Traditional walking machines used in physiotherapy do little to accommodate the evolving needs of patients progressing through various stages of recovery. This paper describes a therapeutic walking machine that adjusts its function in harmony with two directives: the program selected by the therapist, and the real-time performance of the patient. The success of the system depends on the solution of several interesting user-interface problems: the creation of real-time reactions by the machinery that take into account the latency of the equipment; the development of sensors that measure parameters relevant to the process of walking (such as motion in the sagittal plane); the development of sophisticated models for walking at various speeds, climbing, and even stumbling; and emergency subsystems that ensure patient safety.

This paper is one of a series by the authors describing the evolution of their machine. Further work will probably involve increasing the number of degrees of freedom that can be accommodated by the equipment and the underlying computer models. This will be of interest to researchers in the biomechanical field, as well those studying the mechanics of walking for robotic applications. Although the focus of the HapticWalker project is to develop a sophisticated physiotherapy application, there are clear applications to the development of effective human-machine interfaces for industrial exoskeleton devices.