Final Demo Video

Its been a great semester! Here's what we built.

The Reach Goal: Multiple gaits and closed loop

For our reach goal, we decided to implement multiple gaits for the Soft Stepper (wrapped in an API) and implements a simple closed loop in the system.

In addition to the our basic walk, we were able to implement a faster (and far more complex) "power walk" gait, as seen here.

Additionally, we were able to implemented a turn gait.



Currently, our closed loop system is a collision avoidance module. This required the use of a ping sensor and wifi module connected to an additional mbed which was installed directly on the Soft Stepper.

Soft Stepper Demo Video!

It walks!

Soft Stepper: the Baseline

In order to build the Soft Stepper, we were required to design another generation of actuators. Imbued in this version is the sum of our experiences (read: failures) of previous generations. And this time, we got it right!

This generation is short and has relatively shallow cavities like generations 2 and 3, but has larger, divided cells like those of generation 1. The result is a functional mix of stability and flexibility. 

Additionally, in order to allow us to continue using the chassis, the newly created mould has a cross section identical to those of generations 2 and 3. 

The final Soft Stepper walks slowly but surely. Demo video to follow!

Soft Stepper Update 1: The Control Board

Over the past few days, we've made significant progress on some of the most crucial components of the Soft Stepper.

New moulds were designed, printed, and set to cast. We initially designed a shorter, 6 chambered version.

Unfortunately, a mixed axial/bending stress analysis revealed that our application required actuators that were longer and contained more chambers.

Thus, we created a new set of moulds and set the legs to cast in these. 

As soon as they are done and cured together, we will attempt to incorporated them into the chassis we designed and printed on the Makerbot.

Additionally, we designed and laser-cut a control board for the components.

The pump and solenoids were immediately integrated onto it. When the PCB is received, we will be able to add the mbed, pressure sensors, and mosfets. 

We created a short demo video to showcase our recent developments, implementing the rhythm for one of the Soft Stepper gaits. 

Final Project: the Soft Stepper

Since our soft fish idea went down the drain (no pun intended) we will move on to a new idea which will build on our previous work with soft actuators in a more fundamental fashion.

Our proposed project is a take on Harvard's PneuNets Robot for multiple modes of locomotion.

Our robot, the Soft Stepper, will be an adaptive multiple gate walker capable of moving along complex paths using soft-actuated legs attached to a rigid body chassis. 

The legs will be cast from a mould design similar to the fish tail, with enclosed cavities.

The walker will be controlled by an mbed mounted on-board via PCB, which will also contain the pressure sensors. The pump and solenoids, on the other hand, are much heavier and will likely be hosted on off board. 

In the final presentation, we will hopefully be able to demonstrate the versatility of this system by moving it in different directions, running it over terrain, and possibly altering planes of movement (squatting) or different speed settings.

The Fish Fail

Our soft fish cured beautifully and the fillets bonded well to the interface.

Unfortunately, the actuators were far too rigid, and would not bend far enough nor with enough force to simulate swimming.