Dynamics modeling and accuracy evaluation of a 6-DoF Hexaslide robot

Abstract

Parallel Robots are commonly preferred in place of Serial Robots for tasks in which the working volume is limited, compared to the overall extension of the machine, but where the accuracy requirements are very high. In fact, since the errors do not sum together in series, the positive effect of the closed-loop linkages arrangement is a lower overall sensitivity of the end-effector positioning to the various sources of error. The precision depends on many factors among which the flexibility of the components plays a fundamental role. This paper investigates the contribution of belt-driven and screw-ball-driven linear transmission systems to the overall flexibility of the HexaSlide parallel architecture, using an ADAMS®model. The six Degrees-of-Freedom (DoF) of its mobile platform are provided through the actuation of the same number of Linear Transmission Units (LTUs), fixed to the base, while its links have fixed length. The LTUs are integrated together in the robot. The first eigenfrequencies are mapped in a systematic manner over the whole workspace, using a discretized grid of poses.