Instrumented compliant wrist for dexterous robotic interaction

2017

Sensors

Self Cite

Compliance has been exploited in various forms in robotic systems to allow rigid mechanisms to come into contact with fragile objects, or with complex shapes that cannot be accurately modeled. Force feedback control has been the classical approach for providing compliance in robotic systems. However, by integrating other forms of instrumentation with compliance into a single device, it is possible to extend close monitoring of nearby objects before and after contact occurs. As a result, safer and smoother robot control can be achieved both while approaching and while touching surfaces. This paper presents the design and extensive experimental evaluation of a versatile, lightweight, and low-cost instrumented compliant wrist mechanism which can be mounted on any rigid robotic manipulator in order to introduce a layer of compliance while providing the controller with extra sensing signals during close interaction with an object’s surface. Arrays of embedded range sensors provide real-time measurements on the position and orientation of surfaces, either located in proximity or in contact with the robot’s end-effector, which permits close guidance of its operation. Calibration procedures are formulated to overcome inter-sensor variability and achieve the highest available resolution. A versatile solution is created by embedding all signal processing, while wireless transmission connects the device to any industrial robot’s controller to support path control. Experimental work demonstrates the device’s physical compliance as well as the stability and accuracy of the device outputs. Primary applications of the proposed instrumented compliant wrist include smooth surface following in manufacturing, inspection, and safe human-robot interaction.

Section: Instrumented Compliant Wrist Designmentioning

confidence: 99%

Section: Compliant Wrist Experimental Characterization and Performmentioning

confidence: 99%

Instrumented Compliant Wrist with Proximity and Contact Sensing for Close Robot Interaction Control

2017

Sensors

Self Cite

“…Building upon the principle of multiple modality sensors, a design is proposed that provides feedback to the robot arm controller both while the end effector is approaching a surface, and after contact is achieved. This not only provides additional information to the robot but also allows it to take advantage of the pre-contact information, increasing safety during navigation and fulfilling the gap of information available from vision sensors that may be occluded or not accurate enough [13].…”

Section: Instrumented Compliant Wrist Designmentioning

confidence: 99%

“…The output of these IR sensors exhibit a nonlinear relationship to the physical distance, as shown in Figure 2a. Because two different IR sensors typically provide slightly different measurements over identical distances, and given that these measurements are not exactly matched to the specifications, a formal calibration procedure [13] was developed to ensure consistency and to increase accuracy of the compliant wrist measurements. Moving average filtering of the raw signals is also implemented.…”

Section: Instrumented Compliant Wrist Designmentioning

confidence: 99%

See 1 more Smart Citation

Proximity and Contact Sensing with Instrumented Compliant Wrist for Close Guidance of Robotic Manipulators

Proceedings of the 3rd International Electronic Conference on Sensors and Applications, 15–30 November 2016; Availabl

2016

Self Cite

Compliance in robotic systems has been exploited to allow rigid mechanisms to come into contact with complex and possibly fragile objects. By incorporating compliance and instrumentation into a single device nearby objects can be detected before direct contact occurs. That way, safer and smoother robot guidance can be achieved both while approaching and while touching surfaces. Furthermore, the path planning and control problem is simplified as position based algorithms can be used regardless of the state of the system, be it in free motion or constrained motion, or even during transitions between the two modes. This paper presents the design and experimental validation of a lightweight, low-cost and stand-alone instrumented compliant wrist mechanism which can be mounted on the tool plate of any rigid robotic manipulator. Embedded arrays of infrared sensors provide distance measurements. Each is finely tuned via a novel calibration procedure that overcomes inter-sensor variability. All signal processing is also embedded and wireless transmission connects the device to the robot controller to support path control. Real-time acquired measurements on the position and orientation of surfaces located in close proximity or in contact with the robot's end effector permit close guidance of its operation. Experimental work demonstrates how the device provides physical compliance to prevent large impact forces to occur during non-contact to contact transitions by the manipulator's end effector. It also demonstrates the stability and accuracy of the device outputs. Primary applications of the proposed instrumented compliant wrist include smooth surface following in manufacturing and safe human-robot interaction.

Safe Close-Proximity and Physical Human-Robot Interaction Using Industrial Robots

Nakhaeinia

2015 12th Conference on Computer and Robot Vision

et al. 2015

Self Cite

Industrial robots have been employed worldwide in the manufacturing sector for performing tasks quickly, repeatedly and accurately in relatively static environments for over 30 years. In recent years, close physical interaction between industrial robots and human operators has attracted researchers' attention and encouraged a number of technological innovations to turn these robots into humanrobot platforms. In this work a specially designed compliant wrist is developed to support dexterous robotic interaction with live proximity and contact feedback. The compliant wrist incorporates a level of compliance into an initially noncompliant manipulator robot which allows the robot to dynamically adapt to the surfaces it approaches or touches. Furthermore, to facilitate human-robot interactions, the robot must be able to adapt its behavior to the human partner. Therefore, a real-time path planning method is developed to generate online motion, adapt the robot to dynamic changes in the environment and ensure smooth interactions. The performance of the proposed method is demonstrated through experimental results on a CRS-F3 manipulator.