Final Design

The final design is comprised of a bio-inspired sea urchin mouth (Lantern) that is electrically actuated to collect and deposit sediment.  

The design is composed of three systems working together to complete the sampling function:

• The lantern system - The lantern system is controlled with a linear actuator to collect and deposit sediment with the bio-inspired lantern.  

• The screw drive system - This system controls the vertical motion of the system via a motor and screw to move the entire lantern system up and down.  Converts 60 RPM rotational speed to 12cm/min vertical translation with an output of ~1500 N of force.  

• The gear system - The gear system rotates the other two systems to desired sampling positions and depositing positions.  The 6 RPM motor is able to translate 35 Nm of torque to the Slew Bearing with a mechanical advantage of 4.5.  The sampling system will rotate at 1.33 RPM for easy control and limiting and jerking movements that could result in a loss of sediment. 

The sampling rover can take 3 samples and store all the samples in one deployment in the sample holding containers.  The design is fully automated and involves no human interaction other than the control of the wireless transmitters.  The Rover and sampling system are powered by two different batteries and controlled with separate transmitters due to voltage incompatibilities.  

The sample holding containers can hold a maximum of 7.98 cm3 volume of sediment, which is much greater than the required 2.36 cm3.  Depending on the type of sediment being sampled, anywhere from 2-7 cm3 was collected.

Performance:

The Rover was required to drive on soft and compacted beach sand to replicate the different surfaces on Mars.  It was also required to sample and deposit three times in both environments.  The Mars Urchin was able to complete both tasks without any human involvement or battery limitations (a 9.6V rechargeable battery was implemented on the Rover for extra power and life).  

The Lantern was put to further testing by being required to sample Mars simulated sediment.  The sediment was heated to remove water vapor content to 5% and contained in a glove box to replicate Mars conditions.  Once again, the system performed great, sampling and depositing ~ 6cm3 worth of Mars simulant per sample.