Haptics CS327A

Transcription

1 Haptics CS327A hap tic adjective relating to the sense of touch or to the perception and manipulation of objects using the senses of touch and proprioception 1 2 Slave Master 3 Courtesy of Walischmiller Engineering 4 Slave Master Slave Master 5 6 Passive gravity compensation

2 Limitations? 7 8 Courtesy of Walischmiller Engineering Teleoperation Electro-mechanical Limitations? Physical distance between operator and device is limited Passive compensation is not perfect Not easy to handle different reference frames for operator and workstation Not easy to scale workspace up or down 9 1 Teleoperation - Teleoperation - Electro-mechanical Electro-mechanical What feedback does the operator need? 11 What feedback does the operator need? Visual, stereo Tactile Audio?, smell? Other task specific information12

3 Teleoperation -Electromechanical Teleoperation -Electromechanical How do we sense each modality of information on remote manipulator? How do we sense each modality of information on remote manipulator? Visual: Visual: stereo cameras, 3D image sensors Tactile: Tactile: force/torque sensors Audio: Audio: microphones Smell: Smell: sensors for specific gases Teleoperation -Electromechanical Teleoperation -Electromechanical How do we display each modality of information on master manipulator? How do we display each modality of information on master manipulator? Visual: Visual: 3D monitors, head mounted displays Tactile: Tactile: force control Audio: Audio: speakers Smell: Smell:??? Haptic devices Generic master manipulators with force feedback Many shapes, sizes and degrees of freedom measured applied Force displayed Force perceived 17 Operator 18

4 19 2 Courtesy of Intuitive Surgical Courtesy of Intuitive Surgical measured applied Force displayed Force perceived Operator Haptic rendering Haptic rendering measured applied Force displayed Force perceived Operator 23 Components? 24

5 Haptic rendering Haptic rendering Components? Components? Simulated remote manipulator dynamics and controller Simulated remote manipulator dynamics and controller Simulated environment dynamics Simulated environment dynamics Interaction model between manipulator and environment Interaction model between manipulator and environment Interaction model representation Interaction model representation Some possibilities: Polygonal meshes Point clouds Voxels Some possibilities: Polygonal meshes Point clouds Voxels Easy to extract geometrical features such as surface normals Determining sensed contact force Determining sensed contact force At each simulation time step: At each simulation time step: Collision detection Extract geometric information resolution aggregation Collision detection Extract geometric information resolution aggregation Simplest case: contact forces are resolved at a discrete number of surface points 29 3

6 Collision detection Single point contact force resolution: virtual proxy model massless proxy object to represent manipulator end effector co-located with haptic tool point in free space motion Bounding sphere hierarchy Single point contact force resolution: virtual proxy model Single point contact force resolution: virtual proxy model massless proxy object to represent manipulator end effector constrained such that no penetration occurs Haptic contact force is computed as impedance from proxy object Single point contact force resolution: haptic shading Multi-point contact force resolution 35 36

7 Contact space Augmented Contact Space (X ) Full set of contact points Non Independent Active Contact Space (X) Subset of contact points Contact mass properties Augmented space inertial coupling Λ 1 1 J A J = T Active Contact Space inertial coupling x1 1 = x4 x 6 S1 1 x1 x2 x 3 x4 x 5 x6 x7 impulse (p) or contact force (f) > Independent but unknown Active Contact Matrix : X = SX 37 Λ = SΛ 1 S 1 J where is the augmented space Jacobian 38 T Contact mass properties Active Contact Space inertial coupling T Λ = SΛ 1 S 1 J where is the augmented space Jacobian s are determined by enforcing non-penetration constraint 39 4 Multi-point contact force resolution: virtual proxy model Haptic contact force is computed as impedance from proxy object 41 42

8 Demo 43