Project statement:

Though the wheel has been a crucial invention, it is not without its flaws. For instance, it has trouble climbing stairs and is prone to bug down in uneven terrain. In response to these issues, I chose to adopt walker design that would allow us to overcome these challenges.

This project is a continuation of the legged walker I worked on last semester. With the experience I gained from experimenting with legged robot designs, I decided to change the design completely and to start anew. For this new walker robot, I decided to make it as lightweight as possible by removing unnecessary pieces from the structure without compromising the overall integrity. Furthermore, I implemented a new leg design and linked the motion of all 4 legs with gears in order to improve the robot’s effectiveness at walking. In addition, 4 new motors were used to allow the walker to move at faster speeds and to improve its terrain crossing capabilities. Despite these major changes, the robot can be controlled relatively easily through a remote controller. 

This week, I tried to improve on the existing iteration of my walker. I tried to reverse the positioning of the feet in order to give it more stability, but it had the opposite of the wanted effect. I also tried to replace the two piece body with one that is composed of only one section. While it did allow for some weight loss, it was insufficient to solve the core problems. In addition to my inability to improve the performance of the walker, I had issues with the electronic parts of the project. For some unknown reason, even if both the arduino and the motor shield were connected to the battery, the legs would not move. Hence, I also spent quite some time on trying to figure this out, which meant that I did not possess enough time to complete the major changes. I was able to start work on the remodeling the whole design, however, and to print out some pieces that I will need in the future. The new iteration would have some major differences when compared to its predecessor, as it would have 6 legs instead of 4, and all of the motors would power a set of gears rather than individual legs. The addition of new legs is meant to provide more stability when walking and the gears were added in order to allow a certain level of coordination between the 4 motors. Next week, I plan in completing these changes and to start working in my diagrams and presentations. 

This week, I worked to further improve some of the aspects of my walker. For instance, I trimmed the wires connecting the motors to the motorshield. This was done in order to prevent the possibility that they might get entangled when the motors are driving the legs forward. In addition, I also attached metal wires to the hatches of the leg compartment. These were very much needed, for the before the changes were made, these pieces were loose and had a tendency to fall off. By adding the metal wires, I was able to solve this issue while keeping them removable for an easy extraction of the motor from the leg compartment. During this week I also worked on a third addition to the robot that was used to coordinate the rotation of the motors. This was meant to make all of the motors turn at the same time and to prevent the case where some of them might be rotating faster than others. While I was able to design the gears needed for this system to work, I did not have time to print the pieces out in time due to the long queue time on the laser printer. While waiting to print off the gears pieces, I tested the walker's ability to move. Sadly, a number of problems caused it to be unable to walk properly (mainly that the motors are not coordinated). As a response to the lack of stability while moving, I created feet that would allow the walker to stand better on 2 legs and, hopefully, while moving. Unfortunately, I did not have enough time to conduct further testing. Next week, I plan to make major changes to the body. Judging from the results of the test, the walker would be much more effective at walking if the body consisted of only one piece rather than two separate pieces. I would have to sacrifice the turning system in order to ensure that the walker can walk. Furthermore, I also have plans to implement the system that would coordinate the rotation of the motors next week. 

This week, with help from David, I was able to make huge amount of progress in my project. First, I was able to print out and assemble the new legs that I had planned to make last week. Then, I made some testing to judge on their functionality and made small changes to changes in accordance to the issues that arose. I also made new motor housings that were much lighter and more efficient. For instance, I tried to carve out unnecessary pieces from the structure without compromising the overall integrity. Furthermore, thanks to the new leg design, I was able to reduced much of the weight of the motor housings by removing the outer panel that was a very prominent feature of the older design. In addition, the lighter nylon screws and nuts that I ordered arrived this week. This allowed me to replace the much heavier steel screws, which further contributed to reduce the weight of my walker. Once the assembly of the new motor housing and legs were completed, I moved on to work on the electronics part of my project. While we did initially encounter several issues, such as the fact that I was unable to find the full code for the arduino, I was able to complete this task with David's help. I was also able to implement a turning feature in the code and to assign it to a servos. Finally, after all this was complete, I went on to put all of the components together. While I did not have time to link the motors to the motorshield and the arduino, I still managed to complete a presentable model of the walker. After I return from spring break, I will conduct a series of testing on the overall functionality of the walker and to make further changes if needed. Overall, I believe that this week was a very successful week where much progress was made on my walker. 

This week, I was able to complete the final touches to the design of the new and lighter body. After making some inspection on the quality of the new pieces and adding some final touches to it, I proceeded to print out these components. Then, I moved on to the assembly step, which went rather smoothly despite the fact that I was initially worried about the complexity of the new design. Even with a lighter body, however, it seemed as if the legs were still unable to walk.; whenever I powered the motors, the legs would only make half of the walking motion and then bug down when they came into contact with the ground. From my observations, I concluded that the problem laid in the fact that the walking motion created by my leg design contained many flaws. For instance, when the motor is rotating, only a small portion of the each revolution is allocated to the part where the leg was to propel the walker forward. Furthermore, the motion created by the leg was one which involved pushing the robot upwards. Considering the minimum weight of the walker, the motors I am using would never provide enough power to lift the robot upwards even if I was to make it lighter still. Hence, I decided to use the theo jansen leg design instead, for it provided a much more perfected walking motion than my design. To do so, I would also have to rework the leg compartment and to make new leg pieces. And unfortunately, my computer broke down, and I was unable to make much progress pass the development stage of the new legs. Next week, I plan in printing out the first leg and to test its functionality and effectiveness. Then, if all goes well, I will move on to print out and assemble all 4 legs onto my walker. 

This week, I met with David to come up with a plan to make my walker more efficient. One of the major issues of my robot was that it was too heavy, which caused the legs to bend under the enormous pressure. Furthermore, the motors I used were not powerful enough to propel such a heavy robot. Hence, David suggested that I should redesign some parts of the robot in order to reduce weight and to improve on a number of other problems. In addition, David also suggested that I should order a number of electronic parts that would be vital to the functionality of my walker. For instance, he suggested that I should use something to synchronize all of the motors to work at the same time and pointed out that I should use a much lighter battery pack. After this meeting, I went on to work on the new design of the body. In this iteration, I implemented several concepts David suggested, such as the fact that I should cut out as much material from the solid surfaces as possible in order to reduce weight. Furthermore, I also implemented a number of design choices of my own, including the notches I plan to use to fit the robot together. Sadly, I did not have enough time to cut and test out the new body. Hence, my goal next week would be to cut out the new body and to make changes according to the issues that may appear.

This week, I worked hard on my first iteration of my walker and made a number of significant changes to its design. Initially, my goal was to complete the assembly of the final form of the first iteration of the walker. I had all the pieces ready and all that was left to do was to put them together. However, after I finished putting it together, I found out that there was a quite noticeable sag in the middle of the superstructure. This was quite problematic, as it could threaten the stability and the mobility of the robot. I soon started an investigation to find the source of the issue and discovered that this defect was caused notably by two factors: first, due to the fact that the legs were so far apart from one another, the middle portion of the robot didn't have adequate support and was hence prone to sagging; second, after discussing the issue with Mr. Judy, he pointed out that there was a need for larger washers in between each connecting pieces. After summarizing what I had learned, I decided to replace the leg compartments with new ones. The new design was to be shorter and much more compact than its predecessor. In addition, I also made corrections to the middle section of the superstructure, namely, the addition of larger M8 washers, to further reduce sagging. While most of the improvement process went relatively well, the shorter length of the leg compartment meant that some features of the older design were now obsolete. As a result, I also had to add new components to compensate for the loss of the older features. Unfortunately, though I was able to complete all of the pieces I needed for the assembly, I did not have time to start working on putting everything together. Hence, my main goal next week would be to finish the assembly of the improved version of my walker.