A large-scale, light-weight, and soft braided robot manipulator with rapid expansion capabilities

A key challenge in soft robotics is how to design self-supported large-scale soft robots. In order to address this we have created a braided manipulator. The manipulator consists of a biaxially braided cylinder made from twelve glass-fiber enforced rods. The manipulator measures 1.38m in height in its equilibrium state and has a diameter of 8.5cm at the top and 20.0cm at the base and only weighs 35g. The manipulator is fixed to a base which weighs 1.9kg in which three stepper motor driven winches are embedded at 120° intervals. From each winch a string is braided vertically through the braided manipulator and is fixed to the top. In experiments we find that the manipulator can be compressed to 51cm corresponding to 38%. The manipulator compresses in 54s which is determined by stepper speed and winch diameter and expands when the actuators are turned off in 105ms. We also find that the force required to compress the manipulator is constant at 2.6N for most of actuation range. The force generated by the manipulator corresponds to a payload of 265g which is an order of magnitude more then the weight of the manipulator itself. The limitations of the current work is that the actuation, processing, and power is externalized to the manipulator and modelling and control are unaddressed. However, overall we find that the braided manipulator is evidence that braiding holds potential as a construction paradigm for soft robotics as we have demonstrated that it allows for large-scale and light-weight soft robots.