Richard Weir and the BioMechatronics Development Laboratory
Dr. Weir assembles a partial hand prosthesis while PhD student Alex Birdwell looks on
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Our research interests are in the fields of neural engineering, biomechatronics and rehabilitation, specifically, implantable bioelectric sensors, artificial arm/hand systems, manipulators, robotics and their control. The primary focus of this research is the design of upper-limb prosthetic components and their associated control. The current focus of this work is the development of upper-arm components for the Prototype 1 arm and the Intrinsic hand for the Prototype 2 arm of the DARPA Revolutionizing Prosthetics initiative. We are also developing externally-powered partial hand prostheses for clinical use as well as a more clinically viable multiple degree-of-freedom externally-powered prosthetic hands and 2 DOF wrist for persons with amputations proximal to the wrist. In the area of upper-limb control my research is directed towards the long-term goal of achieving meaningful, simultaneous, multi-functional, control of prosthetic arms and/or hands. This work is currently directed at developing physiologically appropriate microprocessor based controllers based on “BION®-like” implantable myoelectric sensors (IMES) for multiple degree-of-freedom prosthetic arm control. Work is also ongoing in the area of series elastic, or compliant, motors/drives/actuators for use in prosthetic components in particular a compliant elbow and wrist. In addition we have a project to develop a powered humeral rotator for upper-limb prosthetic applications.
BioMechatronics Development Laboratory in the Media
"The Pentagon's Bionic Arm” Advanced prosthetic limb systems featured on 60 minutes, April 2009
The arm system featured here was developed by DEKA, in conjunction with researchers here at RIC, including technical and clinical advice from Dr. Richard Weir.
Jonathan Kuniholm wears a prototype of the prosthetic arm created by the DARPA Revolutionizing Prosthetics 2009 project. The intrinsic hand shown was developed at the Biomechatronics development laboratory.
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"Rebuilding Bryan Anderson” by Brian Mockenhaupt, Esquire Magazine, February, 2008.
Discussing the most advanced prosthetics available and upcoming. This includes the intrinsic hand developed by the biomechatronics development laboratory and the IMES implantable myoelectric sensor system developed by Dr. Weir.
Dr. Richard F. ff. Weir, Ph.D, as part of the Revolutionizing Prosthetics 2009 (RP2009) team led by John Hopkins University Applied Physics Laboratory (JHUAPL), was awarded the POPULAR MECHANICS 2007 Breakthrough Innovator Award for the design of the Proto 2 myoelectric arm and IMES sensor system.
Discusing the DARPA RP 2009 project including the IMES sensor system developed by the BioMechatronics Development Laboratory - "To gather signals required for finer control, Revolutionizing Prosthetics 2009 engineers will turn to rice-size injectable myoelectric sensors, or IMES -- devices being developed by RIC scientists Richard Weir and Jack Schorsch, and Philip Troyk of the Illinois Institute of Technology. Once embedded in the muscles to be read, the IMES devices will send much clearer signals, and many more of them."
more. . .
Ongoing Projects
Revolutionizing Prosthetics 2009, Final Limb System - DARPA (DSO) - APL
On this subcontract we were tasked with working with APL and Otto Bock, Vienna, to build a first generation prototype arm, Prototype 1, using “off-the-shelf” technology and to deliver it in the first year. In addition, working with Otto Bock, Vienna, New world Associates and APL we are tasked to complete an intrinsically actuated electromechanical hand solution capable of meeting the full DARPA specifications as part of the Prototype 2 arm. The Intrinsic hand is an 18 DOF hand wrist system. Our other major role in this DARPA initiative is to accelerate the development, testing and integration of a 16 channel implantable myoelectric sensor system.
Implantable MyoElectric Sensors - (IMES) - NIH(NIBIB/NICHD)
Persons with recent hand amputations expect modern hand prostheses to function like intact hands. Unfortunately, current state-of-the-art electric prosthetic hands are generally single degree-of-freedom (opening and closing) devices that function and are controlled very differently than the natural hand. Prosthetic arms that allow multi-degree-of-freedom (DOF) movements require sequential control of these multiple motions, using locking mechanisms and/or special switch signals to change control from one degree-of-freedom to the next. This type of control is slow and counter intuitive. Consequently, because most devices fail to meet users’ expectations, they tend to be under utilized or rejected. For persons with recent hand amputations “Every advancement in limb prosthetics is compared against re-creation of the physiological limb and the experience of the artificial limb. Although many people use prostheses and, in this way, accept the state-of-the-art, they are generally not satisfied with it. It is the nature of the work that prosthetics research is driven by dissatisfaction.”
Consideration of both current and experimental control approaches drove the system requirements for our Implantable Myoelectric Sensor (IMES) system. The major factor limiting the development of more sophisticated hand/arm prostheses is not hand/arm mechanisms themselves but rather the difficulty in finding sufficient control sources to control the many DOFs required to replace a physiological hand and/or arm. Development of an Implantable MyoElectric Sensor (IMES) system that uses a transcutaneous (no wires) magnetic link allows multiple control sources to be created by recording myoelectric signals at their source, with low levels of inter-electrode cross talk, and thus, a high degree of independence between sources PDF
Internal Model based Control for a multi-function hand - VA
The primary objective of this research is to implement a 3D, computer graphics based model of the upper extremity to develop a control system for a multifunction artificial hand. A secondary objective of this research is to establish a strong collaboration between Dr. Wendy Murray, a principal investigator at the VA Palo Alto Health Care System Center of Excellence on Bone and Joint Rehabilitation and Dr. Richard Weir, a principal investigator at the Jesse Brown VAMC (Chicago, IL). This collaboration will highlight both investigators’ interests in understanding the control of upper extremity and hand movement. It will also serve as a means to integrate their complementary skills in the areas of biomechanical modeling (Dr. Murray) and the design and control of prosthetic devices for the upper limb (Dr. Weir). This work will lead to continual collaboration between the two VA investigators on the application of computer simulation to the design of upper extremity prosthesis.
2 DOF Compliant wrist using Series Elastic Actuators - VA
This project involves the development of a more functional prosthetic wrist. Current prosthetic wrists are limited in terms of their functionality. Current wrists on the market only rotate about the central arm axis, causing unnatural and often awkward positioning of the residual limb. Also, all wrists have no impact protection, increasing the probability of user injury and prosthetic damage in uncontrolled situations. Also, most wrists are required to be manually positioned which can be difficult and time consuming.
Through the introduction of a Series Elastic Actuator (SEA), we believe the prosthetic wrist issues can be resolved. Gill Pratt and Matthew Williamson developed the SEA idea to allow for the introduction of controlled compliance into a robotic system. To create a SEA, an elastic element is placed between the gear train and the output of the system. By integrating a SEA into a prosthetic wrist, the functionality of the wrist is improved. The wrist can be designed to more naturally mimic the motion of the human wrist to eliminate much of the awkward positioning. SEA’s allow for practical implementation of a force control algorithm which can provide impact protection. Also, the SEA wrist will be motorized to make the wrist easier to use.
RIC - UNB Multi-Degree of Freedom Hand - AIF
In the US and Canada approximately 60,000 people are missing hands or entire arms while an additional 2,300 people suffer hand amputations each year. There is a limited range of prosthetic solutions to help these people. The Institute for Biomedical Engineering (IBME) and Applied Nanotechnology Lab at the University of New Brunswick (UNB), in partnership with the thin film research group at the University de Moncton (UdeM) and the Biomechatronics Development Lab at the Rehabilitation Institute of Chicago propose to develop a commercially viable and technologically advanced prosthetic hand system. The UNB Hand will feature a movable thumb and fingers, a common left and right hand substructure components and interchangeable parts. It will be lightweight, compact, quiet, robust, affordable and available in a range of sizes. In order to control the hand's gripping motion, the IBME will develop, with the help of UdeM and the Applied Nanotechnology Lab, a prosthetic glove with built-in sensors. Using thin film sensors and flexible electronic circuits, this highly durable life-like multilayer glove will provide electronic feedback to the hand controller that allows incremental adjustments to grip pressure to hold an object without crushing it. Finally, in order to activate and move the new hand unit, the IBME will improve on existing myoelectric control units with a new state-of-the-art myoelectric control unit that incorporates the latest control algorithms developed by the IBME. Current Myoelectric control units use muscle signals to activate and control individual components (arm, wrist, hand). Users must systematically activate individual components in a step-by-step fashion thus producing an unnatural robotic movement. The IBME will extend this functionality by better distinguishing between various muscle signals and automating control sequences to produce a more natural motion while reducing the wearer's cognitive burden.
Externally-Powered Partial Hand Prosthesis- VA
The two hand projects are funded by Veterans Administration Merit Review Proposals. The first of these projects is Merit Review Proposal A3028R: "Technology Transfer of an Externally-Powered Trans-Metacarpal Hand Prosthesis", a three year project started in July 2003. During previous funding we developed a single degree-of-freedom externally-powered hand mechanism for persons with amputations at or more proximal to the level of the metacarpophalangeal joint in the hand (partial hand amputation). more ...
Previous Projects
6-Motor Arm - RIC
Passive Gravity Compensation
The goal of the project was to use linear springs to passively compensate a forearm prosthesis against gravity. The technology was intended for use with powered prostheses, with the goal of relieving joint torque to allow faster powered movement and/or smaller actuators. This was to be accomplished using a concept developed by T. Rahman et al. They proved that one linear spring could provide passive gravity compensation through the full range of motion of an arm if the correct stiffness (K) value for the spring was chosen. If this technology could be successfully applied to a prosthetic forearm, the next step would be to design a controller to actively change the spring's stiffness to passively compensate for varied loading on the arm.
Ultrasonic Ranging System - NIDRR
Surface vs Intramuscular EMG for Pattern Recognition - NIH
Muscle Synergies for Control
Impedance control using SEA elbow
As a future direction for our research, we are working on developing series elastic actuators suitable for use in prosthetics. A series elastic actuator is a way of making an otherwise stiff DC gearmotor drive compliant. more...
