Oscillation Damping, Collision Detection and Reaction for a Multi-Elastic-Link Robot Arm

Video thumbnail (Frame 0) Video thumbnail (Frame 533) Video thumbnail (Frame 765) Video thumbnail (Frame 901) Video thumbnail (Frame 1030) Video thumbnail (Frame 1204) Video thumbnail (Frame 3241) Video thumbnail (Frame 3387) Video thumbnail (Frame 3602) Video thumbnail (Frame 3773) Video thumbnail (Frame 3927) Video thumbnail (Frame 4073) Video thumbnail (Frame 4202) Video thumbnail (Frame 4333) Video thumbnail (Frame 4556) Video thumbnail (Frame 4702) Video thumbnail (Frame 5085) Video thumbnail (Frame 5231) Video thumbnail (Frame 5498) Video thumbnail (Frame 5659) Video thumbnail (Frame 5805) Video thumbnail (Frame 7191)
Video in TIB AV-Portal: Oscillation Damping, Collision Detection and Reaction for a Multi-Elastic-Link Robot Arm

Formal Metadata

Oscillation Damping, Collision Detection and Reaction for a Multi-Elastic-Link Robot Arm
CC Attribution 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
Release Date
Original sound, no spoken text
Production Year
Production Place

Content Metadata

Subject Area
In first place, elasticity in the links of robot arms and structurally comparable mechatronic systems such as construction machines, fire rescue turntable ladders, cherry pickers or automobile concrete pumps is a highly undesired effect. It prolongs settling times and deteriorates the positioning accuracy. Therefore substantial mechanical design efforts are commonly taken to avoid link elasticity in these mechanisms. The presented work approaches from the contrary perspective and intentionally introduces intrinsic structural compliance in the links of an experimental robot platform. The motivation is to exploit the added intrinsic link compliance to reduce the overall robot weight, to cut costs, to add positioning tolerance as well as to add contact force sensing capabilities to the system. The video shows, how robust and rapid settling as well as disturbance rejection can still be accomplished by devising control algorithms [1,2] based on per link strain measurements. In addition, the derivation and identification of mathematical models that accurately describe the load and joint configuration dependent static end effector deflections allows -- through software -- for the compensation of the inaccuracy of the mechanism [3]. The feasibility of time critical and precise end effector positioning for an elastic link arm has been exemplified with ball catching experiments before [4] (http://www.youtube.com/watch?v=P4 i k...). With the mechanical imperfections compensated by the developed inner loop control software, the video demonstrates, how the intrinsic link compliance can be exploited to actively shape the apparent arm compliance, to sensitively sense contact forces, to safely react to accidental collisions as well as to enable intentional physical human machine interaction. The control scheme behind these features uses an identified model of the residual damped arm dynamics [5]. This model is way simpler to derive and identify than a holistic arm model including the oscillatory and actually infinite dimensional arm dynamics. An identified linear mapping from the strain readings acquired close to the hubs on each passively compliant link and the motor torques turns each link into load side joint torque sensors. This way the video shows that collision detection and reaction techniques originally developed by other authors for rigid or elastic joint robots can be readily adopted for the use with elastic link robots [6]. The provided results imply that link elasticity is not necessarily just a problem. In contrast, the devised control concepts are able to compensate for the machine imperfections reveal promising new perspectives. Time-line: 00:12 Introduction to the experimental setup 00:36 Exp I: Oscillation Damping: step motion 00:48 Exp II: Oscillation Damping: harmonic disturbance 02:10 Exp III: Collision detection and reaction: blunt impacts with a balloon 02:37 Exp IV: Collision detection and reaction: sharp impacts with a balloon 03:02 Exp V: Collision detection and reaction: sharp impacts with a Christmas ball 03:23 Exp VI: Collision detection and reaction: sharp impacts with a human arm 03:47 Exp VII: Interaction in zero gravity mode For more information on the project please visit:http://www.rst.e-technik.tu-dortmund....
Keywords oscillation damping collision detection flexible robot elastic link flexible link compliance force control robotics
Steel Gear Computer animation Chain Spring (device) Engine Blade
Steel Gear Computer animation Chain Engine Spring (device) Blade
Computer animation
Computer animation Gas balloon
Computer animation
Computer animation Gas balloon Screw
Computer animation
Ballpoint pen Computer animation Screw
Computer animation Screw
Computer animation
Computer animation Mode of transport
Computer animation Friction