Combining Gait Trainers and Partial Weight Bearing Lifters: A Dynamic Analysis of Seat-to-Stand Transition

We analyzed a new class of passive devices that can help individuals regain their independence. A new walker design has been commercialized under the name of UP’N FREE^®1. This new design can lift the user from a seated posture to a standing position through the employment of a four bar mechanism and gas piston. When the user is standing, the mechanism can provide partial compensation from gravity to help the user regain mobility. By using this system, users can sit and stand without another person’s assistance and can also compensate for gravity loads during walking both indoor and outdoor. This paper illustrates two examples of how to implement the dynamic lifting support and discusses the pros and cons of different system configuratons of a a gas spring cylinder as a passive actuator.