Design and implementation of a low-cost robotic load carrier

Many professional or daily activities demand load displacement by human arms or by human powered vehicles. Those activities may cause muscle-skeleton diseases even in load carrying professionals as in people carrying their daily objects. In the field of robotics, the research developments to help people at those activities are made through human-robot cooperation systems actuated by servo drives. Due to the cost of those drives, many people are not able to acquire the robots and so they are prohibited from getting the associated health benefits. To promote robot-aided solutions, this paper presents the design and implementation of a load carrier human-robot cooperation system, which is built through an electrical load cart and driven by frequency inverter and induction motor. The robot controller is implemented by a force regulation structure which allows the conductor to set the mechanical trajectories through the multiplication of the force applied by his/her arms. Since the arms have a higher positioning bandwidth than the conductor´s legs, the controller dynamic response is tuned with human leg dynamics in mind, so as to increase the operational safety. The paper presents details of mounting, firmware design and measurements to show the robot performance.