We considered some preliminary designs which use actuators (pictured below).
However, after doing some motion studies on our scaled paper model and some height calculations, we concluded that they were not the most suitable for our purposes of lifting a pneumatic unit from the ground and installing it at a height of 2.9m.
For the first and second design (from left), they were not able to pick the unit from the ground.
The first design did not have a long enough second arm and the actuator was placed such that the first arm is not able to go below about 45 degrees parallel to the ground.
For the second design, the placement of the second actuator between the first and second arm caused the arms to be unable to reach the pneumatic unit on the ground too.
For the third design, the design was unable to reach the required height of 2.9m due to the insufficient extension of second actuator. We will need to consider how to increase the reach of the second arm without resorting to cranes or longer actuator units (with lower and insufficient force outputs).