Robotic Grasping and Fine Manipulation

ISBN-13: 9781468468939 / Angielski / Miękka / 2012 / 192 str.

M. R. Cutkosky; M. R. Cutkosky

Opis

When a person picks up a metal part and clamps it in the chuck of a lathe, he begins with his arm, proceeds with his wrist and finishes with his fingers. The arm brings the part near the chuck. The wrist positions the part, giving it the proper orientation to slide in. After the part is inserted, the wrist and fingers make tiny corrections to ensure that it is correctly seated. Today's robot attempting the same operations is at a grave disadvantage if it has to make all motions with the arm. The following work investigates the use of robotic wrists and hands to help industrial robots perform the fine motions needed in a metal working cell. Chapters 1 and 2 are an introduction to the field and a review of previous investigations on related subjects. Little work has been done on grasping and fine manipulation with a robot hand or wrist, but the related subjects of robot arm dynamics and control have an extensive literature.

Spis treści

1. Introduction.- 2. Previous Investigations of Fine Manipulation and Grasping.- 2.1 Fine Motion and Control.- 2.2 Robotic Wrists.- 2.3 Applications to Assembly and Surface Finishing Tasks.- 2.3.1 Assembly.- 2.3.2 Surface Finishing.- 2.4 Passive Hands and Grippers.- 2.5 Active Hands and Grasping.- 3. Robot Tasks in a Metal-Working Cell.- 3.1 Task Descriptions.- 3.1.1 Materials Handling.- 3.1.2 Assembly.- 3.1.3 Grasping.- 3.1.4 Surface Finishing and Shaping.- 3.1.4.1 Contour following.- 3.1.4.2 Contour modification.- 3.2 Discussion: Coupled Fine and Gross Motions.- 4. A Wrist for Fine-Motion Tasks.- 4.1 Wrist Description.- 4.2 Control Architecture.- 4.3 Experiments.- 4.3.1 Contour Following.- 4.3.1.1 State estimation.- 4.3.1.2 Control law.- 4.3.2 Grinding.- 4.4 Discussion of Results.- 5. Analysis for an Active Robot Hand.- 5.1 The Promise of Further Dexterity.- 5.2 Introduction to Grasp Analysis.- 5.2.1 Grasping Model and Assumptions.- 5.2.2 Stiffness, Strength and Stability of a Grasp.- 5.2.3 Procedure for Establishing Grip Properties.- 5.2.4 Two-Dimensional Examples.- 5.2.4.1 Choosing among five grips: an example.- 5.2.4.2 An unstable example.- 5.3 Extension to Three-Dimensional Problems.- 5.3.1 Forward Force and Displacement Relations.- 5.3.2 Summary of Forward Transformations.- 5.3.3 Finger Motions and Constraints.- 5.3.4 Constraints at a Contact.- 5.3.4.1 Case 1: exactly determined.- 5.3.4.2 Case 2: under determined.- 5.3.4.3 Case 3: over determined.- 5.3.5 Computing Changes in Grip Force.- 5.4 A Closer Look at Contact Conditions.- 5.4.1 Point Contact.- 5.4.2 Curved Finger Contact.- 5.4.2.1 Effects of rolling motion.- 5.4.3 Very Soft Finger.- 5.4.3.1 Effects of deforming fingertip.- 5.4.4 Soft, Curved Fingertips.- 5.5 Examples.- 5.5.1 Pointed Fingers.- 5.5.2 Procedure for Left Finger.- 5.5.2.1 Discussion.- 5.5.3 Curved Fingertips.- 5.5.3.1 Discussion.- 5.5.4 Very Soft Fingers.- 5.5.4.1 Discussion.- 5.6 Summary.- 6. Natural Examples of Grasping.- 6.1 The Human Hand.- 6.1.1 Conformability.- 6.1.2 Muscles.- 6.1.3 Hand/Wrist Interaction.- 6.1.4 Finger Coupling and Specialization.- 6.1.5 Grasps.- 6.1.6 Sensation and Control.- 6.2 Other Natural Examples.- 7. Designing Hands and Wrists for Manufacturing.- 7.1 Wrist Design.- 7.2 Hand Design.- 7.2.1 Grasping vs Manipulation.- 7.3 Control.- 8. Summary and Conclusions.- Appendix for Grasp Analysis.- A.1 Matrix Identities.- A.2 Matrix Method for Under Determined Finger Motions.- A.3 Differential Jacobians.- A.4 Rolling Contact.- A.5 Details for Examples in Section 5.5.- References.