Performance Evaluation of Optical Motion Capture Sensors for Assembly Motion Capturing

Abstract

The optical motion capture (MoCap) sensor provides an effective way to capture human motions and transform them into valuable data that can be applied to certain tasks, e.g. robot learning from demonstration (LfD). In spite of the wide utilization of optical MoCaps in LfD studies, there are few works that explore their potentiality in small parts robotic assembly. Robot manipulation skill learning from demonstration has gained the attention of researchers recently and robotic 3C (Computer, Communication, and Consumer Electronics) product assembly turns out to be a promising application thanks to the increasing consumption of 3C products. To further explore the potential of optical MoCaps in robotic 3C product assembly. This work proposes a performance evaluation protocol that takes the characters of both optical MoCaps and 3C product assembly operations into account. The proposed evaluation protocol includes static and trajectory evaluations. The former refers to the widely used evaluation indicators such as precision and accuracy. Meanwhile, the trajectory evaluation takes contour error as an error metric. Three popular optical MoCaps are studied in the experiment. Experiment results show that the static performance of all of the three optical MoCaps can meet the requirements of the 3C product assembly task. What's more, Prime X41 possesses the best trajectory performance. This work sheds light on the wider usage of optical MoCaps in manufacturing industries.

Ergonomic human-robot collaboration in industry: A review

“…Different technologies and solutions have been developed to capture motion, hereafter we analyse some of the most widespread examples in the literature along with some industrial applications. Camera-based systems with infrared (IR) cameras can be used to triangulate the location of retroreflective rigid bodies (markers) attached to the targeted subject ( Nagymáté and Kiss, 2018 ; Chatzitofis et al, 2021 ; Hu et al, 2021 ). In addition, systems based on inertial measurement units (IMU) that track the relative movements of articulated structures have become popular for their versatility ( Vignais et al, 2013 ; Caputo et al, 2018 ; Marín and Marín, 2021 ).…”

Motion Capture Sensing Technologies and Techniques: A Sensor Agnostic Approach to Address Wearability Challenges

“…Human body motion can be tracked by cameras and is mainly concerned with the boundaries or features of human body on the images. Image based systems use computer vision techniques to obtain motion parameters directly from video footage without the use of special markers [5]. By using a proper camera set-up, including a single camera or a distributed-camera configuration, motion capture can be performed.…”

“…Reviewing the techniques shows that most of the motion capture techniques are highly dependent on accurate positioning of sensors and require calibration before measurement [3]. In general, body motion sensing systems are sensitive to sensor positioning and bulky with large batteries [5]. Accurate sensor placement with respect to anatomical landmarks is one of the main factors determining the accuracy of motion capture systems [6].…”

“…For some signals, that are not naturally band-limited, the sampling rate is dictated not by the Shannon theorem but by the desired temporal or spatial resolution. However, it is common in such systems to use an antialiasing low-pass filter to bandlimit the signal before sampling, and so Shannon's theorem plays an implicit role [5]. Reduction in sampling frequency is utilised in this paper up until Nyquist rate leading to less power consumption without missing information.…”

Pose measurement and assembly of spacecraft components based on assembly features and a consistent coordinate system

“…In recent years, it has become an inevitable trend to utilize robots instead of skilled workers to complete precise and complex operations in industrial automation [4,5]. Robotic assembly systems are now widely used in 3C [7,8], automotive [9,10], and aircraft [11,12] assembly lines due to their dexterity, stability, high efficiency and high accuracy [6]. In essence, assembly fits the specific parts (which can be called the assembly features) of two assemblies according to technical requirements.…”