Development of an R-Cube-Based General Purpose Haptic Device System

Abstract

A novel 6-Degree-of-Freedom (DoF) hybrid haptic device is presented in this paper. Hybrid mechanism consists of parallel kinematic structure, R-CUBE and a 3-DoF orientation mechanism. In our previous study, the original configuration of the R-CUBE mechanism was investigated. In this work, the original design of R-CUBE is reconfigured as a haptic mechanism and the final mechanism is reoriented in order to equally distribute the gravitational effects to all grounded actuators. Rotational motions of the end-effector are monitored through the 3-DoF orientation mechanism placed on the moving platform of the parallel platform. The design of this haptic device is suitable to reflect forces in translational motions, thus point-type of contact is available for this system. The designed device is manufactured utilizing various types of manufacturing processes, such as wire erosion, laser cutting, milling and turning. Finally manufactured mechanism is integrated with electromechanical components and tested for manipulability.

Structural Compliance Effects on the Accuracy and Safety of a R-CUBE Haptic Device

“…However, most of these manipulators have coupled motions between the position and orientation of the end-effector as well as they have complex control features also due to singularities. Recent research on parallel manipulators with a reduced number of degrees of freedom (DOFs) has been aiming at possibilities of achieving kinematic architectures with reduction of the number of active DOFs and decoupling of the position and orientation of the end-effector, [7][8][9]. R-CUBE manipulator is a 3 DOFs parallel manipulator, whose kinematic scheme can be modeled as proposed for example in the scheme of Fig.…”

“…All the actuators can be conveniently located at the base frame. Singularity analysis shows that the singularities can be easily avoided by means of a careful design [9]. The above features make R-CUBE architecture suitable as haptic device.…”

Analytical Dynamic Analysis of a Kinesthetic Haptic Device

“…Additionally, since haptic devices should not include singularity position within its workspace, by a careful design, R-CUBE mechanism does not have singularity positions inside its workspace. Design characteristics of the device are listed in [16] and a key feature is that it can produce three-dimensional 0.8 N of continuous force. For this device, the handle motion capturing system's calibration was also presented in [17].…”

“…The orientation of the handle is then calculated by acquiring the data from the position sensors that are directly attached to joints of the serial-spherical wrist mechanism. However, since the dynamic analysis is only carried out for the active translational mechanism, wrist mechanism's full kinematics analysis is excluded from this article and the reader is encouraged to refer to [16] for the full kinematics analysis. The location of the wrist point is also defined as the intersection point of the last link connection surfaces on the moving platform.…”

“…In which, ( ) = [0 0 − ] , = 9.81 m/s 2 , = 45°, and = 35.26°. In (9), ( , ) is the transformation matrix that is defined from the frame orientation to the frame orientation [16]. However, there are still two legs with masses mi4 and mi5 to be compensated by the work of all three actuators.…”