Encountered-type Haptic Display for VR Environment using Per-plane Reachability Maps
Yaesol Kim, Hyun Jung Kim and Young J. Kim
Ewha Womans University
We show a novel encountered-type haptic system, H-Wall, to enable haptic feedback using a 7-DoF manipulator suitable for simulating indoor VR environments, which are characterized and confined by a set of vertical walls and revolving doors.At runtime, our system tracks hand motion using an RGBD sensor and locates its configuration. Then, the robotic manipulator plans a trajectory for the end-effector, attached to a rectangular rigid board, to make a contact with the hand to deliver a sense of touch, as long as the perceived hand contact force is substantial. The force feedback is generated in a passive sense for static walls that the rigid board, corresponding to a vertical wall, holds its position as long as the perceived hand contact force is substantial. For a revolving door, the force feedback is generated in an active sense based on impedance control. In order to address the issue of limited workspace, we also propose a new reachability map, called per-plane reachability maps, that is optimized to answer whether passive haptic feedback can be generated by a manipulator when the user touches a vertical wall at a given orientation. These maps are generated offline using optimization and are looked up at runtime.
Head and hand positions of user are tracked by a RGBD Sensor.
Tracked data are transformed from the camera frame to the robot base frame.
Using pre-computed per-plane reachability maps, check the reachability of manipulator on hand position of the user.
A 7-DoF manipulator, capable of human-robot-coexistence, operates as a haptic device to provide passive and active touch feedback to the user.
A user's virtual hand and an indoor virtual environment are rendered to the HMD.
We use KUKA LBR IIWA 7 R800 manipulator as a haptic device.
A transparent, lightweight Acrylic Panel is attached to the IIWA end-effector and serves as a proxy for a virtual walls and doors.
We use Kinect for Windows for tracking usesr hand and head position.
Oculus Rift CV1 is used for rendering virtual environment and virtual hand.
Per-plane Reachability Maps
Reachability map is a set of points that can be reached by a reference point.
We impose the characteristics of vertical object as additional constraints.
1. Sample the workspace by n different orientation.
2. Sample again into m equidistance planes.
3. Compute the boundary points of each per-plane reachability map.
Per-plane reachability maps with orienrtation of the end-effector r=0.
Per-plane reachability maps with orienrtation of the end-effector r=0.25pi
We formulate a set of equality constraints in terms of orientation and position.
We also formulate a objective function to calculate extremal y values.
Solve the non-linear optimization problem in order to coumpute the boundary points of each per-plane reachability map.
Check the pre-computed reachability map in runtime.
The manipulator position and a virtual hand position are updated when an input value is inside the per-plane reachability map,
The manipulator and a virtual hand maintain their position and wait for the next update when an input value is outside the per-plane reachability map,.
Passive Haptic Interaction Sequences
Active Haptic Interaction Sequences
Ewha Graphics Lab
Department of Computer Science & Engineering, Ewha Womans University
52, Ewhayeodae-gil, Seodaemun-gu, Seoul, Korea, 03760
Yaesol Kim, firstname.lastname@example.org
Hyun Jung Kim, email@example.com
Young J. Kim, firstname.lastname@example.org