Design strategy and issues of the Delthaptic, a new 6-DOF parallel haptic device

Highlights•A 6-DOF versatile haptic device is designed, optimized, and experimentally tested.•The Delta-based architecture provides a large and singularity-free workspace.•The parallel structure has benefits such as stiffness, accuracy, or low inertia.•The design strategy meets essential transparency requirements of haptic devices.•The structure and the actuation systems are optimized through dynamic objectives. The design of an optimal and versatile haptic device should enable human to achieve complex remote tasks in a safe and ergonomic environment. The paper presents a design strategy applied to the development of the Delthaptic, a new 6-DOF parallel haptic device. The Delthaptic is based on a coupled-parallel structure. It combines two Delta robots, linked to the two extremities of the customized ball-screw handle, to obtain its 6 degrees of freedom. The proposed haptic device provides a large and singularity-free workspace while keeping the benefits of parallel mechanisms. The design process first consists in a phase of structural design where the mechanical architecture is defined in order to meet requirements. During a second step, the parameters of this architecture are optimized by minimizing objective functions based on desired kinematic performances. Then, a generic procedure is proposed to select the actuation with respect to dynamic capability-based criteria as well as technological aspects. Actuators and transmission systems are chosen for the Delthaptic. A prototype of the haptic device is built to experimentally assess its mechanical functioning and check the design requirements.