Custom Robot Research Articles

Critical Glenoid Bone Loss in Posterior Shoulder Instability

Background:There is currently no consensus regarding the amount of posterior glenoid bone loss that is considered critical. Critical bone loss is defined as the amount of bone loss that occurs in which an isolated labral repair will not sufficiently restore stability.Purpose:The purpose is to identify the critical size of the posterior defect.Study Design:Controlled laboratory study.Methods:Eleven cadaveric shoulders were tested. With the use of a custom robot device, a 50-N compressive force was applied to the glenohumeral joint, and the peak force that was required to translate the humeral head posteriorly and the lateral displacement that occurred with translation were measured. The defect size was measured as a percentage of the glenoid width. Testing was performed in 11 conditions: (1) intact glenoid and labrum, (2) simulated reverse Bankart lesion, (3) the reverse Bankart lesion repaired, (4) a 10% defect, (5) the reverse Bankart lesion repaired, (6) a 20% defect, (7) the reverse Bankart lesion repa...

Autonomous feature type selection based on environment using expectation maximization in self-localization

Self-localization in autonomous robots is one of the fundamental issues in the development of intelligent robots, and processing of raw sensory information into useful features is an integral part of this problem. In a typical scenario, there are several choices for the feature extraction algorithm, and each has its weaknesses and strengths depending on the characteristics of the environment. In this work, we introduce a localization algorithm that is capable of capturing the quality of a feature type based on the local environment and makes soft selection of feature types throughout different regions. A batch expectation–maximization algorithm is developed for both discrete and Monte Carlo localization models, exploiting the probabilistic pose estimations of the robot without requiring ground truth poses and also considering different observation types as blackbox algorithms. We tested our method in simulations, data collected from an indoor environment with a custom robot platform and a public data set. The results are compared with the individual feature types as well as naive fusion strategy.

Critical Glenoid Bone Loss in Posterior Shoulder Instability

Background: There is currently no consensus regarding the amount of posterior glenoid bone loss that is considered critical. Critical bone loss is defined as the amount of bone loss that occurs in which an isolated labral repair will not sufficiently restore stability. Purpose: The purpose is to identify the critical size of the posterior defect. Study Design: Controlled laboratory study. Methods: Eleven cadaveric shoulders were tested. With the use of a custom robot device, a 50-N compressive force was applied to the glenohumeral joint, and the peak force that was required to translate the humeral head posteriorly and the lateral displacement that occurred with translation were measured. The defect size was measured as a percentage of the glenoid width. Testing was performed in 11 conditions: (1) intact glenoid and labrum, (2) simulated reverse Bankart lesion, (3) the reverse Bankart lesion repaired, (4) a 10% defect, (5) the reverse Bankart lesion repaired, (6) a 20% defect, (7) the reverse Bankart lesion repaired, (8) a 30% defect, (9) the reverse Bankart lesion repaired, (10) a 40% defect, and (11) the reverse Bankart repaired. Results: Force and displacement decreased as the size of the osseous defect increased. The mean peak force that occurred with posterior displacement in specimens with a glenoid defect ≥20% and a reverse Bankart repair (13 ± 9 N) was significantly lower than the peak force that occurred in specimens with an isolated reverse Bankart repair (22 ± 10 N) (P = .0451). In addition, the mean lateral displacement was significantly less in the specimens with a 20% glenoid defect and a reverse Bankart repair (0.61 ± 0.57 mm) compared with the lateral displacement that occurred in specimens with an isolated reverse Bankart repair (1.6 ± 0.78 mm) (P = .0058). Conclusion: An osseous defect that is ≥20% of the posterior glenoid width remains unstable after isolated reverse Bankart repair. Clinical Relevance: A bony restoration procedure of the glenoid may be necessary in shoulders with a posterior glenoid defect that is ≥20% of the glenoid width.

A Closed Loop Inverse Kinematics Solver Intended for Offline Calculation Optimized with GA

This paper presents a simple approach to building a robotic control system. Instead of a conventional control system which solves the inverse kinematics in real-time as the robot moves, an alternative approach where the inverse kinematics is calculated ahead of time is presented. This approach reduces the complexity and code necessary for the control system. Robot control systems are usually implemented in low level programming language. This new approach enables the use of high level programming for the complex inverse kinematics problem. For our approach, we implement a program to solve the inverse kinematics, called the Inverse Kinematics Solver (IKS), in Java, with a simple graphical user interface (GUI) to load a file with desired end effector poses and edit the configuration of the robot using the Denavit-Hartenberg (DH) convention. The program uses the closed-loop inverse kinematics (CLIK) algorithm to solve the inverse kinematics problem. As an example, the IKS was set up to solve the kinematics for a custom built serial link robot. The kinematics for the custom robot is presented, and an example of input and output files is also presented. Additionally, the gain of the loop in the IKS is optimized using a GA, resulting in almost a 50% decrease in computational time.

Prospect of robotic assistance for fully automated brachytherapy seed placement into skull base: Experimental validation in phantom and cadaver

Background and purposeTo investigate the feasibility and accuracy of robot-assisted brachytherapy for skull base tumours. Material and methodsA custom robot system was tested on both phantom and cadaveric specimen. Cone beam CT (CBCT) images were transferred to the graphical user interface (GUI) for planning trajectories and the data were sent to the robot control unit. Following registration, the puncture needle was inserted into the target by the robot under navigation guidance, and seeds were implanted. Placement error was instantly displayed on the GUI; the result was verified after postoperative image scanning. ResultsA total of 150 seeds (100 for phantom experiments, 50 for cadaveric studies) were deposited by the robot system. In phantom experiments the mean placement error was 0.57 ± 0.21 mm (measured by the navigation system) vs. 1.41 ± 0.38 mm (measured by image fusion) (p < 0.001); in cadaveric studies the corresponding figures were 0.60 ± 0.30 mm vs. 2.48 ± 0.32 mm (p < 0.001). There was no significant difference for comparison of accuracy test in phantom experiments (p = 0.173) as well as in cadaveric studies (p = 0.354). Accuracy was better in the phantom experiment than in cadaveric studies (p < 0.001). ConclusionsThe performance of robot-assisted skull base brachytherapy is feasible and accurate. Dosimetric coverage will need to be demonstrated in further studies.

Performance of Robotic Assistance for Skull Base Biopsy: A Phantom Study.

Objectives This study aims to evaluate the feasibility of a custom robot system guided by optical cone beam computed tomography (CBCT)-based navigation for skull base biopsy. Design An accuracy study was conducted. Setting Platform for navigation and robot-aided surgery technology. Participants Phantom skull. Main Outcome Measures The primary outcome measure was to investigate the accuracy of robot-assisted needle biopsy for skull base tumors. A 14-gauge needle was automatically inserted by the five degrees of freedom robot into the intended target, guided by optical navigation. The result was displayed on the graphical user interface after matrix transformation. Postoperative image scanning was performed, and the result was verified with image fusion. Results All 20 interventions were successfully performed. The mean deviation of the needle tip was 0.56 ± 0.22 mm (measured by the navigation system) versus 1.73 ± 0.60 mm (measured by image fusion) ( p < 0.05). The mean insertion depth was 52.3 mm (range: 49.7-55.2 mm). The mean angular deviations off the x-axis, y-axis, and z-axis were 1.51 ± 0.67, 2.33 ± 1.65, and 1.47 ± 1.16 degrees, respectively. Conclusions The experimental results show the robot system is efficient, reliable, and safe. The navigation accuracy is a significant factor in robotic procedures.

Online and automated sample extraction.

Online and automated sample extraction is widely used to increase the throughput and improve the quality of LC-MS/MS analysis. In this article, we review the most commonly used online sample extraction methodologies including online SPE, turbulent flow chromatography, online DBS extraction and online immunoaffinity extraction. We also review the offline automated sample extraction platforms, including custom robot scripts for the automation of individual steps during sample extraction, the robot scripts for the automation of individual assays, and the platform for integrated multiple sample extraction. The most recent developments and future trends in this area are also discussed.

First-year integrative project for computer and software engineering students at Polytechnique Montréal

This paper presents the most important aspects of the first-year project for students in computer and software engineering at Polytechnique Montréal. A small robot is used to introduce students to hardware and software concepts of a complete and autonomous small computer. A custom robot was designed for this course and this gives the flexibility to introduce some concepts in a specific way. The fact that both software and hardware are considered makes it particularly challenging for the students but also for the teaching team. The robot itself is described but also the project structure and how students can progress in this context. The evaluation and the support offered to the students are also explained.

Piezoelectrically Actuated Robotic System for MRI-Guided Prostate Percutaneous Therapy.

This paper presents a fully-actuated robotic system for percutaneous prostate therapy under continuously acquired live magnetic resonance imaging (MRI) guidance. The system is composed of modular hardware and software to support the surgical workflow of intra-operative MRI-guided surgical procedures. We present the development of a 6-degree-of-freedom (DOF) needle placement robot for transperineal prostate interventions. The robot consists of a 3-DOF needle driver module and a 3-DOF Cartesian motion module. The needle driver provides needle cannula translation and rotation (2-DOF) and stylet translation (1-DOF). A custom robot controller consisting of multiple piezoelectric motor drivers provides precision closed-loop control of piezoelectric motors and enables simultaneous robot motion and MR imaging. The developed modular robot control interface software performs image-based registration, kinematics calculation, and exchanges robot commands and coordinates between the navigation software and the robot controller with a new implementation of the open network communication protocol OpenIGTLink. Comprehensive compatibility of the robot is evaluated inside a 3-Tesla MRI scanner using standard imaging sequences and the signal-to-noise ratio (SNR) loss is limited to 15%. The image deterioration due to the present and motion of robot demonstrates unobservable image interference. Twenty-five targeted needle placements inside gelatin phantoms utilizing an 18-gauge ceramic needle demonstrated 0.87 mm root mean square (RMS) error in 3D Euclidean distance based on MRI volume segmentation of the image-guided robotic needle placement procedure.

Energy Efficient Trajectories for an Industrial ABB Robot

This paper presents a systematic methodology for on-site identification and energy-optimal path planning of an industrial robot. The identification experiments are carried out on-site, in a quick, non-invasive way using a CA8335 Qualistar three-phase electrical networks analyser. Next, the collected data is compared with a parametrised dynamic robot model in an optimisation routine. This routine results in the specification of a parametric dynamic robot model. The model is used as a dynamic constraint for a model predictive control problem, where other physical constraints are added i.e. the limited workspace and the constraints on the joint velocities and accelerations. A sequential quadratic programming solver is used to minimise a mechanical energy based cost function. The resulting energy-optimal path is translated into custom robot commands executable on an industrial robot. The systematic methodology is validated on an IRB1600 industrial ABB robot performing a custom pick-and- place operation. The obtained dynamic robot model is given and compared to the collected measurements. To demonstrate the possibility of energy saving by ‘intelligently’ programming a robot trajectory the energy and time-optimal paths are generated taking all physical constraints into account. Simulation results show a significant time and energy improvement (up to 5%) compared to most trajectories generated by the ABB software. The most remarkable result is that the fastest energy-optimal trajectory turns out to be 4% more energy efficient and 3% faster then the commercially available fastest trajectory. Additional stand-still experiments show that activation of the brakes is favoured over an actuated stand-still from an energy point of view, assuming that the start-up time when releasing the brakes is limited.

Improved Resilience Controllers Using Cognitive Patterns

Construction of robotic controllers has been usually done by the instantiation of specific architectural designs. The ASys design strategy described in this work addresses the synthesis of custom robot architectures by means of a requirements-driven application of universal design patterns. In this paper we present three of these patterns —the Epistemic Control Loop, the MetaControl and the Deep Model Reflection patterns— that constitute the core of a pattern language for a new class of adaptive and robust control architectures for autonomous robots. A reference architecture for self-aware autonomous systems is synthesised from these patterns and demonstrated in the control of an autonomous mobile robot. The term “autonomous” gains a deeper significance in this context of reflective, pattern based controllers.

In Vitro Accuracy Evaluation of Image-Guided Robot System for Direct Cochlear Access

A previously developed image-guided robot system can safely drill a tunnel from the lateral mastoid surface, through the facial recess, to the middle ear, as a viable alternative to conventional mastoidectomy for cochlear electrode insertion. Direct cochlear access (DCA) provides a minimally invasive tunnel from the lateral surface of the mastoid through the facial recess to the middle ear for cochlear electrode insertion. A safe and effective tunnel drilled through the narrow facial recess requires a highly accurate image-guided surgical system. Previous attempts have relied on patient-specific templates and robotic systems to guide drilling tools. In this study, we report on improvements made to an image-guided surgical robot system developed specifically for this purpose and the resulting accuracy achieved in vitro. The proposed image-guided robotic DCA procedure was carried out bilaterally on 4 whole head cadaver specimens. Specimens were implanted with titanium fiducial markers and imaged with cone-beam CT. A preoperative plan was created using a custom software package wherein relevant anatomical structures of the facial recess were segmented, and a drill trajectory targeting the round window was defined. Patient-to-image registration was performed with the custom robot system to reference the preoperative plan, and the DCA tunnel was drilled in 3 stages with progressively longer drill bits. The position of the drilled tunnel was defined as a line fitted to a point cloud of the segmented tunnel using principle component analysis (PCA function in MatLab). The accuracy of the DCA was then assessed by coregistering preoperative and postoperative image data and measuring the deviation of the drilled tunnel from the plan. The final step of electrode insertion was also performed through the DCA tunnel after manual removal of the promontory through the external auditory canal. Drilling error was defined as the lateral deviation of the tool in the plane perpendicular to the drill axis (excluding depth error). Errors of 0.08 ± 0.05 mm and 0.15 ± 0.08 mm were measured on the lateral mastoid surface and at the target on the round window, respectively (n =8). Full electrode insertion was possible for 7 cases. In 1 case, the electrode was partially inserted with 1 contact pair external to the cochlea. The purpose-built robot system was able to perform a safe and reliable DCA for cochlear implantation. The workflow implemented in this study mimics the envisioned clinical procedure showing the feasibility of future clinical implementation.

A one-stop solution in robotic control system design

We have presented OpenRob, an integrated open-architecture platform for computer-aided control system design of robotic control systems. The implementation issues have been described in detail. It provides a one-stop solution in the sense that model building, controller design, and simulation are integrated into one platform for the ease of real-time implementation. The open-architecture feature enables users to further develop custom robot models, trajectory-planning schemes, and control algorithms into the system for simulation study and real-time control. The software can also be used as a tool for educational purposes. Several case studies have been provided to demonstrate the features of this open-architecture system.

An open architecture platform for control system development of robots

This paper presents the design and development of OpenRob - an open architecture platform for control system development of robots, which provides a one-stop solution for model building, controller design and numerical simulation for the ease of real-time implementation. By taking advantages of Object Oriented Programming styles and Dynamic Link Library (DLL) technology, this system provides a friendly Graphic User Interface (GUI) as an open environment for user to further develop the custom robot models, trajectory planning schemes and control algorithms into the system for simulation study and real time control implementation. Several case studies are given to demonstrate the functionality of this platform.