Development of a new 3T1R type cable-driven haptic device

Abstract

In this work, structural synthesis of lower-mobility cable-driven parallel mechanisms (CDPMs) is conducted to clearly identify all feasible structures of the lower-mobility CDPMs with n-degrees-of-freedom, which are driven by n +1 cables fixed on the ground. Through the synthesis, geometric information of various and some new promising structures of unconstrained and constrained lower-mobility CDPMs such as actuation cable wrenches, cable position vector, and required constraint wrenches, are successfully extracted. Then a promising 3T1R type CDPM structure is selected to develop as a haptic device. Its position analysis is conducted and its input-to-output force model is derived. Also, its feasible workspace and its input-to-output force transmission characteristics are examined. Then a prototype haptic device is implemented which is controlled by Raspberry Pi microprocessors. Through a virtual wall following operation by the operator, its operational capability as a haptic device is verified.