Real time adaptive control for resistance spot welding process
US4861960A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 1989 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | Jan 19, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/49219
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
This real time adaptive control and method of controlling a spot welding process compensates for electrode wear, oxidized surfaces, fit up variations and machine variations. Workpiece thermal growth is the measurement discriminant and the welding machine heat command is the control input. The control utilizes a least squares estimator to monitor the process and workpiece displacement, a precompensator to shape a desired displacement trajectory command, and a model reference control with a Smith-predictor to compensate for time delays and a proportional-integral-derivative compensator. The model reference control has a mathematical model of the spot welding process and calculates an estimated displacement using a predicated process gain and bias calculated by the estimator. The estimated displacement is compared to the precompensator displacement trajectory and an error is generated which regulates the heat command through the PID compensator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.