Watch: Walk cycle testing and pushups
Between the 6th and the 16th of November, I worked on the control of the legs. The first step was to ensure motors were actually powerful enough to lift the entire body of the rover. Motor strength, however, is not the only parameter affecting this test's success or failure: the length of the leg joints also plays an important role. If the femur or tibia is longer than the other, it can affect the torque required at the joint. Generally, a longer lever arm decreases the torque at the end of the joint. Therefore, if the femur is longer, it may require more torque to move the leg than in a situation where the femur and tibia are more balanced. A combination of the design I was initially using, plus a bottleneck caused by thin cables that were limiting the current draw, was not allowing the robot to lift itself. I use four motors that run between 5 -7 Volts and 1 - 2 Amps powered by a 20000 mAh power bank with an output current of 3 Amps. Nominally, this should not be enough to power four motors. However, good management of the current draw obtained through software allows motors to run anyway. Some suggestions for testing such a configuration are using suitable wires (possibly not jumper wires for connecting the motors to the battery), trying several iterations to find the best leg joint design, recording videos, and taking photos and notes about what you are doing. This helps keep track of your progress, as well as what is not working.