Task-oriented repetitive movements can improve motor recovery in patients with neurological or orthopaedic lesions. The application of robotics can serve to assist, enhance, evaluate, and document neurological and orthopaedic rehabilitation. ARMin is a new robot for arm therapy applicable to the training of activities of daily living in clinics. ARMin has a semiexoskeletal structure with six degrees of freedom, and is equipped with position and force sensors. The mechanical structure, the actuators and the sensors of the robot are optimized for patient-cooperative control strategies based on impedance and admittance architectures. This paper describes the mechanical structure, the control system, the sensors and actuators, safety aspects and results of a first pilot study with hemiplegic and spinal cord injured subjects

This paper presents newly developed algorithms for automatic adaptation of motion for a robotic rehabilitation device. The algorithms adapt the gait pattern of patients that walk on a treadmill. Three different algorithms were developed. The first one is based on inverse dynamics and online minimization of the human-machine interaction torque. The second one is based on direct dynamics and estimation of the desired variation in the gait-pattern acceleration. The third algorithm is based on impedance control and direct adaptation of the gait pattern angular trajectories. The algorithms were tested and compared in computer simulations and actual experiments on healthy subjects and patients. In simulations, all algorithms have adapted the gait pattern toward the desired one, which led to a greater than 40% reduction of interaction torques. The impedance-control-based algorithm performed best in the experiments.