Base force/torque sensor apparatus for the precise control of manipulators with joint friction and a method of use thereof
US5767648A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1996 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Apr 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/40599
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An elegant, cost-effective apparatus and method is disclosed for compensating the effect of joint friction in manipuulators. The invention uses a six axis wrench sensor (also called a force/torque sensor) mounted between the manipulator and a reference body upon which it is supported. From the base wrench measurements, for rotary joints, the joint torques are estimated. The estimation apparatus uses Newton-Euler relations of successive link bodies. The estimated torque is fed back through a torque controller, that virtually eliminates friction and gravity effects. A position control loop encloses the torque controller and provides it with desired torques computed from measured position errors. For linear joints, appropriate forces are estimated. Coupled to link position sensors and the wrench sensor, is a gravity compensator, which generates a dynamic wrench signal that corresponds to the gravity compensated dynamic component of the base wrench signal, based on the position signals and the base wrench signal. Coupled to the gravity compensator and the position sensors is a joint analyzer, which generates a signal that corresponds to the gravity compensated torque that is actually a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.