Direct interaction with an assistive robot for individuals with chronic stroke.

Many robotic systems have been developed to provide assistance to individuals with disabilities. Most of these systems require the individual to interact with the robot via a joystick or keypad, though some utilize techniques such as speech recognition or selection of objects with a laser pointer. In this paper, we describe a prototype system using a novel method of interaction with an assistive robot. A touch-sensitive skin enables the user to directly guide a robotic arm to a desired position. When the skin is released, the robot remains fixed in position. The target population for this system is individuals with hemiparesis due to chronic stroke. The system can be used as a substitute for the paretic arm and hand in bimanual tasks such as holding a jar while removing the lid. This paper describes the hardware and software of the prototype system, which includes a robotic arm, the touch-sensitive skin, a hook-style prehensor, and weight compensation and speech recognition software.

Recent trends in the development and evaluation of assistive robotic manipulation devices.

This review explores recent trends in the development and evaluation of assistive robotic arms, both prosthetic and externally mounted. Evaluations have been organized according to the CATOR taxonomy of assistive device outcomes, which takes into consideration device effectiveness, social significance, and impact on subjective well-being. Questions that have informed the review include: (1) Are robotic arms being comprehensively evaluated along axes of the CATOR taxonomy? (2) Are definitions of effectiveness in accordance with the priorities of users? (3) What gaps in robotic arm evaluation exist, and how might these best be addressed? (4) What further advances can be expected in the next 15 years? Results highlight the need for increased standardization of evaluation methods, increased emphasis on the social significance (i.e., social cost) of devices, and increased emphasis on device impact on quality of life. Several open areas for future research, in terms of both device evaluation and device development, are also discussed.

Development of a skin for intuitive interaction with an assistive robot.

Assistive robots for persons with physical limitations need to interact with humans in a manner that is safe to the user and the environment. Early work in this field centered on task specific robots. Recent work has focused on the use of the MANUS ARM and the development of different interfaces. The most intuitive interaction with an object is through touch. By creating a skin for the robot arm which will directly control its movement compliance, we have developed a novel and intuitive method of interaction. This paper describes the development of a skin which acts as a switch. When activated through touch, the skin will put the arm into compliant mode allowing it to be moved to the desired location safely, and when released will put the robot into non-compliant mode thereby keeping it in place. We investigated four conductive materials and four insulators, selecting the best combination based on our design goals of the need for a continuous activation surface, the least amount of force required for skin activation, and the most consistent voltage change between the conductive surfaces measured during activation.

Investigation of goal change to optimize upper-extremity motor performance in a robotic environment.

Robotic devices for therapy have the potential to enable intensive, fully customized home rehabilitation over extended periods for individuals with stroke and traumatic brain injury, thus empowering them to maximize their functional recovery. For robotic rehabilitation to be most effective, systems must have the capacity to assign performance goals to the user and to increment those goals to encourage performance improvement. Otherwise, individuals may plateau at an artificially low level of function. Frequent goal change is needed to motivate improvements in performance by individuals with brain injury; but because of entrenched habits, these individuals may avoid striving for goals that they perceive as becoming ever more difficult. For this reason, implicit, undetectable goal change (distortion) may be more effective than explicit goal change at optimizing the motor performance of some individuals with brain injury. This paper reviews a body of work that provides a basis for incorporating implicit goal change into a robotic rehabilitation paradigm. This work was conducted with individuals without disability to provide foundational knowledge for using goal change in a robotic environment. In addition, we compare motor performance with goal change to performance with no goal or with a static goal for individuals without brain injury. Our results show that goal change can improve motor performance when participants attend to visual feedback. Building on these preliminary results can lead to more effective robotic paradigms for the rehabilitation of individuals with brain injury, including individuals with cerebral palsy.