Design of Tether Orientation Sensor for Gravity Offloading
The video shows the design of the tether orientation sensor for a gravity offloader. A gravity offloader is a device that pulls up on an object with a tether in order to simulate moon level gravity. It is important that the tether always pull the object straight up instead of at an angle. Thus, having an accurate and rapid tether angle sensor is a must. The red and blue pipes in the design are used to monitor angular displacement in the X and Y directions, respectively. When the tether moves and pushes the pipes, rotary encoders at the end of the pipes will record this angular displacement and transmit this information to the motors which can move the entire sensor/ motor apparatus accordingly and keep the tether going straight up instead of at an angle.
This design incorporates a number of design requirements previously unaccounted for. This includes a non-detachable hook on the offload-tether, which requires that the taut-tether sensor be built around the cable, given that the cable cannot be slipped through a tight space. Furthermore, the cable must be held through a fixed point, due to the 'walking' of the tether while being spooled and unspooled from the offload mechanism. This fixture can be seen in the video as well. A physical representation for this design can be seen in a joystick mechanism, as in this photo.