reducing through-put, normally reported in parts per hour or similar units for the overall assembly process. In a workstation having one fixture and one welding robot, the amount of time that a workpiece sits idle in the fixture is mi
12、nimized because the welding robot immediately commences welding operations as soon as a workpiece is loaded and any other setup procedures are completed. However, in a workstation that has two fixtures and one welding robot, a workpiece is loaded onto one fixture, is setup, and then sits idle until
13、the welding robot completes welding operations at the second fixture. Therefore, in a workstation having one fixture and one welding robot, the workpiece efficiency is maximized while in a workstation having two fixtures and one welding robot the welding efficiency is maximized. It is desirable to p
14、rovide a workstation wherein the welding efficiency and the workpiece efficiency are both enhanced. SUMMARY OF THE INVENTION The present invention can include a single or a plurality of similar workstations positioned in sequence along an assembly line. A movable material handling transportation or
15、transfer robot can be located in between adjacent workstations for moving workpieces from one workstation to the next. The present invention can also include a robot for processing the workpieces while held by the material handling transfer robot in between the adjacent workstations. The present inv
16、ention includes a flexible body shop for assembling workpieces using a single or multiple robots and a single or multiple fixtures. The present invention includes movable material handling robots, and stationary material processing robots in combination at the flexible body workstation. The workstat
17、ion can perform processing operations on multiple workpieces sequentially, and performs different processing operations through the workstation simultaneously. The material processing robots performing processing operations on the workpieces can be located adjacent the at least one processing path,
18、or in between first and second processing paths and are independently movable relative to each other. The workpiece fixtures can be provided in the form of interchangeable end effecters connectable to the at least one material handling robot for holding and supporting different workpiece con-figurat
19、ions by exchanging one interchangeable end effecter configuration for a different interchangeable end effecter workpiece configuration. The interchangeable end effecters can be geometry fixtures for different workpiece configurations to allow processing different workpiece configurations in any desi
20、red sequence by changing end effecters automatically to correspond to the next workpiece configuration to be processed. The present invention can include a plurality of similar workstations positioned in sequence along an assembly line. The at least one material handling robot can hand off a workpie
21、ce from a transfer position at one end of the processing path to another material handling robot for movement along another processing path for moving workpieces from one workstation to the next and/or can position a workpiece at multiple workstations before transfer. The present invention can also include a material processing robot for processing the workpiece while being held by
