Marc Carmichael received his B.Eng. Mechanical and Mechatronic Engineering with First Class Honors, and PhD degree from the University of Technology Sydney (Australia) in 2008 and 2013 respectively. He joined the UTS Centre for Autonomous Systems (UTS:CAS) as a Research Fellow in 2014.
- Dynamics and Control
- Mechanical and Mechatronic Design
Carmichael, M.G., Liu, D. & Waldron, K.J. 2017, 'A framework for singularity-robust manipulator control during physical human-robot interaction', INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH, vol. 36, no. 5-7, pp. 861-876.View/Download from: UTS OPUS or Publisher's site
Carmichael, M.G. & Liu, D. 2013, 'Estimating Physical Assistance Need Using a Musculoskeletal Model', IEEE Transactions On Biomedical Engineering, vol. 60, no. 7, pp. 1912-1919.View/Download from: UTS OPUS or Publisher's site
Technologies that provide physical assistance during tasks are often required to provide assistance specific to the task and person performing it. An example is robotic rehabilitation in which the assistance-as-needed (AAN) paradigm aims to provide operators with the minimum assistance required to perform the task. Current approaches use empirical performance-based methods which require repeated observation of the specific task before an estimate of the needed assistance can be determined. In this paper, we present a new approach utilizing a musculoskeletal model (MM) of the upper limb to estimate the operator's assistance needs with respect to physical tasks. With capabilities of the operator defined at the muscular level of the MM, an optimization model is used to estimate the operator's strength capability. Strength required to perform a task is calculated using a task model. The difference or gap between the operator's strength capability and the strength required to execute a task forms the basis for the new AAN paradigm. We show how this approach estimates the effects of limb pose, load direction, and muscle impairments on a person's ability to perform tasks.
Reeks, C., Carmichael, M., Liu, D. & Waldron, K. 2016, 'Angled sensor configuration capable of measuring tri-axial forces for pHRI', Proceedings - IEEE International Conference on Robotics and Automation, IEEE International Conference on Robotics and Automation, IEEE, Stockholm, Sweden, pp. 3089-3094.View/Download from: UTS OPUS or Publisher's site
This paper presents a new configuration for single axis tactile sensor arrays molded in rubber to enable tri-axial force measurement. The configuration requires the sensing axis of each sensor in the array to be rotated out of alignment with respect to external forces. This angled sensor array measures shear forces along axes in a way that is different to a planar sensor array. Three sensors using the angled configuration (22.5°, 45° and 67.5°) and a fourth sensor using the planar configuration (0°) have been fabricated for experimental comparison. Artificial neural networks were trained to interpret the external force applied along each axis (X, Y and Z) from raw pressure sensor values. The results show that the angled sensor configuration is capable of measuring tri-axial external forces with a root mean squared error of 1.79N, less error in comparison to the equivalent sensor utilizing the planar configuration (4.52N). The sensors are then implemented to control a robotic arm. Preliminary findings show angled sensor arrays to be a viable alternative to planar sensor arrays for shear force measurement; this has wide applications in physical Human Robot Interaction (pHRI).
Woolfrey, J.K., Liu, D.K. & Carmichael, M. 2016, 'Kinematic Control of an Autonomous Underwater Vehicle-Manipulator System Using Autoregressive Prediction of Vehicle Motion and Model Predictive Control', Proceedings - IEEE International Conference on Robotics and Automation, IEEE International Conference on Robotics and Automation, IEEE, Stockholm, Sweden.View/Download from: UTS OPUS or Publisher's site
Carmichael, M.G. & Liu, D. 2013, 'Human Biomechanical Model Based Optimal Design of Assistive Shoulder Exoskeleton', Field and Service Robotics, International Conference on Field and Service Robotics, Springer, Brisbane, pp. 245-258.View/Download from: UTS OPUS or Publisher's site
Carmichael, M.G. & Liu, D. 2015, 'Upper Limb Strength Estimation of Physically Impaired Persons using a Musculoskeletal Model: A Sensitivity Analysis', Proceedings of the 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, Milan, Italy, pp. 2438-2441.View/Download from: UTS OPUS or Publisher's site
Sensitivity of upper limb strength calculated from a musculoskeletal model was analyzed, with focus on how the sensitivity is affected when the model is adapted to represent a person with physical impairment. Sensitivity was calculated with respect to four muscle-tendon parameters: muscle peak isometric force, muscle optimal length, muscle pennation, and tendon slack length. Results obtained from a musculoskeletal model of average strength showed highest sensitivity to tendon slack length, followed by muscle optimal length and peak isometric force, which is consistent with existing studies. Muscle pennation angle was relatively insensitive. The analysis was repeated after adapting the musculoskeletal model to represent persons with varying severities of physical impairment. Results showed that utilizing the weakened model significantly increased the sensitivity of the calculated strength at the hand, with parameters previously insensitive becoming highly sensitive. This increased sensitivity presents a significant challenge in applications utilizing musculoskeletal models to represent impaired individuals.
Carmichael, M.G., Khonasty, R. & Liu, D. 2015, 'A Multi-stage Design Framework for the Development of Task-specific Robotic Exoskeletons', Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, Milan, Italy.View/Download from: UTS OPUS or Publisher's site
Tran, A., Liu, D., Ranasinghe, R., Carmichael, M. & Liu, C. 2015, 'Analysis of Human grip strength in physical Human Robot Interaction', Proceedings - Analysis of Human grip strength in physical Human Robot Interaction, Conference on Applied Human Factors and Ergonomics, ELSEVIER SCIENCE BV, Las Vegas.View/Download from: UTS OPUS or Publisher's site
The purpose of this paper is to explore how an operator's grip plays a role in physical Human Robot Interaction (pHRI). By considering how the operator reacts to or initiates changes in control, it is possible to study the operator's grip pattern. By analyzing the grip pattern, it is possible to incorporate their natural response in order to create safer and more intuitive interfaces. An experiment where an exoskeleton and human collaborate in order to complete a path following task has been chosen to observe the forces applied by the user at the handle to determine the interaction between the operator and robot. A ThruMode Matrix Array sensor has been wrapped around the robot's handle to measure the applied pressure. By introducing the sensor it not only enables the measurement of the applied forces and how they are applied but also a measure of how tight the user is gripping the handle. Previous studies show that the natural response of a human to an unexpected event is to tighten their grip, indicating that how an operator grasps the handle can be related to the operator's intention. In order to investigate how the operator's grip of the handle changes, the experiments presented in this paper examine two different scenarios which might occur during an interaction, the first where the robot attempts to deviate from the path and the second where the operator wishes to deviate to a new path. The results of the experiments show that whether the operator or the robot initiates the transition, a measurable change in how the operator grasps the handle. The information in this paper can lead to new applications in pHRI by exploring the possible uses of an operator's grasping strength.
Carmichael, M.G., Moutrie, B. & Liu, D. 2014, 'A Framework for Task-Based Evaluation of Robotic Coworkers', 2014 13th International Conference on Control Automation Robotics and Vision, ICARCV 2014, International Conference on Control, Automation, Robotics and Vision, IEEE, Singapore, pp. 1362-1367.View/Download from: UTS OPUS or Publisher's site
Compared to a robotic system that performs a task alone, a robot coworker performing tasks in collaboration with a human operator is subject to additional constraints which can limit the ability of the system to perform the task as required. This work presents a framework for analyzing the ability of a robotic coworker to perform specific tasks in collaboration with a human. The framework allows systematic evaluation of robotic systems based on traditional robot performance measures such as reachable workspace and payload capacity, as well as considering additional factors which arise due to the task being performed collaboratively with a human; such as the reach and strength of the human, human-robot collision, and satisfying desired assistance paradigms. Application of the framework is demonstrated in a case study analyzing a robot designed to assist a human during a materials handling task.
Carmichael, M.G. & Liu, D. 2013, 'Admittance Control Scheme for Implementing Model-based Assistance-As-Needed on a Robot', 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, Osaka, Japan, pp. 870-873.View/Download from: UTS OPUS or Publisher's site
A model-based assistance-as-needed paradigm has been developed to govern the assistance provided by an assistive robot to its operator. This paradigm has advantages over existing methods of providing assistance-as-needed for applications such as robotic rehabilitation. However, implementation of the model-based paradigm requires a control scheme to be developed which controls the robot so as to provide the assistance calculated by the model-based paradigm to its operator. In this paper an admittance control scheme for providing model-based assistance-as-needed is presented. It is developed considering its suitability for human-robot interaction, and its role within the model-based assistance-as-needed framework. Results from the control implemented on an example robot showed it is capable of providing the operator with the desired level of assistance as governed by the model-based paradigm. This is an essential requirement for the paradigm to be capable of providing efficacious assistance-as-needed in applications such as robotic rehabilitation.
Carmichael, M.G. & Liu, D. 2013, 'Experimental Evaluation of a Model-based Assistance-As-Needed Paradigm using an Assistive Robot', 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, Osaka, Japan, pp. 866-869.View/Download from: UTS OPUS or Publisher's site
In robotic rehabilitation a promising paradigm is assistance-as-needed. This is because it promotes patient active participation which is essential for neuro-rehabilitation. A model-based assistance-as-needed paradigm has been developed which utilizes a musculoskeletal model representing the subject to calculate their assistance needs. In this paper we experimentally evaluate this model-based paradigm to control an assistive robot and provide a subject with assistance-as-needed at the muscular level. A subject with impairments defined in specific muscle groups performs a number of upper limb tasks, whilst receiving assistance from a robotic exoskeleton. The paradigm is evaluated on its ability to provide assistance only as the subject needs, depending on the tasks being performed and the impairments defined. Results show that the model-based assistance-as-needed paradigm was relatively successful in providing assistance when it was needed.
Carmichael, M.G. & Liu, D. 2012, 'A Task Description Model for Robotic Rehabilitation', 34th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, International Conference of the IEEE Engineering in Medicine and Biology Society, The Printing House, San Diego, pp. 3086-3089.View/Download from: UTS OPUS or Publisher's site
The desire to produce robots to aid in physical neurorehabilitation has led to the control paradigm Assistance- As-Needed. This paradigm aims to assist patients in performing physical rehabilitation tasks whilst providing the least amount of assistance required, maximizing the patients effort which is essential for recovery. Ideally the provided assistance equals the gap between the capability required to perform the task and the patients available capability. Current implementations derive a measure of this gap by critiquing task performance based on some criteria. This paper presents a task description model for tasks performed by a patients limb, allowing physical requirements to be calculated. Applied to two upper limb tasks typical of rehabilitation and daily activities, the effect of task variations on the tasks physical requirements are observed. It is proposed that using the task description model to compensate for changing task requirements will allow better support by providing assistance closer to the true needs of the patient
Carmichael, M.G. & Liu, D. 2011, 'Towards using Musculoskeletal Models for Intelligent Control of Physically Assistive Robots', International Conference of the IEEE Engineering in Medicine and Biology Society, International Conference of the IEEE Engineering in Medicine and Biology Society, The Printing House, Boston, MA, pp. 8162-8165.View/Download from: UTS OPUS or Publisher's site
With the increasing number of robots being developed to physically assist humans in tasks such as rehabilitation and assistive living, more intelligent and personalized control systems are desired. In this paper we propose the use of a musculoskeletal model to estimate the strength of the user, from which information can be utilized to improve control schemes in which robots physically assist humans. An optimization model is developed utilizing a musculoskeletal model to estimate human strength in a specified dynamic state. Results of this optimization as well as methods of using it to observe muscle-based weaknesses in task space are presented. Lastly potential methods and problems in incorporating this model into a robot control system are discussed.
Carmichael, M.G., Liu, D. & Waldron, K. 2010, 'Investigation of Reducing Fatigue and Musculoskeletal Disorder with Passive Actuators', Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Taipei, Taiwan, pp. 2481-2486.View/Download from: UTS OPUS or Publisher's site
Robotic systems such as exoskeletons can be effectively used in the reduction of fatigue and musculoskeletal disorders (MSD) associated with physical tasks, but robots which work in physical contact with humans pose problems with user safety. A novel approach to developing intrinsically safe robots is to use passive actuators which have the advantage of being safer, ensuring stability, high force/weight ratios and lower power consumption. It is however not clear how effective an exoskeleton utilizing passive actuators would be in reducing fatigue and the risk of MSD. This paper analyzes the benefit of using such a system with results from dynamic simulations and an experiment using a specially designed mechanism used for evaluation. Results indicate that fatigue and effort could be reduced if robot impedance is minimized. Experiments also highlighted issues of implementing such a system into practice.
Behrens, M.J., Carmichael, M.G. & Patel, M.N. 2008, 'Designing SANDRA: An Autonomous Tour Guide Robot for the University of Technology, Sydney', 2008 Australasian Conference on Robotics & Automation, Australasian Conference on Robotics and Automation, Australian Robotics and Automation Association, Canberra, pp. 1-7.View/Download from: UTS OPUS
This paper describes how a team of final year mechatronic engineering students developed an autonomous robotic system intended to act as a tour guide during events such as University open days and explores the opportunities this project presented to extend their knowledge and skills. The specifications of the project required the system to localise and navigate autonomously within a known environment while avoiding collisions with any people or obstacles not included in the prior area map. In addition to these requirements, the system needed to locate humans as potential clients, approach and greet them, offer directions and if required take the guest on a guided tour of the university. While taking the subject Advanced Robotics the students were able to develop a functional first prototype of the system and carry out initial tests. Following the completion of the subject a small number of the students opted to continue working on the project developing a second prototype using the knowledge gained and further enhancing their learning experiences. While this project mainly involved integrating existing well known algorithms, software and hardware, it provided an excellent opportunity to enhance the mechatronic engineering skills of the students involved.
Kwok, N., Carmichael, M.G., Ha, Q.P. & Tan, K. 2007, 'Statistical decision based gray-level image feature matching', Proceedings of the 8th International Conference on Intelligent Technologies (InTech'07), International Conference on Intelligent Technologies, University of Technology Sydney, Sydney, Australia, pp. 269-274.View/Download from: UTS OPUS