Method for identifying elastostatic parameters of a multi-link manipulator using a three-axis accelerometer

Abstract

The elastostatic (compliance) parameters of an industrial manipulator (IM) are used to calculate its deformations under its own weight or external forces. The calculated deformations are compensated by the manipulator control system, which allows to increase positioning accuracy in absolute coordinate system. However, the compliance parameters are usually unknown. This article proposes a method for identifying these parameters based on a consumer-grade three-axis accelerometer mounted on the IM flange and operating in inclinometer mode. During data collection for identification, the IM is moved to several positions and loaded with a known mass in each position. In each position, the accelerometer measures the flange tilt angle before and after loading. Numerical optimization methods are then used to find elastostatic parameters that accurately predict the IM deformations when an external force is applied to its flange. The proposed method, unlike existing methods, does not require expensive or bulky high-precision measuring equipment and lends itself well to automation. Furthermore, the method allows the use of uncalibrated consumer-grade microelectromechanical accelerometers, which are very inexpensive and widely available. The results of mathematical modeling confirm the method's feasibility.