Pneumatic assistant of one degree of freedom for lifting

Exoskeletons are wearable robots i.e. robots coupled to the body of a user and commanded by him/her. The fields of application involve among others, the military as well as the medical industries. This paper presents the design of part of an exoskeleton aimed to enhance the performance of people that have had spinal injury or that suffer from some problem or pain in the lumbar area. An experimental platform was built that allows the wearer to perform his/her tasks without making a big effort that could cause pain or injuries in the lumbar zone. The experimental platform employs Pneumatic Artificial Muscles (PAM) as actuators because they are suitable for applications were force is required. However being these actuators highly nonlinear devices, the control as well as the electronics involved in the design of the experimental set up are not a simple tasks. The experimental set up presented here is a one degree of freedom device attached to the trunk of a user. To start with a PD controller was employed. This set up is part of a bigger project that considers a complete exoskeleton that involves the four limbs and the middle part of a human body. However this device can be used to assist, as mentioned before, people with problems in the lumbar area.